Originally published 9/29/2016
Immunotherapy in prostate cancer (PCa) “has not yet given the revolutionary results it has in other types of tumors.” So write Maselli, et al. in their 2023 paper published in Current Oncology.[i]
They present a genomic analysis of the tumor microenvironment factors that make PCa resistant to immunotherapy. They also identify genetic regulators of a patient’s immune system, and ways in which an individual patient’s deficiencies in one or more genes allow PCa tumor cells to thrive. Most importantly, they summarize numerous relevant clinical trials of checkpoint inhibitors, cell therapies, antibodies, cancer vaccines, and combination therapies (e.g., ablation + checkpoint inhibitors).
Their extensive article goes into biological detail at the cellular and molecular levels. They conclude that protocols that have succeeded with other cancer types have been disappointing with PCa, which is termed a “cold tumor.”
However, there is new hope for experimental combination therapies that aim to “transform the PCa TME from ‘cold’ to ‘hot’ in order to improve strategy and rewrite the treatment of PCa.”
The challenge to overcome cancer has been around as long as the human race has known about cancer. An Egyptian papyrus from 1600 B.C. identifies cancer and describes removal of a breast tumor by cauterizing (burning) it. The writer notes that there is no known cure for cancer.[ii] In modern times, the three main methods of battling cancer have been surgery, radiation, and chemotherapy. Each of these is an attack from outside the body.
Now a new approach attempts to activate or boost the body’s own defense system to beat cancer from within. Because this is so promising, huge investments are being poured into research. There are several categories[iii] of immunotherapy that are currently in clinical trials:
- Checkpoint inhibitors are intravenous (IV) drugs that block the ability of cancer cells to put the brakes on the immune system. By “aborting” the cancer’s “mission”, the action of the drug allows the killer T-cells to proceed with their work of attacking and destroying tumor cells. There are checkpoint inhibitors available for certain cancers: melanoma, lung, and others. They are not equally effective for every patient.
- Cell therapy uses a patient’s own immune cells that are harvested from the patient, genetically manipulated and multiplied in the lab, and returned to the patient’s body. This approach tailors the treatment to each unique patient.
- Bispecific antibodies are proteins that can attach to both a T-cell and a cancer cell, bringing them into close enough contact for the T-cell to do its job.
- We all had vaccines in childhood in which an inactive form of an illness such as measles is injected as a way to prompt the immune system to prevent us from getting the illness, and this is called inoculation. Cancer vaccines, on the other hand, help the body go after a cancer that already exists in the patient. Prostate cancer is the first type of cancer to have an FDA-approved vaccine, Provenge®, which is available for patients with metastatic disease. In clinical trials testing Provenge vs. a placebo, patients receiving the vaccine added months to their survival.
Unlike chemotherapy, immunotherapy does not have the kind of side effects caused by the toxic chemicals that harm healthy cells as well as cancer. With immunotherapy, some patients do have an autoimmune reaction in which the immune system “goes overboard”. This can include inflammation and other problems, but these can often be managed with steroids. However, the positive results can be dramatic, and therein lies the promise of immunotherapy. In particular, the checkpoint inhibitors have inspired hope for thousands of patients, and the growing number clinical trials involving experimental combinations of existing drugs, and brand new drugs, give occasion for great optimism.
On the other hand, none of today’s immunotherapies has proven curative, and for those patient whose cancer goes into remission, relapse is likely to occur within a year to five years. This is disappointing, to be sure, but much gratitude is due to the patients whose experience and clinical records illuminate future directions. The New York Times carried the personal account of one patient’s journey with Hodgkin’s lymphoma, with its powerful ups and downs, and his amazing courage in the midst of it[iv]. See the full article at http://www.nytimes.com/2016/08/01/health/immunotherapy-offers-hope-to-a-cancer-patient-but-no-certainty.html?partner=IFTTT&_r=1. As his story shows, immunotherapy is very much a work in progress, and yet every step makes the journey worth it. For information on clinical trials, visit https://clinicaltrials.gov/.
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] Maselli FM, Giuliani F, Laface C, Perrone M et al. Immunotherapy in Prostate Cancer: State of Art and New Therapeutic Perspectives. Curr Oncol. 2023 Jun 13;30(6):5769-5794.
[ii] https://en.wikipedia.org/wiki/History_of_cancer
[iii] http://www.nytimes.com/2016/07/31/health/what-is-immunotherapy-cancer-treatment.html
[iv] Matt Ricthel. “Immunotherapy Offers Hope to a Cancer Patient, but No Certainty.” New York Times, July 31, 2016. http://www.nytimes.com/2016/08/01/health/immunotherapy-offers-hope-to-a-cancer-patient-but-no certainty.html?partner=IFTTT&_r=1
About Dr. Dan Sperling
Dan Sperling, MD, DABR, is a board certified radiologist who is globally recognized as a leader in multiparametric MRI for the detection and diagnosis of a range of disease conditions. As Medical Director of the Sperling Prostate Center, Sperling Medical Group and Sperling Neurosurgery Associates, he and his team are on the leading edge of significant change in medical practice. He is the co-author of the new patient book Redefining Prostate Cancer, and is a contributing author on over 25 published studies. For more information, contact the Sperling Prostate Center.
