Encouraging Results For Folic Acid As A Cancer Prevention Drug

15/06/06 Folic acid supplements may prevent cancer progression and promote regression of disease, according to a new study. Published in the July 15, 2006 issue of CANCER, a peer-reviewed journal of the American Cancer Society, the small study found that 31 of 43 patients with the precancerous laryngeal lesion called leucoplakia demonstrated 50 percent or greater reduction in the lesion size after six months of taking folate supplements. In 12 of 31 responders, there was no evidence of the original lesion. Folate levels in the patients' blood also increased significantly from baseline while homocysteine levels decreased significantly. This study provides data to support the hypothesis that folate insufficiency is a risk factor for cancer progression.

Folate deficiency is the most common vitamin deficiency in the United States. Folate is a naturally occurring B vitamin (B-9) found abundantly in fresh vegetables and fruits. Folic acid is its more stable synthetic form found in dietary supplements and fortified foods. At the biochemical level, folate is incorporated into coenzymes that are essential in facilitating a variety of reactions in nucleic acid and amino acids metabolism. Some of which are critical to healthy life, such as DNA synthesis, DNA repair, and converting homocysteine to methionine. The latter is particularly important because excess homocysteine is linked to chronic health problems, such as cancer and cardiovascular disease.

Animal and human studies have increasingly demonstrated associations between folate deficiency, serum homocysteine elevations, and a variety of cancers. Some studies have suggested folate supplementation or at least a high folate dietary intake may protect against some cancers. This body of evidence suggests folate to be an effective chemopreventive drug. Other chemopreventive drugs are being tested, and while the retinoids demonstrate the most promise, they are highly toxic. Giovanni Almadori, M.D. of the Institute of Otolaryngology, Università Cattolica del Sacro Cuore, Policlinico A. Gemelli in Rome, Italy and colleagues investigated the efficacy of folic acid dietary supplementation to treat precancerous lesion and prevent cancer.

The investigators enrolled 43 patients with untreated laryngeal leucoplakia and treated them with folic acid (5mg three times a day) and evaluated the progression of leucoplakia every 30 days for six months.

Over six months of treatment, 12 patients (28 percent) had complete resolution of their leucoplakia lesions; 19 patients (44 percent) had reduction of 50 percent or more in the size of their lesions and 12 patients (28 percent) had no response. Mean folate levels increased and mean homocysteine levels decreased significantly. There were no moderate or severe adverse events reported.

Comparison to another promising chemopreventive drug regimen that includes a retinoid, "our complete response rate is lower than the one reported in a smaller population," the authors write. Nevertheless, folate "is characterized by a lower grade of toxicity," and there was no progression of disease.

These results suggest, according to the researchers, "folate supplementation, alone or in combination with other chemopreventive drugs, could effectively reduce the risk of progression in an already genetically altered mucosa, especially in patients with hypofolatemia."