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E. Van Der Bijl
MINI 33 - Radiotherapy and Complications (ID 164)
- Event: WCLC 2015
- Type: Mini Oral
- Track: Treatment of Locoregional Disease – NSCLC
- Presentations: 1
MINI33.03 - Heart Dose Is Associated with Shorter Overall Survival for Patients Treated with Chemo-Radiation for Locally Advanced NSCLC (ID 2755)
18:30 - 20:00 | Author(s): E. Van Der Bijl
Traditionally, sparing the heart in chemo-radiotherapy of locally advanced lung cancer has a low priority compared to the lungs and esophagus. Recently, however, the randomized phase III trial RTOG 0617 showed that the volume of the heart receiving a dose of at least 5Gy (V5) was associated with a lower overall survival (OS). The aim of the current study is to validate this in an independent database.
Patients treated with IMRT (24x2.75Gy with daily low-dose cisplatin) at our hospital between 2006 and 2014 were retrospectively selected. For the heart both mean dose and Vx denoting the volume receiving x Gy or more (x in range 5-50Gy with 5Gy increments) were calculated. Associations of these parameters with OS were evaluated using univariate and multivariate proportional hazards analysis. In multivariate analysis we separately paired the total GTV (primary tumor plus involved lymph nodes) to Vx and mean dose.
375 pts were available for analysis. Median follow up was 16 months and median OS was 26 months. Using univariate proportional hazard modeling mean dose and all Vx for x<40Gy were significantly associated (p<0.05) with OS. For V5, which was most significant in the analyzed set, the hazard ratio (HR) was 1.008. When pts are split at the median V5 = 37.0%, the median OS was 29 ± 2.5 months versus 19 ± 2.4 months for pts below and above the median respectively (p=0.03, Log Rank). Similarly, the figure illustrates significant separation in Kaplan-Meier plots of OS with the pts divided in V5 quartiles. In the multivariate analysis the correlation between GTV (median volume 109 cc) and mean dose or Vx was less than 0.15, indicating that a higher heart dose is not the effect of larger tumor volumes and hence a worse survival due to more advanced decease. Both GTV (p<0.001, HR=1.001) and V5 (p=.003, HR=1.007) were significant in multivariate analysis as was the case with GTV (p<0.001, HR=1.001) and mean dose (p=0.033, HR=1.018).
For pts treated with chemoradiation the dose received by the heart is strongly associated with overall survival. Our results are in accordance with the results of RTOG 0617  for the V5 with similar HR despite the different fractionation scheme and chemo regimen. This indicates that cardial toxicity might be more important in lung cancer patients treated with chemoradiation than previously anticipated. Consequently, better sparing of the heart potentially improves outcome.  Bradley et.al. J Clin Oncol 31, 15 pp. 7501
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