Potential interest of developing an integrated boost dose escalation for stereotactic irradiation of primary prostate cancer.

INTRODUCTION: The stereotactic irradiation is a new approach for low-risk prostate cancer. The aim of the present study was to evaluate a schema of stereotactic irradiation of the prostate with an integrated-boost into the tumor. MATERIAL AND METHODS: The prostate and the tumor were delineated by a radiologist on CT/MRI fusion. A 9-coplanar fields IMRT plan was optimized with three different dose levels: 1) 5 × 6.5 Gy to the PTV1 (plan 1), 2) 5 × 8 Gy to the PTV1 (plan 2) and 3) 5 × 6.5 Gy on the PTV1 with 5 × 8 Gy on the PTV2 (plan 3). The maximum dose (MaxD), mean dose (MD) and doses received by 2% (D2), 5% (D5), 10% (D10) and 25% (D25) of the rectum and bladder walls were used to compare the 3 IMRT plans. RESULTS: A dose escalation to entire prostate from 6.5 Gy to 8 Gy increased the rectum MD, MaxD, D2, D5, D10 and D25 by 3.75 Gy, 8.42 Gy, 7.88 Gy, 7.36 Gy, 6.67 Gy and 5.54 Gy. Similar results were observed for the bladder with 1.72 Gy, 8.28 Gy, 7.01 Gy, 5.69 Gy, 4.36 Gy and 2.42 Gy for the same dosimetric parameters. An integrated SBRT boost only to PTV2 reduced by about 50% the dose difference for rectum and bladder compared to a homogenous prostate dose escalation. Thereby, the MD, D2, D5, D10 and D25 for rectum were increased by 1.51 Gy, 4.24 Gy, 3.08 Gy, 2.84 Gy and 2.37 Gy in plan 3 compared to plan 1. CONCLUSIONS: The present planning study of an integrated SBRT boost limits the doses received by the rectum and bladder if compared to a whole prostate dose escalation for SBRT approach.

Intraoperative radiotherapy in resected pancreatic cancer: feasibility and results.

BACKGROUND AND PURPOSE: To evaluate the impact of intraoperative radiotherapy (IORT) combined with postoperative external beam irradiation in patients with pancreatic cancer treated with curative surgical resection. MATERIALS AND METHODS: From January 1986 to April 1995 25 patients (11 male and 14 female, median age 61 years) underwent a curative resection with IORT for pancreatic adenocarcinoma. The tumour was located in the head of the pancreatic gland in 22 patients, in the body in two patients and in the tail in one patient. The pathological stage was pT1 in nine patients, pT2 in nine patients, pT3 in seven patients, pN0 in 14 patients and pN1 in 11 patients. All the patients were pM0. A pancreaticoduodenectomy was performed in 22 patients, a distal pancreatectomy was performed in two patients and a total pancreatectomy was performed in one patient. The resection was considered to be complete in 20 patients. One patient had microscopic residual disease and gross residual disease was present in four patients. IORT using electrons with a median energy of 12 MeV was performed in all the patients with doses ranging from 12 to 25 Gy. Postoperative EBRT was delivered to 20 patients (median dose 44 Gy). Concurrent chemotherapy with 5-fluorouracil was given to seven patients. RESULTS: The overall survival was 56% at 1 year, 20% at 2 years and 10% at 5 years. Nine local failures were observed. Twelve patients developed metastases without local recurrence. Twenty patients died from tumour progression and two patients died from early postoperative complications. Three patients are still alive; two patients in complete response at 17 and 94 months and one patient with hepatic metastases at 13 months. CONCLUSION: IORT after complete resection combined with postoperative external beam irradiation is feasible and well tolerated in patients with pancreatic adenocarcinoma.