Preference of Choosing Intensity-Modulated Radiation Therapy (IMRT) in Breast Cancer Patients with Pre-existing Heart or Lung Disease Open Access

Wang, Siyu (Spring 2019)

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Background: Currently, breast-conserving surgery (lumpectomy) followed by radiotherapy has become the most commonly used treatment combination for breast cancer patients who have been diagnosed at relatively early stages. Among breast cancer patients who take radiotherapy, the use of IMRT has increased dramatically. It is known that the use of IMRT makes it possible to protect surrounding tissues away from exposure to radiation doses and may decrease possible damage to patients’ nearby organs. However, whether this advantage of IMRT could affect physician’s behavior and patients’ preference is uncertain, especially for breast cancer patients with pre-existing heart or lung disease.

Methods: Study sample derived from SEER-Medicare database. Women aged 66 years and older diagnosed with a primary invasive breast cancer and received some form of radiotherapy in the timeframe from 2007 through 2013 enrolled in the sample. Pearson Chi-square and logistic regression model were used to estimate the association between breast cancer patients with pre-existing heart or lung disease and the use of IMRT.

Results: 39181 subjects have been included in the model. 31.1% of them had previously diagnosed heart or lung disease before their diagnosis of breast cancer. 18.7% of enrolled breast cancer patients with previous heart or lung disease took IMRT. Among patients who took IMRT, patients with both left-sided tumors and heart disease have a higher proportion of taking IMRT (58.8%) compared to patients with right-sided tumors and same disease. Women with pre-existing heart or lung disease (unselected) were more likely (4.6 percentage point, 95% confidence interval (CI): 0.003-0.117) to use IMRT compared to conventional radiotherapy. Women with pre-existing heart disease had an even higher possibility (7.9 percentage point) of taking IMRT.

Conclusions: These findings suggested that patient’ health status could affect their treatment options. Breast cancer patients who have pre-existing heart disease were more likely to choose IMRT. Differences could be explained by physicians prefer to be more conservative for breast cancer with previous cardiac risk. Further studies with deeper data and quality studies about patient’s preference should be considered.

Table of Contents


Literature review

�  Epidemiology of breast cancer

�  Breast cancer in the U.S.

�  Mammography for breast cancer

�  Treatment for breast cancer

�  Comparison of 3D-CRT and IMRT

�  The advantage and controversy of IMRT

�  The current use of IMRT

�  NCCN guideline for radiotherapy

�  Medicare coverage for radiotherapy

�  Medicare coverage policy for IMRT

�  Literature gap

Conceptual model

Focal relationship



�  Data description

�  Analytic sample derivation

�  Measures

Statistical analysis



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