Author of

• 12544

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  P3.08 - Poster Session 3 - Radiotherapy (ID 199)

  • Event: WCLC 2013
  • Type: Poster Session
  • Track: Radiation Oncology + Radiotherapy
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/30/2013, 09:30 - 16:30, Exhibit Hall, Ground Level

  • 12561

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    P3.08-017 - High-dose, conventionally fractionated thoracic reirradiation for second primary lung tumors or recurrent disease (ID 2335)

    09:30 - 09:30  |  Author(s): P. Ven Van De
    • Abstract

    Background
    Although loco-regional recurrences and second primary lung tumors are not uncommon following prior high-dose thoracic radiotherapy, only a minority of patients undergo reirradiation. Reirradiation performed at short intervals, and to low total doses, is generally associated with median overall survival (OS) of only 5-7 months. Few studies report outcomes following high-dose reirradiation. We describe institutional experience after high-dose, conventionally fractionated reirradiation.

    Methods
    High-dose conventional reirradiation was defined as fraction sizes of 2-3Gy and minimum total dose of 39Gy. A retrospective chart review of patients treated between Feb 2004-Feb 2013 was performed. Where possible, overlap in planning target volumes (PTV) and radiation doses were determined. New primary tumors were defined as new histology or reirradiation interval ≥5 years.

    Results
    24 patients were identified, 13 (54%) had recurrent disease, and 46% a new primary. Most (63%) had stage III NSCLC at initial and second treatments; median reirradiation interval was 51 months, and median follow-up from reirradiation 19.1 months. Median overall survival (OS) after reirradiation was 13.5 months, with 1-year survival 51%, median local progression-free survival (LPFS) 14.1 months and median distant progression-free survival (DPFS) 18.5 months. One-year disease-free survival was 47%. Three patients died from bleeding (2/3 had high-dose overlap in the mediastinum, of whom one had prior hemoptysis and was anticoagulated, the 3rd patient had extensive endobronchial therapy prior to reirradiation). Other post-retreatment toxicity was uncommon. The size of the second PTV (median 250cc) was prognostic. OS was 17.4 versus 8.2 months for patients with a 2nd PTV <300cc and >300cc respectively (p=0.02). Differences in DPFS (p=0.007) and for DFS (p=0.03) were also significant. LPFS was shorter when reirradiation interval was <24 months (p=0.02), however it was not different when groups were defined by the median interval of 51 months. Magnitude of PTV and dose overlap between the two treatments did not influence survival. Figure 1 Figure 1: Example of reirradiation for a new primary lung cancer. Planning target volume (PTV) and dose-cloud shown from treatment in 2004 (A, 23 fractions of 2.6Gy) and 2010 (B, 33 fractions of 2Gy) and the overlap of both treatments (C).

    Conclusion
    High-dose, conventionally fractionated reirradiation for new primary or recurrent lung cancer can deliver meaningful survival, especially for patients with a smaller PTV at the time of reirradiation. A shorter reirradiation interval may be associated with less chance of loco-regional control. Prospective studies are needed to confirm these findings, and establish reliable normal tissue tolerances for reirradiation.