The addition of cetuximab to perioperative chemotherapy for operable colorectal liver metastases resulted in a shorter progression free survival. Details of disease progression are described to further inform the primary study outcome.
A total of 257 KRAS wild-type patients were randomised to chemotherapy alone or chemotherapy with cetuximab. Data regarding sites and treatment of progressive disease were obtained for the 109 (chemotherapy n=48, chemotherapy and cetuximab n=61) patients with progressive disease at the cut-off date for analysis of November 2012.
The liver was the most frequent site of progression (chemotherapy 67% (32/48); chemotherapy and cetuximab 66% (40/61)). A higher proportion of patients in the cetuximab group had multi-site/other sites of progressive disease (chemotherapy 8%, 4/48; chemotherapy and cetuximab 23%, 14/61 p=0.04). Further treatment for progressive disease is known for 84 patients of whom 69 received further chemotherapy, most frequently irinotecan based. Twenty two patients, 11 in each arm, received cetuximab as a further line agent.
Both the distribution of progressive disease and further treatment are as expected for such a cohort. The pattern of disease progression seen is consistent with failure of systemic micrometastatic disease control rather than failure of local disease control following liver surgery.