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Currently submitted to: JMIR Research Protocols

Date Submitted: Feb 7, 2020
(closed for review but you can still tweet)

Warning: This is an author submission that is not peer-reviewed or edited. Preprints - unless they show as "accepted" - should not be relied on to guide clinical practice or health-related behavior and should not be reported in news media as established information.

The Effects of Radiotherapy and Comorbidity on Health-Related Quality Of Life and Mortality among Older Women with Low-Risk Breast Cancer: Proposal For a Retrospective Longitudinal Study

  • Eunkyung Lee; 
  • Robert B. Hines; 
  • Jean L. Wright; 
  • Eunji Nam; 
  • Michael J Rovito; 
  • Xinliang Liu; 

ABSTRACT

Background:

The National Comprehensive Cancer Network Breast Cancer Guidelines Committee has suggested that the omission of adjuvant radiation therapy (RT) after breast-conserving surgery can be a reasonable option among older women with low-risk breast cancer (early-stage, ER-positive, and node-negative) if they are treated with endocrine therapy. However, RT usage in this group of women still exceeds 50%. On the other hand, older women tend to forego RT (even when necessary) due to cost, inconvenience, and potential adverse responses associated with RT. Understanding health-related quality of life (HRQOL) change with receipt of RT among older women in the modern era is limited due to the underrepresentation of this population in clinical trials.

Objective:

The proposed study aims to examine the associations of RT with HRQOL trajectories as well as survival outcomes among older women over 5-10 year follow-up. We will also assess whether pre-diagnosis comorbidity burden influences receipt of RT and whether the associations between RT and HRQOL trajectory and survival outcomes are modified by comorbidity burden.

Methods:

We will use a retrospective cohort study design with the population-based database of Surveillance, Epidemiology, and End-Results linked to the Medicare Health Outcomes Survey (SEER-MHOS). Older women (65+) diagnosed with low-risk breast cancer in 1998-2014, received BCS, and participated in MHOS 1998-2016 are eligible for the current analysis. The clustering method, latent class analysis, will be used to identify each patient’s pre-diagnosis comorbidity burden, and HRQOL will be evaluated using SF-36/VR-12 scales. The inverse-weighted estimates of the probability of treatment will be included as a covariate to control for treatment selection bias and confounding effects in subsequent analysis. The association of RT with HRQOL trajectory will be evaluated using inverse-weighted semiparametric B-splines models. The inverse-weighted Cox regression model will be used to obtain hazard ratios with 95% confidence intervals for the association of RT with survival outcomes. Differential effects of RT on both outcomes according to comorbidity burden class will also be evaluated.

Results:

As of January 2020, the study was approved by the institutional review board, and the SEER-MHOS data was obtained from the National Cancer Institute and SEER. Women with low-risk breast cancer who met inclusion and exclusion criteria have been identified, and pre-diagnosis comorbidity burden has been characterized using latent class analysis. Further data analysis will begin in February 2020, and the first manuscript will be submitted in a peer-reviewed journal in June 2020.

Conclusions:

This research has the potential to improve clinical outcomes of older women with low-risk breast cancer by providing them additional information on the HRQOL trajectories when they make RT treatment-decision. It will facilitate informed, shared treatment decision and cancer care planning and ultimately will improve the HRQOL of older women with breast cancer. Clinical Trial: NA


 Citation

Please cite as:

Lee E, Hines RB, Wright JL, Nam E, Rovito MJ, Liu X

The Effects of Radiotherapy and Comorbidity on Health-Related Quality Of Life and Mortality among Older Women with Low-Risk Breast Cancer: Proposal For a Retrospective Longitudinal Study

JMIR Preprints. 07/02/2020:18056

URL: https://preprints.jmir.org/preprint/18056

Per the author's request the PDF is not available.