Meanwhile, the ASCO guideline makes several recommendations regarding radiotherapy for patients with mesothelioma, including an informal consensus that radiotherapy may be offered to patients with localized recurrence even when recurrence is not symptomatic.3
Clear communication is key to conveying options and recommendations to patients. The ASCO guideline authors emphasized “increasing information asymmetry between physician and patient” with advances in the field, and the “nearly impenetrable” complexity of relevant information for patients when it is presented using technical jargon.3 Patients should be told of the limited available clinical-trial evidence base and the goals of different treatment options. (ASCO has separately promulgated a consensus guideline on patient-clinician communication [J Clin Oncol. 2017;35(31):3618-3632].)
The ASCO mesothelioma clinical guideline includes several evidence-based recommendations about radiotherapy.
- Adjuvant radiotherapy should be offered to patients with histologically positive resection procedure-tract samples.3 (Quality of evidence: Intermediate)
- Radiotherapy should be offered for palliation of symptoms. Electrons, IMRT, 2D, and 3DCRT techniques should be selected based on target tissue location.3 (Quality of evidence: Intermediate)
- Standard dosing regimens offered to patients should include 8 Gy in a single fraction, 4 Gy in 5 fractions, or 3 Gy in 10 fractions.3 (Quality of evidence: Intermediate)
- Neoadjuvant radiotherapy should be avoided with patients undergoing lung-sparing cytoreductive surgery because of the potential for severe pulmonary toxicity.3 (Quality of evidence: Intermediate)
- Adjuvant and neoadjuvant hemothoracic radiotherapy, 3DCRT, or IMRT may be offered but proton beam therapy should be considered only at centers with significant experience, preferably in the context of a clinical trial.3 (Quality of evidence: Intermediate)
- Hemithoracic adjuvant radiotherapy may be offered after non-lung-sparing cytoreductive surgery (EPP). Such treatment should be undertaken at centers of excellence. Hemithoracic neoadjuvant radiotherapy or adjuvant IMRT may also be offered to these patients, but because of the potential for toxicity, these regimens should be performed only at highly experienced centers of excellent for patients participating in clinical trials.3 (Quality of evidence: Intermediate)
Despite the limited rate of advances over recent decades in treating mesothelioma, there is some reason for hope that radiotherapy might be combined with immuno-oncology treatment to improve patient symptoms and outcomes. Ablative radiotherapy has been tied to immune system stimulation and preclinical lab-animal studies suggest that short-course ablative radiation therapy combined with an immune checkpoint blockade might improve immune system recognition and attack of tumor tissue.6 Clinical trials are now underway for the combination of immunotherapies with chemotherapy, radiotherapy, and/or surgery.6
Bryant Furlow is a medical journalist based in Albuquerque, New Mexico.
1. Beebe-Dimmer JL, Fryzek JP, Yee CL, et al. Mesothelioma in the United States: a Surveillance, Epidemiology, and End Results (SEER)-Medicare investigation of treatment patterns and overall survival. Clin Epidemiol. 2016;8:743-750.
2. Scherpereel A, Wallyn F, Albelda SM, Munck C. Novel therapies for malignant pleural mesothelioma. Lancet Oncol. 2018;19(3):e161-e172.
3. Kindler HL, Ismaila N, Armato SG 3rd, et al. Treatment of malignant pleural mesothelioma: American Society of Clinical Oncology Clinical Practice Guideline [published online January 18, 2018]. J Clin Oncol. doi:10/1200/JCO.2017.76.6394
4. Ashton M, O’Rourke N, Currie S, Rimner A, Chalmers A. The role of radical radiotherapy in the management of malignant pleural mesothelioma: a systematic review. Radiother Oncol. 2017;125:1-12. doi:10.1016/j.radonc.2017.08.003
5. Buikhuisen WA, Burgers JA, Vincent AD, et al. Thalidomide versus active supportive care for maintenance in patients with malignant mesothelioma after first-line chemotherapy (NVALT 5): an open-label, multicentre, randomised phase 3 study. Lancet Oncol. 2013;14(6):543-551.
6. Perrot M, Wu L, Wu M, Cho BCJ. Radiotherapy for the treatment of malignant pleural mesothelioma. Lancet Oncol. 2017;18(9):e532-e542.
7. Clive AO, Taylor H, Dobson L, et al. Prophylactic radiotherapy for the prevention of procedure-tract metastases after surgical and large-bore pleural procedures in malignant pleural mesothelioma (SMART): a multicentre, open-label, phase 3, randomised controlled trial. Lancet Oncol. 2016;17(8):1094-1104.
8. Ashton M, O’Rourke N, Macleod N, et al. SYSTEMS-2: a randomised phase II study of radiotherapy dose escalation for pain control in malignant pleural mesothelioma. Clin Transl Radiat Oncol. 2017;8:45-49.
9. MacLeod N, Chalmers A, O’Rourke N, et al. Is radiotherapy useful for treating pain in mesothelioma?: a phase II trial. J Thorac Oncol. 2015;10(6):944-950.