Purpose: To describe the initial experience at Dana-Farber Cancer Institute/Brigham and Women’s
Hospital with intensity-modulated radiation therapy (IMRT) as adjuvant therapy after
extrapleural pneumonectomy (EPP) and adjuvant chemotherapy.
Methods and Materials: The medical records of patients treated with IMRT after EPP and adjuvant chemotherapy
were retrospectively reviewed. IMRT was given to a dose of 54 Gy to the clinical target
volume in 1.8 Gy daily fractions. Treatment was delivered with a dynamic multileaf
collimator using a sliding window technique. Eleven of 13 patients received heated
intraoperative cisplatin chemotherapy (225 mg/m2). Two patients received neoadjuvant intravenous cisplatin/pemetrexed, and 10 patients
received adjuvant cisplatin/pemetrexed chemotherapy after EPP but before radiation
therapy. All patients received at least 2 cycles of intravenous chemotherapy. The
contralateral lung was limited to a V20 (volume of lung receiving 20 Gy or more) of
20% and a mean lung dose (MLD) of 15 Gy. All patients underwent fluorodeoxyglucose
positron emission tomography (FDG-PET) for staging, and any FDG-avid areas in the
hemithorax were given a simultaneous boost of radiotherapy to 60 Gy. Statistical comparisons
were done using two-sided t test.
Results: Thirteen patients were treated with IMRT from December 2004 to September 2005. Six
patients developed fatal pneumonitis after treatment. The median time from completion
of IMRT to the onset of radiation pneumonitis was 30 days (range 5–57 days). Thirty
percent of patients (4 of 13) developed acute Grade 3 nausea and vomiting. One patient
developed acute Grade 3 thrombocytopenia. The median V20, MLD, and V5 (volume of lung
receiving 5 Gy or more) for the patients who developed pneumonitis was 17.6% (range,
15.3–22.3%), 15.2 Gy (range, 13.3–17 Gy), and 98.6% (range, 81–100%), respectively,
as compared with 10.9% (range, 5.5–24.7%) (p = 0.08), 12.9 Gy (range, 8.7–16.9 Gy) (p = 0.07), and 90% (range, 66–98.3%) (p = 0.20), respectively, for the patients who did not develop pneumonitis.
Conclusions: Intensity-modulated RT treatment for mesothelioma after EPP and adjuvant chemotherapy
resulted in a high rate of fatal pneumonitis when standard dose parameters were used.
We therefore recommend caution in the utilization of this technique. Our data suggest
that with IMRT, metrics such as V5 and MLD should be considered in addition to V20
to determine tolerance levels in future patients.