From the Journals

Lung cancer with ILD patients fare poorly after thoracic radiotherapy


 

FROM CLINICAL ONCOLOGY

Most lung cancer patients with interstitial lung disease will not benefit from thoracic radiotherapy, based on data from a systematic review of 24 studies.

Thoracic radiotherapy remains a key part of lung cancer treatment for early and metastatic disease. However, patients with both small cell lung cancer (SCLC) and non–small cell lung cancer (NSCLC) associated with interstitial lung disease (ILD) fare worse than do those without ILD, often because of acute exacerbation of ILD and severe or fatal pneumonitis, wrote Animesh Saha, MD, of Apollo Multi-Specialty Hospitals, Kolkata, India, and colleagues. Consequently, clinicians may hesitate to offer radiotherapy to these patients.

In a review published in Clinical Oncology, the researchers identified 24 studies, including phase II and phase III randomized or nonrandomized trials, as well as prospective, observational studies and retrospective real-world studies. The goal of the review was to report the incidence and predictors of radiation pneumonitis associated with different types of thoracic radiotherapy for lung cancer patients with ILD, the researchers said. Treatment types included curative-intent fractionated radiotherapy or chemoradiotherapy or moderately hypofractionated (nonstereotactic ablative radiotherapy [SABR]) and hyperfractionated radiotherapy as well as particle beam therapies.

The studies included patients with SCLC or NSCLC and any form of ILD, including subclinical, radiologically diagnosed, or symptomatic, the researchers said.

Overall, the median incidence of grade 3 or higher radiation pneumonitis was 19.7%; the median incidence in patients treated with conventional radical radiotherapy, SABR, and particle beam therapy was 31.8%, 11.9%, and 20.25%, respectively.

Eighteen studies reported grade 5 radiation pneumonitis; the overall median incidence was 6%, but as high as 60% in some studies. When separated by treatment type, the median incidence was 2.7%, 6.25%, and 6.25%, respectively, in patients treated with radical radiotherapy (non-SABR), SABR, and particle beam therapy.

Independent predictors of severe radiation pneumonitis (grade 2 or higher and grade 3 or higher) included subclinical or radiological ILD, the researchers said. Among ILD subtypes, studies have shown increased risk for severe radiation pneumonitis among those with non-IPF or non-UIP pattern fibrosis.

In addition, patient-related factors of low forced vital capacity (FVC) and low forced expiratory volume in 1 second (FEV1), have been associated with severe radiation pneumonitis, the researchers said. They also found increased risk for patients with lower lobe tumor location compared to other lobes.

As for treatment-related factors, a history of gemcitabine chemotherapy was associated with an increased risk of grade 3 or higher radiation pneumonitis.

“There is always concern about using thoracic radiotherapy in lung cancer patients with coexisting ILD in view of the risks involved,” the researchers wrote in their discussion of the findings. “Although thoracic radiotherapy is expected to produce similar local control, overall survival is worse in lung cancer patients with ILD than without, probably due to the poor prognosis associated with ILD and associated treatment-related mortality,” they said.

The findings were limited by several factors including the heterogeneity of the studies and study population and the retrospective design of most of the studies, the researchers noted.

However, the results highlight the increased risk of severe and fatal radiation pneumonitis in lung cancer patients with ILD and the need for careful patient selection and counseling if thoracic radiotherapy is to be considered, they concluded.

The study received no outside funding. The researchers had no financial conflicts to disclose.

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