11C-Choline PET/CT predicts prostate cancer-specific survival in patients with biochemical failure during androgen-deprivation therapy

Several studies have shown that ¹¹C-choline PET/CT may be useful for restaging prostate cancer (PCa) patients with biochemical failure after radical prostatectomy. However, validation of ¹¹C-choline PET/CT findings scarcely relied on histologic findings, and prognostic implications of ¹¹C-choline PET/CT are currently unknown. The aim of this study was to assess whether ¹¹C-choline PET/CT predicts survival in PCa patients. Methods: This retrospective study included 195 PCa patients treated with radical prostatectomy who underwent ¹¹C-choline PET/CT from December 1, 2004, to July 31, 2007, due to biochemical failure (prostate-specific antigen > 0.2 mg/mL) during androgen-deprivation therapy. PCa-specific survival was computed as the interval from radical prostatectomy to PCa-specific death. Results: The median interval after radical prostatectomy was 8.9 y (95% confidence interval [CI], 1.7-18.9 y). The median follow-up after ¹¹C-choline PET/CT was 4.5 y (95% CI, 0.4-8.5 y). ¹¹C-choline PET/CT results were positive in 57% of patients. The median PCa-specific survival was 16.4 y (95% CI, 14.0-18.8 y) in patients with negative ¹¹C-choline PET/CT results and 11.2 y (95% CI, 9.8-12.6 y) in patients with positive ¹¹C-choline PET/CT results (log-rank: x² = 19.3, P <0001). At multivariate analysis, statistical significance was obtained for ¹¹C-choline PET/CT (hazard ratio, 2.53; 95% CI, 1.41-4.53; P = 0.002), prostate-specific antigen (hazard ratio, 1.03; 95% CI, 1.00-1.05; P = 0.037), and Gleason score (>7: hazard ratio, 2.49; 95% CI, 1.25-4.95; P = 0.009). Patients with pathologic ¹¹C-choline uptake in the prostatic bed or in pelvic or retroperitoneal lymph nodes had longer PCaspecific survival (median, 12.1 y; 95% CI, 10.5-13.7 y) in comparison to patients with pathologic tracer uptake in the skeleton (median, 9.9 y; 95% CI, 6.8-13.1 y) (log-rank: x² = 6.5, P <0.010). Two internally validated nomograms predicted 10- and 15-y PCa-specific survival probability with an accuracy of 76% and 74%, respectively. In an ancillary analysis, we also showed that ¹¹C-choline PET/CT predicts PCa-specific survival after PET/CT, with similar statistical power. Conclusion: ¹¹C-choline PET/CT predicts PCa-specific survival in PCa patients treated with radical prostatectomy who develop biochemical failure during androgen-deprivation therapy. If independent or multicenter confirmation of these findings is obtained, ¹¹Ccholine PET/CT might be more widely used in the follow-up of PCa patients for tailoring salvage therapy.