3329 - Unknown Causes of Death in Localized Prostate Cancer: Long-Term Data from Two Phase III Trials
Presenter(s)
A. Nabid1, N. Carrier2, A. G. Martin3, E. Vigneault4, J. P. Bahary5, T. V. Nguyen6, P. Vavassis7, M. A. Brassard8, B. Bahoric9, R. Archambault10, F. Vincent11, R. Bettahar12, M. Duclos13, D. R. Wilke14, and L. Souhami15; 1CIUSSS de l'Estrie - CHUS, Sherbrooke, QC, Canada, 2Centre hospitalier universitaire de Sherbrooke, Sherbrooke, QC, Canada, 3CHU de Québec – Université Laval, Québec, QC, Canada, 4Centre Intégré Cancérologie et Centre de recherche CHU de Québec Université Laval, Quebec City, QC, Canada, 5Department of Radiation Oncology, Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Montreal, QC, Canada, 6Centre Hospitalier de l'Université de Montréal, Montréal, QC, Canada, 7Maisonneuve-Rosemont Hospital, Montreal, QC, Canada, 8Centre Intégré Universitaire de Santé et de Services Sociaux du Saguenay-Lac-Saint-Jean, Chicoutimi, QC, Canada, 9Département de radio-oncologie, Jewish General Hospital, Montreal, QC, Canada, 10Centre Intégré de Santé et de Services Sociaux de l'Outaouais, Gatineau, QC, Canada, 11Centre hospitalier regional de Trois-Rivieres, Trois-Rivieres, QC, Canada, 12CSSS Rimouski-Neigette, Rimouski, QC, Canada, 13Cedars Cancer Center, Montreal, QC, Canada, 14Department of Radiation Oncology, QE2 Cancer Centre, Nova Scotia Health, Halifax, NS, Canada, 15McGill University Health Centre, Montreal, QC, Canada
Purpose/Objective(s): Based on long-term follow up of two randomized trials in localized prostate cancer, we examined patients’ (pts) unknown causes of death.
Materials/Methods: We included all 630 pts with high-risk prostate cancer (HRPCa) treated with androgen deprivation therapy (ADT) and radiotherapy (RT) and 600 with intermediate risk prostate cancer (IRPCa) treated with RT with or without ADT. In pts with unidentified cause of death, date of the demise was retrieved from public records.
Results:
With a median follow up of 17 years, 783/1230 pts (63.7%) have died: 450/630 (71.4%) with HRPCa and 333/600 (55.5%) with IRPCa. Of these, in 87 pts (11.1 %), had an unknown cause of death: 48 (10.7%) in the HRPCa cohort and 39 (11.7%) in the IRPCa cohort. Median age at randomization was 72 years and it was 81 years at death. Pts who died from unknown cause were older, had lower PSA at baseline and lower stage, but comorbidities were similar in the two groups. Most deaths occurred late in life, 58.6% (51/87) died between the age of 80 and 89 years and 18.4% (16/87) after the age of 90. At the time of the last known follow up, comparatively to pts who died from an establish cause, pts who died from unknown cause had significantly lower biochemical recurrence (17.2% vs. 32.8%, p=0.003) and developed fewer second malignancy (9.2% vs 34.1%, p<0.001). The median survival of pts dying from unknown cause was 12.2 (IQR 9.2-14.9) years post RT, compared to 9.5 (IQR 6.4-13.6) years for those with an established cause. Pts who died from unknown cause survived longer than patients who died from known cause [HR (95% CI) = 0.76 (0.62-0.93), p=0.017]. The 10-year survival rates were 74% and 47% for patients with unknown vs known cause of death, respectively.Conclusion: Overall survival remains a gold standard in oncology. Collecting accurate survival data on all pts remains critical, particularly when measuring cancer-specific mortality. In our series, unknown cause of death represented 11.1% of all deaths. Given the advanced age of pts, it is probable that the main cause of death for most of these pts resulted from competing illness other than prostate cancer.