Can removal of the primary tumor improve survival outcomes in stage IV colorectal cancer?

The aim of this study was to evaluate the impact of primary tumor removal and lymph node dissection on disease outcome in metastatic colorectal cancer. 

Approximately 15-20% of patients with colorectal cancer are diagnosed with distant metastasis (spread of the cancer) despite widespread screening. While in some cases resection (surgical removal) of the cancer can be effective, a treatment for unresectable tumors remains to be found.

In incurable cancer, palliative surgery of the primary tumor may still be performed in an attempt to improve the patient’s quality of life by relieving pain or discomfort. In patients who undergo surgery to cure cancer, the extent of the surgery (including lymph node dissection) is suggested to affect the disease outcome in patients. However, this association is less clear in patients who undergo palliative surgery.

This study aimed to evaluate the prognostic impact (impact on the outcome of the disease) of primary tumor resection and the extent of lymph node dissection in patients with metastatic colorectal cancer.

The records of 1,982 patients with stage IV unresectable metastatic lesions were evaluated in this study.  The primary colorectal tumor was palliatively resected in 1,782 patients and was not resected in 200 patients. The average follow-up was 13.3 months. 1,619 deaths were observed.

Patients that underwent primary tumor resection had a significantly greater overall survival than those who did not. Primary tumor resection was associated with an average overall survival of 13.8 months compared to 6.3 months where no resection was undertaken. Compared to those who did not undertake resection, patients who underwent resection had a 59% decrease in the risk of death during the study follow-up.

Compared to those without lymph node metastasis (spread of cancer to the lymph nodes), those with lymph node metastasis had a 22% increased risk of death during the study follow-up. D3 lymph node dissection involves surgical removal of lymph nodes surrounding the major and minor arteries that supply blood to a tumor. Patients who underwent D3 lymph node dissection had a significantly greater overall survival than those who did not. D3 lymph node dissection was associated with an average overall survival of 17.2 months, compared to 13.7 months following less extensive surgery.

The authors suggest that primary tumor resection with D3 lymph node dissection may improve survival in patients with metastatic colorectal cancer.