Under-representation of peritoneal metastases in published clinical trials of metastatic colorectal cancer

Cytoreduction for colorectal metastases: liver, lung, peritoneum, lymph nodes, bone, brain. When does it palliate, prolong survival, and potentially cure?

“…Spread of cancer to the peritoneal surfaces – carcinomatosis – is common and is negatively associated with survival of patients with colorectal cancer (150, 151). This process generates a lot of suffering for the patients and caregivers by causing malignant bowel obstruction, weight loss, obstructive nephropathy and symptomatic ascites.…”

“…For patients with unresectable disease confined to the peritoneal cavity, combination chemotherapy with or without targeted therapy has become the standard of care (152). However, patients with peritoneal carcinomatosis are under-represented in metastatic colorectal cancer trials leading to limitations in extrapolating data from these trials to patients with peritoneal carcinomatosis (151). Alternatively, multiple observational studies have demonstrated that incomplete cytoreduction with gross residual disease does not offer survival benefit in this setting and is not recommended (175, 176).…”

“…Alternatively, multiple observational studies have demonstrated that incomplete cytoreduction with gross residual disease does not offer survival benefit in this setting and is not recommended (175, 176). Increased purposeful representation of peritoneal carcinomatosis patients is needed in phase 3 and 4 systemic trials because these patients fare worse than those patients without peritoneal carcinomatosis (151). One explanation is the higher proportion of patients with an aggressive BRAF mutant genotype.…”

Cytoreduction and hyperthermic intraperitoneal chemotherapy in metastatic colorectal cancer

“…Therefore, drawing inferences on the effectiveness of systemic chemotherapy in this population is fraught with error. 20 In addition, symptomatology from PM may be simply due to anatomic location, and may not necessarily reflect the actual biology of the PM themselves. 5 While a known challenge in the management of these patients results from the limitation of current imaging modalities, data on modalities that may provide a better image of PM is emerging.…”

“…Due to inadequate imaging modalities, patients with PM only have been significantly underrepresented in recent major clinical trials. Therefore, drawing inferences on the effectiveness of systemic chemotherapy in this population is fraught with error . In addition, symptomatology from PM may be simply due to anatomic location, and may not necessarily reflect the actual biology of the PM themselves .…”