Obesity and Chemotherapy Dosing in Patients with Cancer
Some studies have shown that up to 40% of obese patients receive lower doses of chemotherapy.
Obesity has become an epidemic in the United States and worldwide in both adults and children. Up to one-third of all adults in the United States are considered obese, which is categorized as a body mass index (BMI) of 30 kg/m2 or more.1
An additional one-third of American adults are also overweight, with a BMI between 25.0 and 29.9 kg/m2. Obesity carries numerous health risks including cardiovascular disease and diabetes.
In addition to these risks, obesity also increases the risk, recurrence, and associated mortality of many different types of cancer.
Currently, smoking has become one of the most commonly identified preventable causes of cancer, however, obesity does and will continue to rival smoking for this designation. Clinical studies have linked approximately 84,000 new cancer diagnoses per year to obesity and upwards of 20% of total cancer mortality can be associated with a BMI 25.0 kg/m2 or more.1
The common perception of what the BMI of a patient with new or established cancer is may be contributing to this overall lack of awareness.
Obesity has been linked to numerous cancers including colorectal, renal cell, thyroid, esophageal, gallbladder, liver, cervical, ovarian, post-menopausal breast, and endometrial.2,3
Of these cancers, 10% or more of liver, gallbladder, kidney, and colorectal cancer may be attributable to being overweight or obese.3
One retrospective study conducted in the United Kingdom approximated that a 1 kg/m2 increase in BMI in the entire UK population would lead to approximately 3,800 new cancer diagnoses annually in the 10 aforementioned cancers.3
RELATED: Obesity Increases Risk of Developing 10 Common Cancers
Chemotherapy can be dosed based on body surface area (BSA) or a patient's actual body weight, however certain regimens have been approved using different dosing strategies.
In addition to U.S. Food and Drug Administration–approved dosing, many chemotherapeutic agents can eventually accumulate enough off-label data to support alternate dosing regimens.
One such factor that can be easily overlooked when dosing a patient's chemotherapy is whether or not that patient is overweight or obese. Some studies have shown that up to 40% of obese patients receive lower doses.4
One potential explanation of this under-dosing is that an obese patient's actual body weight may be considered too “high” or result in calculated doses that are unfamiliar to healthcare practitioners.