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The influence of breast cancer subtype on survival after palliative radiation for osseous metastases. Cancer Med 2020 12;9(23):8979-8988

Date

11/05/2020

Pubmed ID

33146466

Pubmed Central ID

PMC7724488

DOI

10.1002/cam4.3597

Scopus ID

2-s2.0-85096653407   2 Citations

Abstract

BACKGROUND: Among patients with osseous metastases, breast cancer (BC) patients typically have the best prognosis. In the palliative setting, BC is often considered a single disease, but based on receptor status there are four distinct subtypes: luminal A (LA), luminal B (LB), triple negative (TN), and HER2-enriched (HER2). We hypothesize that survival and palliative outcomes following palliative RT for osseous metastases correlate with breast cancer subtype (BCS).

METHODS: We identified 3,895 BC patients with known receptor status who received palliative RT for osseous metastases from 2004-2013 in the National Cancer Database. Kaplan-Meier method with log-rank testing and univariate/multivariate Cox-regression was used to identify survival factors. Incomplete radiation courses, 30-day mortality rate, and percentage remaining life spent receiving RT (PRLSRT) were calculated.

RESULTS: Subtypes were 54% LA, 33% LB, 8% TN, and 5% HER2 with median survival of 34.1, 28.2, 5.3, and 15.7 months, respectively (p < 0.001). Overall 82% of patients received ≥10 fractions. Although BCS had limited effect on radiation regimens, TN received nearly twice as many single or hypofractionated (≤5 fractions) treatments, but the overall rate of these fraction schemes was low at 3.7 and 13.7%, respectively. Compared to LA and LB, TN and HER2 patients had worse palliative outcomes; higher rates of incomplete courses at 18.8% and 18.3% versus 12.7%-14.4%; higher 30-day mortality post-radiotherapy at 21.5% and 16.0% versus 6.3%-7.9%, and higher median PRLSRT of 7.7% and 3.7% versus 2.2%-2.4% for LA and LB. On multivariate analysis, BCS was associated with overall survival with TN (HR 3.7), HER2 (HR 1.75), and LB (HR 1.28) fairing worse than LA (p < 0.001).

CONCLUSIONS: BCS correlated with survival and palliative outcome following radiation to osseous metastases. BCS should be considered by physicians when planning palliative RT to maximize quality-of-life, avoid unnecessary treatment, and ensure palliative benefits.

Author List

Abdelhakiem MK, Johnstone C, Bergom C, Currey A, Robbins JR

Author

Candice A. Johnstone MD, MPH Professor in the Radiation Oncology department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Adult
Aged
Aged, 80 and over
Biomarkers, Tumor
Bone Neoplasms
Breast Neoplasms
Databases, Factual
Female
Humans
Middle Aged
Palliative Care
Quality of Life
Receptor, ErbB-2
Receptors, Estrogen
Receptors, Progesterone
Risk Assessment
Risk Factors
Time Factors
Treatment Outcome
Triple Negative Breast Neoplasms
Unnecessary Procedures
Young Adult