Bacille Calmette-Guerin (BCG)Therapy

Bacille Calmette-Guerin (BCG) is an immunotherapy that uses a weakened form of bacteria and has been shown effective in treating different forms of cancer. The bacterium used in BCG therapy is mycobacteria, first isolated by French immunologist Albert Calmette in 1908, which were used to create a tuberculosis vaccine. BCG is made from the strain of tuberculosis bacteria found in cows.

In BCG therapy, avirulent (non-disease causing) microorganisms are injected into the body and help strengthen the body’s immune response to foreign substances. The body’s natural defenses, such as white blood cells, lymphocytes and T cells attack the foreign substance.

In the treatment of cancer, BCG is used to help the body’s defenses attack cancer cells. BCG is particularly known for its effectiveness as a treatment for bladder cancer. Researchers applied this experimental therapy to mesothelioma patients and were encouraged by the positive results.

Though BCG therapy is not considered a cure, studies have shown that immunotherapy like BCG can improve the quality of life in patients in all stages of mesothelioma.

Want to learn more about immunotherapy and other mesothelioma treatment options? The Mesothelioma Center’s free information packet has information on all types of treatment options.

BCG Therapy and Mesothelioma

BCG is approved for treating bladder cancer and as a vaccine for tuberculosis. In the 1970s and ‘80s, studies were conducted on its usefulness as a treatment for mesothelioma and pleural effusions. In one study, BCG was injected into mesothelioma patients and repeated monthly. The injections prevented reaccumulation of fluid in the lung cavity.

Another study involved 30 patients with various stages of malignant pleural mesothelioma. Patients first underwent a thoracotomy in which as much of the cancerous tissue as possible was removed. Following chemotherapy or radiation, BCG injections were administered every three weeks. After six weeks, the treatment interval was lengthened to four, five and then six weeks.

Twenty-eight out of 30 patients continued to receive injections and they reported that the injections made them feel much better and that pain was significantly reduced. The researchers noted that the best prognosis was achieved when BCG was used in patients with a relatively light tumor load who had undergone thoracotomy. Average survival time was 21.5 months.

In a study conducted on rats, BCG injected directly into the pleural space actually suppressed the growth of tumors and extended the life of the test subject.

The common side effects of BCG treatment include mild flu-like symptoms and the development of a small ulcer at the injection site, which usually heals in a few weeks.

While BCG showed early promise in the 1970s and ‘80s, it is not currently being offered as a treatment for mesothelioma. However, current immunotherapy studies have been conducted with other forms of mycobacterium, including SRL 172, which has been shown to improve quality of life in patients with mesothelioma and non-small-cell lung cancer.