Intensity-modulated radiation therapy: a novel approach to the management of malignant pleural mesothelioma.
OBJECTIVE
Malignant pleural mesothelioma (MPM) causes symptoms and death mainly due to local progression, even after combined modality treatment. Poor local control after conventional radiotherapy may be due to the low dose of radiation that has been administered or to restriction of the target volume to avoid critical organs. Intensity-modulated radiation therapy (IMRT) has the potential to overcome these geometric/dosimetric constraints.


METHODS
Seven patients with MPM who had an extrapleural pneumonectomy (EPP) were treated with adjuvant IMRT. The clinical target volume (CTV) included the surgically violated area inside the chest wall with particular attention to the insertion of the diaphragm, pleural reflections, and the deep margin of the thoracotomy incision. Treatment was delivered by intensity-modulated 6-MV photon beams using dynamic multileaf collimation.


RESULTS
The CTV ranged from 2667 to 7286 mL. The average CTV covered to 50 Gy was 94% (range, 92% to 98%). Respiratory motion was minimal. The average volume of the boost areas covered by 60 Gy was 92% (range, 82% to 99%). Dose-volume constraints for normal tissue were met in almost all cases. Acute toxicity was mild to moderate. The most severe side effects were anorexia, nausea or vomiting, and dyspnea. Esophagitis was absent or mild. After a minimum of 13 months follow-up care there were no cases of disease recurrence within the ipsilateral hemithorax.


CONCLUSIONS
Treatment of the extensive operative area after an EPP is feasible using IMRT. Input from the radiologist and from the surgeon in the planning process facilitates definition of the high dose volumes. In light of patients' tolerance to post-EPP IMRT, it may be feasible to incorporate systemic therapy, including novel biologic therapies into the treatment regimen.
Ahamad
Anesa
A
Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston 77030, USA.
Stevens
Craig W
CW
Smythe
W Roy
WR
Vaporciyan
Ara A
AA
Komaki
Ritsuko
R
Kelly
Jason F
JF
Liao
Zhongxing
Z
Starkschall
George
G
Forster
Kenneth M
KM
D000368:Aged; D006801:Humans; D007103:Immobilization; D008297:Male; D008654:Mesothelioma / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D008875:Middle Aged; D010997:Pleural Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D011013:Pneumonectomy; D011832:Radiation Injuries / Q000517:prevention & control*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D018714:Radiotherapy, Adjuvant / Q000379:methods; D020266:Radiotherapy, Conformal / Q000379:methods*; D016896:Treatment Outcome