Preoperative radiotherapy for rectal cancer. The 1985-1996 Lyon experience. Prognostic study based on 312 patients.

Aim of study: preoperative radiotherapy is used increasingly in rectal canc er in Europe. This study is a retrospective analysis of a series of 312 pat ients with rectal adenocarcinoma treated by preoperative radiotherapy. Mate rial and method: From 1985 to 1996, 312 patients were included in this stud y. Preoperative staging was: T2: 83, T3: 192 et T4: 21. On digital rectal e xamination, 25 patients were classified as N1. Endorectal sonographic stagi ng was: uT1 : 3, uT2: 77, uT3 : 163, uno: 122, uN1-2: 127. After surgery, p athological staging was: pT0: 43 (14%), pT1 24, pT2: 81, pT3: 151, pN0: 229 , pN1-2: 81. Radiotherapy was delivered to the posterior pelvis with an acc elerated schedule 39 Gy/13 fractions/17 days with x18 MV. Results: Median f ollow-up is 54 months. For pM0 patients (297 patients), the overall 5-year survival rate is 67%. Local failure rate is 9%. Since 1986, the rate of sph incter saving surgery is close to 65%. Various parameters related to the tu mor were found to be significant prognostic factors on multivariate analysi s in relation to 5-year overall survival rate: the T stage as judged by dig ital rectal examination and endorectal sonography, the N stage as evaluated on digital rectal examination but not with endorectal sonography. Patholog ical examination of the operative specimen retains a very strong prognostic value for pT and pN. Conclusion: Pathological examination of the specimen of rectal carcinoma retains a very strong prognostic value after preoperati ve radiation therapy. Endorectal sonography is of interest to evaluate T st aging of the tumor but is not reliable for N stage.