# Proton Therapy to Reduce Heart Damage for Lung Cancer Patients

> **NIH NIH R21** · UNIVERSITY OF TX MD ANDERSON CAN CTR · 2020 · $176,175

## Abstract

PROJECT SUMMARY/ABSTRACT
The relationship between radiation therapy to the thorax and heart damage has been established through
long-term studies of patients with breast cancer and Hodgkin lymphoma as cardiac disease became the
primary non-cancer cause of death among such patients. Clinical treatments for both diseases have been
adjusted to minimize radiation heart exposure by simple shielding and technical advances. For patients with
locally advanced lung cancer, meaning that the mediastinal lymph nodes directly behind the heart are
already involved with cancer, it is extremely difficult to avoid heart exposure during treatment owing to the
physical location of the tumor. Yet little attention has been paid to this problem because of the assumption
that radiation-induced cardiac damage is problematic only for patients who live longer than 5 years after
their diagnosis. This excludes the vast majority of lung cancer patients, as their longevity with the current
standard of care is estimated in the range of 18-24 months. This assumption that radiation causes only late-
onset cardiac problems has been recently called into question. A recent phase III study suggested that poor
survival rates of lung cancer patients may reflect the amount of heart tissue that is inadvertently exposed to
radiation during treatment, which may cause premature death. We recently completed a randomized trial
comparing protons and photons for lung cancer patients and found that proton therapy can significantly
reduce unwanted radiation to the heart. However, we have not investigated if the reduction of radiation to
the heart has reduced heart damage, nor if the reduction in heart exposure can translate to improved
survival in patients with lung cancer. Damaged heart tissue releases cardiac troponin T (TnT), which is used
widely in cardiology to diagnose and monitor heart damage after chemotherapy and radiation for breast
cancer or lymphoma. Damaged heart tissue can also be visualized and quantified by PET scans. In this
proposal, we will determine if reduced heart exposure to radiation by proton therapy can indeed reduce
heart damage due to radiation in lung cancer patients. We will also determine if the reduced heart damage
will improve the survival of these patients. Both of these goals will be analyzed by using a highly sensitive
assay for cardiac TnT and the changes on the PET images from samples collected during the course of a
completed randomized clinical trial. We will also investigate if certain heart structures are more sensitive to
radiation by leveraging detailed dosimetry of implemented treatment plans. While this proposal carries risk
that no cardiac benefit will be found after proton radiation, it also carries the potential of significant clinical
impact as it could lead to practice-changing findings.

## Key facts

- **NIH application ID:** 10017671
- **Project number:** 5R21CA222749-02
- **Recipient organization:** UNIVERSITY OF TX MD ANDERSON CAN CTR
- **Principal Investigator:** ZHONGXING LIAO
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $176,175
- **Award type:** 5
- **Project period:** 2019-09-17 → 2022-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10017671

## Citation

> US National Institutes of Health, RePORTER application 10017671, Proton Therapy to Reduce Heart Damage for Lung Cancer Patients (5R21CA222749-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10017671. Licensed CC0.

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