Table 4. Adjusted Percentage of Prostate Cancer-Specific and Overall 15-Year Survival in High- and Low-Use Areasa.
| Cancer Grade | High Primary ADT Use | Low Primary ADT Use | High vs Low Difference (95% CI) | ||
|---|---|---|---|---|---|
| Deaths/Person-year | Adjusted Survival, % | Deaths/Person-year | Adjusted Survival, % | ||
| Prostate cancer-specific survivalb | |||||
| Moderately differentiated | 987/87 649 | 90.6 | 802/72 579 | 90.6 | 0.04 (−1.1 to 1.2) |
| Poorly differentiated | 995/28 858 | 78.6 | 928/27 162 | 78.5 | 0.05 (−1.8 to 2.4) |
| All localized | 1886/112 544 | 85.4 | 1835/114 676 | 85.4 | 0.02 (−1.1 to 1.2) |
| Overall survivalc | |||||
| Moderately differentiated | 9553/102 341 | 20.0 | 7313/85 428 | 20.8 | −0.8 (−2.2 to 0.4) |
| Poorly differentiated | 4705/35 259 | 8.6 | 4362/33 629 | 9.2 | −0.5 (−1.5 to 0.4) |
| All localized | 13 522/134 094 | 15.9 | 13 091/134 015 | 16.8 | −0.8 (−1.8 to−0.1) |
Abbreviation: ADT, primary androgen-deprivation therapy.
Covariates included age, race, comorbidity status, cancer stage, zip code income quartiles, zip code education quartiles, urban area, marital status, year of diagnosis, state buy-in status and cancer grade (all patients only). The 95% CIs are bootstrapped. Because date of last follow-up differed for overall (December 31, 2011) and cancer-specific survival (December 31, 2009), the number of person-years of follow-up differs for each end point.
In order to calculate prostate cancer-specific survival, death due to other cause was treated as a competing risk.
Most patients were followed for less than 10 years. Therefore, the observed 15 years overall survival (16%-20%) is far less than the proportion of patients who remained alive (40%) at the end of the study.