Prospective study of proton-beam radiation therapy for limited-stage small cell lung cancer

Cancer. 2017 Nov 1;123(21):4244-4251. doi: 10.1002/cncr.30870. Epub 2017 Jul 5.

Abstract

Background: Existing data supporting the use of proton-beam therapy (PBT) for limited-stage small cell lung cancer (LS-SCLC) are limited to a single 6-patient case series. This is the first prospective study to evaluate clinical outcomes and toxicities of PBT for LS-SCLC.

Methods: This study prospectively analyzed patients with primary, nonrecurrent LS-SCLC definitively treated with PBT and concurrent chemotherapy from 2011 to 2016. Clinical backup intensity-modulated radiotherapy (IMRT) plans were generated for each patient and were compared with PBT plans. Outcome measures included local control (LC), recurrence-free survival (RFS), and overall survival (OS) rates and toxicities.

Results: Thirty consecutive patients were enrolled and evaluated. The median dose was 63.9 cobalt gray equivalents (range, 45-66.6 cobalt gray equivalents) in 33 to 37 fractions delivered daily (n = 18 [60.0%]) or twice daily (n = 12 [40.0%]). The concurrent chemotherapy was cisplatin/etoposide (n = 21 [70.0%]) or carboplatin/etoposide (n = 9 [30.0%]). In comparison with the backup IMRT plans, PBT allowed statistically significant reductions in the cord, heart, and lung mean doses and the volume receiving at least 5 Gy but not in the esophagus mean dose or the lung volume receiving at least 20 Gy. At a median follow-up of 14 months, the 1-/2-year LC and RFS rates were 85%/69% and 63%/42%, respectively. The median OS was 28.2 months, and the 1-/2-year OS rates were 72%/58%. There was 1 case each (3.3%) of grade 3 or higher esophagitis, pneumonitis, anorexia, and pericardial effusion. Grade 2 pneumonitis and esophagitis were seen in 10.0% and 43.3% of patients, respectively.

Conclusions: In the first prospective registry study and largest analysis to date of PBT for LS-SCLC, PBT was found to be safe with a limited incidence of high-grade toxicities. Cancer 2017;123:4244-4251. © 2017 American Cancer Society.

Keywords: intensity-modulated proton therapy; intensity-modulated radiotherapy; limited stage; proton therapy; small cell lung cancer.

Publication types

  • Comparative Study
  • Evaluation Study

MeSH terms

  • Aged
  • Aged, 80 and over
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use*
  • Carboplatin / administration & dosage
  • Cisplatin / administration & dosage
  • Dose Fractionation, Radiation
  • Esophagitis / epidemiology
  • Esophagitis / etiology
  • Esophagus / radiation effects
  • Etoposide / administration & dosage
  • Female
  • Heart / radiation effects
  • Humans
  • Lung / radiation effects
  • Lung Neoplasms / drug therapy*
  • Lung Neoplasms / mortality
  • Lung Neoplasms / pathology
  • Lung Neoplasms / radiotherapy*
  • Male
  • Middle Aged
  • Organs at Risk / radiation effects
  • Prospective Studies
  • Proton Therapy / adverse effects
  • Proton Therapy / methods*
  • Radiation Pneumonitis / epidemiology
  • Radiotherapy Planning, Computer-Assisted / methods
  • Radiotherapy, Intensity-Modulated / adverse effects
  • Radiotherapy, Intensity-Modulated / methods*
  • Small Cell Lung Carcinoma / drug therapy*
  • Small Cell Lung Carcinoma / mortality
  • Small Cell Lung Carcinoma / pathology
  • Small Cell Lung Carcinoma / radiotherapy*
  • Spinal Cord / radiation effects
  • Treatment Outcome

Substances

  • Etoposide
  • Carboplatin
  • Cisplatin