In a nutshell
This study evaluated the relapse-free survival and disease-free survival in patients with stage II colorectal cancer according to treatments received.
Stage II of colorectal cancer (CRC) represents a large tumor that invades the entire wall of the large intestine and potentially the nearby organs, but has not yet spread to the lymph nodes. The primary (main) therapy for these patients usually includes surgery to remove the cancerous tissue. After primary therapy, they may or may not be given further (adjuvant) chemotherapy. Adjuvant chemotherapy (AC) refers to use of cytotoxic drugs to kill any cancer cells that may have been left after surgery. This reduces the risk of cancer coming back (recurring), hence improving their survival. This study assessed the effect of using AC on the disease-free survival or DFS (the percentage of patients who survived without evidence of cancer for a defined period of time) and relapse-free survival or RFS (the percentage of patients who survived without the cancer returning for a defined period of time).
Methods & findings
The study involved 834 patients with stage II CRC who had undergone surgery as primary treatment. Among these patients, there were 335 patients with low risk of recurrence and 387 patients with high risk of recurrence. For the remaining patients, their risk level was either unknown or they had shown symptoms at diagnosis. 353 of the included patients were assigned to receive AC and the other 481 patients did not undergo further treatment (the surgery alone group).
After approximately 5 years of follow up, the low risk patients who were in the AC treated group had 87.3% RFS and 86.4% DFS compared to the ones in the surgery alone group, whose RFS was 74.7% and DFS was 72.4%. The high-risk patients who were in the AC treated group had 82.7% RFS and 80.5% DFS compared to the ones in the surgery alone group whose RFS and DFS was 71.4% and 70.3%, respectively.
The bottom line
In summary, the study showed that adjuvant chemotherapy improved both RFS and DFS in stage II CRC patients.