For Patients & Caregivers
Bottom Line: Insulin Potentiation Therapy is not effective in treating cancer.
Insulin potentiation therapy involves administering insulin at the same time as chemotherapy drugs, with the idea that lower doses of chemo are needed because insulin lets more of the drugs enter cells. However, this has never been proven experimentally. In general, insulin should not been taken by non-diabetics because it can decrease blood sugar to dangerously low levels, causing symptoms such as headache and delirium.
For Healthcare Professionals
Insulin Potentiation Therapy (IPT) is an alternative cancer therapy that uses insulin to potentiate the effect of chemotherapy and other medications. This therapy was developed in Mexico by Dr. Donato Perez Garcia in the 1930s and has been used together with other unconventional therapies for many years (1). Advocates of IPT believe that cancer cells consume more sugar than healthy cells and are therefore more sensitive to insulin and insulin-like growth factor (IGF) (2)(7). Insulin is also believed to increase the permeability of cell membranes, increasing the intracellular concentration and cytotoxic effect of anticancer drugs (1). According to the theory underlying this therapy, if cancer cells can be activated by exogenous insulin, a reduced dose (up to one-tenth the normal dose) of a chemo drug can provide the same cytotoxic effects with less severe adverse reactions. No clinical trials have been performed to validate these claims. In addition, the pharmacokinetic profiles on concurrent use of insulin and chemo drugs are lacking and it is unclear whether the insulin also potentiates the toxic effects of chemotherapy on healthy cells.
Although proponents cite anecdotal case reports suggesting that IPT may be effective, there are no data comparing the efficacy of IPT to conventional chemotherapy. Most of the medications used, such as insulin and other chemo drugs, are approved by the FDA, but the IPT clinics administer them “off-label.” Some clinics that administer IPT are not operated or staffed by oncologists. Side effects of IPT include hypoglycemic reaction. A systematic review of 21 studies showed a correlation between circulating levels of IGF-I, IGFBP3 (IGF-binding protein) and an increased risk of common cancers (8).
IPT is a treatment strategy that utilizes the physiological activities of insulin. It is based on the theory that insulin and insulin-like growth factor (IGF) play an important role in the cell cycle. IGF has been shown to affect the proliferation, adhesion and migration of normal as well as cancerous cells (2). Certain IGF receptors are found to be overexpressed in many forms of cancer, therefore, cancer cells may be selectively more sensitive than normal cells to IGF (1)(7). IGF receptors can be activated by exogenous insulin. Insulin is also believed to increase the permeability of cell membranes, leading to the increase in intracellular concentration and cytotoxic effect of anticancer drugs. Proponents argue that insulin synergistically enhances the efficacy of anticancer drug so that a reduced dose can be used with similar cytotoxic effects (5)(6). The mechanism of IGF receptor’s role in cancer treatment appears to be more complex. At least one study has demonstrated the inhibition of IGF receptors can also increase the effects of anticancer drugs (3).