A “considerable portion” of cancer patients experience dose delays, dose reductions, and missed doses, a retrospective study of patients receiving adjuvant or neoadjuvant chemotherapy across multiple cancer settings has found.1

The study included 16 233 patients aged 18 years or older who received chemotherapy for breast cancer, ovarian cancer, non-small cell lung cancer, Hodgkin and non-Hodgkin’s lymphoma, or colorectal cancer. Patients initiated treatment at McKesson Specialty Health and US Oncology sites between January 1, 2007, and March 31, 2011.

The study found that dose delays, dose reductions, and reduced relative dose intensity (RDI) rates were “common among patients treated in community oncology practices in the United States.”

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For most tumor types, reduced RDI rates were higher in patients 65 years or older, in obese patients, and patients whose daily activities were restricted. The study suggested that in some cases, physicians may be reducing chemotherapy doses preemptively due to concerns of excessive toxicity.

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“We’re not saying that all of these dose reductions are inappropriate,” said Gary Lyman, MD, MPH, of the Hutchinson Institute for Cancer Outcomes Research, Fred Hutchinson Cancer Research Center, Seattle, WA, in an interview with Cancer Therapy Advisor.

“Clearly some are appropriate, if the patient is frail or has other medical problems that would pose an excessive risk with full doses. At the same time, we see such broad reductions in dose intensity that aren’t fully explained by the other medical issues or age to suggest that in some practices there may be excessive reductions in dose intensity.”

One area that Dr Lyman considers to be of particular concern is the frequency of dose reduction in obese and overweight patients. Previous studies have found that obese patients often receive intentionally reduced chemotherapy doses.2,3

“What this means is that often overweight and obese patients are getting under-dosed despite evidence from clinical trials and observational studies that they have poor outcomes,” said Dr Lyman, “and they have no greater risk of chemotherapy toxicity if they’re dosed based on their weight than would normal weight individuals.”