Explore stage II colon cancer, upper rectal cancer patients with general risk benefit from single agent adjuvant chemotherapy or not.

Forty cases of tumor tissues detected MLH1, MSH2, MSH6, PMS2 proteins by IHC test and confirmed as pMMR status. Twenty cases as adjuvant chemotherapy group confirmed as MSS phenotype by PCR who treated Raltitrexed which dose was 3 mg/m², d1, ivgtt in 15 min, Q21d for 4 cycles. The survival time was determined according to the follow-up results, and the objective efficiency was evaluated. Adverse events were evaluated according to the NCI-TC3.0 version of toxicity classification criteria. The non-adjuvant chemotherapy group 20 cases were control.

Adjuvant chemotherapy group objective effective rate was 95.0% (19/20), the recurrence rate was 5.0% (1/20), the control group recurrence rate 15.0% (3/20), adjuvant chemotherapy group recurrence rate was lower than control group (χ²=5.556, P=5.556). Adjuvant chemotherapy group only occurred I or II degree adverse events, no cardiac toxicity, no influence on blood sugar.

pMMR and MSS phenotype stage II colon cancer, upper rectal cancer patients with general risk using Raltitrexed single-agent adjuvant chemotherapy were safe and effective.