Prostate cancer news reports: Wednesday, September 23, 2009

Today’s news reports cover items on:

  • Extent and number of biopsy cores and eligibility for active surveillance
  • Intermittent vs. complete androgen deprivation
  • Hormone therapy and risk for cardiovascular disease and death
  • Surrogate markets for disease progression in men with CRPC

Ploussard et al. have studied the role of biopsy core number in evaluation of whether patients are appropriate for inclusion on active surveillance (AS) protocols. Their study included 411 men, all of whom underwent a 21-core biopsy with cores mapped by location and who acted as controls of themselves for the analysis of biopsy core number (based on 6-, 12- and 21-core schemes). Radical prostatectomy was subsequently performed in 297/411 men (72 percent). They found that the percentage of patients actually eligible for AS ranged from 22.5 to 35.4 percent based on AS protocol criteria. In men who fulfilled AS criteria only in a 12-core strategy, tumor length and percentage of cancer involvement on biopsy were significantly greater than in those who fulfilled AS criteria in a 21-core scheme. The rate of unfavorable disease on RP specimens was also higher in the 12-core group (from 28.6 to 35.9 percent relative to AS criteria). They conclude (somewhat unsurprisingly) that men eligible for AS based on a 21-core strategy have cancers with a lower extent of disease on biopsies and a lower risk of unfavorable disease on RP specimens regardless of how AS criteria are defined, compared with men eligible in a 12-core scheme. However, it would not be appropriate, based on these data, to state that every man needed a 21-core biopsy before being included on an AS protocol. Such a conclusion would require 15 to 20 years of follow-up of the patients involved in this study!

Abrahamsson has published a systematic review of the literature on the potential benefits of intermittent androgen suppression therapy in the treatment of prostate cancer. Based on the published literature, he concludes that intermittent therapy seems to be as effective as combined androgen deprivation, while showing greater tolerability and other quality of life advantages, especially recovery of sexual potency. However, he also notes that there are insufficient data to determine whether intermittent therapy can either prevent or reverse the long-term complications associated with androgen deprivation.

According to HealthDay, a report at the ongoing ECCO/ESMO meeting in Europe has stated that hormonal therapy for prostate cancer was associated with a 26 percent increase in risk of death from heart failure, and a 5 percent increase in risk of fatal arrhythmia, based on data from a 3-year study of 30,000+ Swedish patients with prostate cancer who got hormone therapy between 1997 and 2006. According to the lead author, “the lowest increase in risk for ischemic heart disease, heart attack and heart failure was seen in the group taking anti-androgen therapy, and we saw no increase in risk of death from heart disease in this group. Patients on [LHRH] agonist therapy had the highest risk of these problems.” These data correlate closely with other data suggesting an increased risk of death from cardiovascular problems linked to the use of hormone therapy. The impact of hormone therapy on cardiovascular risk is not new information. The “New” Prostate Cancer InfoLink believes that the widespread use of early hormone therapy in men with low PSA levels may not be in the best interests of the majority of these patients.

Armstrong and Febbo have reviewed available data on the role of surrogate markers in the attempt to predict clinical benefit in men with castration-resistant prostate cancer (CRPC). They discuss such markers as changes in PSA level, circulating tumor cells (CTCs), bone scan alterations, markers of bone metabolism, pain improvements, and progression-free survival. However, they conclude that because there are no validated surrogate markers of overall survival for assessing early clinical benefit from systemic therapy in metastatic CRPC, incorporation of relevant biomarkers into all phases of clinical development is essential to accelerate drug development in this field. They also note that men with CRPC should generally be encouraged to participate in clinical trials of investigational drugs whenever appropriate.

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