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Radiotherapy plus hormone therapy halved prostate cancer mortality
The addition of radiation therapy to antiandrogen therapy halved the 10- and 15-year rates for mortality among men with high-risk nonmetastatic prostate cancer compared with hormone therapy alone, according to updated study results presented at the 2014 Genitourinary Cancers Symposium.
“In 1996, lifelong castration treatment was viewed as standard treatment for patients with locally advanced or high-risk prostate cancer without metastasis in Scandinavia, Europe and also in the United States,” Sophie Dorothea Fosså, MD, a professor in the department of oncology at Oslo University Hospital in Norway, said during a press conference. “Most of these patients were viewed at that time as inoperable. At the same time, we had data that showed anti-androgens resulted in fewer side effects than castration treatment without having a negative impact on survival. Therefore, the primary aim of our trial was to have at least a 10% reduction of the 10-year prostate cancer specific mortality by adding local radiation therapy to hormone treatment.”
Sophie Dorothea Fosså
From 1996 to 2002, Fosså and colleagues assigned 875 men with locally advanced or histologically aggressive prostate cancer to total androgen blockade followed by radiation therapy or continuous antiandrogen therapy alone for 3 months.
The researchers used death registry data for Norwegian patients and the Case Report Form database for Swedish patients to conduct an extended analysis after a median observation time of 10.7 years.
More prostate cancer-related deaths occurred among patients assigned antiandrogen therapy alone (118 of 439) than antiandrogen therapy plus radiation therapy (45 of 436; P˂.0001).
More men assigned antiandrogen therapy alone also died from any cause (210 vs. 161; P=.0006).
Researchers determined the prostate cancer-specific mortality rate was more than twice as high among patients assigned to hormone therapy alone at 10 years (18.9% vs. 8.3%) and 15 years (30.7% vs. 12.4%).
“When this study started in 1996, the standard treatment was hormone therapy alone, but this trial continues to show that adding radiotherapy substantially boosts long-term survival,” Fosså said in a press release. “This combination more than doubles the 10-year survival rate and confirms that this approach should be a standard option for men with this type of prostate cancer who are expected to live at least another 10 years.”
For more information:
Fosså SD. Abstract #4. Presented at: 2014 Genitourinary Cancers Symposium; Jan. 30-Feb. 1, 2014; San Francisco.
Disclosure: The researchers report no relevant financial disclosures.
Perspective
Back to TopFossa and colleagues report an updated analysis of the outcome of the study by The Scandinavian Prostate Group in which 875 patients with locally advanced or histologically aggressive prostate cancer with clinically localized disease were randomly assigned to 3 months of total androgen deprivation followed by prostate irradiation and continuous anti-androgen therapy (n=436) vs. continuous anti-androgen therapy (n=439).
Eligibility criteria are important to emphasize and, as outlined in the initial report of this study, included age younger than 76 years, good performance status, a life expectancy of more than 10 years, PSA ≤70 ng/mL and with no evidence of metastases. All participants were categorized as clinical T1b-T2, G2-G3 or T3, with any WHO grade 1-3. Those with PSA ≥11 ng/mL had pelvic lymph node dissection, and those with nodal disease were excluded (Widmark A. Lancet. 2009;373:301–308).
In the previous report, at a median follow-up of 7.6 years, those assigned to total androgen deprivation followed by prostate irradiation experienced a 12% reduction in prostate cancer-specific mortality compared to those assigned to continuous anti-androgen therapy.
In this report, follow-up is updated at 10 and 15 years. Prostate cancer death continued to occur less often in the total androgen deprivation followed by prostate irradiation group compared with the continuous antiandrogen therapy group. Deaths from all causes were also reduced in the total androgen deprivation plus prostate irradiation group. Prostate cancer and all-cause mortality were reduced significantly at 10 and 15 years. Interestingly, deaths from any cause were more frequent in the total androgen deprivation and prostate irradiation group compared with the continuous anti-androgen therapy group (116 vs. 92). Significance, or lack thereof, of this difference was not reported in the abstract.
These continue to be intriguing data, and not what many (including this reviewer) predicted, emphasizing once again the need to do clinical trials. Among men with localized prostate cancer, fulfilling the criteria specified in this study — in which long term continuous antiandrogen therapy is chosen as appropriate therapy — localized irradiation to the prostate does improve prostate-cancer specific survival and OS. Whether continuous antiandrogen therapy is necessary in these patients is not addressed by these data; however, substantial trials evidence demonstrates the merit of androgen combined-modality therapy in patients with high-risk, apparently localized prostate cancer. Unfortunately, there are not clear data with regard to the optimal duration of antiandrogen therapy in the multimodality management of localized disease.
Perspective
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This is an important study from a couple standpoints. One, it’s very interesting to see that these results have continued to improve over time. This is somewhat different than some of the other randomized trials, where sometimes the results actually worsen over time. Also of note, this is the use of an anti-androgen as opposed to lifelong medical castration, which makes this trial somewhat unique and may be a source for some questions down the road.