High risk features of primary colorectal carcinomas which subsequently undergo peritonectomy.

OBJECTIVE

Determine what portion of colorectal cancer (CRC) patients with peritoneal metastases (PM) undergoing peritonectomy would have been identified/treated if second-look surgery protocol existed for high-risk primary tumours.

BACKGROUND

The prognosis of CRC PM greatly improves following peritonectomy/HIPEC. Survival remains dependent upon stage of PM and there is some knowledge of high-risk factors for its development. Subsequently, there is interest in routine second-look laparotomy to follow-up high-risk CRC patients so to 'prevent' PM.

METHODS

Patients were retrospectively selected from the St George database, all of whom had had PM recurrence after primary CRC resection thus underwent peritonectomy/HIPEC. Each patient's primary tumour pathology was obtained with incidence of high-risk stage (T4), macroscopic (peritoneal involvement, ovarian metastases, perforated primary) and microscopic (mucinous, signet ring) features noted.

RESULTS

125 patients were included. At primary diagnosis, 34.4%, 46.4% and 19.2% were of T3, T4a and T4b stage. Primary tumour macroscopic features included 41.1%, 12.6% and 23.7% with synchronous peritoneal involvement, perforated primary and ovarian metastases. Primary tumour microscopic features included 8.1%, 44.0% and 5.6% with signet ring, mucinous and both pathologies. Individually T4 status, macroscopic and microscopic features would have identified 65.6%, 56.8% and 46.5% of patients. Any high-risk factor would have identified 85.6%.

CONCLUSION

Our study suggests that T4 stage, high-risk macroscopic and high-risk microscopic features at time of primary diagnosis identifies the majority of CRC patients who later develop PM. This provides support for a selective second-look protocol in such patients to enable early identification and, potentially, 'prevention' of CRC PM.