However, while treatment responders do experience excellent disease-specific survival, it still falls short of that seen in patients with stage I disease who undergo resection alone.
“To our knowledge, there has been no population-based study to date that has noted the effect of pathologic response to neoadjuvant radiation therapy on survival,” Dr. Nipun B. Merchant, from Vanderbilt University Medical Center, Nashville, and colleagues write.
The present study featured an analysis of data from the Surveillance, Epidemiology, and End Results registry from 1994 to 2003 and included 3760 patients treated with neoadjuvant radiotherapy and 7211 patients with stage I disease who underwent resection alone.
Disease-specific and overall survival were 94% and 82%, respectively, for responders to radiation therapy compared with 78% and 60% for non-responders. Stage I disease patients treated with resection alone had corresponding rates of 97% and 79%.
Comparing the survival rates, the authors found that radiation responders had significantly better disease-specific and overall survival than did non-responders (p < 0.001 for both). Resection-only patients had better disease-specific survival than responders (p = 0.01), but comparable overall survival.
The results suggest that “patients with stage II or III rectal cancer who have a complete or near-complete response to neoadjuvant radiation therapy can achieve survival rates similar to that of patients who present with stage I disease,” the authors conclude.
Arch Surg 2009;144:129-134.