NEW YORK (Reuters Health) – Most patients with synchronous metastatic (stage IV) colorectal cancer can forgo surgery to remove the primary tumor, at least initially, opting instead for chemotherapy only, according to research presented this week at the American Society of Clinical Oncology’s annual meeting in Orlando.

“In the absence of symptoms (bleeding, perforation, obstruction) or resectable metastatic disease, primary tumor resection in patients who present with synchronous metastatic colorectal cancer is of uncertain benefit,” the study team notes in a meeting abstract.

The current study indicates that, with modern chemotherapy, “routine surgery to remove the primary tumor in patients with unresectable metastases is no longer supported by the data,” senior author Dr. Philip B. Paty said in a prepared statement.

“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,” added Dr. Paty, an attending surgeon and vice chairman of clinical research at Memorial Sloan-Kettering Cancer Center in New York.

He and his colleagues retrospectively studied 233 consecutive patients who presented with metastatic colorectal cancer and an unresected primary tumor between 2000 and 2006. They received oxaliplatin- or irinotecan-based, triple-drug chemotherapy, with or without bevacizumab as their initial treatment. None of the patients had any serious symptoms to prompt immediate surgery.

According to the investigators, 93% of the patients (217 of 233) never needed surgery to remove the primary tumor due to the development of symptoms or complications.

For the 16 patients (7%) who did require emergent surgery for primary tumor obstruction or perforation, 14 had successful operations.

“In addition, the mortality attributable to surgery was very low (0.8%), “suggesting that this approach, by avoiding unnecessary surgery, improves the overall safety of treatment,” according to an ASCO statement.