“Munich, Germany: A strategy of alternately flooding and starving the body of testosterone is producing good results in patients who have metastatic prostate cancer that is resistant to treatment by chemical or surgical castration, according to new findings.
“In a presentation at the 28th EORTC-NCI-AACR Symposium on Molecular Targets and Cancer Therapeutics in Munich, Germany, today (Thursday), researchers reported that results from 47 men who have completed at least three cycles of bipolar androgen therapy (BAT) showed that the strategy was safe and effective. Prostate specific antigen (PSA) levels fell in the majority of the men, tumours shrank in some men, in several the disease did not progress and this included some whose disease continued to be stable for more than a year. One man appears to have been ‘cured’, in that his PSA levels dropped to zero after three months and have remained so for 22 cycles of treatment, with no trace of the disease remaining. The researchers are planning to treat a group of 60 men in total.”
“A new retrospective study of patient medical records suggests that men with prostate cancer who are treated with testosterone-lowering drugs are twice as likely to develop dementia within five years as prostate cancer patients whose testosterone levels are not tampered with.
“The study, by researchers at the Stanford University School of Medicine and the University of Pennsylvania Perelman School of Medicine, also demonstrates emerging techniques for extracting biomedical data from ordinary patient medical records.”
“In an analysis from the PR-7 trial reported in the Journal of Clinical Oncology, Klotz et al found that in men with prostate cancer with biochemical failure after radiotherapy with or without surgery, a nadir serum testosterone level ≤ 0.7 nmol/L during the first year of continuous androgen-deprivation therapy was predictive of improved cause-specific survival and prolonged time to hormone resistance.
“In the PR-7 trial, 1,386 patients were randomly assigned to continuous androgen-deprivation therapy (n = 696) or intermittent androgen-deprivation therapy (n = 690). Of 626 men in the continuous androgen-deprivation therapy group eligible for the current analysis, 226 developed castration-resistant prostate cancer, with a median time to diagnosis of 10.0 years; the 5-year event-free rate was 69%…
“The investigators concluded: ‘Low nadir serum testosterone (ie, < 0.7 nmol/L) within the first year of androgen-deprivation therapy correlates with improved [cause-specific survival] and duration of response to androgen deprivation in men being treated for biochemical failure undergoing [continuous androgen deprivation].’ ”
A recent study suggests that crizotinib (Xalkori) can reduce kidney function. Lung cancer patients treated with Xalkori saw their kidney function decrease by 23.9% on average. Kidney function recovered when Xalkori was discontinued. However, as patients usually have to take Xalkori for months or years, these findings still warrant caution, especially in patients taking other medications that affect kidney function or with preexisting kidney damage. In an earlier study, investigators had found that Xalkori decreased testosterone levels in 84% of male patients. Because cancer drugs like Xalkori increasingly receive accelerated approval, not all of their side effects are known by the time they are approved. Doctors therefore need to carefully monitor their patients for possible adverse effects.