HealthDay News — For localized mismatch repair-deficient (dMMR) colorectal cancer (CRC), neoadjuvant programmed death-1 (PD-1) inhibitor treatment is effective, according to a study published online January 11 in the Journal of the National Comprehensive Cancer Network.
Bin-Yi Xiao, MD, from the Sun Yat-sen University Cancer Center in Guangzhou, China, and colleagues examined the efficacy and feasibility of neoadjuvant anti-PD-1 treatment for localized dMMR CRC among 73 patients, aged 18 to 75 years.
The researchers found that most of the tumors were locally advanced, including 26.0 and 39.7% T4a and T4b, respectively. PD-1 inhibitor monotherapy was received by 79.5% of the participants. Overall, 84.9% of the patients achieved objective response per radiologic assessment, including 17 and 45 patients (23.3 and 61.6%) with complete response (CR) and partial response, respectively, with a median of 9.6 weeks to response. The response rate was similar for patients with T4a/T4b disease and those with T2-3 disease (84.0 vs 85.4%). In most of the 50 patients undergoing surgery (57.1%), pathologic CR was achieved, and remained high (59.5%) even for the 38 patients with T4a/T4b disease. Surgery was not performed in the 17 patients with CR but a watch-and-wait strategy was adopted. The median recurrence-free and overall survivals were not reached after a median of 17.2 months. The two-year tumor-specific disease-free and overall survival rates were 100% among patients undergoing surgery or achieving CR.
“Care providers, especially surgeons, should refrain from scheduling immediate surgery for patients with locally advanced, or even early-stage dMMR/microsatellite instability-high colorectal cancer,” a coauthor said in a statement.
Abstract/Full Text (subscription or payment may be required)