Table 3.
PROSTQA Model–Predicted Probabilities of Men Having Functional Erections Suitable for Intercourse 2 Years After External Radiotherapy for Prostate Cancer
| Planned Neoadjuvant Hormone Therapy |
Pretreatment PSA Level, ng/mL |
Predicted Functional Erections After Treatment, % (95% CI) (by Pretreatment Sexual HRQOL Score)a,b |
||
|---|---|---|---|---|
| 67 | 83 | 100 | ||
| No | <4 | 67 (47–83) | 83 (66–92) | 92 (81–97) |
| ≥4 | 39 (30–49) | 60 (49–70) | 79 (67–87) | |
| Yes | <4 | 39 (19–63) | 60 (35–80) | 79 (55–92) |
| ≥4 | 16 (9–28) | 31 (19–48) | 53 (35–71) | |
Abbreviations: HRQOL, health-related quality of life; PROSTQA, Prostate Cancer Outcomes and Satisfaction With Treatment Quality Assessment; PSA, prostate-specific antigen.
Specific values of pretreatment sexual functioning (Expanded Prostate Cancer Index Composite scores of 67, 83, and 100; range of 0–100, with a higher score representing better function) are tabulated to represent cohort distribution (25th, 50th, and 75th percentiles of scores among prostatectomy-treated patients) as well as to reflect a clinically relevant set of possible pretreatment sexual functioning. These values correspond to 50th, 80th, and 93rd percentiles of the distribution among patients treated with external radiotherapy. Across all treatment groups, these percentiles correspond to 358 patients (36%) with pretreatment sexual HRQOL scores of 67 or less, 441 (45%) with scores of 68–99, and 186 (19%) with scores of 100.
Individual model-predicted probabilities were calculated using the inverse logistic function {exp[X′ β]/[1 + exp(X′ β)]}, where X′ β is the sum with X representing individual characteristics observed and β representing the associated model parameter estimates for the individual characteristics in Table 1.