Expert Discusses Developments, Challenges With Radiation in NSCLC

Holger L. Gieschen, MD

Radiation therapy can be a highly effective tool for the treatment of patients with lung cancer, but Holger L. Gieschen, MD, notes that practitioners should take caution with potential adverse events associated with the modality.

“Side effects may induce skin reactions and some irritation of the lung. Acute side effects are usually transient and are not cause for concern,” says Gieschen. “Long-term side effects can result in lung fibrosis and diminished lung volume and capacity. One of the most significant side effects that can result from radiation therapy is radiation pneumonitis, which is not due to bacteria or infection, but the radiation itself. Some of these patients require steroid treatments, which can be difficult to handle.”

Other challenges with the use of radiation therapy include tumor definition, correct treatment volumes, and motion management, he says, but adds that multimodal therapeutic approaches—which include radiation—are being explored for patients with advanced non—small cell lung cancer (NSCLC).

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In an interview during the 2018 OncLive^® State of the Science Summit^TM on Advanced Non—Small Cell Lung Cancer, Gieschen, an assistant professor, Department of Radiology, University of Tennessee Health Science Center, radiation oncologist, West Cancer Center, discussed the latest developments with radiation therapy in NSCLC.Gieschen: There are 2 clinical scenarios: early-stage lung cancer that we are treating with stereotactic treatment, and advanced NSCLC that hugely requires a multidisciplinary approach.Immunotherapy is a whole different aspect of the treatment. Radiation is more akin to surgery because it is a focal, localized treatment. Even though we don't cut out any tumors, we're treating tumors locally, whereas immunotherapy is systemic. We are working in the area of personalized medicine and treating patients with multiple modality approaches, such as radiation and surgery. It really requires a multidisciplinary team effort to treat patients. One is not surmounting the other—they’re being used in conjunction now. We've seen a recently published trial from the New England Journal of Medicine showing a significant benefit for patients on durvalumab who are treated with immunotherapy after chemoradiotherapy. We’re now going to have patients who are treated with concurrent chemotherapy and radiotherapy in advanced NSCLC before progressing to immunotherapy. The challenges are tumor definition, correct treatment volumes, and motion management. In the past, tumors were missed because they were not adequately imaged or could not be treated with modern techniques like we have now. Imaging modalities are going to be very important in the future as improvements continue to be made.There’s the volume and the dose. The volume is determined by visible tumor size and the [select] gland of the disease. You’ll have to decide what you want to treat. Second, you’ll have to determine how much radiation to give, and that is the dose. Both have to be correct in order to treat the tumor without undue side effects. The larger the volume, the greater the risk of the treatment. Balance is key.In general, patients who are suitable for surgery should undergo surgical resection of the disease site because that is still the standard of care. However, there are a lot of patients who cannot have surgery. Often patients who have lung cancer may have also been smokers and may have comorbidities, including poor lung function and poor cardiac function. For those patients, radiation is a good alternative. Physicians will usually have to differentiate between acute side effects that may occur when the patient is undergoing treatment and long-term side effects that may manifest months or years after the treatment. As in surgery, the concern is a patient’s insufficient lung capacity after treatment. Hopefully, we will see less lung cancer because, based on trends, there are fewer smokers in the country now. We will also see much more individualized medicine. What we do for stage III lung cancer is going to vary from patient to patient. The same prognosis does not always warrant the same treatment. It is going to be a multidisciplinary approach, but with much more individualized and personalized medicine. These tests are expensive; they may come down [in price] over time, but it's going to be a burden on the healthcare system.