New research, presented at the American Society of Clinical Oncology, shows that patients who are newly diagnosed with metastatic, surgically incurable colorectal cancer do not need immediate surgery to remove their primary tumour unless the tumour is causing complications.

Surgical removal of the primary tumour at the time of diagnosis was once standard practice and is still common in patients with metastatic colorectal cancer. Because cancer has already spread to other parts of the body by this stage, the purpose of this surgery is not to extend survival, but to prevent future complications, such as intestinal blockage, perforation of the bowel, and severe bleeding. However, over the past decade several new effective chemotherapy drugs for colorectal cancer have been introduced and until now there has been little data to assess whether this pre-emptive surgery is still warranted.

"In this era of modern chemotherapy, routine surgery to remove the primary tumour in patients with unresectable metastases is no longer supported by the data," said Dr. Philip Paty, an attending surgeon and vice chairman of clinical research at Memorial Sloan-Kettering Cancer Center (MSKCC) and the study’s senior author. "In addition to being an unnecessary procedure that carries its own risks of morbidity and mortality, surgery delays the start of chemotherapy for several weeks, and in some cases may make the patient less fit for and less tolerant of chemotherapy. Unless there is an immediate need for surgery, patients should begin chemotherapy first."

This retrospective study identified 233 consecutive patients who presented with metastatic colorectal cancer between 2000 and 2006, and were treated with chemotherapy at MSKCC, but had no serious symptoms to prompt immediate surgery. The patients received one of three triple-drug chemotherapy combinations as their initial treatment (the regimens known as FOLFOX, IFL, and FOLFIRI). Some were also treated with the targeted therapy bevacizumab (Avastin).

Investigators determined that 93 per cent of patients never developed complications that required removal of their tumor. For the 7 per cent who did eventually need surgery, the vast majority (14/16) had successful operations. In addition, the mortality attributable to surgery was very low (0.8 per cent), suggesting that this approach, by avoiding unnecessary surgery, improves the overall safety of treatment.