Chemotherapy may benefit metastatic colon cancer patients

NEW YORK (Reuters Health) - Metastatic colon cancer patients with lower performance status (PS2) show similar benefits from combination chemotherapy as do patients with higher performance status (PS0 to PS1), according to a report in the March 2nd Journal of Clinical Oncology.

"Carefully chosen patients with poor performance status are able to tolerate and do receive benefit from combination chemotherapy for advanced colon cancer, and thus should be considered for such treatment," Dr. Daniel J. Sargent from Mayo Clinic, Rochester, Minnesota, told Reuters Health.

Dr. Sargent and colleagues performed a pooled analysis of clinical trials using fluorouracil-based chemotherapy in conjunction with irinotecan or oxaliplatin for 6286 patients with advanced colorectal cancer in an effort to assess the risks and benefits of chemotherapy in PS2 patients (n=509).

Although PS2 patients had significantly shorter median progression-free survival (progression-free survival) and median overall survival (overall survival) than did PS0 to PS1 patients, the authors report, both groups experienced significant benefits from experimental treatment, compared to control treatment.

Response rates were approximately doubled in both PS0 to PS1 and PS2 patients assigned to experimental treatment.

Similarly, combination chemotherapy provided progression-free survival, overall survival, and response rates superior to those provided by monotherapy in both PS0 to PS1 and PS2 patient groups.

Severe nausea and vomiting were significantly more common in PS2 patients, the researchers note, but the rates of stomatitis, diarrhea, and neutropenia did not differ by performance status.

Just over half the deaths among PS2 patients in the first 60 days were preceded by disease progression, the investigators say, "suggesting that the difference in 60-day all-cause mortality is likely a result of more aggressive disease in PS2 patients, other comorbid disease beyond the patients' malignancy, and potential toxic effects of therapy."

"We had a fear that the PS2 patients would not be able to tolerate the combination therapy as well as the PS0 to PS1 patients, and therefore may not receive the same benefit," Dr. Sargent explained. "However, to the extent that the patient's disease was the factor causing the patient's poor progression-free survival, then these patients should receive benefit, and perhaps even greater benefit, than patients with less debilitating disease."

"Based on our data we feel strongly that we need to include PS2 patients in cancer trials," Dr. Sargent said. "Many recent trials have included only PS0 and PS1 patients, which precludes our ability to gain the critical data that we need to decide whether new treatments benefit this population."

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