Pathologic complete response after neoadjuvant treatment for rectal cancer decreases distant recurrence and could eradicate local recurrence.

Background: The aim of this study was to evaluate the clinical implications of pathologic complete response (pCR) (i.e., T0N0M0) after neoadjuvant chemoradiation and radical surgery in patients with locally advanced rectal cancer.
Materials and Methods: A single-center, prospectively maintained colorectal cancer database was queried for patients with primary cII and cIII rectal cancer staged by CT and ERUS/MRI undergoing long-course neoadjuvant chemoradiation followed by proctectomy with curative intent between 1997 and 2007. Patients were stratified into pCR and no-pCR groups and compared with respect to demographics, tumor and treatment characteristics, and oncologic outcomes. Outcomes evaluated were 5-year overall survival, disease-free survival, disease-specific mortality, local recurrence, and distant recurrence.
Results: The query returned 238 patients (73% male), with a median age of 57 years and median follow-up of 54 months. Of these, 58 patients achieved pCR. Patients with pCR vs no-pCR were statistically comparable with respect to demographics, chemoradiation regimens, tumor distance from anal verge, clinical stage, surgical procedures performed, and follow-up time. No patient with pCR had local recurrence. Overall survival and distant recurrence were also significantly improved for patients achieving pCR.
Conclusions: Achievement of pCR after neoadjuvant chemoradiation is associated with greatly improved cancer outcomes in locally advanced rectal cancer. Future studies should evaluate the relationship between increases in pCR rates and improvements in cancer outcomes in this population.