Is chemo after surgery necessary if no cancer is present in the lymph nodes?

This study evaluated whether patients whose cancer has not spread to the lymph nodes would benefit from additional chemotherapy following surgery.

Locally advanced rectal cancer means the cancer has spread from the rectum (the lowest part of the large bowel) into surrounding tissues and organs. The recommended treatment for locally advanced rectal cancer is neoadjuvant chemotherapy (chemotherapy given before surgery) followed by surgical removal of the affected intestine (radical resection). The cancer is graded after this initial treatment, with grade ypN0 indicating that the cancer has not spread to nearby lymph nodes.

Following surgery it is unclear which patients should continue to receive chemotherapy. Some studies suggest that further chemotherapy may not be necessary for patients with no cancer in the nearby lymph nodes. However, this remains controversial.

This study included 160 rectal cancer patients with no cancer in the lymph nodes (grade ypN0). Patients were sub-grouped based on the spread of the cancer through the layers of the intestine: T0 (no spread) to T4 (cancer has spread through the wall of the intestine). Adjuvant chemotherapy (chemotherapy after surgery) was given to 115 patients (71.9%).

For patients whose cancer had not yet spread beyond the thin layer of muscle surrounding the rectum (T0 – T2) and who did not have cancer in the lymph nodes (ypN0), all survival results were similar between patients who did and did not receive adjuvant chemotherapy.

For patients whose cancer had spread into the tissues surrounding the rectum or to nearby organs (T3 – T4) and who did not have cancer in the lymph nodes (ypN0), those who were given adjuvant chemotherapy exhibited a higher 5-year overall survival and disease-free survival than those who were not. Adjuvant chemotherapy also decreased the rates of distant metastases for these patients.

The authors conclude that adjuvant chemotherapy may be meaningful for patients with a more advanced primary tumor by decreasing rates of distant metastases. Due to this, they strongly suggest selective use of adjuvant chemotherapy for patients with no cancer present in the lymph nodes.