Radiotherapy for early vocal cord cancer: a dosimetric analysis of 60CO versus 6 MV photons.

BACKGROUND: Currently, many patients with early vocal cord cancers are treated with 6 MV photons, but almost all the published radiotherapy data are based on patients treated with 60Co, 2-MV, or 4-MV X-rays. A theoretical risk of underdosage exists with higher energy beams due to lack of dose build-up. This dosimetric study compares 6-MV photons with 60Co. METHODS: A tissue-equivalent phantom was constructed of a stack of 0.5-cm-thick acrylic plates. With a male subject in treatment position as the model, the external surfaces of the phantom were machined to match the contour of the neck. To precisely represent the internal contour of the airway, computed tomography (CT) was performed on the subject in treatment position, with images at 0.5-cm intervals, and the airway shown on the CT was cut out of each corresponding acrylic plate. Thermoluminescent dosimetry (TLD) rods were inserted into the phantom. For each measurement, a calculated tumor dose of 10 Gy was delivered to the volume specified as the entire right true vocal cord in the phantom, with either 60Co or 6-MV photons (15 measurements were made with each). In a second series of eight experiments with each modality, TLD minichips were used to measure the dose received by the immediate surface of the vocal cords with delivery of a calculated tumor dose of 0.5 Gy. RESULTS: The doses received at the vocal cords, as well as a point 6 mm beneath the anterior skin surface, did not differ significantly for the two energies compared. The dose delivered to the skin and a point 3 mm beneath the anterior skin surface was significantly lower with the use of 6-MV photons. CONCLUSION: Although there is no difference in the dose received by the vocal cords, underdosage of the anterior tissues may occur with the use of 6-MV photons.

Testicular seminoma: a failure analysis and literature review.

PURPOSE: A retrospective analysis of 74 patients with pure seminoma, treated at the University of Florida between 1964 and 1989, was undertaken. METHODS AND MATERIALS: All patients received megavoltage irradiation, with chemotherapy reserved for salvage. At 10 years, the probability of relapse-free survival was 91% for Stage I, 93% for Stage IIA, 83% for Stage IIB, and 75% for Stage III patients. RESULTS: There were seven recurrences, none of which occurred in irradiated areas. Only two of seven patients (29%) with recurrence were salvaged. CONCLUSION: A literature review revealed an increasing rate of mediastinal or supraclavicular recurrence, correlating with the size of the subdiaphragmatic disease, in Stage II patients who did not receive elective mediastinal irradiation. Recommendations are made regarding the role of elective mediastinal irradiation for Stage II disease. We conclude that patients with Stage I or II seminoma can have high cure rates when treated with radiotherapy alone. Patients with Stage III seminoma should be treated initially with cisplatin-based chemotherapy.

Downstaging of esophageal cancer after preoperative radiation and chemotherapy.

OBJECTIVE: This retrospective, nonrandomized review evaluates 125 patients with esophageal carcinoma (adenocarcinoma and squamous cell) who underwent either surgery only or preoperative chemotherapy and/or radiation therapy followed by surgery. Major end points were survival and postchemoradiation downstaging. METHODS: Forty-four patients underwent radiation therapy of 4500 cGy over 5 weeks. Fluorouracil and cisplatin were administered on the first and fifth week of radiotherapy. Ninety-eight patients underwent "potentially curative" resections-transhiatal esophagectomy (70), Lewis esophagogastrectomy (25), and left esophagogastrectomy (3). All patients with preoperative adjuvant therapy underwent endoscopy and biopsy before surgery. RESULTS: There were no differences in overall mortality (5%) or surgical complications in either group. Fourteen of 44 patients (32%) downstaged to complete pathologic response, with 5-year survival of 57%. Fifteen of 44 patients (34%) downstaged to microscopic residual tumor, with 1- and 3-year survival of 77% and 31%, respectively. Twenty-eight of 29 patients in the two downstaged groups were lymph node negative. Overall, 5-year survival in the adjuvant therapy plus surgery group versus surgery only was 36% and 11% (p = 0.04). Five-year survival in lymph node-negative adjuvant therapy and surgery patients was 49% (p = 0.005). Positive nodes in the surgery only group was 48% versus 23% in the adjuvant therapy and surgery group (p = 0.02). CONCLUSION: Although retrospective and nonrandomized, these results suggest that preoperative chemoradiation results in significant clinical and pathologic downstaging, increases survival, and may sterilize local and regional lymph nodes, accounting for both downstaging and survival statistics.

The role of lymphangiography in designing fields for elective pelvic node irradiation in Hodgkin's disease.

PURPOSE: We attempted to design a standard pelvic nodal treatment field such that all lymph nodes usually visualized on lymphangiogram would be irradiated with optimal midline blocking of normal tissues. METHODS AND MATERIALS: Two standard fields for treatment of pelvic lymph nodes were designed, based on bony landmarks. The standard fields were applied to the anterior-posterior view of 35 pretherapy lymphangiograms, and the fields were then assessed for inclusion of visible lymph nodes. Measurements were done on the lymphangiograms to assess the amount of additional midline blocking that could be added. RESULTS: All visualized nodes were included in 30 patients (86%) using Standard Field I and in 33 patients (94%) using Standard Field II, but visualized nodes plus a 1.5-cm minimum margin were included in only two patients (6%) with Field I and 24 patients (69%) with Field II. The most frequent sites of close margins were the lateral and medial borders adjacent to the external iliac nodes. Based on the lymphangiograms, a mean of 1.6 cm in male patients and 3.1 cm in female patients could be added to the width of the midline blocks. CONCLUSION: Lymphangiography is useful in designing fields for pelvic node irradiation, both to improve coverage of nodes with a 1.5 cm margin and to increase the amount of central shielding of normal tissues.

Radiotherapy alone for carcinoma of the vagina: the importance of overall treatment time.

PURPOSE: Review treatment results, complications, and the importance of overall treatment time for carcinoma of the vagina treated with radiotherapy alone. METHODS AND MATERIALS: Between October 1964 and October 1990, 65 patients with histologically confirmed carcinoma of the vagina received definitive radiotherapy at the University of Florida. All patients had a minimum 2-year follow-up. Most patients were treated with a combination of external-beam radiotherapy and brachytherapy. The probability of pelvic control, cause-specific survival, and complications was calculated and multivariate analyses were performed. The log-rank test was used to determine significance levels between the curves. RESULTS: The 5-year cause-specific survival rates were, Stage 0 (six patients), 100%; Stage I (17 patients), 94%; Stage IIA (six patients), 80%; Stage IIB (ten patients), 39%; Stage III (twn patients), 79%; and Stage IVA (six patients), 62%. The pelvic control rates at 5 years were: Stage 0, 100%; Stage I, 87%; Stage IIA, 88%; Stage IIB, 68%; Stage III, 80%; and Stage IVA, 67%. The parameters of stage, patient age, total dose to primary site, and overall treatment time were evaluated in a multivariate analysis. The single most important predictor of pelvic control was overall treatment time. If the entire course of radiotherapy (external beam + implant) was completed within 9 weeks (63 days), the pelvic control rate was 97%. The pelvic control rate was only 54% if treatment time extended beyond 9 weeks (p = .0003). The rate of severe complications was 12%, and the incidence increased with increasing total primary dose. CONCLUSION: Radiotherapy alone can cure a significant proportion of patients with carcinoma of the vagina. Treatment should be completed without significant interruption, preferably within 9 weeks.

Current management of squamous cell carcinoma of the anal canal.

The management of squamous cell carcinoma of the anal canal is controversial. Treatment currently varies from abdominoperineal resection to combined radiotherapy and chemotherapy. Our aim is to review the management of this disease and present our current treatment policies. Twenty-six patients treated at the University of Florida with surgery and adjuvant radiotherapy are compared with 12 patients treated with radiotherapy alone. The pertinent literature is reviewed to determine the role of primary surgery, the efficacy of adjuvant chemotherapy, and the optimal chemotherapy schedule. The preferred management of anal canal cancer is radiotherapy; abdominoperineal resection should be reserved for salvage after local recurrence and for patients with faecal incontinence caused by the destruction of the sphincter muscle. Adjuvant chemotherapy is probably indicated for patients with lesions that are stage T2 or larger. The optimal chemotherapy regimen consists of 5-fluorouracil and mitomycin. Preliminary data suggest that cisplatin may be substituted for mitomycin with equivalent efficacy and less toxicity.

Long-term complications of laparotomy in Hodgkin's disease.

OBJECTIVE: The authors determined the incidence of complications in 133 patients who had undergone staging laparotomy with splenectomy before treatment for Hodgkin's disease (stages I-IV). METHODS AND MATERIALS: Medical records were reviewed, and the patients or their relatives were interviewed. Median follow-up after laparotomy was 15.7 years (range = 2.5-28 years). RESULTS: Ten episodes of overwhelming postsplenectomy infection (OPSI) were documented in nine patients (6.8%). None of 25 patients who received pneumococcal vaccine before splenectomy developed OPSI. Patients with advanced (stages III-IV) or recurrent Hodgkin's disease were at higher risk of OPSI than those with early disease, and those who received combined modality oncologic therapy were at greater risk than those receiving less intensive treatment. Surgical complications included small bowel obstruction in 13 patients (9.8%), necessitating repeat laparotomy in 9 patients (6.8%), atelectasis in 17 patients, abscess in 3 patients, and 1 wound dehiscence. No deaths occurred as a result of surgical complications. Causes of death in the 29 patients who died included Hodgkin's disease (12 patients), acute treatment-related morbidity (1 patient), leukemia (5 patients), bone marrow failure (3 patients), solid malignancy (2 patients), intercurrent disease (4 patients), unknown causes (1 patient), and OPSI (1 patient). CONCLUSION: With presplenectomy pneumococcal vaccination and modern surgical techniques, the long-term risks of laparotomy with splenectomy are acceptable if knowledge of the pathologic extent of abdominal Hodgkin's disease would alter treatment regimens.

Stage III ovarian carcinoma: an analysis of treatment results and complications following hyperfractionated abdominopelvic irradiation for salvage.

PURPOSE: Patients with persistent disease found at laparotomy following platinum-based chemotherapy for Stage III ovarian carcinoma have a remote chance of cure with second-line chemotherapy or conventional radiotherapy. To decrease relapse rates and improve tolerance, we have used twice-daily radiotherapy in 28 such patients. METHODS AND MATERIALS: Twenty-eight patients with Stage III epithelial ovarian carcinoma were treated with curative intent at the University of Florida with hyperfractionated, continuous-course radiotherapy for persistent disease at laparotomy after administration of platinum-based chemotherapy. All patients received .8 Gy per fraction, twice daily, to a mean total dose of 30.2 Gy to the whole abdomen and pelvis; 20 patients had additional radiotherapy to the pelvis (mean, 14.54 Gy). All patients had undergone two to four (mean, 2.6) laparotomies for ovarian carcinoma and had received 6-28 (mean, 12) cycles of chemotherapy before irradiation. RESULTS: With a 2-year minimum follow-up, survival rates at 1, 2, and 5 years were as follows: absolute survival, 79%, 50%, 21%; relapse-free survival, 52%, 36%, 19%. For the 11 patients with no evidence of gross residual disease after the second-look laparotomy, the absolute survival rates were 100%, 73%, and 27%. This was superior to the rates of 65%, 34%, and 18% for the 17 patients who had gross residual disease. Only two patients required treatment breaks. Four patients required surgical intervention for small-bowel obstruction, which in two cases revealed recurrent disease. Two patients died of treatment-related complications. Twenty-two of 23 failures occurred in the abdomen and/or pelvis. CONCLUSION: Although most patients eventually relapse, a small percentage have had a prolonged disease-free interval. Since treatment was relatively well tolerated, escalation of the dose of hyperfractionated abdominopelvic irradiation is being investigated.

Conservative alternatives in the management of early adenocarcinoma of the rectum.

The majority of patients with adenocarcinoma of the rectum are treated with radical surgical procedures. Lesions located in the distal third of the rectum are usually treated by abdominoperineal resection, and those situated in the proximal portion of the rectum are treated by low-anterior resection. Relatively small, moderately or well differentiated lesions have a low risk of lymph node metastasis, and are therefore amenable to conservative (ie, rectum-sparing) procedures. Conservative management options consist of transrectal excision, transrectal excision and preoperative or postoperative radiotherapy, endocavitary contact radiotherapy, and interstitial therapy. Discussion of these options, the experience at the University of Florida with two of these options, and review of the literature follow.

Correlation of lymphangiography, computed tomography, and laparotomy in the staging of Hodgkin's disease.

PURPOSE: To determine the predictive value of lymphangiography and computed tomography of the abdomen and pelvis for infradiaphragmatic involvement of Hodgkin's disease. METHODS AND METHODS: We retrospectively reviewed the findings on 125 patients with Hodgkin's disease treated at the University of Florida who underwent lymphangiography and staging laparotomy; 33 patients also underwent computed tomography of the abdomen and pelvis. The positive predictive value and negative predictive value were calculated for both studies. RESULTS: The positive predictive value of lymphangiography for paraaortic or pelvic disease was 35%, while the negative predictive value was 95%. The positive predictive value of computed tomography of the abdomen and pelvis for paraaortic or pelvic disease was 20%; the negative predictive value was 93%. There was no advantage in predicting paraaortic or pelvic disease when both studies were obtained as compared to either study alone. For splenic disease, the positive predictive value of computed tomography was 43%; the negative predictive value was 77%. Of the patients with a positive lymphangiography, 57% were found at laparotomy to have either no abdominal disease or upper abdominal disease only, with or without minimal splenic disease, making them reasonable candidates for radiotherapy alone. Of the patients with a negative lymphangiogram, 14% were found at laparotomy to have either lower abdominal disease or extensive splenic disease, and so were not good candidates for radiotherapy alone. CONCLUSION: We recommend laparotomy for patients who may be candidates for radiotherapy alone or combined modality therapy with limited chemotherapy.