Progress in the application of intraoperative radiotherapy in pancreatic cancer / 实用肿瘤学杂志

Although surgery,radiotherapy and chemotherapy have made great progress,pancreatic cancer is still the most fatal malignant tumor,with a 5-year overall survival rate of only about 4% . Many studies have demonstrated that the local recurrence of pancreatic cancer is an important cause of high mortality,and the failure rate after local excision is still as high as 50~80% . There-fore,how to improve the local control rate of pancreatic cancer has been a hot spot of concern. Due to the adjacent organs and tissues (such as bone marrow,spinal cord,kidney,liver,intestine,etc. ),the dose of external irradiation(EBRT) is limited. Increasing local control rates and reducing treatment side effects are trends in future treatments. Intraoperative radiotherapy has the advantages of do-simetry and direct vision treatment to be increasingly used in the treatment of pancreatic cancer,becoming an important part of com-prehensive treatment. This article summarizes the clinical research results of intraoperative radiotherapy for pancreatic cancer in recent years,in order to provide the reference for clinicians.

Effect of Intraoperative Radiation Therapy (IORT) in Unresectable Pancreatic Cancer

PURPOSE: Pancreatic cancer is a devastating disease and the complete resection is difficult due to its the aggressive histologic behavior. Among the possible treatments for the unresectable pancreatic cancer, intraoperative radiation therapy (IORT) has the several advantages. But the impacts of the IORT on survival and local control are not clear. We analyzed the effects of the IORT on pain control, survival duration and local control in patients with unresectable pancreatic cancer. METHODS: We reviewed 6 years of the medical records of 94 patients who had undergone operations involving the pancreatic adenocarcinoma (33 patient IORTs, 39 palliative surgerys only and 22 curative resections involving a curative resection). The clinicopathologic factors and outcomes of the 33 patients treated with the IORT were compared with those of the palliative surgery groups. RESULTS: The age and sex distribution and tumor stage were same for the two groups. The average tumor size in the IORT group was larger than those of the palliative surgery group. The preoperative serum CA19-9 level in the IORT group was higher than the other group. The most common reason for unresectability in the IORT group was local invasion to the adjacent organs including of the great vessels. On the contrary, distant metastasis was a more common cause unresectability in the palliative surgery group. The postoperative complications and operative times were similar in both groups. Pain relief after treatment was observed in 12 cases of the 26 patients in the IORT group, and 5 of 29 patients in the palliative surgery group (P<0.05). The cases of minor and partial remission were more common in the IORT group than the palliative surgery group. However, the survival rate of the IORT group was no better than the palliative surgery group. CONCLUSION: This study suggests that IORT may have an important palliative role especially in ameliorating visceral pain in patients with unresectable pancreatic cancer. However, IORT appears to have no significant effect on overall survival.

Intraoperative Radiation Therapy(IORT) for the Treatment of Brain Tumors

Intraoperative Radiation Therapy(IORT) delivers a high single dose of radiation to a localized volume encompassing the tumor tissue as well as a minimal amount to the surrounding brain. The aims of the study are to evaluate the feasibility of IORT for the treatment of brain tumors, its effect on survival, and possible complications. Nineteen brain tumor patients underwent wide resection of the tumor followed by IORT at the first surgery or at the second salvage surgery. IORT was given for primary tumors in two patients, but was used for treating recurrent tumors in the other 17 patients. IORT doses of 15-25Gy was delivered depending on the tumor volume and previous radiation therapy. The mean follow-up after IORT was 11.5 months(range: 1-40 months). There were several complications after IORT; 1 radiation necrosis, 1 hydrocephalus,and 3 wound infections. For Glioblastomas cases, the median survival time after initial diagnosis was 14 months(SD, 6.4mo; range 10-28mo). An Unresectable huge highly vascularized meningioma was removed successfully after IORT. Based on our limited experiences, IORT may be considered as an adjuvant therapeutic modality, especially for malignant brain tumors and large rich vascularized meningioma.

Preliminary experiences with intraoperative radiation therapy (IORT) for the treatment of brain tumors

Ten brain tumor patients underwent wide resection of the tumor followed by Intraoperative Radiation Therapy (IORT) at the first surgery or at the second salvage surgery after failure of conventional external beam irradiation. Two patients(1 meningioma, 1 glioblastoma multiforme) were treated at the first surgery and 8 patients(3 anaplastic astrocytoma, 3 glioblastoma multiforme, 1 meningioma, 1 gliosarcoma) were treated after salvage surgery. The IORT doses were ranged from 15-25 Gy depending on the tumor volume and previous radiation therapy. The neurological status(Karnofsky performance status) was improved in 4 cases, not changed in 6 cases after IORT. There were several complications after IORT; radiation necrosis, communicating hydrocephalus, wound infection, and abnormal CT findings such as diffuse low density area in an around operation site. The radiation necrosis was confirmed by operation in a recurrent meningioma patient 12 months after IORT. At follow-up, ranging from 1 to 16 months, there was no deaths. Based on our limited experiences, the IORT might be one of the adjuvant therapeutic modalities especially for the malignant brain tumors and unresectable huge meningioma.

Development of Detachable IORT Table for Colorectal Cancer / 대한치료방사선과학회지

In spite of remarkable improvement of surgical skills and anesthesia, local failure still occurred in 36-45% of locally advanced colorectal cancer after curative resection with or without pre-or post-operative irradiation. Intraoperative radiation therapy (IORT) is the ideal modality which respectable lesions are removed surgically and the remaining cancer nests are sterilized by irradiation during a surgical procedure. Therefore, the excellent local control without the damage of the adjacent normal tissues can be achieved. In IORT, judicious set up of the treatment cone on the treatment surface of the patient is required for accurate and homogenous dose distribution within treatment field, especially on the slopping surface of sacrum and pelvic sidewall which are the common sites of the local recurrence in rectal cancer. For this purpose, adequate coordination of gantry rotation and table tilting are essential. Adjusting gantry rotation is not difficult but tilting of the table is impossible inconventional treatment couch. Department of Therapeutic Radiology in Yeungnam University Medical Center developed the IORT table for colorectal cancer which is easy to set up and detach on head-down is about 30 degree which is efficient and easy-to-use, not only for IORT but also for colorectal surgery. So far, authors performed IORT with newly developed treatment table in 2 patients with rectal cancer and we found that this newly developed table could contribute in improving the dose distribution of IORT and surgical procedure for colorectal cancer.

Dose Characteristics for IORT Applicator of ML-15MDX Electron Beam / 대한치료방사선과학회지

Experimental measurements of dose characteristics with pentagonal applicator at nominal energy of 4, 6, 9, 12 and 15 MeV electron beam were performed for intraoperative radiotherapy (IORT) in ML-15MDX linear accelerator. This paper presents the percent depth dose, surface dose, beam flatness and output factors of using the IORT applicator in different electron beam energy. The output factor showed as a 24 percent higher in IORT applicator than that of reference 10x10 cm? applicator. The surface dose of using the IORT applicator showed 7.7 and 2.7 percent higher than that of reference field in 4 and 15 MeV electron beam, respectively. In our experiments, the variation of percent depth dose was very small but the output factor and flatness at 0.5 cm depth have showed a large value in IORT applicator.

Complication of Intraoperative Radiation Therapy (IORT) in Gastric Cancer / 대한치료방사선과학회지

Local control is the important prognostic factor in cancer treatment because local control decrease the relative risk of metastatic spread and increse distant metastasis free survival. IORT is the modality which could increase local control without incressing complication, combined with curative operation. Eventhough we could achieve significant deacreased local failure by IORT and curative resection, it should not be committed as a main treatment modality without proving acceptable complications. Therapeutic Radiology Department of Yeungnam University Medical Center have tried 58 IORT from June 15, 1988, and performed 53 IORT in patients with gastric cancer. No local failure has been reporte? by regular follow up so far. Nine cases(17%) of treatment related complifaiton were reported including intestinal obstrution, hemorrhage, sepsis, and bone marrow depression. These complications could be comparable to Jo's 25.2% (chemotherapy + operation), Kim's 18% (chemotherapy only in inoperable patients), because our treatment regimen is consisted of IORT (1500 cGy), external irradiation(--4500 cGy) and extensive chemotherapy (FAM, 5FU+MMC, BACOP). Our data encouraged us to re-inforce further IORT in stomach cancer treatment.

IORT in Gastric Cancer / 대한치료방사선과학회지

Total 28 patients with respectable, locally advanced gastric cancer were entered in our prospective randomized study from June 15, 1988 to Sep. 15, 1990 in Yeungnam University Hospital. This study consisted of curative resection, IORT, external irradiation and combination of chemotherapy. Twenty-four of 28 patients were treated with single dose of 1500 cGy per fraction, 5 days per week was started within 4th weeks postoperative days. Various chemotherapy with or without external irradiation were added for reducing hematogenous and/or peritoneal dissemination and determination of complication of each arm. Duration of follow up was 4~31 months. No serious complication related with radiation were reported compare to resection and chemotherapy only group. Although our follow up period is too short to draw any conclusion, IORT appears to improve local control, hopely further survival. Continuous follow up should be needed for evaluation of real therapeutic gain such as complication vs. improved survival.

Intraoperative Radiotherapy (IORT) for Locally Advanced Colorectal Cancer / 대한치료방사선과학회지

Colorectal cancer is the second most frequent malignant tumor in the United States and fourth most frequent tumor in Korea. Surgery has been used as a primary treatment modality but reported overall survivals after curative resection were from 20% to 50%. Local recurrence is the most common failure in the treatment of locally advanced colorectal cancer. Once recurrence has developed, surgery has rarely the role and the five year survival of locally advanced rectal cancer is less than 5%, this indicated that significant improvement of local conrol could be achieved. We performed 6 cases of IORT for locally advanced colorectal cancer which is he first experience in Korea. Patient's eligibility, treatment applicator, electron energy, dose distribution on the surface and depth within the treatment field and detailed skills are discussed. We hope that our IORT protocol can reduce local failure and increase the long term survival significantly.