Neoadjuvant radiochemotherapy and surgery for advanced rectal cancer : prognostic significance of tumor regression.

ABSTRACT

PURPOSE: Preoperative radiochemotherapy is widely used in the treatment of locally advanced rectal cancer. The predictive value of response to neoadjuvant treatment remains uncertain. We retrospectively evaluated the impact of downstaging and tumor regression as prognostic factors and its influence on the ability to perform sphincter-sparing surgery. PATIENTS AND METHODS: A total of 72 consecutive patients with advanced rectal cancer were included in this retrospective analysis. All patients were treated with preoperative 5-fluorouracil-based chemotherapy and pelvic radiation with a total dose of 50.4 Gy followed by surgery 6 weeks later. RESULTS: A sphincter-preserving procedure could be performed on 42 patients, and in all 72 patients complete resection (R0) was achieved. A pathological complete response (ypT0, ypN0) was achieved in 8 (11%) patients. None of the patients showing a complete pathological response relapsed or died during the follow-up period. At a median follow-up of 28 months, 65 patients were alive, none of these patients had local recurrence and 15 patients had metastatic disease. Patients showing a complete pathological response had a significantly better 2-year disease-free survival compared to patients with ≥10% residual tumor cells (p = 0.024). Patients < 65 years showed a significantly better response rate, compared with those > 65 years of age (p = 0.036). Acute toxicity was moderate. CONCLUSION: Preoperative radiochemotherapy is an effective and safe treatment for patients with locally advanced rectal cancer. Pathological parameters after preoperative radiochemotherapy, including tumor regression grading, could be correlated with disease-free survival. The impact of tumor regression grading needs to be further validated in prospective clinical trials.