Science of Quality
Community oncology treatment patterns and clinical effectiveness in metastatic castration-resistant prostate cancer (mCRPC) patients who progressed after docetaxel.
Background: Cabazitaxel (C) and abiraterone (A) improve survival in mCRPC after progression on docetaxel (D). We examined whether mCRPC patients progressing on D received C and/or A, in which sequence, and how they compared with patients not receiving C or A. Methods: This retrospective study used medical records from the ACORN Data Warehouse. Eligible patients were: diagnosed with mCRPC, progressed after 1st-line D, treated 2nd-line with C (DC) or A (DA). Some went to 3rd-line C or A (DCA, DAC). A random sample of comparable patients without A or C (DO) was included. Demographic and clinical characteristics were extracted. Cox regression analyses assessed PFS and OS by 2nd-line group after D. Results: Screened out patients were: 60 with no progression on D; 41 absent records; 18 with another cancer. Table below shows patients by treatment sequence group. Age, PS, and PSA did not differ significantly. More patients appear to have received A after C (56.7%) than C after A (25.7%). In the 3-drug sequence groups, more patients received DCA in the 6-month period from April-October 2011 (n = 17/19) than in the 6-month period from June-December 2012 (n = 2/10), suggesting a drop-off in use of C immediately after D. Cox PFS treatment effect was not significant. Cox OS treatment effect was significant (DA vs DC, HR = 1.693 [95% CI: 1.066, 2.691], p = 0.0258). Conclusions: Patterns suggest comparable outcomes in PFS. Controlling for patient characteristics, OS may be longer in DC vs DA. Patients appear undertreated in third line with fewer receiving C after A than the opposite sequence. We hypothesize that DAC may not be as feasible as DCA. Reasons for underutilization of C are being examined.
n = 60
n = 71
n = 34
n = 18
n = 129
|Age (median years)||68.97||70.83||68.88||67.00||68.95||69.47|
|PS, n (%) impaired vs. not indicated impaired||8 (13.33)||12 (16.90)||5 (14.71)||3 (16.67)||16 (12.4)||36 (13.85)|
|PSA ng/mL (n)||49||50||27||14||95||194|
Abbreviations: A, abiraterone; C, cabazitaxel; and D, docetaxel.
*Baseline characteristics assessed end of D. DCA and DAC are subsets of DC and DA.