Peritoneal metastases from colorectal cancer in the absence of lymph node metastases show a high survival rate despite unfavorable prognostic indicators.

BACKGROUND

Patients with colorectal cancer die as a result of metastases to liver, lymph nodes or the peritoneal surfaces. The primary is almost always controlled by colon or rectal cancer resection.

METHODS

Consecutive patients with isolated metastases to peritoneal surfaces (no lymph node, liver or systemic metastases) were referred to the Washington Cancer Institute from all over the United States and abroad. The study of this particular group of patients was to determine the impact of clinical and histologic features on overall survival. These variables were collected from the primary colorectal cancer resection performed at the referring institute and from the cytoreductive surgery (CRS) performed at the Washington Hospital Center. The data was prospectively accumulated and retrospectively analyzed.

RESULTS

Thirty-one consecutive patients had a complete cytoreduction. This restricted cohort of patients was studied in an attempt to eliminate confounding variables. The median age was 47 years (range 19-80). There were 14 (45%) males. The median overall survival following CRS was 67.9 months with a 5-year and 10-year survival of 51.9% and 43.6%, respectively. None of the clinical or histologic features, including peritoneal cancer index (PCI) and presence of signet ring cells, significantly predicted survival except for carbohydrate antigen 19-9 (CA19-9) (p = 0.0033). None of the involved abdominopelvic regions predicted a guarded outcome.

CONCLUSIONS

In this restricted group of lymph node negative colorectal PM patients with a complete cytoreduction, a high PCI or the presence of signet ring cells should not exclude patients from CRS and perioperative chemotherapy.