Preoperative radiotherapy for locally advanced rectal cancer and prognostic factors influencing outcome
Abstract
The aim of presented study was to evaluate the impact of different factors on survival, local recurrence and development of metastatic disease in patients with rectal cancer treated with preoperative radiotherapy or 5-fluorouracil (5-FU) based concurrent chemoradiation. Retrospective clinical evaluation was performed in 165 patients (33% women and 67% men) with locally advanced rectal adenocarcinoma treated with preoperative radiotherapy or chemoradiotherapy in the period January 1998 - March 2003.
Tumor extent was evaluated by CT and/or MRI and/or TRUS examination and tumor biopsy was performed during colonoscopy. The median follow up is 21 month.
All patients received preoperative external beam radiation to primary tumor, adjacent lymphnodes and presacral region. Computed tomography localisation of target volume was used for 3D radiotherapy treatment planning.
Accelerated short term regimen (25 Gy/5 fraction/1 week) was performed in 14% of patients especially in year 1998-2000 and normofractionated regimen (40-50 Gy/20-25 fractions/4-5 weeks) was performed in 86% of patients. Chemoradiotherapy with 5-FU was carried out in 22% of patients.
Radical resection underwent 85% of patients, inoperable tumor persisted in 7% and distant metastases were detected peroperatively in 8%. The 2-year overall survival (OS) was 84% and 5-year OS was 60% following radical resection.
The important prognostic factors affecting survival were postradiotherapy determined pathological staging (p=0.005), postradiotherapy tumor grade (p<0.001) and the presence of angioinvasion and/or perineural spread (p=0.023). Prognostic factors for disease-free survival were identical with those for OS.
Higher local recurrence rate was associated in preradiotherapy tumor staged T4 (p=0.048) and in presence of angioinvasion and/or perineural spread (0.049). Age, tumor location, histological grade before radiotherapy and tumor downstaging were not statistically significant for survival and/or for local recurrence rate.
The best survival rates were obtained in patients with postradiotherapy grade 1 tumors (5-years survival 100%), tumors without angioinvasion and perineural spread (5-years survival 65%) and in patients who obtained complete remission after preoperative radiotherapy (5-years survival 86%).