Excess weight may increase the risk that a benign blood disorder will progress into cancer, according to a new study which suggests that shedding extra pounds may prevent the deadly disease.
Being overweight or obese has been known to increase the risk of multiple myeloma, a cancer of the plasma cells in the blood and bone marrow that develops more often after age 60.
Multiple myeloma is preceded by a blood disorder called monoclonal gammopathy of undetermined significance (MGUS) in which abnormal plasma cells produce many copies of an antibody protein.
This precancerous condition does not cause symptoms and often goes undiagnosed.
“But our findings show that obesity can now be defined as a risk factor for developing multiple myeloma through this condition,” said Su-Hsin Chang, assistant professor at Washington University.
“For patients diagnosed with MGUS, maintaining a healthy weight may be a way to prevent the progression to multiple myeloma, if further confirmed by clinical trials,” Chang said.
The researchers analysed data from 7,878 patients, predominately men, who were diagnosed with MGUS from October 1999 through December 2009.
Among these patients, 39.8 per cent were overweight and 33.8 per cent were obese. The researchers then tracked whether the patients developed multiple myeloma.
They found that 4.6 per cent of overweight patients and 4.3 percent of obese patients developed multiple myeloma, compared with 3.5 per cent of people at normal weight – a difference that is statistically significant.
Overweight and obese MGUS patients had a 55 per cent and 98 per cent higher risk of progression to multiple myeloma, respectively, than normal-weight MGUS patients.
MGUS is caused by elevated levels of an antibody protein, known as M protein, that is found in 3 per cent of people over age 50. By itself, MGUS is difficult to diagnose and often does not warrant treatment.
“The diagnosis is usually by accident, often driven by tests performed for the diagnosis or management of other conditions,” Chang said.
“Although our study does not directly suggest screening for MGUS, regular check-ups can help physicians monitor whether MGUS is progressing to other disorders, including multiple myeloma,” she said.
Multiple myeloma is the third most common type of blood cancer. An estimated 30,330 new cases of the cancer will be diagnosed in 2016, and 12,650 deaths will be attributed to the disease, researchers said.
“Based on our finding that being overweight or obese is a risk factor for multiple myeloma in MGUS patients, and since extra weight is a modifiable risk factor, we hope that our results will encourage intervention strategies to prevent the progression of this condition to multiple myeloma as soon as MGUS is diagnosed,” Chang said.
The study was published in the Journal of the National Cancer Institute.
