Open AccessRisk of skeletal related events among elderly prostate cancer patients by site of metastasis at diagnosis
Author(s) -
Hussain Arif,
Aly Abdalla,
Daniel Mullins C.,
Qian Yi,
Arellano Jorge,
Onukwugha Eberechukwu
Publication year - 2016
Publication title -
cancer medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.403
H-Index - 53
ISSN - 2045-7634
DOI - 10.1002/cam4.914
Subject(s) - medicine , prostate cancer , metastasis , proportional hazards model , hazard ratio , bone metastasis , oncology , confidence interval , epidemiology , retrospective cohort study , cancer , cohort , androgen deprivation therapy
Abstract The purpose of this study was to estimate the risk of developing skeletal‐related events ( SRE s) based on site of metastasis at diagnosis and identify other predictors of developing SRE s among metastatic prostate cancer patients. We conducted a retrospective cohort study using linked SEER (Surveillance, Epidemiology, and End Results) and Medicare data and identified men over the age of 65 with incident metastatic prostate cancer diagnosed during 2005–2009. SRE s included radiation ( RAD ), pathological fractures ( PF ), bone surgery ( BS ), and spinal cord compression ( SCC ). The association between site of metastasis at diagnosis and SRE was examined using a Cox proportional hazards model that accounts for death as a competing risk. Among 4404 men (median age: 79 years) with incident metastatic prostate cancer, 44% experienced SRE s at a median of 9.6 months post diagnosis. Compared to bone metastasis only, our model showed that patients were significantly less likely to develop SRE s if they had LN ‐only metastasis at diagnosis (Sub‐Hazard Ratio [ SHR ] 0.56; 95% Confidence Interval [ CI ]: 0.43–0.72) or unknown site of metastasis ( SHR : 0.79; CI : 0.64–0.97). Other predictors of reduced SRE risk were age 80+ years ( SHR : 0.83; CI : 0.75–0.91), non‐Hispanic Black ( SHR : 0.77; CI : 0.65–0.90), or being diagnosed in year 2009 ( SHR : 0.85; CI : 0.72–0.99). Patients were significantly more likely to develop SRE s if they received androgen deprivation therapy ( SHR : 1.73; CI : 1.48–2.02) or had Gleason score 8–10 disease ( SHR : 0.79; CI : 0.64–0.97). Compared to patients who present with bone metastasis only at diagnosis, patients presenting with other metastatic sites have similar risk of developing SRE s, with the exception of those presenting with lymph node only metastasis who have a significantly reduced risk of SRE s.