Needle-track metastases and prophylactic radiotherapy for mesothelioma

SummaryBackgroundMesothelioma invades the tracts made by chest instrumentation. Prophylactic radiotherapy is effective at preventing malignant seeding at these sites.MethodsWe assessed the use and effectiveness of radiotherapy at our centre in 39 of the 40 patients identified with mesothelioma between January 2000 and September 2003.ResultsThirty-seven (95%) patients received radiotherapy to their chest instrumentation site between 6 and 42 days (median 26 days) following the diagnosis of mesothelioma. The radiotherapy field size varied, from 4 cm square to 14×10.5 cm. The radiotherapy was given as 21 Gy in 3 fractions over 1 week. In 3 patients (8%), there was already tumour invasion of the skin at the time of radiotherapy. In 2 other patients (5%), there was tumour recurrence following radiotherapy; in both this was at the edge of the previous radiotherapy fields. Further treatment was administered to an adjacent field in both. One patient with an indwelling pleural catheter developed tumour growth at the catheter insertion site. This was treated successfully with radiotherapy, with no catheter damage.ConclusionsPrompt radiotherapy referral and radiotherapy field selection is important to maximise the effect of radiotherapy given to prevent chest wall tumour growth. There was no tumour growth in areas that were treated with radiotherapy. Further chest interventions outside the radiotherapy field should be followed with further radiotherapy.