Comorbidity, treatment, and mortality among Swedish prostate cancer patients


A clear appreciation of the associations between life expectancy, comorbid conditions (e.g., diabetes, obesity, cardiovascular disorders), and mortality is critically important to treatment decisions for all patients with prostate cancer, but most especially the newly diagnosed, low-risk patient.

Berglund et al. have been able to use data from PCBaSe Sweden (derived by combining data in the National Prostate Cancer Register of Sweden with additional data from other sources) to further investigate such associations.

PCBaSe Sweden contains data on 77,536 men diagnosed with prostate cancer between 1997 and 2006 — virtually all the patients diagnosed with prostate cancer in Sweden over this 10-year period. Berglund et al. were able to use data from these patients to examine associations among Charlson comorbidity index (CCI), treatment, and mortality. The patients were classified into three groups based on their CCI: no comorbidity (CCI = 0), mild comorbidity (CCI = 1), and severe comorbidity (CCI ≥ 2).

It is important to appreciate, in assessing these results, that during the period from 1997 to 2006 PSA screening was still relatively uncommon in Sweden, and so the majority of patients in this database would have been diagnosed as a consequence of symptomatic disease or a positive digital rectal examination. A Swedish “low-risk” patient in this database is by no means equivalent to a low-risk patient as defined by current US standards.

The results of their analysis were as follows:

  • 55,621/77,536 men (71.7 percent had no comorbid conditions (CCI = 0).
  • 11,233/77,536 men (14.5 percent) had one comorbid condition (CCI = 1).
  • 10,682/77,536 men (13.7 percent) had severe comorbidity (CCI ≥ 2).
  • 16,788/55,621 men with no registered comorbidity (30.2 percent) were younger than 65 years at prostate cancer diagnosis compared to 1,087/10,682 (10.2 percent) with severe comorbidity.
  • In men without no comorbid conditions 13,888/55,621 (25.0 percent) were diagnosed with low-risk prostate cancer compared to 1,525/10,682 (14.3 percent) of those with severe comorbidity.
  • In men with low-risk prostate cancer …
    •  5,975/13,245 patients (45.1 percent) with no comorbidity (CCI = 0) underwent radical prostatectomy.
    • 256/1,399 (18.9 percent) men with severe comorbidity (CCI ≥ 2) underwent radical prostatectomy.
    • 38.9 percent of patients with no comorbidity were simply monitored (active surveillance or watchful waiting).
    • 63.3 percent of patients with severe comorbidity were simply monitored (active surveillance or watchful waiting).
    • Radical prostatectomy was significantly less likely to be offered to men with severe comorbidity (odds ratio [OR] = 0.48).
    • Surveillance was significantly more likely in men with severe comorbidity (OR = 1.50)
  • In men with high-risk prostate cancer …
    • Immediate LHRH agonist therapy was the most common form of treatment in men with no comorbid conditions (31.8 percent) and in men with severe comorbidity (44.9 percent).
    • Radiotherapy was more common (range 7.7 to 21.3 percent) than radical prostatectomy (range 3.0 to 11.2 percent) regardless of comorbidity.
    • Patients with severe comorbidity were significantly less likely to receive radiation therapy than those with no comorbid conditions (OR = 0.57).
  • All-cause and competing-cause but not prostate cancer-specific mortality were increased in men with severe comorbidity.
    • For all-cause mortality, the hazard ratio (HR) = 1.99.
    • For competing cause mortality the HR = 2.66.
    • For prostate cancer-specific mortality, the HR 0.98.
  • Patients with low-risk prostate cancer and severe comorbidity had a risk of death from other causes more than three times that of their risk of death from prostate cancer (HR = 3.39).
  • Patients with high-risk prostate cancer and severe comorbidity had a risk of death from other causes that was 2.60 times that  of their risk of death from prostate cancer.
  • Patients with high-risk prostate cancer and severe comorbidity had a risk for prostate cancer-specific mortality that was lower than that of patients with low-risk prostate cancer and severe comorbidity (HR 0.86).
  • Across all risk groups, the cumulative probability of prostate cancer-specific mortality (given no death from competing causes) was significantly higher in men with severe comorbidity.

While these results should hardly be surprising, they add to the accumulating data that help us to counsel newly diagnosed patients with prostate cancer. The presence of comorbid clinical conditions clearly affects treatment choice, and was associated with all-cause, competing-cause and conditional prostate cancer-specific mortality in this study.

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