Candidate: Metformin, a synthetic of a compound found in French lilac, is the most widely prescribed drug to control blood sugar for Type 2 diabetes.
Potential benefit: May improve the effect of chemotherapy and limit the recurrence in many different cancers including prostate and breast.
Evidence: Metformin has shown promise in animal studies when used in conjunction with chemotherapy. There is retrospective human data showing its benefit on prolonging survival and decreasing recurrence in multiple types of cancer. In 2010, the National Cancer Institute joined with the Canadian Health ServiceCancer Society and others to pay for a large clinical study of metformin in early stage breast cancer.
More info: The National Cancer Institute's drug definition. Why metformin might work isn't precisely known, but many cancer cells are believed to thrive on excess glucose, which metformin can limit. It may affect the mitochondria within cells, limiting cancer cell growth. Metformin has also demonstrated promise in killing chemotherapy-resistant cancer stem cells.
Candidate: Cimetidine is an over-the-counter heartburn drug originally created to reduce stomach acid by blocking histamine type 2 receptors.
Potential benefit: Decrease or halt tumor growth.
Evidence: Scientists have been looking at using cimetidine to treat cancer for decades. It has shown promise in cell-culture, human and animal studies, usually in conjunction with standard treatments. Patients with colorectal cancer have benefited.
More info: The National Cancer Institute's drug definition. A review of six limited trials using histamine type 2 receptor antagonists in a total of 1,229 colorectal cancer patients "revealed a statistically significant improvement in overall survival," but not enough to be conclusive.
Candidate: Nitroglycerin is a low-cost compound created to make explosives and used for more than 130 years to treat chest pains.
Potential benefit: May improve the response to chemotherapy.
Evidence: Multiple laboratory and human studies have shown that nitroglycerin, sometimes in conjunction with chemotherapy, created an improved response to different cancers, including lung and prostate cancer.
More info: The National Cancer Institute's drug definition.
Candidate: Beta blockers are a class of drugs used to treat heart conditions, such as arrhythmias and hypertension.
Potential benefit: May control the growth of a wide range of cancers, including breast, bowel, lung, melanoma and ovarian cancer.
Evidence: Multiple laboratory and epidemiological studies have shown that beta blockers may inhibit breast cancer progression and metastasis. An animal study indicated they may increase the response of chemotherapy. Another animal and retrospective human study showed they may decrease the progression of ovarian cancer. Beta blockers have also shown promise in pancreatic and lung cancer.
Candidate: Mebendazole is commonly prescribed to humans and animals to treat parasitical worms such as tapeworms or roundworms.
Potential benefit: May decrease tumor growth used in conjunction with drugs such as chemotherapy agents.
Evidence: Laboratory studies for brain cancer, adrenocortical carcinoma and other cancers have shown reduction in tumor size and numbers. Several individual case studies showed limited promise, including in a patient with metastatic adrenocortical carcinoma and another with metastatic colon cancer.
More info: The National Cancer Institute's drug definition. No clinical trial on humans for mebendazole's effect on cancer have been completed to date.
Source : http://projects.propublica.org/graphics/cancer-drug-alternatives