Surgical Approach for Oropharyngeal Cancer / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: In order to eradicate the disease and preserve function of oropharynx and facial contour, appropriate surgical approach should be chosen for surgical treatment of oropharyngeal cancer. This study was performed to evaluate the usefulness and effectiveness of various surgical approaches in the surgical treatment of oropharyngeal cancer. SUBJECTS AND METHOD: We analyzed 65 patients with oropharyngeal cancer who underwent surgery as a primary treatment from Jan. 1994 to Jun. 2009, retrospectively. Primary tumor site, TNM stage, surgical approach, management of neck, reconstruction method, complication, recurrence rate were analyzed to assess advantages and disadvantages of various surgical approaches. RESULTS: The surgical approaches applied were transoral approach in 25, mandibulotomy in 23, lower cheek flap in 4, trans-pharyngeal in 9, and mandibular lingual releasing approach in 4. Most of T1 lesion was resected by transoral approach (65.0%). For advanced T3 and T4, mandibulotomy was mainly used. Lateral pharyngotomy and mandibular lingual release approach were used for the surgery of moderate size of oropharyngeal cancer. The locoregional recurrence rate did not differ according to different surgical approaches with regard to T and N stages. CONCLUSION: Transoral approach is very useful for the most of small oropharyngeal cancer. Mandibulotomy provides most wide surgical view for advanced T3, T4 oropharyngeal cancer.

Surgical Approach for Oral Cavity Cancer / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: In the treatment of oral cancer, appropriate surgical approaches should be chosen in order to eradicate cancer while preserving the function of oral cavity and facial contour. This study was performed to evaluate the usefulness and effectiveness of various surgical approaches in the surgical treatment of oral cancer. SUBJECTS AND METHOD: A total of 112 oral cancer patients, excepting those with lip cancer, and who underwent surgery from 1994 to Aug 2008, were enrolled. We reviewed medical records retrospectively and analyzed the primary sites, stage, surgical approaches, management of mandible and neck, reconstruction methods, recurrence and survival rates. RESULTS: Of the 112 patients, 64 were transoral, 23 pull-through, 6 mandibular lingual releasing, 6 upper cheek flap , 5 lower cheek flap , 6 mandibulotomy and 2 visor flap approach. Most of T1, T2 lesions could be resected by transoral (71.6%) or pull-through approach (21.0%). In the advanced T3, T4 lesions, transoral (21.9%), pull-through (37.5%), cheek flap (21.9%), mandibulotomy (15.6%) were used. There was no statistically significant difference with respect to locoregional recurrence and survival rate according to surgical approach. CONCLUSION: The transoral approach was the effective method for the surgery of T1, T2 and part of T3 oral cancer. The pull-through or mandibular lingual releasing approach was the effective method of surgery for T2, T3 tongue or floor of mouth (FOM) cancer while avoiding mandibulotomy.

The Treatment Outcome of Hypopharynx Cancer : Surgery versus Organ Preservation Therapy / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Hypopharynx cancer usually presents with late stage diseases requiring radical resection including total laryngectomy with reconstruction resulting in severe functional deficits. In order to preserve organ function, chemotherapy in combination with radiotherapy was introduced and it showed similar treatment. The aim of this study is to compare the treatment outcomes of surgery and organ preservation therapy. SUBJECTS AND METHOD: A retrospective review of 55 patients who were diagnosed with hypopharynx cancer and underwent curative treatment from 1994 to 2006 was performed. Patients who underwent surgery or surgery plus postoperative radiotherapy were assigned to surgical treatment group and patients who underwent radiotherapy or radiotherapy with chemotherapy were assigned to organ preservation therapy group. RESULTS: Surgical treatment group consisted of 29 patients (52.7%) and organ preservation therapy group consisted of 26 patients (47.3%). The overall 5 year survival rate was 34%. The survival rate was decreased significantly according to the N stage (p=0.02). There was no statistically significant difference in 5 year survival rates between the two groups. The larynx preservation rate was 35.8% for the organ preservation therapy group and 44% for the conservation surgery group. CONCLUSION: Treatment of hypopharynx cancer could be individualized according to the status of diseases.

Results of Radiation Therapy for Squamous Cell Carcinoma of the Esophagus / 대한방사선종양학회지

PURPOSE: This study was designed to evaluate the effectiveness and prognostic factors for patients treated with postoperative radiation therapy following surgery or with radiation therapy alone for squamous cell carcinoma of the esophagus. MATERIALS AND METHODS: We retrospectively analyzed 132 esophageal cancer patients treated with postoperative radiation therapy following surgery or patients who were treated with radiation therapy alone at our institution from 1989 to 2006. Thirty-five patients had stage II disease, 88 patients had stage III disease and nine patients had stage IV disease. Tumors were located at the upper esophagus in 18 patients, the mid esophagus in 81 patients and the distal esophagus in 33 patients. Sixty patients were treated with radiation therapy alone and 72 patients were treated with postoperative radiation therapy following surgery. Eight patients received a dose less than 40 Gy and 78 patients received a dose of 40 to 50 Gy. The remaining 46 patients received a dose of 50 to 60 Gy. The majority of patients who underwent postoperative radiation therapy received a dose of 45 Gy. RESULTS: Actuarial survival rates for all of the patients at two years and five years were 24% and 5%, respectively. The median survival time was 11 months. Survival rates for patients who underwent postoperative RT at two years and five years were 29% and 8%, respectively. The corresponding survival rates for patients who received radiation alone were 18% and 2%, respectively. Survival rates at two years and five years were 43% and 15% for stage II disease, 22% and 2% for stage III disease and 0% and 0% for stage IV disease, respectively; these findings were statistically significant. Two-year survival rates for patients with upper, middle and distal esophageal cancer were 19, 29% and 22%, respectively. Although there was a trend of slightly better survival for middle esophageal tumors, this finding was not statistically significant. Complete response to radiation was achieved in 13 patients (22%) and partial response to radiation was achieved in 40 patients (67%) who received radiation alone. No response to radiation was noted in seven patients (12%). A statistically significant difference in survival rates was seen between patients that had a complete response and patients that had a partial response. Two-year survival rates for patients that had a complete response versus patients that had a partial response were 31% and 17%, respectively. There were no survivors for patients with no response as determined at two-year follow-up. CONCLUSION: We conclude that radiation therapy is an effective treatment for esophageal cancer. Stage and response to radiation therapy were noted to be prognostic factors. A more effective treatment modality is needed to improve long term survival because of the relatively dismal prognosis for this tumor.

External Beam Radiotherapy in the Management of Low Grade Astrocytoma of the Brain / 대한방사선종양학회지

PURPOSE: This study was designed to evaluate the effectiveness of postoperative radiotherapy for patients with low-grade astrocytomas and to define an optimal radiotherapeutic regimen and prognostic factors. MATERIALS AND METHODS: A total of 69 patients with low-grade astrocytomas underwent surgery and postoperative radiotherapy immediately following surgery at our institution between October 1989 and September 2006. The median patient age was 36 years. Forty-one patients were 40 years or younger and 28 patients were 41 years or older. Fourteen patients underwent a biopsy alone and the remaining 55 patients underwent a subtotal resection. Thirty-nine patients had a Karnofsky performance status of less than 80% and 30 patients had a Karnofsky performance status greater than 80%. Two patients were treated with whole brain irradiation followed by a coned down boost field to the localized area. The remaining 67 patients were treated with a localized field with an appropriate margin. Most of the patients received a dose of 50~55 Gy and majority of the patients were treated with a dose of 54 Gy. RESULTS: The overall 5-year and 7-year survival rates for all of the 69 patients were 49% and 44%, respectively. Corresponding disease free survival rates were 45% and 40%, respectively. Patients who underwent a subtotal resection showed better survival than patients who underwent a biopsy alone. The overall 5-year survival rates for patients who underwent a subtotal resection and patients who underwent a biopsy alone were 57% and 38%, respectively (p<0.05). Forty-one patients who were 40 years or younger showed a better overall 5-year survival rate as compared with 28 patients who were 41 years or older (56% versus 40%, p<0.05). The overall 5-year survival rates for 30 patients with a Karnofsky performance status greater than 80% and 39 patients with a Karnofsky performance status less than 80% were 51% and 47%, respectively. This finding was not statistically significant. Although one patient was not able to complete the treatment because of neurological deterioration, there were no significant treatment related toxicities. CONCLUSION: Postoperative radiotherapy following surgery is a safe and effective treatment for patients with low-grade astrocytomas. The extent of surgery and age were noted as significant prognostic factors in this study. However, further effective treatment might be necessary in the future to improve long-term survival rates.

Neoadjuvant Chemotherapy Followed by Concurrent Chemoradiation in Locally Advanced Head and Neck Squamous Cell Carcinoma / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Surgery with postoperative radiotherapy has been the standard treatment for locally advanced head and neck squamous cell carcinoma (HNSCC). However, the prognosis still remains dismal. To increase survival rate and organ preservation rate, alternative approach is needed. Incorporating the taxane regimen into the treatment of HNSCC, the new treatment strategy of sequential therapy has been introduced. The purpose of this study is to determine the efficacy of neoadjuvant chemotherapy, followed by concurrent chemoradiotherapy for the HNSCC. SUBJECTS AND METHOD: Between January 2001 and June 2005, 19 patients with HNSCC were treated with neoadjuvant chemotherapy, followed by concurrent chemoradiotherapy. The sites of primary tumors were hypopharynx in eight patients, oropharynx in six patients, and larynx in five patients. Neoadjuvant chemotherapy included 70 mg/m2 of docetaxel on day 1, 70 mg/m2 of cisplantin on day 2 and 800 mg/m2 of 5-fluorouracil on day 2-4. The cycles were repeated every three weeks. Concurrent chemoradiotherapy starts after two cycles of neoadjuvant chemotherapy. Radiation dose was 200 cGy/dayx5/week with a total of 6,000-7,000 cGy, and the concurrent chemotherapy of 20 mg/m2 of docetaxel or 20 mg/m2 of cisplantin was given weekly. RESULTS: The median follow-up was 21 months. The overall 2-year survival rate was 70.1% and the 2-year organ preservation rate was 59.4%. The survival rate and organ preservation rate of larynx cancer patients were higher than those of hypopharynx and oropharynx cancer patients, but it was not statistically significant (p=0.09, 0.16). The patients of the lower stage showed higher survival rate and organ preservation rate, but it was not statistically significant (p=0.19, 0.48). The most common Grade 3 or 4 toxicities of neoadjuvant chemotherapy were leukopenia, anorexia, nausea and vomiting, whereas the most common Grade 3 or 4 toxicities during concurrent chemoradiotherapy were mucositis, stomatitis, and leukopenia. One patient died due to sepsis during treatment. CONCLUSION: Neoadjuvant chemotherapy with three combined regimens followed by concurrent chemoradiotherapy might be effective treatment modality for HNSCC. Further studies with large number of patients and longer follow-up will be needed.

Molecular phylogeny of parasitic Platyhelminthes based on sequences of partial 28S rDNA D1 and mitochondrial cytochrome c oxidase subunit I

The phylogenic relationships existing among 14 parasitic Platyhelminthes in the Republic of Korea were investigated via the use of the partial 28S ribosomal DNA (rDNA) D1 region and the partial mitochondrial cytochrome c oxidase subunit 1 (mCOI) DNA sequences. The nucleotide sequences were analyzed by length, G + C %, nucleotide differences and gaps in order to determine the analyzed phylogenic relationships. The phylogenic patterns of the 28S rDNA D1 and mCOI regions were closely related within the same class and order as analyzed by the PAUP 4.0 program, with the exception of a few species. These findings indicate that the 28S rDNA gene sequence is more highly conserved than are the mCOI gene sequences. The 28S rDNA gene may prove useful in studies of the systematics and population genetic structures of parasitic Platyhelminthes.

Role of Postoperative Radiation Therapy in the Management of Cervical Cancer / 대한방사선종양학회지

PURPOSE: To evaluate the effectiveness of postoperative radiation therapy in cervical cancer patients and define the prognostic factors to affect survival rates. MATERIALS AND METHODS: Eighty one patients with cervical cancer who were treated with postoperative radiation therapy following surgery at our institution between May 1992 and April 2000 were retrospectively analyzed. Forty two patients had stage IB disease, 17 had stage IIA disease, and remaining 22 had stage IIB disease, respectively. Histological examination revealed 76 squamous cell carcinoma and 5 adenocarcinoma. Sixty one patients were noted to have stromal invasion greater than 8 mm and 20 patients were noted to have stromal invasion 7 mm or less. Sixteen patients had parametrial invasion and 65 patients did not. Positive vaginal resection margin was documented in only eight patients and positive lymphovascular invasion was in twelve patients. All of the patients were treated with external beam radiation therapy alone. Majority of the patients were treated with 4 field brick technique to encompass whole pelvis. Total of 5,500 cGy was delivered to the primary surgical tumor bed. Minimum follow up period was four years. RESULTS: Actuarial disease free survival rates for entire group of the patients were 95% and 89% at 2 and 5 years, respectively. Five year disease free survival rates for patients with stage IB, IIA, and IIB disease were 97%, 87% and 70%, respectively. Local recurrences were documented in 5 patients. Cumulative local failure rate at 3 years was 6%. Five year disease free survival rates for patients with stromal invasion greater than 8 mm and 7 mm or less were 88% and 92%, respectively (p>0.05). Five year disease free survival rate for patients with parametrial invasion was significantly lower than those with no invasion (72% vs 92%, p<0.05). Also there was significantly lower survival in patients with positive vaginal resection margin, compared with patients with negative resection margin (64% vs 94%, p<0.05). However, lymphovascular invasion was not a statistically significant prognostic factor. Parametrial invasion and positive surgical resection margins were noted to be significant prognostic factors. Conclusions: Postoperative radiation therapy appears to be beneficial in controlling local disease in cervical cancer patients with high pathologic risk factors. Parametrial invasion and positive resection margins were noted to be significant prognostic factors to affect survival and more effective treatment should be investigated in these patients.

Radiotherapy for Nasopharyngeal Carcinoma / 대한방사선종양학회지

PURPOSE: To evaluate the results of radiation management on recurrence, survival and prognostic factors of patients with nasopharyngeal cancer. MATERIALS AND METHODS: Forty-nine patients, treated for nasopharyngeal cancer by radiotherapy between January 1984 and June 2000, were retrospectively studied. All patients were followed up for at least 2.5 years. Their median age was 52 years (range 17~78). The histological types were 21 squamous cell carcinoma, 25 undifferentiated carcinoma, and 3 adenoid cystic carcinoma. The tumor stages were as follows: T1 in 14 patients, T2 in 24, T3 in 3, and T4 in 8, and N0 in 17 patients, N1 in 15, N2 in 4 and N3 in 13. Stages I, IIa, IIb ,III, IV and IVb were 4, 7, 12, 5, 8, and 13 patients respectively. Radiation doses of 58~70 Gy (median 68.7 Gy) were given to the nasopahryngeal and involved lymphatic areas and of 46~50 Gy to the uninvolved neck areas. RESULTS: The overall 5 and 10-year actuarial and disease free survival rates were 54.53% and 47%, and 55.7% and 45.3%, respectively. The overall five-year survival rates were 100% in stage I , 80% in stage IIa, 59.5% in stage IIIb, 40% in stage III, and 42.2% in stage IV tumors. Twenty-three patients failed either loco-regionally or distantly. Incidences of local failure, regional failure and distant metastasis for the first failure were 20.4%, 8.2% and 20.4%, respectively. Local recurrences were 4.3% in T1, 12.5% in T2, 0% in T3, and 62.5% in T4 lesions. Distant metastasis was seen in 41.2% of N2-3 lesions. Fifty percent of local recurrence appeared within 2 years of treatment at the primary lesion, whereas 70% of distant metastasis appeared within 2 years following treatment. Young age, female, early T stage, N0 stage, and poorly differentiated carcinoma were all related with good survival. However only stage showed statistically significance. CONCLUSION: Based on the results of this study, radiation therapy to nasopharyngeal cancer showed high local recurrence in T4 and increased metastasis in N2-3 lesions. To improve local failure, further radiation doses, such as stereotactic radiation or IMRT radiation, are necessary especially in T4 lesions. The high incidence of distant metastasis in positive lymph node patients, indicates that combined radiation and effective chemotherapeutic agents with appropriated schedule are necessary.

Experimental Study for the Teratogenic Effect of Gamma-ray on the Heart of Chick Embryo

PURPOSE: To investigate the teratogenic effect of gamma-ray on the heart of chick embryo. METHODS: 50 rad, 100 rad, 150 rad, 200 rad, 250 rad, and 300 rad of gamma-ray were used to irradiate three days old chick embryos. The control group was not irradiated. After three weeks, the embryos were sacrificed and examined for cardiovascular malformation. RESULTS: The survival rate of the gamma-ray irradiated group was significantly lower than that of the control group(33.3-63.3% vs 76.4%, P=0.001). The cardiac malformation rate of the experimental group was 11.0%. In the control group, no congenital cardiac malformations were observed. The experimental groups had a significantly higher malformation rate(P=0.001). The types of malformation were ventricular septal defect, tricuspid atresia, Ebstein anomaly and aortic arch anomaly. In the gamma-ray irradiated group, the cardiac malformations were : 14 small ventricular septal defects (VSDs), five large VSDs, two tricuspid atresias, and one Ebstein anomaly. The higher the dose of radiation applied, the higher the incidence of cardiac malformation was noted. CONCLUSION: Gamma-ray irradiation of 3 days old chick embryos increased the rate of death and the rate of cardiac malformation significantly.

Radiation Therapy for Operable Breast Cancer after Conservative Surgery / 대한방사선종양학회지

PURPOSE: To evaluate the result of conservative management on recurrence, survival and prognostic factors of patient with operable breast cancer. MATERIALS AND METHODS: Fifty three patients, treated for localized breast cancer by lumpectomy or quadrantectomy followed by radiotherapy between January 1985 and December 1996, were retrospectively studied. All patients followed up for at least five years. Their median age was 43 years (range 24~72). The tumor stages were as follows : T1 in 30 patients, T2 in 21, Tis in 2. Thirty-eight patients had negative and 15 had positive axillary nodes. The histological types were 42 infiltrating ductal, 2 infiltrating lobular, and 2 intraductal carcinomas with 7 other histologies. The tumor locations were the outer quadrant in 38 breasts, the inner quadrant in 13 and central in 2. Radiation doses of 46~50 Gy were given to the entire breast areas with additional doses of 14-18 Gy delivered to the tumor bed areas. RESULTS: The overall five and 10 year actuarial and disease free survivals were 94.3 % and 92.4%, 91.2 and 81%, respectively. The overall five year survivals were 100% in stage I and IIa, and 66.7% in stage IIb and IIIa tumors. Seven patients failed either locally or distantly. Incidence of local failure and distant metastasis for the first failure were 7.5% and 5.7%, respectively. Local recurrence appeared within 2 years of treatment at the primary site and after more than 8 years outside of primary lesion, whereas distant metastasis appeared between 2 and 6 years following treatment. The overall recurrences were high at a young age (< or = 35 years), with 5 out of 12 (2 local, 3 distant), and in T2 lesions with 5 out of 21 (1 local, 3 distant, and 1 in both). Distant metastasis was high in the positive axillary lymph node group with 4 out of 15 (26.6%). A high incidence in the axillary node was noted at a young age with 7 out of 12 (58.3%) and in T2 lesions with 8 out of 21 (38.4%). A young age, positive axillary node and large tumor size were all related with poor survival. CONCLUSION: Based on this study, lumpectomy or quadrantectomy, followed by radiation appears to be an adequate therapeutic method in operable breast cancer. A long term follow-up is necessary because a recurrence of breast can occur long time after treatment. The poor prognostic group, especially young patients with an aggressive biological behavior needs more effective treatment modalities to improve their survival.

Radiation Therapy Alone for Early Stage Non-small Cell Carcinoma of the Lung / 대한방사선종양학회지

PURPOSE: To evaluate the outcome of early stage non-small cell lung cancer patients who were treated with radiation therapy alone and define the optimal radiotherapeutic regimen for these patients. MATERIALS AND METHODS: A retrospective review was performed on patients with sage I or II non-small cell carcinoma of the lung that were treated at our institution between June, 1987 and May, 2000. A total of 21 patients treated definitively with radiation therapy alone were included in this study. The age of the patients ranged from 53 to 81 years with a median of 66 years. All the patients were male. The medical reasons for inoperability were lack of pulmonary reserve, cardiovascular disease, poor performance status, old age, and patient refusal in the decreasing order. Pathological evidence was not adequate to characterize the non-small cell subtype in two patients. Of the remaining 19 patients, 16 had squamous cell carcinoma and 3 had adenocarcinoma. Treatment was given with conventional fractionation, once a day, five times a week. The doses to the primary site ranged from 56 Gy to 69 Gy. No patients were lost to follow-up. RESULTS: The overall survival rates for the entire group at 2, 3 and 5 years were 41, 30 and 21%, respectively. The cause specific survivals at 2, 3 and 5 years were 55, 36 and 25%, respectively. An intercurrent disease was the cause of death in two patients. The cumulative local failure rate at 5 years was 43%. Nine of the 21 patients had treatment failures after the curative radiotherapy was attempted. Local recurrences as the first site of failure were documented in 7 patients. Therefore, local failure alone represented 78% of the total failures. Those patients whose tumor sizes were less than 4 cm had a significantly better 5 year disease free survival than those with tumors greater than 4 cm (0% vs 36%). Those patients with a Karnofsky performance status less than 70 did not differ significantly with respect to actuarial survival when compared to those with a status greater than 70 (25% vs 26%, p>0.05). CONCLUSION: Radiation therapy alone is an effective and safe treatment for early stage non-small cell lung cancer patients who are medically inoperable or refuse surgery. Also we believe that a higher radiation dose to the primary site could improve the local control rate, and ultimately the overall survival rate.

Postoperative Radiotherapy for Non-Small Cell Lung Cancer / 대한방사선종양학회지

PURPOSE: To evaluate effect of postoperative radiotherapy on survival and local control for patients with non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: Ninety two NSCLC patients with N1or N2 involvement who were treated with postoperative radiotherapy following surgery with curative intent from May 1987 to October 1999 were retrospectively analyzed. Age of the patients was ranged from 32 to 78 years. According to TNM Stage, 35 patients had Stage II and 57 had Stage III disease. There were 49 patients with N1 involvement and 43 patients with N2 involvement. Fifty six patients were noted to have T1~2 tumors and 36 patients to have T3~4 tumors. Delivered total dose was ranged from 40 to 60 Gy. Majority of patients received 50 Gy or 50.4 Gy. Follow-up period was ranged from 9 month to 7 years with median follow-up of 26 months. RESULTS: Overall survival rates at 3 and 5 years for entire group of patients were 46% and 38%, respectively. Corresponding disease free survival rates were 44% and 36%. There was significant difference in survival between patients with Stage II and Stage III disease (50% vs 28% at 5-year). Five year survival rates for N1 and N2 patients were 52% and 20%, respectively (p<0.05). These were 40% and 34% for patients with T1~2 tumors and T3~4 tumors. There were documented local relapses in 13% of the patients. For patients with N1 and N2 Stage, local relapse rates were 8% and 18%, respectively. CONCLUSION: Our study confirms that postoperative radiotherapy for patients with non-small cell lung cancer improves local control. However, influence of postoperative radiotherapy on long-term survival is less clear. More effective systemic treatment to prevent distant metastasis should be investigated in future study to improve long-term survival.

Optimization of Total Arc Degree for Stereotactic Radiotherapy by Using Integral Biologically Effective Dose and Irradiated Volume / 대한방사선종양학회지

PURPOSE: To find the optimal values of total arc degree to protect the normal brain tissue from high dose radiation in stereotactic radiotherapy planning. METHODS AND MATERIALS: With Xknife-3 planning system & 4 MV linear accelerator, the authors planned under various values of parameters. One isocenter, 12, 20, 30, 40, 50, and 60 mm of collimator diameters, 100degrees, 200degrees, 300degrees, 400degrees, 500degrees, 600degrees of total arc degrees, and 30degrees or 45degrees of arc intervals were used. After the completion of planning, the plans were compared each other using V50 (the volume of normal brain that is delivered high dose radiation) and integral biologically effective dose. RESULTS: At 30degrees of arc interval, the values of V50 had the decreased pattern with the increase of total arc degree in any collimator diameter. At 45degrees arc interval, up to 400degrees of total arc degree, the values of V50 decreased with the increase of total arc degree, but at 500degrees and 600degrees of total arc degrees, the values increased. At 30degreesdegreesof arc interval, integral biologically effective dose showed the decreased pattern with the increase of total arc degree in any collimator diameter. At 45degrees arc interval with less than 40 mm collimator diameter, the integral biologically effective dose decreased with the increase of total arc degree, but with 50 and 60 mm of collimator diameters, up to 400degrees of total arc degree, integral biologically effective dose decreased with the increase of total arc degree, but at 500degrees and 600degrees of total arc degrees, the values increased. CONCLUSION: In the stereotactic radiotherapy planning for brain lesions, planning with 400degrees of total arc degree is optimal. Especially, when the larger collimator more than 50 mm diameter should be used, the uses of 500degrees and 600degrees of total arc degrees make the increase of V50 and integral biologically effective dose. Therefore stereotactic radiotherapy planning using 400degrees of total arc degree can increase the therapeutic ratio and produce the effective outcome in the management of personal and mechanical sources in radiotherapy department.

Role of Radiation Therapy for Stage III Thymoma / 대한방사선종양학회지

PURPOSE: To evaluate the effectiveness and tolerance of the postoperative radiation therapy for patients with Stage III thymoma and to define the optimal radiotherapeutic regimen. MATERIALS AND METHODS: We retrospectively analyzed the records of 24 patients with Stage III thymoma who were referred for postoperative radiation therapy in our institution from June, 1987 to May, 1999. Surgical therapy consisted of total resection in one patient, subtotal resection in seventeen, and biopsy alone in six patients. Age of the patients was ranged from 20 to 62 years with mean age of 47 years. Male to female ratio was 14 to 10. Radiation therapy was delivered with linear accelerator producing either 6 MeV or 10 MeV photons. The irradiated volume included anterior mediastinum and known residual disease. The supraclavicular fossae were not irradiated. The delivered total dose was ranged from 30 to 56 Gy. One patient received 30 Gy and eighteen patients received minimum of 50 Gy. Follow up period was ranged from 12 months to 8 years with median follow up of 40 months. RESULTS: The overall local control rate for entire group of patients was 67% at 5 years. The cumulative local failure rates at one, three and five year were 18%, 28% and 33%, respectively. In patients treated with subtotal resection and biopsy alone, local control rate was 76% and 33%, respectively. The actuarial observed survival rate at 5 years was 57%, and actuarial adjusted survival at 5 years was 72%. The difference between 5 year survival rates for patients treated with subtotal resection and biopsy alone was not statistically significant (62% vs 30%). CONCLUSION: We might conclude that postoperative radiation therapy was safe and effective treatment for patients with Stage III thymoma. Postoperative radiation therapy is recommended in cases where tumor margin is close or incomplete resection is accomplished.

Radical Radiotherapy for Carcinoma of the Prostate / 대한방사선종양학회지

PURPOSE: To evaluate effect and tolerance of external beam radiotherapy for carcinoma of the prostate and define the optimal radiotherapeutic regimen. MATERIALS AND METHODS: We retrospectively analyzed the records of 60 patients with prostate cancer who were treated with external beam radiotherapy with curative intent in our institution between September, 1987 and March, 2000. Histologic diagnosis was established by transurethral resection or ultrasonography guided biopsy. The major presenting symptoms were a nodule at routine prostatic examination and frequency and urgency of urination, along with dysuria. The median age was 63 years with range of 51 to 87 years. There were 6 patients in Stage A, 20 in Stage B, 26 in Stage C, and 8 in Stage D1. All patients were treated with megavoltage equipment producing 10 MV photons. The 4 field pelvic brick technique was used to a dose of 45 Gy or 50.4 Gy at 1.8 Gy per day in 5 to 6 weeks, after which a small boost field was delivered 2.0 Gy per day to a total dose of 66 to 70 Gy. The follow-up period ranged from 1 to 8 years. RESULTS: Actuarial 5-year and 7-year survival rates for Stage A, B, C, and D1 were 100% and 84%, 83% and 72%, 67% and 54%, and 40% and 30%, respectively. The corresponding 5-year and 7-year relapse free survival rates were 84% and 84%, 77% and 67%, 48% and 40%, and 33% and 25%, respectively. Relapse free 5-year survival rates for Stage B were 80%, 80%, and 50% for well, moderately, and poorly differentiated tumors, respectively. These were 64%, 44%, and 33% for Stage C, respectively. The local control rates at 5 years were 84%, 85%, 78%, and 60% for Stage A, B, C, and D1, respectively. Mild to moderate complications were observed in 22% of patients. Severe complications requiring surgical procedures were documented in only 3% of patients. CONCLUSION: This study confirms that external beam irradiation is an effective and safe treatment for prostatic cancer, providing long-term local control and good survival with acceptable complications.

Postoperative Radiotherapy for Intracranial Meningioma / 대한방사선종양학회지

PURPOSE: To evaluate the effectiveness and tolerance of postoperative external radiotherapy for patients with intracranial meningiomas. MATERIALS AND METHODS: The records of thirty three patients with intracranial meningiomas who were treated with postoperative external irradiation at our institution between Feb, 1988 and Nov, 1999 were retrospectively analyzed. Median age of patients at diagnosis was 53 years with range of 17 to 68 years. Sites of involvement were parasagital, cerebral convexity, sphenoid ridge, parasellar and tentorium cerebelli. Of 33 evaluated patients, 15 transitional, 10 meningotheliomatous, 4 hemangiopericytic, 3 atypical and 1 malignant meningioma were identified. Four patients underwent biopsy alone and remaining 29 patients underwent total tumor resection. A dose of 50 to 60 Gy was delivered in 28-35 daily fractions over a period of 5 to 7 weeks. Follow-up period ranged from 12 months to 8 years. RESULTS: The actuarial survival rates at 5 and 7 years for entire group of patients were 78% and 67%, respectively. The corresponding disease free survival rates were 73% and 61%, respectively. The overall local control rate at 5 years was 83%. One out of 25 patients in benign group developed local failure, while 4 out of 8 patients in malignant group did local failure (p<0.05). Of 4 patients who underwent biopsy alone, 2 developed local failure. There was no significant difference in 5 year actuarial survival between patients who underwent total tumor resection and those who did biopsy alone. Patients whose age is under 60 showed slightly better survival than those whose age is 60 or older, although this was not statistically significant. There was no documented late complications in any patients. CONCLUSION: Based on our study, we might conclude that postoperative external beam radiotherapy tends to improve survival of patients with intracranial meningiomas comparing with surgery alone.

Postoperative Radiotherapy for Low Grade Glioma of the Brain / 대한방사선종양학회지

PURPOSE: To evaluate the effectiveness and tolerance of postoperative external beam radiotherapy for patients with low grade glioma of the brain and define the optimal radiotherapeutic regimen. MATERIALS AND METHODS: Between June, 1985 and May, 1998, 72 patients with low grade gliomas were treated with postoperative radiotherapy immediately following surgery. Median age was 37 years with range of 11 to 76 years. Forty one patients were male and 31 patients were female with male to female ratio of 1.3:1. Of those patients, 15 underwent biopsy alone and remaining 57 did subtotal resection. The distribution of the patients according to histologic type was as follows: astrocytomas-42 patients (58%), mixed oligodendrogliomas-19 patients (27%), oligodendrogliomas-11 patients (15%). Two patients were treated with whole brain irradiation followed by cone down boost and remaining 70 patients were treated with localized field with appropriate margin. All of the patients were treated with conventional once a day fractionation. Most of patients received total tumor dose of 5000~5500 cGy. RESULTS: The overall 5 and 7 year survival rates for entire group of 72 patients were 61% and 50%. Corresponding disease free survival rates for entire patients were 53% and 45%, respectively. The 5 and 7 year overall survival rates for astrocytomas, mixed oligodendrogliomas, and oligodendrogliomas were 48% and 45%, 76% and 56%, and 80% and 52%, respectively. Patients who underwent subtotal resection showed better survival rates than those who did biopsy alone. The overall 5 year survival rates for subtotal resection patients and biopsy alone patients were 67% and 43%, respectively. Forty six patients who were 40 years or younger survived better than 26 patients who were 41 years or older (overall survival rate at 5 years, 69% vs 45%). Although one patient was not able to complete the treatment because of neurological deterioration, there was no significant treatment related acute toxicities. CONCLUSION: Postoperative radiotherapy was safe and effective treatment for patients with low grade gliomas. However, we probably need prospective randomized trial to define optimal treatment timing and schedule for low grade gliomas and select patient group for different treatment philosophies.

Postoperative External Beam Radiotherapy for Medulloblastoma / 대한방사선종양학회지

PURPOSE: This study was performed to evaluate the effectiveness and tolerance of craniospinal irradiation for patients with medulloblastoma and to define the optimal radiotherapeutic regimen. MATERIALS AND METHODS: We retrospectively analyzed the records of 43 patients with medulloblastoma who were treated with external beam craniospinal radiotherapy at our institution between May, 1984 and April, 1998. Median follow up period was 47 months with range of 18 to 86 months. Twenty seven patients were male and sixteen patients were female, a male to female ratio of 1.7 : 1. Surgery consisted of biopsy alone in 5 patients, subtotal excision in 24 patients, and gross total excision in 14 patients. All of the patients were treated with craniospinal irradiation. All of the patients except four received at least 5,000 cGy to the posterior fossa and forty patients received more than 3,000 cGy to the spinal cord. RESULTS: The overall survival rates at 5 and 7 years for entire group of patients were 67% and 56%, respectively. Corresponding disease free survival rates were 60% and 51%, respectively. The rates of disease control in the posterior fossa were 77% and 67% at 5 and 7 years. Gross total excision and subtotal excision resulted in 5 year overall survival rates of 76% and 66%, respectively. In contrast, those patients who had biopsy alone had a 5 year survival rate of only 40%. Posterior fossa was a component of failure in 11 of the 18 recurrences. Seven recurrences were isolated to the posterior fossa. Four patients had neuraxis recurrences, three had distant metastasis alone and four had multiple sites of failure, all involving the primary site. CONCLUSION: Craniospinal irradiation for patients with medulloblastoma is an effective adjuvant treatment without significant treatment related toxicities. There is room for improvement in terms of posterior fossa control, especially in biopsy alone patients. The advances in radiotherapy including hyperfractionation, stereotactic radiosurgery and 3D conformal radiotherapy would be evolved to improve the tumor control rate at primary site.

A Case with Cerebral Radiation Necrosis Mimicking Recurrent Brain Tumor

Regardless of an appropriate radiation therapy administered to a patient with a brain tumor, clinical and radiological evidence of progression may still develop because of a recurrence of the tumor and/or radiation necrosis, or even rarely, a radiation induced neoplasm. The evaluation of tumor recurrence and radiation-induced necrosis presents a diagnostic challenge. A thirty eight year old woman was treated for a focal motor seizure on the right side of her face.with a fractionated external beam radiotherapy under the impression of cystic astrocytoma in the left frontoparietal region. After 6 months, she developed a headache, nausea and vomiting, dysphagia, and secondary generalized seizure. A follow-up brain MRI showed a high signal mass lesion in a T2 weighted image and a fluorodeoxyglucose PET revealed hypometabolism in the left frontoparietal lobe, suggesting radionecrosis. It was confirmed as radionecrosis with an expanding edema by open biopsy. We report a cerebral radiation necrosis mimicking recurrent brain tumor.