Bariatric surgery reduces risk of leukemia and lymphoma in obese patients

Credit University of North Carolina Rex Medical Center

CANCER DIGEST – Sept. 23, 2023 – Obese patients who underwent bariatric surgery for weight loss had a 55 percent lower risk of lymphoma and a 40 percent lower risk of other blood cancers compared to similar patients who did not undergo the surgery, a new Swedish study has found.

The drastic reduction in risk was more pronounced in women with high blood sugar at the start of the study. The study results appear in the Sept. 13, 2023 journal Lancet Healthy Longevity.

The researchers led by Magdalena Taube of the University of Gothenburg followed 2,007 obese people who underwent bariatric surgery over a 14 year period from 1987 to 2001. In addition they followed 2,040 similarly obese patients matched for age, gender, body composition, cardiovascular risk factors and psychosocial variables who did not undergo the surgery.

“The results provide further support of considering obesity a risk factor for hematological cancer,” says Taube in a press release, "and that bariatric surgery can reduce the risk of blood cancer in obese women.

Bariatric surgery is a method of surgically changing the digestive system to help a person lose weight. There are several types of bariatric surgery, the most common are gastric bypass, sleeve gastrectomy, gastric band and duodenal switch.

Gastric bypass restricts how much your stomach can hold and how much nutrition the small intestine can absorb. Gastric sleeve constricts the stomach by as much as 80 percent to limit the amount of food that can be consumed. Duodenal switch combines the bypass and sleeve procedures.

During the 14 year study, 34 patients in the surgery group developed a blood, or hematological cancer. That compared to 51 patients among the non-surgery group who came down with leukemia or lymphoma, a reduction in risk of 40 percent among the surgery group. Most of the blood cancers were lymphoma and when the researchers looked only at lymphomas the reduction in risk for the surgery group was 55 percent.

The most pronounced reduction in risk was among obese women who had high blood sugar levels before the surgery, which suggests that part of the mechanism in risk reduction may be related to blood sugar levels and suggests that blood sugar is an important risk factor in cancer development.

Other possible mechanisms of risk reduction include reducing chronic inflammation and metabolic improvements, and so-called clonal hematopoiesis, a type of genetically related risk factor for blood cancers.

Sources: University of Gothenburg press release and the journal Lancet Healthy Longevity.