Insulin potentiation therapy

Insulin potentiation therapy (IPT) is an unproven alternative cancer treatment using insulin as an adjunct to low-dose chemotherapy. It was promoted by a paper in the controversial and non-peer reviewed journal "Medical Hypotheses".
According to Quackwatch, "Insulin Potentiation Therapy (IPT) is one of several unproven, dangerous treatments that is promoted by a small group of practitioners without trustworthy evidence that it works."
History.
It was developed by Donato Perez Garcia, MD in 1930. Originally, Garcia targeted syphilis, and later tried the treatment for chronic degenerative diseases and some types of cancer.
Method.
Generally, a dose of insulin is injected into a vein, followed by a low dose of chemotherapy drugs when the insulin has been absorbed. The chemotherapy dose is usually 10% to 25% of the proven dose. Then sugar water is injected to stop the hypoglycemia (low blood sugar) caused by the insulin injection.
Efficacy.
IPT has not been proven to work. Long-term outcomes, such as survival, have never been published. Four individual case studies, one small, uncontrolled clinical trial and one small prospective, randomized controlled trial have shown temporary reductions in the size of tumors for some patients.
Adverse effects.
The immediate risk is hypoglycemia.
The use of lower than normal doses of chemotherapy can cause drug resistance, which could make future treatment at standard, proven doses ineffective. For some cancers, especially breast and colon cancers, insulin may promote tumor growth.
Mechanism of action.
Two main ideas about how it might work have been proposed. The first idea is that insulin makes cells more permeable, so that the chemotherapy drugs are absorbed faster into cells. The other idea is that insulin might cause the cells to start dividing, which makes them more susceptible to destruction of many cytotoxic chemotherapy drugs.
Cost.
Costs run up to US$2,000 per treatment session. Multiple sessions are normal. Patients often pay the full cost out of pocket, because it is an unproven therapy that is not covered by health insurance.