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Standard treatment for T3–4 or node-positive rectal cancer is preoperative fluoropyrimidine-based chemoradiotherapy followed by surgery. An emerging strategy in patients achieving a clinical complete response is observation with reservation of surgery as a salvage procedure for local tumor recurrence.
Investigators now report a propensity-score matched cohort analysis of a watch-and-wait approach in rectal cancer patients treated with chemoradiotherapy. Of 259 patients treated at a tertiary-care center, 228 who had local recurrence underwent surgical resection and 31 who achieved a clinical complete response were observed without surgery. The authors added another 98 patients with clinical complete response to the observation group, bringing the total to 129. Patients in the observation group were more likely than those in the surgery group to have earlier pretreatment T stage disease (cT2, 24% vs. 11%; P=0.001) and node-negative disease (N0, 35% vs. 21%; P=0.003).
At a relatively brief median follow-up of 33 months, 44 (34%) of the 129 patients in the observation group had local tumor regrowth, and 3 of these (2%) developed metastatic disease. Of the 41 patients in the observation group with local recurrence, 31 had salvage surgery; of these, 30 had R0 resection, and 5 received salvage radiotherapy. In a paired cohort of 218 patients undergoing observation or surgery, 3-year nonregrowth disease-free survival (the primary endpoint) was similar in both groups (88% and 78%, respectively), as was overall survival (96% and 87%).
Renehan AG et al. Watch-and-wait approach versus surgical resection after chemoradiotherapy for patients with rectal cancer (the OnCoRe project): A propensity-score matched cohort analysis. Lancet Oncol 2016 Feb; 17:174. (http://dx.doi.org/10.1016/S1470-2045(15)00467-2)
Comment
In this large study, the rate of clinical complete response was relatively low and the follow-up was relatively short. Observation without surgery remains an attractive strategy in select patients, but it remains an investigational approach. Longer follow-up is required to ensure that observation without surgery does not compromise long-term survival. The identification of more specific biomarkers to identify patients at low risk for local disease recurrence, potentially including circulating tumor biomarkers, is needed.