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Time to Nadir PSA
- Source :
- American Journal of Clinical Oncology. 38:465-471
- Publication Year :
- 2015
- Publisher :
- Ovid Technologies (Wolters Kluwer Health), 2015.
-
Abstract
- The objective of the study was to investigate prostate-specific antigen (PSA) nadir (nPSA) and time to nPSA (TnPSA) as prognostic variables for outcomes after definitive high-dose (75 Gy) external beam radiation therapy (RT) without androgen deprivation therapy while correcting for immortal-time bias.nPSA and TnPSA were available for 410 patients. nPSA and TnPSA's impact on freedom from biochemical failure, freedom from metastasis, and prostate cancer-specific survival was assessed on univariate and multivariate analysis using Kaplan-Meier and Cox proportional hazards regression. Outcomes were also evaluated relative to the time since achieving nPSA and not relative to the time of RT, given the intrinsic time bias in TnPSA.Median nPSA was 0.7 ng/mL (interquartile range: 0.4 to 1.1), with a median TnPSA of 25.0 months (IQR: 15.0 to 40.0). On univariate analysis both nPSA and TnPSA were predictive of all endpoints: freedom from biochemical failure, freedom from metastasis, and prostate cancer-specific survival, as categorical (all P0.0001) and continuous (all P0.01) variables. However, after adjusting for immortal-time bias the benefit of long TnPSA was mostly lost. On Cox proportional hazards, a TnPSA12 months did have worse prognosis for biochemical failure and distant metastasis as compared with longer TnPSA, but for those who achieved nadir12 months from the time of RT the TnPSA was no longer prognostic.For dose-escalated RT a lower nPSA is prognostic, but the benefit of a long TnPSA is largely an immortal-time bias and that a longer TnPSA is not in and of itself a significant favorable factor except as compared with those with the shortest TnPSA of12 months.
- Subjects :
- Male
Oncology
Cancer Research
Prognostic variable
medicine.medical_specialty
Multivariate analysis
Kaplan-Meier Estimate
Androgen deprivation therapy
Interquartile range
Prostate
Internal medicine
Humans
Medicine
Aged
Proportional Hazards Models
Univariate analysis
business.industry
Proportional hazards model
Univariate
Prostatic Neoplasms
Middle Aged
Prostate-Specific Antigen
Prognosis
Treatment Outcome
medicine.anatomical_structure
Multivariate Analysis
business
Subjects
Details
- ISSN :
- 02773732
- Volume :
- 38
- Database :
- OpenAIRE
- Journal :
- American Journal of Clinical Oncology
- Accession number :
- edsair.doi.dedup.....e9b406ad9285e3673f0ef995fea3a0dc
- Full Text :
- https://doi.org/10.1097/coc.0b013e3182a468b2