Insulin Potentiation Therapy: A Silver Bullet Against Metastatic Prostate Cancer?

Recent years have brought increased hope for detecting and diagnosing prostate cancer (PCa) when it is in its early stages and confined to the prostate gland. At that point, treatment success rates approach 100% within five years of intervention. However, the picture is not as rosy for men found to have metastatic prostate cancer (mPCa). This means the disease has spread to nearby and remote locations, particularly the lymph system and bones.

A 2017 statistical analysis out of the National Cancer Institute/National Institutes of Health offers a rather dark picture. At the time of publication, the authors wrote:

Approximately 6% of new PCA cases present with metastatic disease, with a 5-yr survival rate of only 29%. Metastatic PCA often becomes androgen independent, which contributes to its poor prognosis. No improvement has been noted in overall or cause-specific survival for men presenting with metastatic PCA over the last 2 decades.^[i]

No cure for metastatic PCa

Initial treatment of mPCa with androgen deprivation therapy (ADT) puts the brakes on its progression and spread. However, depriving the cancer cells of the testosterone that fuels them is a temporary stopgap. As the above quote states, sooner or later the cancer outsmarts this strategy. Then it is called hormone resistant mPCa, and chemotherapy is the next line of defense.

Chemotherapy prolongs survival, but the side effects can be harsh. Much research goes into ways to boost the effectiveness of chemotherapy while reducing the impact of side effects. For example, there have been studies of alternating lower doses of chemotherapy with “off” periods, an approach that lessens side effects but does not improve survival rates.^[ii] Thus, mPCa continues to be incurable.

Insulin potentiation therapy (IPT)

Naturally, patients with hormone resistant mPCa hope that a “silver bullet” will soon be discovered to improve survival and quality of life—best yet, to cure their disease. Thus, in the late 1980s word began to spread of a novel addition to conventional chemotherapy that had been developed in Mexico. In fact, a patient of mine recently brought it to my attention even though it is not intended as a treatment for localized low risk PCa. It is called insulin potentiation therapy (IPT) and it involves using IV insulin in combination with lower doses of chemotherapy in order to reduce side effects. Following the injection of insulin and chemotherapy drug(s), an infusion of a sugar solution is necessary to keep the patient from going into a coma, since the insulin rapidly drops a normal blood sugar level to a risky point.

Use of the hormone insulin as a pharmaceutical agent was originally developed to manage diabetes by lowering blood sugar, which it does quite well. Some laboratory experiments exposing cancer cells to insulin suggested that it could also make cancer cells more susceptible to chemotherapy, though the mechanisms are still not completely understood.^[iii] This gave rise to the theory that integrating insulin use with chemotherapy would boost its effectiveness while lowering side effects.

In fact, there have been numerous small clinical trials with patients. Sadly, there is no conclusive evidence that the claims made by its proponents are valid. In fact, Survival seems more likely to be shorter. One study with mPCa patients found that those on standard chemotherapy alone survived on average for 18.9 months while those on the IPT protocol had average survival of only 11 months.^[iv]

In 2013, medical researcher/adviser Dr. Robert Baratz published a summary of IPT claims in which he debunks the theories behind it, and summarizes disciplinary action that has been taken against doctor who provide it. He sternly warns,

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. It is claimed to be effective against cancer, infectious diseases, arthritis, and many other conditions. Several patents have been issued, but patents are based on whether or not something appears to be original. Proof of effectiveness is not required.

After having learning more about it for myself, I feel responsible to alert patients to the inadvisability of seeking out this treatment. Not only is it not a hoped-for silver bullet, it has the potential to actually shorten survival by using less effect doses of chemotherapy. Thankfully, the research into immunotherapy and genomically targeted treatments offers true promise for one day conquering mPCa. Meanwhile, I want to emphasize the importance of screening and early detection, and the diagnostic power of real-time multiparametric MRI for targeting biopsies into suspicious areas. The best way to manage mPCa is to not get it at all!

NOTE: This content is solely for purposes of information and does not substitute for diagnostic or medical advice. Talk to your doctor if you are experiencing pelvic pain, or have any other health concerns or questions of a personal medical nature.

References

[i] Kelly SP, Anderson WF, Rosenberg PS, Cook MB. Past, Current, and Future Incidence Rates and Burden of Metastatic Prostate Cancer in the United States. Eur Urol Focus. 2018 Jan;4(1):121-127.
[ii] Kerbel RS, Klement G, Pritchard K, Kamen B. Continuous low-dose anti-angiogenic/metronomic chemotherapy: from the research laboratory into the oncology clinic. Annals of Oncology. 2002;13(1):12–15.
[iii] 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. 
[iv] Sissung, Tristan M; Schmidt, Keith T; Figg, William D (February 2019). “Insulin potentiation therapy for cancer?” The Lancet Oncology. 20 (2): 191–192.