The drug Prazosin is sometimes used to manage lower urinary tract symptoms (LUTS) experienced by men receiving radiotherapy for localized prostate cancer. There is evidence that some alpha1-adrenoceptor antagonists such as Prazosin reduce prostate cancer incidence and increase apoptosis in the prostate.
The potential dual LUTS and anti-cancer actions of these antagonists may be beneficial in men treated with radiotherapy for localized prostate cancer. Exploring the premise that alpha1-adrenoceptor antagonists could have an anti-cancer effect, a study using Prazosin and the antagonist Tamsulosin was undertaken to see if these drugs would affect the time to biochemical relapse and influence recurrence in men with prostate who have received radiotherapy as part of their treatment regimen.
The study was a retrospective evaluation of data from 303 men with confirmed prostate cancer who received radiotherapy between 1998 and 2017. One hundred and forty-seven (147) men received Prazosin, and seventy-two (72) had Tamsulosin, while eighty-four (84) men did not receive either of these drugs. Baseline demographic characteristics including age at diagnosis, Gleason score, tumor staging, and any treatment modalities were collected. PSA values were recorded periodically from diagnosis up to 120 months (10 years) if available.
Two primary outcomes were evaluated, including relapse rates (%) at two and five years and time to biochemical relapse (months). Recurrence-free survival (%) was also calculated
.RESULTS
The number of men who experienced a biochemical relapse at both the two and five-year points was significantly lower in the prazosin group (2.7%, 8.8%; p<0.01) when compared to the control (22.6%, 34.5%) and tamsulosin (15.2%, 25.0%) groups. Kaplan Meier survival analysis demonstrated that the recurrence-free survival was strikingly higher in the prazosin group, and median survival was significantly extended.
Men taking Prazosin to manage LUTS had a 3.9 times lower relative risk of biochemical relapse than those who did not take Prazosin. The difference in time to biochemical relapse was not significantly altered by prazosin or tamsulosin (p=0.1258); despite this, the use of Tamsulosin and Prazosin extended recurrence-free survival by 13.15 and 9.21 months, respectively.
Take-Home
Exposure to the quinazoline alpha1-ADR antagonist prazosin reduces the risk of prostate cancer recurrence and delays time to biochemical relapse. Although Tamsulosin delayed time to biochemical relapse, there was no effect on two and five-year relapse rates
.These findings indicate that Prazosin's use to manage LUTS in men with prostate cancer may also improve treatment outcomes by reducing the risk of biochemical relapse. However, this was not true of the non-quinazoline Tamsulosin.
This study is the first study to provide an argument for the use of Prazosin in the treatment of prostate cancer as an adjunct treatment option, so additional research needs to be considered
