Background: Using data from a randomized Phase III trial and based on testosterone recovery after androgen suppression therapy (ADT), we compared quality of life (QOL) between patients (pts) considered cured of high-risk prostate cancer (HRPC). Methods: 630 pts with HRPC were randomised to pelvic and prostate radiotherapy plus either 36 or 18 months (m) of ADT (10-2000 / 01-2008). Serum testosterone (T) was measured at baseline then at each visit. Abnormal T was defined as below the normal level. We considered cured pts those with a PSA nadir < 2 ng/ml, QOL was assessed by the validated EORTC30 (30 items). Patient-reported outcomes were filled out before treatments, every 6 m during ADT, 4 m after ADT and then once a year for 5 years. The 30 items were regrouped into 9 scales. All items and scales scores were linearly transformed to a 0-100 points scale. We analysed all items and scales scores with general linear model and repeated measures to evaluate changes between pts who did versus those who did not recover normal levels of T over time. Effect of T recovery was adjusted in multivariable model including age, initial normal/abnormal T and ADT duration (18 or 36 m). P-value < 0.01 was considered statistically significant to account for multiple comparisons and a difference in mean scores of ≥ 10 points was considered clinically relevant. Results: We selected those pts considered cured to avoid subsequent T variations due to reintroduction of ADT for recurrence. We excluded 361 pts: not receiving exactly 18 or 36 m of ADT (63), survival < 1 year (15), no T measured at baseline or during follow-up (55), biochemical failure (105) or evidence of metastatic/recurrent disease (92), no QOL questionnaire (31). 269 pts were retained for the analysis. With a median follow-up of 14 years, 140/269 (52%) pts recovered T to a normal level: 94/166 (56.6%) in 18 m and 46/103 (44.7%) in 36 m ADT, p=0.056. Among pts regaining a normal T, the median time to recovery was 3 years (IQR: 2.5 to 3.6) for 18 m vs. 5 years (IQR: 4.5 to 6.0) for 36 m, p<0.001. The global adherence to QOL questionnaires was 83.9% (2649/3156) and it was higher for 36m than for 18 m [86.4% (1255/1452) vs. 81.8% (1394/1704) p<0.001]. When comparing EORTC30 between pts who recovered with those who did not recover T, pts with T recovery had a better QOL: 15/30 items and 6/9 scales were statistically significant principally scale and items related to physical, role, emotional, fatigue, pain, dyspnoea, insomnia, diarrhoea, and financial difficulties. 2 items were also clinically relevant, trouble to take a long walk and feeling tense. Conclusions: In pts cured from HRPC, T recovery is associated with a betterQOL. 18 m of ADT should be the preferred duration since a significantly faster and a higher proportion of pts recover a normal T level with the shorter schedule without detriment in long term outcomes, as previously reported.