High-dose, conventionally fractionated thoracic reirradiation for lung tumors
Menée sur 24 patients atteints d'un second cancer primitif du poumon ou présentant une récidive loco-régionale, cette étude évalue le bénéfice, en termes de survie, d'une nouvelle irradiation du thorax par radiothérapie conventionnelle à haute dose
Background : Loco-regional recurrences and second primary lung tumors are not uncommon after high-dose thoracic radiotherapy. The availability of improved radiotherapy techniques increases options for reirradiation. We describe a single-institutional experience with high-dose conventional thoracic reirradiation for both loco-regional recurrences and new primary tumors. Methods : Retrospective chart review of patients undergoing reirradiation between Feb 2004 and Feb 2013. Results : Of 24 patients identified, 54% had loco-regional recurrence, and 46% a new primary tumor. The majority (63%) had stage III NSCLC at both initial and second treatment; median interval between treatments was 51 months (5-189), median follow-up after reirradiation was 19.1 months (95%CI: 2.7-35.9). Median overall survival (OS) after reirradiation was 13.5 months, with 1-year survival 51%. Median event-free survival (EFS) was 8.4 months. Median time between reirradiation and local progression (n = 8) or distant progression (n = 8) was 6.7 and 11.8 months, respectively. Three patients died with possible grade 5 bleeding. Other toxicities were uncommon. Planning target volume (PTV) at reirradiation was the most important prognostic factor; PTV <300 versus ≥300cc was significantly associated with median OS (17.4 vs 8.2 months, p = 0.02) and EFS (18.5 vs 5.5 months, p = 0.03). Magnitude of overlap between the initial and subsequent PTVs, and between dose distributions, did not influence survival. Conclusion : Thoracic reirradiation with high dose conventional radiotherapy appears to deliver a meaningful survival benefit in low volume new primary or recurrent lung cancer. Further studies are needed to confirm these findings, and to establish reliable normal tissue tolerance doses for reirradiation.