Age at diagnosis and prostate cancer treatment and prognosis: a population-based cohort study

Abstract

Background

Old age at prostate cancer diagnosis has been associated with poor prognosis in several studies. We aimed to investigate the association between age at diagnosis and prognosis, and if it is independent of tumor characteristics, primary treatment, year of diagnosis, mode of detection and comorbidity.

Patients and methods

We conducted a nation-wide cohort study including 121,392 Swedish men aged 55-95 years in Prostate Cancer data Base Sweden (PCBaSe) 3.0 diagnosed with prostate cancer in 1998-2012 and followed for prostate cancer death through 2014. Data were available on age, stage, grade, PSA-level, mode of detection, comorbidity, educational level and primary treatment. We used Cox regression to calculate hazard ratios (HR) and 95% confidence intervals (CIs).

Results

With increasing age at diagnosis, men had more comorbidity, fewer PSA detected cancers, more advanced cancers and were less often treated with curative intent. Among men with high-risk or regionally metastatic disease, the proportion of men with unknown M stage was higher among old men versus young men. During a follow-up of 751,000 person-years, 23,649 men died of prostate cancer. In multivariable Cox-regression analyses stratified by treatment, old age at diagnosis was associated with poorer prognosis among men treated with deferred treatment (HR_{age 85+ vs. 60-64}: 7.19; 95% CI: 5.61-9.20), androgen deprivation therapy (HR_{age 85+ vs. 60-64}: 1.72; 95% CI: 1.61-1.84) or radical prostatectomy (HR_{age 75+ vs. 60-64}: 2.20; 95% CI: 1.01-4.77), but not radiotherapy (HR_{age 75+ vs. 60-64}: 1.08; 95% CI: 0.76-1.53).

Conclusion

Our findings argue against a strong inherent effect of age on risk of prostate cancer death, but indicate that in current clinical practice, old men with prostate cancer receive insufficient diagnostic work-up and subsequent curative treatment.