Radiotherapy of the pleural cavity in patients with primary and secondary malignancies of the pleura.

Background: Although there have been various attempts to find appropriate treatment from best conservative care to multimodal treatments, curative outcomes remain poor.

Materials and methods: 30 patients with primary and secondary malignant tumors of the pleura were treated in the Radiotherapy Clinic of USHATO during the period from December 2016 to April 2023. Video-assisted thoracoscopic surgery (VATS) and talc pleurodesis was performed in 18 patients (60%). In all patients, radiotherapy for the pleura was performed on a helical tomotherapy machine. In 21 patients (70%), normal fractionated radiotherapy was performed at daily dose of 1.8-2 Gy to total dose of 40 Gy (5 times a week), and in 6 patients (20%), integrated surdosage to 50 Gy was also performed for visible lesions. Hypofractionated radiotherapy (10 fractions of 3 Gy and 4 fractions of 4 Gy) was performed in 3 (10%) patients.

Results: Patients were followed up from 1 month to 57 months (median 14 months) or until death. The observed median survival for all patients was 19.2 months [95% confidence interval (CI): 11.5-26.9] (Fig. 3). The 1-, 2- and 3-year survival rates were 40%, 23% and 7% of patients, respectively. Malignant mesothelioma patients had 1-, 2- and 3-year survival rates of 31%, 10% and 0%, respectively. The 1-, 2-, and 3-year survival rates for patients with secondary malignancies were 54%, 45%, and 18%, respectively.

Conclusion: Our results suggest that helical tomotherapy is a feasible therapeutic option for patients with malignant mesothelioma or malignant secondary pleural involvement with a reasonable toxicity profile relative to other unaffected lung.