Vitamin B12 and folic acid supplements are often given to mesothelioma patients who are on chemotherapy in an effort to ward off neutropenia, a dangerous drop in white blood cells that can leave patients vulnerable to infection. Neutropenia has been linked to elevated levels of an amino acid called homocysteine, and pemetrexed can raise homocysteine. While some studies have found that supplementation makes chemotherapy less toxic, a team of British doctors found the supplements had little impact on a group of mesothelioma patients who were not on pemetrexed.
Scientists at the Royal Marsden Hospital in Sutton, UK randomly assigned 83 patients with advanced lung cancer or malignant mesothelioma to receive platinum-based chemotherapy with or without B12 and folic acid supplementation. They were looking specifically for incidence of neutropenia.
The researchers found no significant difference in the incidence of serious neutropenia or deaths within 30 days among the lung cancer and mesothelioma patients, whether or not they were on the supplements. There was also no different in overall mesothelioma or lung cancer survival rates, regardless of patients’ pre-treatment homocysteine levels. In fact, only 9 out of the 36 patients (25%) given the supplements even saw a decrease in their homocysteine levels.
“The addition of vitamin B12 and folic acid to platinum-containing regimens did not overall improve the toxicity, quality of life or overall survival,” writes Dr. Mary O’Brien, one of the authors of the study. Seventy-three percent of patients in the study who were given supplements still experienced serious neutropenia. Dr. O’Brien and her colleagues say further testing is needed to improve the success of supplementation and to determine how pre-treatment homocysteine levels influence chemotherapy success in mesothelioma and lung cancer.
Chemotherapy is typically the first-line treatment for patients with malignant pleural mesothelioma, a serious cancer closely linked with asbestos exposure. While the incidence of mesothelioma has slowly begun to taper off in the U.S., it is expected to reach a peak in the UK, Australia, and several European countries in the next decade.
Minchom, AR et al, “An unblinded, randomised phase II study of platinum-based chemotherapy with vitamin B12 and folic acid supplementation in the treatment of lung cancer with plasma homocysteine blood levels as a biomarker of severe neutropenic toxicity”, December 11, 2014, BMJ Open Respiratory Research