[Proton beam therapy with concurrent chemotherapy for non-small cell lung cancer -- our experiences and future...

Concurrent chemoradiotherapy is the gold standard of care for patients with unresectable locally advanced non-small cell lung cancer (NSCLC). Proton beam therapy (PBT) can reduce the doses for normal lungs because of the penetration energy peak. PBT with concurrent chemotherapy for locally advanced NSCLC has been introduced in National Cancer Center Hospital East since December 2011. Thirty-three patients received PBT with concurrent chemotherapy for 2 years. Nine patients received PBT because they were not suited for radical photon radiotherapy due to excessive V20 Gy or doses to the spinal cord. Thirty-one patients received cisplatin plus vinorelbine; the remaining 2 patients received weekly carboplatin and paclitaxel, or daily carboplatin. All but 1 patient received the planned PBT dose (60 GyE[n=15]or 66 GyE[n=17]). PBT was terminated in 1 patient after the delivery of 36 GyE because of the development of liver metastases. PBT was suspended in 8 patients because of the development of febrile neutropenia (n=6) and esophagitis (n=3). Two patients (6%) experienced grade 3 esophagitis. The grade 2 toxicities included esophagitis (n=12), dermatitis (n=10), and pneumonitis (n=2). Grade 3 pneumonitis was not observed. Disease progression was observed in 17 patients. In-field recurrence was observed in 4 patients, distant metastases were observed in 14 patients, and both types of recurrence were observed in 1 patient. With a median follow-up time of 6.0 months for censored cases, the median progression-free survival time was 9.9 months (95% confidence interval: 5.2-14.6). Our retrospective study demonstrates that PBT with concurrent chemotherapy is feasible, although the possible complications, such as radiation esophagitis and dermatitis, might be rather severe compared with standard chemoradiotherapy using photons.