IMRT Reduces Side Effects in Lung Cance

The use of intensity modulated radiation therapy (IMRT) reduces serious side effects caused by standard 3D radiation in locally advanced lung cancer. These results were recently presented at the 57th annual meeting of the American Society for Radiation Therapy (ASTRO).

Locally advanced lung cancer refers to cancer that has spread from its site of origin, but has remained within the lung or nearby lymph nodes. One component of treatment for locally advanced lung cancer includes radiation. Unfortunately, side effects associated with radiation can be serious, as the radiation can damage healthy tissues surrounding the cancer, including healthy lung tissue and/or the heart.

IMRT is a type of radiation technique that delivers radiation more directly to the cancer cells than 3D radiation, thus sparing nearby healthy tissues from the damaging effects of direct exposure to radiation.

Researchers recently conducted a subgroup analysis from a prior clinical trial to evaluate side effects associated with different types of radiation. The trial included 482 patients with locally advanced lung cancer who were treated with either 3D radiation or IMRT.

Researchers evaluated the rates of pneumonitis, which was defined as inflammation of the lung that required treatment with oxygen, steroids and/or mechanical ventilation, and/or resulted in death. They also determined radiation doses delivered to the heart.

Pneumonitis occurred in 3.5% of patients treated with IMRT, compared with 7.9% of patients treated with 3D radiation.
IMRT delivered significantly lower doses of radiation to the heart than 3D radiation, which was highly associated with survival.
37% of patients treated with IMRT were able to complete high dose consolidative chemotherapy, compared with 29% treated with 3D radiation.
The researchers concluded that IMRT significantly reduces the rates of pneumonitis and radiation delivered to the heart, compared to 3D radiation in locally advanced lung cancer. Ultimately, this reduces the rates of hospitalization and extra therapy to treat pneumonitis, while improving quality of life and the ability to tolerate subsequent chemotherapy.

Reference: Chun S, et al. Comparison ofn3D conformal and intensity modulated radiation therapy outcomes for locally advanced non-small cell lung cancer in NRG Oncology/RTOG 0617. Proceedings from the 57th annual meeting of the American Society for Therapeutic Radiation (ASTRO). Presented October 18, 2015.