Researchers from the Johns Hopkins Kimmel Cancer Center have found that breast cancer survivors are likelier to gain weight than their counterparts who have never had the disease.
In a study published in the journal Cancer Epidemiology, Biomarkers & Prevention, the researchers pointed out that they discovered that survivors of breast cancer with a history of the disease in the family, including carriers of the gene mutations BRCA1 and BRCA2, gained at least 11 pounds within four years, most especially when they are receiving chemotherapy treatment.
Gaining weight is problematic because not only does it increase risks of developing cardiovascular disease but it also ups the likelihood of cancer returning, as suggested by earlier studies.
The researchers went over baseline and follow-up questionnaires completed by 303 survivors of breast cancer as well as 307 cancer-free women from 2005 to 2013; the follow-up questionnaires were accomplished four years after the baseline questionnaires were administered. All the subjects were part of a long-term study at the Kimmel Cancer Center and had histories of ovarian or breast cancer in the family. About 25 percent of them were pre-menopausal.
Within a four-year period, the breast cancer survivors group gained an average of 3.6 pounds more than the cancer-free group. Out of the 180 survivors that experienced a relapse in the last five years of the study, 21 percent put on a minimum of 11 pounds, which only 11 percent of the cancer-free group did.
According to Kala Visvanathan, an epidemiology associate professor from the Johns Hopkins, their findings suggest that chemotherapy is a contributing factor to why breast cancer survivors are gaining weight. Survivors who complete their treatment with chemotherapy within a five-year period during the study were 2.1 times likelier to gain at least 11 pounds of weight compared to women who don't have the disease.
Other researchers suggest that chemotherapy promotes weight gain because it increases insulin resistance and inflammation levels, interfering with metabolic processes. At the same time, patients who underwent chemotherapy may also be engaging in less physical activity, making them prone to gain weight.
"We're [also] looking at biomarkers in urine and blood in our survivors and in women who are cancer-free to look for the biochemical changes that may be related to this higher weight gain," added Visvanathan.
For the study, the researchers controlled for factors like level of physical activity, the presence of BRCA genes, menopausal status, weight at the beginning of the study and age. They intend to follow up on the study's subjects every three to four years to see how long weight changes will persist.
Weight gain intervention is not yet recommended for those undergoing chemotherapy but oncologists are urged to monitor the weight of their patients.
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