Comparison of multileaf collimator and customized blocks for 3-D conformal radiotherapy of prostate cancer with six-field technique

The recent technological advances in radiation oncology gave us the opportunity to increase the doses given to the tumor tissues while reducing the doses of normal tissues. The shaping of the conformal fields may be achieved by using lead customized (C) blocks, multileaf collimators (MLC) or intensity modulated beams. In this study, in order to minimize the doses of normal tissues, we compared the different conformal treatment techniques and shapes for the radiotherapy in the case of prostate cancer. Dose volume histograms of the six patients' treatment plans generated with multileaf collimation technique and the customized blocks are presented. Six patients with localized prostatic carcinoma who have been treated with conformal irradiation between January 2001 and September 2002 were evaluated retrospectively. They were all chosen to assess the differences between customized blocks and MLC configuration in the definitive radiation therapy of prostate cancer with six-field technique. A total dose of 68.4 -72 Gy to the prostate and seminal vesicles were given to all of the patients with a fractionation of 1.8 Gy/daily. The dose calculation and dose volume histograms were used to compare the resulting dose distributions. The dose was calculated using the pencil beam algorithm in the Theraplan plus treatment planning system. The dose volume histograms for blocks and multileaf collimation technique were compared in terms of normal tissue volume for rectum, bladder and femoral heads and it was assumed that, although there were small discrepancies between the plans and all of the doses were under the critical dosages stated for rectum, bladder and femoral heads for each technique, the doses given to the critical organs were higher with the MLC technique. Regarding the late toxicity and the critical organ doses, each of these shaping methods is suitable for the definitive irradiation of prostate carcinoma with six-field technique

Continuous hyperfractionated accelerated radiotherapy in the treatment of high-grade astrocytomas

Between May 1993 and January 1995, 36 patients with high-grade astrocytomas were treated with 1.05 Gy continuous hyperfractionated accelerated radiotherapy three times daily to a total target dose of 59.85 Gy in 19 days with 6-h intervals. The median age of the patients was 51 years and the median follow-up was 58 weeks. The median survival rate was 58 weeks and the cumulative survival rare was 22% at 2 years, No severe toxicity occurred in patients treated with this fractionation scheme. These results suggest that continuous hyperfractionated accelerated radiotherapy is an altered fractionation schedule for: high-grade astrocytomas with tolerable acute toxicity and survival rates comparable to conventional fractionation and to other altered fractionation schedules. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved

A randomised study of ornidazole as a radiosensitiser in carcinoma of the cervix: Long-term results

This paper presents long-term results of a randomised study of ornidazole as a radiosensitiser in locally advanced carcinoma of the cervix. A total of 76 patients were randomised and followed-up with a median of 85 months. All patients were treated with external and intracavitary irradiation. The 10 year actuarial local control rate was 61% in patients receiving ornidazole, compared with 50% for placebo group. This difference was not statistically significant. Ten year actuarial overall and disease-free survival rates were also similar in the two treatment groups. Although, when analysed by stage, there was a significant advantage in the local control (54% vs 15%; P=0.044) and disease-free survival rates (37% vs 8%; P=0.047) in ornidazole group for stage IIIB cases, its implication is obscure because of the small number of patients. In this study moderate and severe complication rates were found to be 30%. These results suggest that ornidazole seems to have relatively weak sensitisation and it may show a possibility of a marginal benefit with unconventional irradiation using relatively large radiation doses. However, the results are insufficient for a real gain in the probability of local tumour control and survival

MULTIVARIATE-ANALYSIS OF PROGNOSTIC FACTORS IN 75 PATIENTS WITH SOFT-TISSUE SARCOMA

The results of 75 patients with soft-tissue sarcomas treated by the combination of local surgical excision plus postoperative radiotherapy are reported. Thirty-five tumors were situated in the extremities, 32 in the trunk, and eight in the head and neck. Twenty-eight tumors were high grade, 33 intermediate and 14 low grade. Sixty-two patients had complete resections (wide or marginal) and 13 incomplete resections (intralesional). Radiation was administered with a shrinking-field technique (median total dose, 64 Gy; range, 50-78). Twenty-five patients developed local recurrence (33%). The 5-year local control rate was 67%. On univariate analysis, a tumor site other than extremity (p < 0.05), unfavorable histology (p < 0.01), and incomplete resection (p < 0.01) were poor risk factors for local recurrence. When multivariate analysis were performed, only incomplete resection (relative risk (RR) 7.2) remained a poor risk factor. The 5-year overall survival rate was 50.5% for the entire group. Following a univariate analysis of host tumor and treatment-related factors, a tumor site other than extremity (p < 0.05), high tumor grade (p < 0.01) unfavorable histology (p < 0.05), and incomplete tumor resection (p < 0.01) were found to significantly increase the risk of further tumor death. Multivariate analysis found high tumor grade (RR 5.6), and incomplete resection (RR 7) to be independent poor risk factors for survival

Cervical cancer coexisting with small lymphocytic lymphoma detected during positron emission tomography/computed tomography simulation: a case report

Background: Positron emission tomography (PET)/computed tomography (CT) simulation in cervical cancer may help radiation oncologists to better define the target volumes. It may also detect extrapelvic lesions and incidental second malignancies, leading to significant changes in treatment management. Case: A 63-year-old woman who was deemed inoperable due to carcinoma of the cervical stump extending to the parametria and paraaortic lymph nodes detected on MR images presented for extended field radiotherapy. PET/CT simulation revealed an FDG avid mass in the cervical stump, and an enlarged axillary lymphadenopathy showing moderate FDG uptake. The excisional biopsy was consistent with small lymphocytic lymphoma (SLL). Conclusion: In our case, PET/CT simulation not only led to changes in treatment management, but also revealed a very rare coexistence of SLL and invasive squamous cell carcinoma of the cervix