Radiation Dose, Local Disease Progression, and Overall Survival in Patients with Inoperable Non–Small-Cell Lung Cancer After Concurrent Chemoradiation Therapy
Menée à partir de données portant sur 491 patients atteints d'un cancer du poumon non à petites cellules de stade IIIA à IIIB, inopérable et traité entre 2005 et 2013 par radiothérapie en combinaison avec une chimiothérapie concomitante, cette étude identifie les facteurs prédictifs associés à la survie sans progression locale et à la survie globale
Purpose : To identify predictors of local control and overall survival (OS) for patients with inoperable non-small-cell-lung cancer (NSCLC) treated with concurrent chemoradiation therapy.
Methods : We identified 491 patients with newly diagnosed stage IIIA-IIIB NSCLC who had received 60–74 Gy (with concurrent chemotherapy) from January 2005 through December 2013 and grouped them by radiation dose received: 60–63 Gy, 64–66 Gy, 67–70 Gy, or 71–74 Gy. Local progression (LP) was that appearing within the high-dose volume (planning target volume [PTV]+ 1-cm margin). Times to events were calculated from the completion of radiotherapy. Potential predictors of LP and OS were analyzed with a Cox regression model.
Results : LP rates for all patients were 16.2% at 1 year, 26.2% at 2 years, 31.0% at 3 years, 32.9% at 4 years, and 32.9% at 5 years; corresponding OS rates were 85.3%, 61.2%, 44.5%, 37.0%, and 31.6%. Median OS time was 21 months (range 2.9-99.9 months). In multivariate analysis, receipt of 67–70 Gy was associated with improved LP-free survival (LPFS) relative to 60–63 Gy (hazard ratio [HR] 1.83, 95% confidence interval [CI] 1.062–3.150, P=0.030) or 64–66 Gy (HR 2.14, 95% CI 1.159–3.969, P=0.015). Non-squamous histology (HR 0.23, 95% CI 0.114–0.478, P=0.000), gross tumor volume (HR 1.00, 95% CI 1.000–1.003, P=0.018) and induction chemotherapy (HR 1.86, 95% CI 1.239–2.778, P=0.003) were independent predictors of LPFS. LPFS was the only independent predictor of OS (HR 2.71, 95% CI 1.331–5.512, P=0.006). Incidence of grade ≥3 radiation pneumonitis was no different among dose groups (P=0.307).
Conclusions : Squamous histology, large tumor volumes, and receipt of induction chemotherapy all predicted worse LPFS. Doses of 67–70 Gy were associated with improved LP-free survival after chemoradiotherapy. The link between LP and reduced OS suggests that more effective local-control strategies are warranted.
International Journal of Radiation Oncology • Biology • Physics , article en libre accès, 2016