The association between measures of progression and survival in castrate-metastatic prostate cancer.
OBJECTIVE
To explore the association between progression-free survival and overall survival time in patients with castration-resistant prostate cancer treated with microtubule-targeted therapies.


METHODS
We retrospectively studied patients treated in three trials evaluating a taxane or an epothilone for progressive castration-resistant prostate cancer. Study subjects were 98 patients with bone metastases; 63 of them also had soft tissue lesions. All scans were reviewed independently. Associations of radiographic progression-free survival and prostate-specific antigen (PSA) progression-free survival with survival time were measured using Kendall's tau, adjusted for right censoring. A smoothing procedure was applied to estimate Kendall's tau within each neighborhood of the follow-up process.


RESULTS
The overall associations between progression-free survival time and overall survival time were moderate: 0.4 for radiographic progression-free survival and 0.33 for PSA progression-free survival. The association between radiographic progression-free survival and overall survival was weakest early in the follow-up process, whereas the PSA association was weakest when the progression-free survival-related event (PSA progression, death, or censoring) occurred after 6 months from the start of treatment.


CONCLUSIONS
Current measures of progression-free survival time for men with castration-resistant prostate cancer are not strongly concordant with survival time. Factors that attenuate the association include interval censoring and the discontinuation of therapy early in the follow-up due to imaging changes that may not reflect true failure of the treatment. For radiographic progression-free survival, the association may be increased by requiring confirmation of progression with a second scan, as is routinely done when assessing response.
Scher
Howard I
HI
Genitourinary Oncology Service, Department of Medicine, Sidney Kimmel Center for Prostate and Urologic Cancers, Weill Medical College of Cornell University, New York, New York, USA. scherh@mskcc.org
Warren
Mary
M
Heller
Glenn
G
D000230:Adenocarcinoma / Q000401:mortality* / Q000556:secondary*; D000726:Androgen Antagonists / Q000627:therapeutic use; D000970:Antineoplastic Agents / Q000627:therapeutic use; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D001859:Bone Neoplasms / Q000556:secondary; D002986:Clinical Trials as Topic; D018450:Disease Progression; D018572:Disease-Free Survival; D034261:Epothilones / Q000627:therapeutic use; D006801:Humans; D008297:Male; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000401:mortality* / Q000556:secondary*; D012189:Retrospective Studies; D012983:Soft Tissue Neoplasms / Q000556:secondary; D015996:Survival Rate; D043823:Taxoids / Q000627:therapeutic use
D000726:Androgen Antagonists; D000970:Antineoplastic Agents; D018931:Antineoplastic Agents, Hormonal; D034261:Epothilones; D043823:Taxoids; D017430:Prostate-Specific Antigen