Improving clinical prognostic stratification models for men with prostate cancer: a practical step closer to more individualized care without added costs

Impact of radiation dose on recurrence in high-risk prostate cancer patients

BACKGROUND

Dose escalated radiation therapy (RT) combined with long-term androgen deprivation therapy (ADT) is a standard of care option for men with high-risk and locally advanced prostate cancer (PCa). However, the optimal dose of escalated RT and ADT is not known. Here we assessed the impact of radiation dose and length of ADT on biochemical recurrence in a multi-institutional cohort stratified by the Cambridge prognostic group (CPG). We hypothesized that radiation dose and length of ADT would impact outcome in similar risk groups of our patients.

METHODS

Two-hundred and forty-four patients were included, 132 from Oslo University Hospital, Department of Oncology and 112 from Johns Hopkins Hospital, Department of Radiation Oncology. Biochemical recurrence was defined as prostate-specific antigen (PSA) nadir +2 ng/mL. Time to recurrence was estimated using Kaplan-Meier analysis and when stratified by CPG the log-rank test was used. Cox regression analysis was performed to identify factors associated with risk of recurrence. Site of recurrence was investigated.

RESULTS

The median follow-up time was 7.4 years. The vast majority (71%) of patients were classified as high-risk (CPG 4) or very high-risk features (CPG 5). Significantly more PSA recurrences occurred in CPG 5 (41%) compared with CPG 4 (25%) (P = .04) and five-year cumulative recurrence-free survival was lower for CPG 4 and 5 (89% and 68%) compared with CPG 1, 2, and 3 (100%, 100%, and 93%). The recurrence-free survival for CPG 5 was significantly higher for prostate irradiation of 80 Gy as compared with 74 Gy (P = .011). For CPG 4 and 5 no local recurrences were detected in patients receiving 80 Gy. On stepwise Cox regression analysis neither age nor length of ADT were independent prognostic factors for recurrence free survival.

CONCLUSION

Prostate dose escalation from 74 to 80 Gy decreases risk of recurrence in high-risk PCa. Further studies are needed to identify the optimal combination of ADT and RT.

Perceptions of Risk Stratification Workflows in Primary Care

Risk stratification (RS) in primary care is frequently used by policy-makers, payers, and health systems; the process requires risk assessment for adverse health outcomes across a population to assign patients into risk tiers and allow care management (CM) resources to be targeted effectively. Our objective was to understand the approach to and perception of RS in primary care practices. An online survey was developed, tested, and administered to 148 representatives of 37 primary care practices engaged in RS varying in size, location and ownership. The survey assessed practices’ approach to, perception of, and confidence in RS, and its effect on subsequent CM activities. We examined psychometric properties of the survey to determine validity and conducted chi-square analyses to determine the association between practice characteristics and confidence and agreement with risk scores. The survey yielded a 68% response rate (100 respondents). Overall, participants felt moderately confident in their risk scores (range 41–53.8%), and moderately to highly confident in their subsequent CM workflows (range 46–68%). Respondents from small and independent practices were more likely to have higher confidence and agreement with their RS approaches and scores (p < 0.01). Confidence levels were highest, however, when practices incorporated human review into their RS processes (p < 0.05). This trend was not affected by respondents’ professional roles. Additional work from a broad mixed-methods effort will add to our understanding of RS implementation processes and outcomes.