OK, I confess—I am a television addict—always have been and always will be. And one of my favorite shows is “Law & Order.” In 1994, one of its episodes concerned a woman who was administered laetrile by a quack doctor in order to avoid undergoing a mastectomy for management of her operable breast cancer. The unfortunate outcome was that she succumbed to cyanide poisoning, one of the toxicities of laetrile; our hero, Assistant District Attorney Jack McCoy, prosecuted the quack doctor for manslaughter and the result is obvious.
Laetrile is a derivative of bitter almonds, but can also be isolated from various fruits, such as apricots, and was actually utilized as an herbal treatment for sundry illnesses, including cancer, going back centuries. In the 20th century, it was patented in 1952 as Laetrile and became the most widely used unorthodox therapy for cancer ever. Despite the complete absence of scientific evidence showing any benefit, it was made legal in 24 states for use for this purpose.
Hydrogen cyanide is a product of the decomposition of laetrile. The most popular theory for laetrile’s anti-tumor effect is that cancer cells contain more enzymes than normal cells that metabolize the chemical in a way that enhances the release of the cyanide and thus render the tumor cells more susceptible to its poisoning. Actually, the usual laetrile tablet already contains some cyanide, and, therefore, this is its main toxicity.
There was widespread support and advocacy for the use of laetrile for cancer treatment after it became available. Proponents believed there was a conspiracy by the medical establishment to block its use. It is estimated that between 50,000 and 100,000 cancer patients received laetrile treatments, which were highly remunerative to the doctors or others who provided them to desperate patients. It was famously used by Steve McQueen for his pleural mesothelioma in the year prior to his death in 1980. It should be borne in mind that we are discussing an era in the 1960s-1970s when legitimate effective cancer treatments were rather scarce. Editorials in 1976 by the editor of the New England Journal of Medicine and by George Crile, a prominent surgeon at the Cleveland Clinic, advocated placing laetrile on the open market. Apparently, they felt it would lose popularity once it was freely available. In contrast, others were ethically opposed to any clinical trials of laetrile because of the total absence of any evidence that it had efficacy—they felt there was no justification for a trial. Around this time, the head of public affairs for Memorial Sloan Kettering announced at a press conference that results showing a benefit for laetrile were being suppressed by Memorial—he was promptly fired.
Into this controversy stepped Charles Moertel, an advocate of clinical trials as a means of demonstrating conclusively if there were any benefit to the drug. An editorial he published in 1978 in the New England Journal lobbied for such a study, which was ultimately conducted by Moertel and his colleagues. They recruited, prior to May 1981, 178 patients with cancers for which no standard treatment was known. They were selected to be in good physical condition at study entry and ambulatory, and to have measurable disease. Each was given the standard doses of laetrile along with a “metabolic therapy,” which included high doses of various vitamins and minerals, which was a standard part of laetrile therapy at that time. The largest group of patients were colorectal, but also included lung, breast, melanoma, sarcoma, pancreas, stomach cancer and others.
Three patients were judged unable to be evaluated. The median survival for the 175 evaluable patients was 4.8 months from the start of therapy. Survival for each tumor site was considered to be consistent with the survival generally observed for patients with that tumor. Only one patient met the criteria for a partial response. He had a gastric carcinoma metastatic to cervical lymph nodes and was judged to have a partial remission after 10 weeks of treatment. This remission persisted for 10 more weeks at which time the disease progressed—he died 37 weeks after initiation of therapy.
This study was published in 1982 in the New England Journal of Medicine and provided clear-cut evidence of a lack of benefit under controlled circumstances of laetrile therapy for the treatment of cancer. It ultimately led to the outlawing of the drug. However, it must be acknowledged that extensive promotion of laetrile continued, and many patients went abroad to clinics in Mexico or elsewhere to be treated with it.
Alfred I. Neugut, MD, PhD, is a medical oncologist and cancer epidemiologist at Columbia University Irving Medical Center/New York Presbyterian and Mailman School of Public Health in New York. Email: [email protected].
This article is for educational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment, and does not constitute medical or other professional advice. Always seek the advice of your qualified health provider with any questions you may have regarding a medical condition or treatment.
