Insulin potentiation therapy (IPT) is an complementary cancer therapy that uses insulin to potentiate the effects of chemotherapy. 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) (1, 2). Insulin is also believed to increase the permeability of cell membranes, increasing the intracellular concentration and cytotoxic effect of anticancer drugs (3). According to the theory underlying this therapy, if cancer cells can be activated by exogenous insulin, a reduced dose of a chemotherapy drug can provide the same cytotoxic effects with less severe adverse reactions. Exploratory studies suggest some benefit with a combination of chemotherapy and IPT (4, 5).
In the scientific research conducted by Shan Y and his colleagues, the effect of insulin treatment on cholangiocarcinoma that did not respond to the drug 5-fluorouracil was investigated. The study showed that insulin treatment increased the killing effect of the drug 5-fluorouracil on cancer cells. As a result, it has been suggested that co-administration of chemotherapy drug and insulin may increase the response to chemotherapy and improve survival in cancer patients (6). In the in vitro study we conducted with our research team, we showed that the lethal effect of the chemotherapy drug docetaxel on breast cancer cells was significantly increased by the addition of low-dose insulin (7). Many of the medications used in IPT, such as insulin and other chemotherapy drugs, are FDA- approved. In our clinic, low-dose or standard-dose chemotherapy treatments accepted in the guidelines for cancer treatment are applied with complementary insulin potentiation.

References:
1. Leroith D, Roberts C. The insulin-like growth factor system and cancer. Cancer Lett. 2003;195(2):127-37.
2. Holdaway IM, Friesen HG. Hormone binding by human mammary carcinoma. Cancer Res. 1977;37(7 Pt 1):1946-52.
3. Ayre SG, et al. Insulin, chemotherapy, and the mechanisms of malignancy: the design and the demise of cancer. Med Hypotheses. 2000;55(4):330-4.
4. Damyanov C, Gerasimova D, Maslev I, Gavrilov V. Low-dose chemotherapy with insulin (insulin potentiation therapy) in combination with hormone therapy for treatment of castration-resistant prostate cancer. ISRN Urol. 2012;2012:140182.
5. Lasalvia-Prisco E, Cucchi S, Vázquez J, Lasalvia-Galante E, Golomar W, Gordon W. Insulin- induced enhancement of antitumoral response to methotrexate in breast cancer patients. Cancer Chemother Pharmacol. 2004 Mar;53(3):220-4.
6. Shan Y, Li Y, Han H, Jiang C, Zhang H, Hu J, Sun H, Zhu J. Insulin reverses choriocarcinoma 5- fluorouracil resistance. Bioengineered. 2021 Dec;12(1):2087-2094.
7. Aygünes D, Kara HG, Vardarlı AT, Sezgin C. The effects of docetaxel with insulin ER (+) breast cancer cells on cellular toxicity and molecular mechanism. Oral Presentation – 01. VI. International Congress of Molecular Medicine, 22 – 25 May 2017, Istanbul, Turkey.