Switching Patients With Prostate Cancer from GnRH Antagonist to Long-acting LHRH Agonist for Androgen Deprivation: Reducing Hospital Visits During the Coronavirus Pandemic

Impact of the COVID-19 pandemic on delivery of prostate cancer care in Australia: An interrupted time series analysis

The COVID-19 pandemic led to a major disruption to health services across the world. The aim of this population-based study was to assess the downstream effects of the pandemic on diagnostic tests and treatment activities related to prostate cancer (PC). The Australian Government Department of Health Medicare Benefits Schedule and the Pharmaceutical Benefits Scheme databases were queried from January 2010 to June 2022. Two interrupted time series were performed Pre-COVID (January 2010 to February 2020) and peri-COVID (March 2020 to June 2022). Temporal modeling was performed to account for seasonal variation. Pre-COVID-19, monthly prostate-specific antigen (PSA) testing showed a declining trend and testing decreased by 81 tests per 100 000 annually. A single-month 38% drop in PSA testing was observed in April 2020; this corresponded to Australia's first wave. No change was observed in the rate of prostate biopsies. Peri-COVID-19 outbreaks, there was a slight shift toward the use of long-acting androgen deprivation therapy (ADT) at 4% with a predilection still for short-acting agents. with no registered change in the overall volume of radiotherapy or surgery. There were no deficits in the number of diagnostic and treatment activities for men with PC. Aside from a slight shift toward long-acting ADT use during the pandemic, no other patterns were observed. The longer-term impact such as missed diagnosis or late presentation affecting chances of survival due to COVID-19 is yet to be ascertained.

Androgen Flare after LHRH Initiation Is the Side Effect That Makes Most of the Beneficial Effect When It Coincides with Radiation Therapy for Prostate Cancer

Simple Summary

Prostate cancer tumor growth is stimulated by androgens. Surgical castration or medical castration using long-acting luteinizing hormone-releasing hormone (LHRH) agonists or antagonists is the backbone of the treatments of metastatic disease. Treatment of locally advanced prostate cancer was accomplished with radiation therapy alone until multiple studies showed that combining radiation therapy with LHRH agonists results in significant survival benefit. While the goal of the use of LHRH agonists was to suppress testosterone levels during radiation, we show, through review of previous studies, that survival benefit was achieved only when LHRH was initiated during the course of radiation, and thus androgen flare during the first 1–3 weeks after the initiation of LHRH is most likely the reason for higher survival. Androgens drive tumor cells into mitosis, and mitotic death is the dominant mechanism of tumor cell kill by radiation.

Abstract

Treatment of metastatic prostate cancer was historically performed via bilateral orchiectomy to achieve castration. An alternative to surgical castration is the administration of subcutaneous recombinant luteinizing hormone-releasing hormone (LHRH). LHRH causes the pituitary gland to produce luteinizing hormone (LH), which results in synthesis and secretion of testosterone from the testicles. When LHRH levels are continuously high, the pituitary gland stops producing LH, which results in reduced testosterone production by the testicles. Long-acting formulations of LHRH were developed, and its use replaced surgical orchiectomy in the vast majority of patients. Combining LHRH and radiation therapy was shown to increase survival of prostate cancer patients with locally advanced disease. Here, we present a hypothesis, and preliminary evidence based on previous randomized controlled trials, that androgen surge during radiation, rather than its suppression, could be responsible for the enhanced prostate cancer cell kill during radiation. Starting LHRH agonist on the first day of radiation therapy, as in the EORTC 22863 study, should be the standard of care when treating locally advanced prostate cancer. We are developing formulations of short-acting LHRH agonists that induce androgen flare, without subsequent androgen deprivation, which could open the door for an era in which locally advanced prostate cancer could be cured while patients maintain potency.