Quality-adjusted survival (Q-TWiST) analysis of EORTC trial 30853: comparing goserelin acetate and flutamide with bilateral orchiectomy in patients with metastatic prostate cancer. European Organization for Research and Treatment of Cancer.
BACKGROUND
The first data analysis of the European Organization for Research and Treatment of Cancer (EORTC) 30853 trial indicated a significantly longer time to progression and duration of survival for the maximal androgen blockade (MAB) treatment arm. However, the MAB treatment arm had a higher frequency of reported side effects.


METHODS
The quality-adjusted survival (Q-TWiST) method was applied to perform a secondary analysis of the EORTC 30853 trial in order to obtain a quality-adjusted survival (QAS) analysis. Two models with different definitions of the progression health state were used for the analysis. In the first model, progression was defined by both objective and subjective criteria, and in the second model only by increase in pain score. The approach was also extended to include an analysis using actual utility scores (Q-tility) of patients in the relevant health states.


RESULTS
Based on Q-tility scores obtained from a separate study of a cohort of prostate cancer patients, the QAS analysis resulted in a 5.2-month difference (95% CI, -1.1; 11.5 months) in favor of zoladex and flutamide, equal in magnitude to the benefit found in the unadjusted survival analysis.


CONCLUSIONS
A QAS analysis such as the Q-TWiST method may be preferred over the unadjusted approach in clinical trials where the health states are clearly distinct, and differ significantly in either duration or quality of life (QOL), or both. The second model, with progression defined as increase in pain score, made no difference to the results in this study because of the small difference in duration of the pain-progression health state between treatment arms. However, Q-tility scores from the separate cross-sectional study that was used in this Q-TWiST analysis showed that a subjective definition of health states better reflects differences in QOL between the health states that the patients experience during follow-up.
Rosendahl
I
I
Data Center, European Organization for Research and Treatment of Cancer, Brussels, Belgium. ingvar@onkc.ks.se
Kiebert
G M
GM
Curran
D
D
Cole
B F
BF
Weeks
J C
JC
Denis
L J
LJ
Hall
R R
RR
D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use*; D003131:Combined Modality Therapy; D005485:Flutamide / Q000627:therapeutic use*; D017273:Goserelin / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D009362:Neoplasm Metastasis; D009919:Orchiectomy; D010147:Pain Measurement; D011471:Prostatic Neoplasms / Q000473:pathology / Q000628:therapy*; D011788:Quality of Life; D019057:Quality-Adjusted Life Years; D016019:Survival Analysis