Men who are receiving androgen deprivation therapies (ADT) for prostate cancer appear to be less likely to catch Covid-19 than those not on ADT. The observation could help explain why men are twice as likely to die of the virus as women. Although in theory it opens up a possible form of protection, it also faces a potential obstacle in public acceptance.
More men die of Covid-19 than women, although infection rates are more even. Several theories have been proposed as to why this might be and Professor Andrea Alimonti of the Università della Svizzera Italiana (confusingly located in Switzerland) found a way to home in on the cause.
Prostate cancer is frequently treated with ADT, which prevents testosterone production or blocks its binding to receptors, as the cancers thrive on male hormones and starve without. If these hormones (known as androgens) are the problem, suppressing them with ADT might save lives.
In the Annals of Oncology, Prof. Alimonti provides evidence in favor of the idea.
Alimonti reports cancer, including prostate cancer, was a risk factor for being diagnosed with Covid-19 in Italy's hard-hit Vento region. Whether this was because the cancer lowers defenses, or if existing patients were just more likely to be tested is unclear.
Either way, men with cancer were 1.8 times as likely to be diagnosed with Covid-19 as men without. But this reversed for men on ADT.
Among men with prostate cancer not on ADT, the infection rate was 0.31 percent during the period Alimonti studied, slightly less than the proportion for other cancers. For the more than 5,000 men on ADT the rate was a quarter that.
Without a randomized trial, it's possible there's some other difference between the men on ADT and those who aren't that accounts for the difference, but it's not obvious what this might be. Moreover, a sixth of cancer patients, prostate cancer included, who got Covid-19 died, but all those on ADT survived, although a sample of four is not statistically significant.
“We... have found that those being treated with ADT for prostate cancer are protected, even though all patients with cancer have a greater risk of Covid-19 infection than non-cancer patients,” Alimonti said in a statement.
Men with severe Covid-19 symptoms, like those with aggressive prostate cancer, might be willing to try just about anything in the hope of survival, but Alimonti also suggests something more radical. In addition to giving temporary ADT to men infected with the coronavirus, he proposes those at greatest risk of catching the virus use ADT until the danger has passed. Although Alimonti assures us testosterone levels return to normal once a patient goes off ADT, this could be a hard sell, considering the most common form of ADT is also known as chemical castration.