Paper of the Month for August is a systematic review and meta analysis of prognostic factors and their relationship with outcomes in colorectal metastasis

Meta‐analysis of prognostic factors for patients with colorectal peritoneal metastasis undergoing cytoreductive surgery and heated intraperitoneal chemotherapy
Hallam et al. BJS Open https://doi.org/10.1002/bjs5.50179


HIPEC for peritoneal cancer is a topic of interest and features at many conferences. This is a constantly developing technique and work is required to improve and refine this. One was to improve outcomes is by good information to guide patient selection.

The authors of this study undertook a systematic review and meta analysis of prognostic factors and their relationship with outcomes in colorectal metastasis. The authors found 24 studies describing outcomes from 3128 patients. They found that increasing peritoneal carcinomatosis index, incomplete cytoreduction, and complications related to the primary tumour affected outcomes (perhaps unsurprisingly).

From the clinical side, this study identified one baseline factor to help select patients (carcinomatosis index) and one related to treatment. This perhaps reinforces the importance of well performed surgery, which is technically feasible from the outset. PRior obstruction or primary perforation may make this more difficult to achieve.

Perhaps the more interesting finding in this study is the number of candidate prognostic markers that were found to be unrelated to outcomes, such as timing of metastasis, tumour differentiation, adjuvant and neoadjuvant therapy, in the supporting studies. These are mechanistically plausible factors and this could reflect Type II error arising from reporting bias in the underlying studies, and that some factors were reported in one or two of the 24 studies.

In summary, this paper gives us a couple of unsurprising candidate papers, and suggests we need to look closely reporting potential prognostic factors across all studies.