Abstract 3292: Cause-specific mortality of nonmetastatic prostate cancer patients
Authors: Matthes Katarina , Pestoni Giulia , Korol Dimitri , Hemelrijck Mieke Van , Rohrmann Sabine 
Published: July 2017

Background: Prostate cancer (PCa) is the most frequent incident cancer in men in Switzerland. One of the major challenges in the treatment of PCa is to reliably distinguish between patients at risk of dying as a direct result of the disease and those more likely to die of other causes. The purpose of this study was to assess the associations of age and risk group based on stage, grade and PSA level with primary treatment of non-metastatic PCa patients, and to evaluate whether this treatment was associated with cardiovascular death or prostate cancer specific mortality (PCSM).

Methods: Population-based data from the Cancer Registry of Zurich and Zug in Switzerland were used. We identified 1919 non-metastatic PCa patients diagnosed between 2000 and 2009 who were living in the City of Zurich. PCa risk groups were stratified into three groups based on T stage, Gleason score and initial PSA concentration as described by D’Amico (low-risk: T1-2a, and Gleason score &lt;=6, and PSA &lt;=10 ng/mL; intermediate risk: T2b and/or Gleason score = 7 and/or PSA &gt; 10 and &lt;=20; high-risk: &gt;= T2c or Gleason score 8-10 or PSA &gt; 20). Multiple imputation methods were applied to deal with missing risk group information. We distinguished between surgical procedures, radiotherapy, androgen deprivation therapy (ADT), active surveillance, and watchful waiting. Fine and Gray competing risk regression analysis was used to estimate sub-distribution hazard ratios for the outcomes cardiovascular death, PCSM or other-cause mortality.

Results: Unadjusted competing risk model revealed an increased risk of cardiovascular death for patients with ADT (HR=2.00 [1.27 - 3.14]), or watchful waiting compared to surgery (HR = 2.19 [1.58 - 3.02]). However, after adjustment for age and risk group, an increased risk of cardiovascular death was no longer observed (ADT HR=1.51 [0.93 - 2.46], watchful waiting HR = 1.31 [0.91 - 1.89]). Only men ≥80 years of age still had an increased risk of cardiovascular death. Furthermore, we observed an increased adjusted risk of PCSM in men with ADT (HR=2.84 [1.97 - 4.01]) or under watchful waiting (HR=1.78 [1.29 - 2.46]) compared to surgery, for men ≥70 years (HR= 4.18 [2.18 - 8.00]) compared to men &lt; 70 years old, and for patients with intermediate risk (HR=2.69 [1.34 - 5.39]) and high risk (HR=6.37 [3.30 - 12.30]) compared to patients with low risk.

Discussion: The study suggests that ADT use for non-metastatic PCa patients may not be associated with an increased risk of cardiovascular death in general, but with an increased risk of PCSM. This is likely explained by the more frequent ADT use in older men and in men with a high-risk PCa. In addition, we observed that older men and men with an intermediate- or high-risk PCa had an increased risk of PCSM.

Citation Format: Katarina Matthes, Giulia Pestoni, Dimitri Korol, Mieke Van Hemelrijck, Sabine Rohrmann. Cause-specific mortality of nonmetastatic prostate cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3292. doi:10.1158/1538-7445.AM2017-3292