New radiotherapy technique aims to protect the heart during lung cancer treatment

A new study presented at ESTRO 2025 introduces the RAPID-RT study, which uses an innovative rapid-learning approach to evaluate the impact of treatment modifications in radiotherapy. The paper also appears in Radiotherapy and Oncology.

Traditional clinical trials are often lengthy and are not representative of real-world patient populations due to complex consent processes and strict eligibility criteria. In contrast, RAPID-RT offers a more inclusive, real-world alternative.

Researchers at The Christie NHS Foundation Trust in Manchester, UK, have applied this method in lung cancer patients to assess whether reducing the dose to the top of the heart—a hypothesized risk area—can improve survival by minimizing cardiac toxicity associated with conventional radiotherapy.

Targeting tumors, protecting the heart

Radiotherapy is a highly effective treatment for lung cancer, yet the heart is often located close to the tumor site. It is important that the dose to the heart is minimized to reduce the risk of serious complications. Previous research in Manchester using radiotherapy planning images identified the top of the heart as a particularly radiosensitive area in lung cancer patients, with radiation dose to this region found to be associated with overall survival.

Based on these results, a new “heart-sparing” technique was implemented in the routine clinical setting to address this challenge.

“RAPID-RT represents a shift towards more inclusive research, designed to reflect the realities of everyday clinical practice and ensure that all patients, not just those who meet narrow trial criteria, benefit from innovation in radiotherapy,” said co-lead investigator Dr. Gareth Price, senior lecturer and medical physicist, at the University of Manchester.

“We also hope that by reducing cardiac exposure, we may improve both survival and quality of life for patients.”

Key data from over 1,700 patients

The RAPID-RT study analyzed data from 1,708 patients with stage I–III lung cancer who received curative-intent radiotherapy between January 2021 and February 2025:

• Standard curative-intent radiotherapy treatment was given to 922 patients treated before April 2023.
• The new heart-sparing technique was applied prospectively to 786 patients from April 2023 onwards, using two key innovations:
  • An inclusive rapid-learning study design: this approach enables fast recruitment by including all patients treated at the institution, unless they actively opt out of data collection.
  • Limiting radiation to a defined Cardiac Avoidance Area (CAA): Radiation dose to sensitive parts of the heart was limited to 19.5 Gy (or equivalent) over 20–33 sessions, unless this restriction compromised adequate tumor coverage
• Early results show that the rapid-learning method is highly inclusive, as to date, all patients with stage I–III NSCLC treated with conventional curative-intent radiotherapy received the new technique, with only one out of 786 patients choosing to opt out of the study. Initial findings suggest a modest improvement in 12-month survival following implementation of a dose limit to the top of the heart.

Faster answers with real-world evidence

Unlike traditional clinical trials, which can take years to deliver results, the RAPID-RT study used a “rapid-learning” model, to evaluate and adapt treatments in real time using routine anonymized data from the electronic care record. This approach allows researchers to refine treatment strategies more quickly, bringing effective innovations to patients faster.

“This research is a perfect example of how innovation in radiotherapy is not only about technology, but also about how we learn, adapt, and deliver better care,” said Professor Matthias Guckenberger, President of ESTRO and Chair of Radiation Oncology at the University Hospital Zurich.

“It demonstrates the power of combining cutting-edge technology with real-world data to make radiotherapy safer and even more effective.”

Towards smarter, more inclusive evaluation of radiotherapy modifications

RAPID-RT represents an important step towards more inclusive and pragmatic clinical trials in radiotherapy. The study provides compelling evidence that novel trial methods can effectively evaluate treatment modifications, especially in situations where traditional randomized trials are not feasible.

The study will continue to recruit and follow patients’ progress to confirm these early results and allow clinical teams to decide if patients might benefit from further refinement of the new radiotherapy technique. Ongoing analyses will assess the potential impact on long-term survival, radiotherapy-related toxicities, and explore alternative modeling approaches to better understand treatment outcomes.