How much chemotherapy does an obese woman need? Typically an obese woman with breast cancer would receive reduced doses of chemotherapy as they battle breast cancer.

Back in June of 2005, a study published in the Archives of Internal Medicine concluded that obese women should receive chemotherapy based on their actual weight, and not in reduced as amounts as it the standard practice.

And now again a study presented in the August 2005 edition of Lancet claims that doctors should not reduce chemotherapy doses for obese women when no receptors for the hormone oestrogen have been found on the breast cancer cells. This type of cancer is called oestrogen-receptor negative.

Clinicians often reduce chemotherapy doses for obese patients because of worries about how the treatment may react with the patient and affect their overall health.

According to the studys director Marco Colleoni of the European Institute of Oncology, Italy, and his colleagues, reducing the first course of chemotherapy for obese patients with oestrogen-receptor negative breast cancer proves detrimental.

Colleoni and his team looked at the relation between body-mass index (BMI), chemotherapy dose reduction, oestrogen receptor expression, and outcome for pre-menopausal women with breast cancer by examining data from four randomized trials.

They found that 97 out of 249 obese patients received less than 85% of protocol specified dose during the first course of chemotherapy compared with patients with normal and intermediate BMI.

Obese patients with oestrogen-receptor negative disease that received 85% or more of the first protocol specified dose had significantly better disease-free survival and overall survival than those who received less than 85% of the normally recommended dosage.

Yet, obese patients with oestrogen-receptor positive breast cancer who had reduced doses of chemotherapy did not have a significant difference in their outcome compared with those given the recommended chemotherapy doses.

And contrary to popular practice, the researchers also noticed that obese patients initially treated with protocol doses of chemotherapy did not have more toxicity than patients who received reduced doses.

Dr Marco Colleoni concluded that, Our findings suggest that for women with ER-absent or ER-low tumours, reduction in chemotherapy dose should be avoided.

The message for obese women coping with cancer is to be aware of your risks and rights. Ask your doctor will she recommend lower doses of chemotherapy for you based on your weight and ask why.

Resources: Lancet, Archives of Internal Medicine