60O - Analysis of local recurrences following stereotactic ablative radiotherapy (SABR): Data from a large institutional database

Date 16 April 2015
Event ELCC 2015
Session New treatment avenues
Topics Non-Small-Cell Lung Cancer, Early Stage
Surgery and/or Radiotherapy of Cancer
Presenter Naomi Verstegen
Citation Annals of Oncology (2015) 26 (suppl_1): 18-23. 10.1093/annonc/mdv048
Authors N. Verstegen, F.J. Lagerwaard, M. Dahele, B.J. Slotman, S. Senan
  • Dept Of Radiation Oncology, Vrije University Medical Centre (VUMC), 1007MB - Amsterdam/NL

Abstract

Aim/Background

SABR is a guideline-recommended treatment for early stage non-small cell lung cancer (ES-NSCLC). Local control rates of ≥90% have been reported. To identify risk factors for recurrences and determine optimal follow-up schedules, we analyzed local recurrences (LR) in patients treated with SABR to the recommended minimal biologically effective dose (BED10) of 100Gy [ESMO Clinical practice guidelines 2013].

Methods

All patients treated with SABR at the VUmc are recorded in a institutional database. We excluded patients with double tumors, TNM-stages other than T1-T2N0M0 and previous treatment for the index tumor. Cox regression analysis was performed to investigate the prognostic value of age, gender, TNM-stage, fractionation scheme, PTV-size, histology, and a history of prior malignancy.

Results

LR were diagnosed in 46 out of 855 patients treated with SABR for ES-NSCLC. Median follow-up was 52 months; actuarial local control rates at 3 and 5 years were 92.4% and 90.9% respectively. Median time to LR was 22 months (range 7-87 months). LR was diagnosed based on CT scans in all but two patients and confirmed with pathology in 18 patients (39%) and/or FDG-PET scans in 32 patients (70%). Recurrence was local only in 25 patients (54%) and loco-regional in 31 patients (67%). None of the investigated factors correlated significantly with local control on multivariate analysis. Because 74% of patients with LR were initially considered inoperable, only 10 patients (21%) underwent radical salvage therapy, in the form of surgery (n = 6) with adjuvant chemotherapy (n = 3) or radiotherapy (n = 1), high-dose radiotherapy (n = 3), or chemo-radiation (n = 1). The median survival following diagnosis of a LR was 12 months, with a 2-year survival of 23%. In patients who underwent radical salvage median survival following diagnosis was 36 months.

Conclusions

In a relatively large cohort of patients with a LR following SABR for ES-NSCLC, none of the investigated factors correlated with local failure. Given the large variation in time to LR of up to 87 months, and the presence of isolated LR in 54% of such patients, we suggest that long term follow-up is important for patients who are eligible for salvage therapies.

Disclosure

F.J. Lagerwaard and S. Senan: have received speaker honoraria from Varian Medical Systems.

B.J. Slotman and M. Dahele: have received honoraria from Varian Medical Systems.

The dept of Radiation Oncology at the VUmc has a research agreement with Varian Medical Systems.

All other authors have declared no conflicts of interest.