Prophylactic Irradiation of Chest Wall Procedure Sites in Malignant Pleural Mesothelioma
In a phase III trial reported in the Journal of Clinical Oncology, Bayman et al found that prophylactic radiotherapy to the chest wall after diagnostic or therapeutic procedures did not reduce the risk of chest wall metastases in patients with malignant pleural mesothelioma.
In the open-label, multicenter trial, 375 patients were randomly assigned between July 2012 and December 2015 to receive prophylactic radiotherapy within 42 days of a chest wall procedure (n = 186) or no prophylactic radiotherapy (n = 189) after undergoing a chest wall procedure. Open thoracotomies, needle biopsies, and indwelling pleural catheters were excluded as procedures. Prophylactic radiotherapy was given at 21 Gy in 3 fractions over 3 consecutive days using a single electron field adapted to maximize coverage of tracts from skin surface to pleura. The primary outcome was the incidence of chest wall metastases within 6 months in the intention-to-treat population.
Chest Wall Metastases and Toxicity
The incidence of chest wall metastasis at 6 months was 3.2% (6 patients) in the prophylactic radiotherapy group vs 5.3% (10 patients) in the no-radiotherapy group (odds ratio [OR] = 0.60, P = .44). At 12 months, the incidence was 8.1% vs 10.1% (OR = 0.79, P = .59).
Skin toxicity was the most common radiotherapy-related adverse event in the prophylactic radiotherapy group, with grade 1 radiation dermatitis occurring in 96 patients (51.6%), grade 2 in 19 (10.2%), and grade 3 in 1 (0.5%).
The investigators concluded, “There is no role for the routine use of prophylactic irradiation to chest wall procedure sites in patients with [malignant pleural mesothelioma].
Corinne Faivre-Finn, MD, PhD, of the University of Manchester, The Christie NHS Foundation Trust, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was funded by the National Institute for Health Research under its Research for Patient Benefit Program. The study authors’ full disclosures can be found at jco.ascopubs.org.
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