What factors predict early relapse in colorectal cancer patients treated for peritoneal metastases?

This study examined whether any factors can predict early relapse in colorectal cancer patients treated for peritoneal metastases. 

Peritoneal metastasis indicates that the cancer has spread to the peritoneum, the lining of the abdomen. At least 10% of patients with colorectal cancer develop peritoneal metastases during the course of their disease. The main treatment is cytoreductive surgery followed by hyperthermic intraperitoneal chemotherapy (CS/HIPEC). CS/HIPEC involves the surgical removal of all visible tumors before bathing the abdominal cavity in heated chemotherapy.

Unfortunately, the rate of cancer relapse is high even after successful CS/HIPEC treatment. Being able to predict which patients are most likely to relapse early would allow for these patients to be monitored more closely. This could allow for earlier detection of the relapse and improved patient outcome.

This study examined the medical records of 133 colorectal cancer patients who were treated with CS/HIPEC. Patients were followed-up for an average of 22.9 months. Local recurrence (relapse of the cancer in the peritoneum or abdominal wall) and systemic recurrence (relapse of the cancer in the liver, lung or other organ) were assessed for each patient. Rates of complications and patient survival were also assessed following treatment.

Overall, the cancer returned in 62% of patients. The average time before it returned was 12.4 months. 35% of patients relapsed within 1 year of treatment (early recurrence). 37% of patients with early recurrence had local recurrence, 32.6% had systemic recurrence and 30.4% had local plus systemic recurrence. Patients with early recurrence had shorter survival time than patients with late or no recurrence, an average of 19.3 months compared to 43.2 months.

The only factors found to statistically increase the risk of early recurrence were severe adverse events after treatment. Patients with severe adverse events, that required further medical treatment, had 2.3 times higher odds of having early recurrence compared to patients who did not have severe adverse events. 

The authors concluded that early recurrence after CS/HIPEC is associated with worse survival. As severe adverse events were found to be risk factors for early recurrence, the authors highlighted the need to minimize severe adverse events in order to improve patient outcome.