Phase III randomised trialA randomised controlled trial of intervention site radiotherapy in malignant pleural mesothelioma
Section snippets
Patients and methods
Patients with a histological diagnosis of malignant pleural mesothelioma and an intervention site to the pleura within the preceding 21 days were considered for entry into the study. Exclusion criteria were expected survival less than 3 months and prior systemic chemotherapy or local radiotherapy for their disease. Patients were allocated to treatment using the minimization technique to ensure the two arms were well balanced. Facilities for central telephone registration/randomisation were
Statistical analysis
On the basis of the previous Boutin study this trial was designed to detect a difference in the incidence of patients developing tract metastasis from 40% (no radiotherapy) to 5% (with radiotherapy). Based on a comparison of proportions using Pearson’s chi-square test (80% power, 5% two-sided level of statistical significance) this required 22 patients to be recruited to each treatment arm.
In view of the high attrition rate on study due to patient deaths this calculation was subsequently
Pre-treatment
All randomised patients are included in the analysis (by intention-to-treat). Sixty-one patients were recruited between February 1998 and August 2004. There were 56 men and five women, age range 47–84 years, median age 70. Fifty-three patients were entered from Glasgow and eight from Newcastle. ECOG Performance status (PS) was 0 in 21 patients (34%), PS 1 in 27 patients (44%), PS 2 in 10 patients (16%) and PS 3 in 3 patients (5%). Age, performance status and centre were very balanced between
Discussion
Prophylactic radiotherapy to intervention sites in malignant pleural mesothelioma has been widely adopted around the world following publication of two small studies ten years ago. It is recognised that mesothelioma patients are at risk of developing subcutaneous tumour deposits following intervention and it seemed that local radiotherapy in short fractionated courses to superficial depth was effective in preventing this complication.
Our local experience in Glasgow on adopting this treatment
Conclusion
Radiotherapy to the drain site in mesothelioma patients does not reduce the incidence of seeding of tumour subcutaneously. Tract metastases, when they do occur, may be small and asymptomatic. We do not recommend routine prophylactic irradiation of drain sites.
Acknowledgements
The authors acknowledge the support of Cancer Research UK, for statistical input to design and analysis of the trial, and to the data collection staff in Glasgow and Newcastle, as well as the respiratory physicians who referred their patients for consideration of treatment.
References (4)
- et al.
Prevention of tumour seeding following thoracoscopy in mesothelioma by prophylactic radiotherapy
Clin Oncol
(1995) - et al.
Prevention of malignant seeding after invasive diagnostic procedures in patients with pleural mesothelioma
Chest
(1995)