Recurrence rates and prognostic factors in ypN0 rectal cancer after neoadjuvant chemoradiation and total mesorectal excision.

Abstract

Neoadjuvant chemoradiation followed by surgery and adjuvant chemotherapy is typically recommended for patients with locally advanced rectal cancer. Patients with pathologically node-negative tumors have an improved prognosis, but recurrence patterns and independent prognostic factors in these patients have been incompletely characterized. Using a retrospective cohort study design, we included all rectal cancer patients treated with neoadjuvant chemoradiation and curative surgery from 1993 through 2003, who had ypN0 tumors. We characterized recurrence rates and patterns in patients not treated with adjuvant chemotherapy. Secondarily, we compared them to patients who did receive adjuvant treatment and assessed for independent prognostic factors, using univariate and multivariable survival analyses. Overall, 324 ypN0 patients (ypT0: n = 73; ypT1-2: n = 130; ypT3-4: n = 120) were followed for a median of 5.8 years. The risk of recurrence was associated with pathologic stage-2.7% ypT0, 12.3% ypT1-2, 24.2%ypT3-4. Five-year recurrence-free survival in patients who did not receive adjuvant treatment was 100% (ypT0), 84.4% (ypT1-2) and 75% (ypT3-4). There was no significant difference in 5-year recurrence-free survival between patients who did and did not receive adjuvant treatment. In multivariable analysis, pathologic stage was the factor most strongly associated with recurrence (hazard ratio 3.6 for ypT3-4 vs. ypT0-2, 95% confidence interval 1.9-6.7, P < 0.0001). The recurrence rates for selected patients with ypT0-2N0 rectal cancer after neoadjuvant chemoradiation and total mesorectal excision are low. Although standard practice remains completion of planned postoperative adjuvant chemotherapy for all patients undergoing chemoradiation, these data suggest prospective trials may be warranted to measure the benefit of adjuvant chemotherapy in favorable subgroups, such as ypT0-2N0.