Using Conditional Survival to Predict Survival of Poor-Prognosis Cancers in the U.S. Open Access

Barkley, Jonathan (2014)

Permanent URL: https://etd.library.emory.edu/concern/etds/kw52j840j?locale=en
Published

Abstract

Background: Conditional survival estimates show that patients diagnosed with poor-prognosis cancer types have a much improved outlook if able to survive the first few years of high mortality. The primary aim of this investigation was to better understand the clinical and demographic characteristics that influence survival and how these associations change as patients survive past diagnosis.

Methods: Data were obtained from the Surveillance, Epidemiology, and End Results (SEER) program November 2012 submission. Five-year cause-specific survival conditional on surviving 0-5 years was estimated for 13 cancers using the period method in SEER*Stat. The five-year hazard of death was modeled at diagnosis (overall model) and 2 years past diagnosis (conditional model) for pancreatic and esophageal cancers diagnosed between 2001 and 2009 using Cox proportional hazard (PH) models. Age, sex, race/ethnicity, marital status, grade, stage, region, urban-rural status, and treatment were controlled for in each model. After exclusions for missing data, the final overall and conditional models for esophageal cancer consisted of 23,383 and 7,592 patients respectively, while models for pancreatic cancer consisted of 63,380 and 10,140 patients respectively.

Results: Five-year conditional survival increased by the greatest magnitude for pancreatic (+67%) and esophageal cancers (+61%), 2 of the cancers with the lowest 5-year survival at diagnosis. Cox PH models identified increasing age, increasing stage, and the absence of treatment as statistically associated with an increased hazard of death in both the overall and conditional cohorts. For esophageal cancer, marital status, race, and grade were associated with hazard of death in the overall model, but were no longer significant in the conditional model. For pancreatic cancer, a significant interaction between marital status and race was observed for the conditional model, where patients of other races who were married had a significantly lower hazard compared to whites (HR=0.73, 95% CI: 0.60, 0.88) versus those who were non-married (HR=0.96, 95% CI: 0.96, 1.67).

Conclusions: The risk profile of patients diagnosed with esophageal and pancreatic cancer changes as these patients survive past diagnosis. Prognostic models such as these could be used to obtain individualized hazard estimates and could assist clinicians in patient counseling during the survivorship period.

Table of Contents

Background....................................................................................................... 1

Objectives................................................................................................. 2

Methods........................................................................................................... 11

Estimating survival of a variety of cancers..................................................... 11

Modeling overview..................................................................................... 11

Results............................................................................................................ 16

Discussion........................................................................................................ 21

Significance and Conclusions............................................................................... 28

References....................................................................................................... 30

Tables............................................................................................................. 35

Table 1.................................................................................................... 35

Tables 2a and 2b....................................................................................... 36

Tables 3a and 3b....................................................................................... 37

Tables 4a and 4b....................................................................................... 38

Tables 5a and 5b....................................................................................... 39

Table 6............................................................................................................ 40

Appendix.......................................................................................................... 41

Copy of SEER data agreement...................................................................... 41

About this Master's Thesis

Rights statement
  • Permission granted by the author to include this thesis or dissertation in this repository. All rights reserved by the author. Please contact the author for information regarding the reproduction and use of this thesis or dissertation.
School
Department
Degree
Submission
Language
  • English
Research field
Keyword
Committee Chair / Thesis Advisor
Partnering Agencies
Last modified

Primary PDF

Supplemental Files