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Prostatectomy plus radiotherapy may improve survival in advanced prostate cancer

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October 15, 2018

Patients who underwent primary radical prostatectomy followed by radiotherapy for locally or regionally advanced prostate cancer had better survival outcomes than patients treated with radiotherapy plus androgen deprivation therapy, according to findings from a population-based, retrospective study published in Cancer.

“There is a lot of debate about whether to remove the whole prostate and follow-up with radiation therapy or, as a second option, spare the prostate and treat it using radiation therapy plus hormone-blocking therapy,” Grace Lu-Yao, PhD, associate director of population science at the Sidney Kimmel Cancer Center at Jefferson Health, said in a press release. “Our study suggests that removing the prostate followed by adjuvant radiotherapy is associated with greater OS in men with prostate cancer.”

Lu-Yao and colleagues pooled data on 13,856 men aged 65 years and older in the SEER-Medicare database who were treated for locally or regionally advanced prostate cancer between 1992 and 2009. The researchers compared outcomes between men treated with radical prostatectomy plus adjuvant radiotherapy (6.1%) and men treated with radiotherapy plus ADT (23.6%).

Prostate cancer-specific survival and OS according to cancer stage, Gleason score and treatment served as primary endpoints. Secondary endpoints included the prevalence of treatment-related complications according to treatment type.

The researchers used propensity score methods to balance cohort characteristics between the two groups.

Median follow-up was 14.6 years.

Overall, there were 2,189 deaths, including 702 secondary to prostate cancer.

A greater proportion of men who underwent radical prostatectomy plus adjuvant radiotherapy achieved 10-year prostate cancer-specific survival (88.9% vs. 74.2%, survival difference, 14.7%; 95% CI, 11.4-17.2) and OS (64.2% vs. 48.3%, survival difference, 15.8%; 95% CI, 11.3-20.2) than those treated with radiotherapy and ADT.

Researchers observed an increased risk for death associated with radiotherapy plus ADT vs. radical prostatectomy plus adjuvant radiotherapy for patients with T3aN0M0 disease (HR = 4.22; 95% CI, 2.83-6.28), T3bN0M0 disease (HR = 1.84; 95% CI, 1.34-2.53) and T4N0M0 disease (HR = 2.31; 95% CI, 1.05-5.12).

The finding persisted for all-cause mortality (HR for T3N0M0= 1.75; 95% CI, 1.45-2.11; HR for T3bN0M0 = 1.49; 95% CI, 1.22-1.84; HR for T4N0M0 = 1.62; 95% CI, 1-2.64).

However, men treated with prostatectomy plus adjuvant radiotherapy experienced higher rates of erectile dysfunction (28% vs. 20%; P = .0212) and urinary incontinence (49% vs. 19%; P < .001).

Approximately half of the men were treated with a single intervention, results showed. Specifically, 20.8% of men were treated with radical prostatectomy alone, 18.3% were treated with radiotherapy alone and 11.2% were treated with ADT alone.

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“Two modes of treatment are recommended by both the United States and European guidelines for cancer treatment. It was surprising to see only 29% of patients received the recommended combination therapies, and as many as 20% are not getting any treatment 6 months after their diagnosis,” Lu-Yao said in the release. “Our data cannot tell us the reason for this deviation from guidelines and further studies are needed.” – by Jennifer Southall

Disclosures: Lu-Yao reports support from NCI. Please see the study for all other authors’ relevant financial disclosures.