Does downstaging predict improved outcome after preoperative chemoradiation for extraperitoneal locally advanced rectal cancer? A long-term analysis of 165 patients

Purpose: To evaluate the impact of tumor response; tumor and nodal downstaging; and cTNM, yTNM (clinical stage after chemoradiation, based on preoperative imaging), and pTNM classifications on long-term outcome in patients with rectal cancer treated with preoperative 5-fluorouracil (5-FU)-based concurrent chemoradiation. Methods and Materials: Between January 1990 and March 1998, 165 consecutive patients with locally advanced extraperitoneal cancer of the rectum were treated with preoperative chemoradiation. Four patients had a cT2 lesion (2.5%), 120 had a cT3 lesion (74.5%), and 41 had a cT4 lesion (23%). The nodal involvement at combined imaging was cN0 in 21%, cN1 in 41%, cN2 in 34%, and cN3 in 4%. Preoperative chemoradiation was delivered according to 1 of 3 schedules: (1) FUMIR-T3 (from 1990 to 1995) for patients with cT3N0-2 or cT2N1-2 rectal carcinoma (82 patients): 37.8 Gy (1.8 Gy/fraction) plus 5-FU, 1 g/m2/d on Days 1-4, continuous infusion, and mitomycin-C, 10 mg/m2/d on Day 1; (2) FUMIR-T4 (from 1990 to 1999) for patients with cT4N0-3 or cT3-4N3 rectal carcinoma (40 patients): 45 Gy (1.8 Gy/fraction) plus 5-FU, 1 g/m2/d on Days 1-4 and 29-32, continuous infusion, and mitomycin-C, 10 mg/m2/d on Days 1 and 29; and (3) PLAFUR-4 (from 1995 to 1998) for patients with cT3N0-2 or cT2N1-2 rectal carcinoma (42 patients): 50.4 Gy (1.8 Gy/fraction) plus 5-FU, 1 g/m2/d on Days 1-4 and 29-32, continuous infusion, and cisplatin, 60 mg/m2/d on Days 1 and 29. Four to five weeks after chemoradiation, patients were reevaluated for clinical response by imaging studies (CT scan, transrectal ultrasonography, barium enema, liver ultrasonography, chest X-rays) and restaged (yTNM). Surgery was performed 6-8 weeks after chemoradiation. Adjuvant chemotherapy (5-FU + l-folinic acid) was delivered to 26 patients in the FUMIR-T4 protocol group. Local control (LC), freedom from distant metastases (FDM), disease-free survival, and overall survival (OS) were evaluated according to the