Aim: To determine influence of preoperative chemoradiation (CRT) for rectal cancer (RC) on long-term results.
Patients and Methods: 169 patients with locally advanced RC were included into prospective trial. Of them 83 received CRT [T3(89.7%) and T4(10.3%)] and 86 had surgery alone [T3(88.2%) and T4(11.8%)]. CRT was delivered as external beam irradiation in 2 sessions per day 5 days a week up to total dose of 4500cGy with chemotherapy of 5FU 225mg/m2 daily given as bolus IV before RT. Surgery was performed 4-6 weeks later.
Results: CRT resulted in downsizing of 73 (87.9%) RC and downstaging in 54.4%. Damage of tumor cells detected in 65.6% of specimens. Downstaging of tumor after CRT for T stage was seen in 32, for N stage - in 2, and for both - in 3 patients. There was 3 fold decrease in T4 (from 10.3% to 2.9%) and 2 fold in T3 (from 89.7% to 50%). Following downstaging has been found: T2 - 25%, T1- 2.9%, Tx (focal adenocarcinoma) - 2.9%. Complete pathologic response was found in 9 specimens (T0N0 - 13.2%) and T0N1 in 2(2.9%). Curative resection with TME was done in 68 (81,9%) of CRT group and 77 (89.5%) in control group. It is of importance, that CRT allows to perform sphincter-saving procedures for 16.2% patients with low rectal carcinomas located within 4-5cm from anal verge initially regarded as candidates for APR.Local recurrences rate (LRR) was 8.6% in radiosensitive RC and 14.3% in radioresistant RC (p=0.47), distant metastases were occurred in 8.6% and 19.3% accordingly (p=0.13). There was increase in 5-year disease-free survival (DFS) of patients with radiosensitive RC 68.6% comparing to radioresistant RC 39.3% (p=0.015). In accordance to T-stage DFS was 100% for complete pathologic response; 100% for T1; 68.7% for T2; 40% for T3. Both patients with T0N1 died because of distant recurrence. DFS was significantly better for pT0-1 -75.8% vs. pT3 - 40% (p=0.02) and for pN0 - 73.3% vs. pN1 25.0% (p=0.017). The majority (90%) of died patients, who undergone CRT had T2-T3. Only 2 patients had T0N1 and in 1 case - TxN0.Despite no difference in DFS between CRT 55.6% and surgery alone 45.8%, (p=0.26), the trend towards better local control in radiosensitive RC (LRR 8.6%) comparing to surgery alone (LRR 21.4%) was found. Also significantly better survival was achieved in radiosensitive RC vs. surgery alone: 68.6% and 45.76%, correspondingly (p=0.04).
Conclusion: CRT significantly improves 5-year survival in patients with radiosensitive RC. Further investigations aimed at determination of radio- and chemosensitivity criteria for RC are mandatory. In our opinion it will allow better selection of patients for preop-CRT.