Clinical outcomes of stereotactic body radiotherapy for stage I non-small cell lung cancer using different doses depending on tumor size

Abstract

BackgroundThe treatment schedules for stereotactic body radiotherapy (SBRT) for lung cancer vary from institution to institution. Several reports have indicated that stage IB patients had worse outcomes than stage IA patients when the same dose was used. We evaluated the clinical outcomes of SBRT for stage I non-small cell lung cancer (NSCLC) treated with different doses depending on tumor diameter.MethodsBetween February 2004 and November 2008, 124 patients with stage I NSCLC underwent SBRT. Total doses of 44, 48, and 52 Gy were administered for tumors with a longest diameter of less than 1.5 cm, 1.5-3 cm, and larger than 3 cm, respectively. All doses were given in 4 fractions.ResultsFor all 124 patients, overall survival was 71%, cause-specific survival was 87%, progression-free survival was 60%, and local control was 80%, at 3 years. The 3-year overall survival was 79% for 85 stage IA patients treated with 48 Gy and 56% for 37 stage IB patients treated with 52 Gy (p = 0.05). At 3 years, cause-specific survival was 91% for the former group and 79% for the latter (p = 0.18), and progression-free survival was 62% versus 54% (p = 0.30). The 3-year local control rate was 81% versus 74% (p = 0.35). The cumulative incidence of grade 2 or 3 radiation pneumonitis was 11% in stage IA patients and 30% in stage IB patients (p = 0.02).ConclusionsThere was no difference in local control between stage IA and IB tumors despite the difference in tumor size. The benefit of increasing the SBRT dose for larger tumors should be investigated further.

Early response and local control of stage I non‐small‐cell lung cancer after stereotactic radiotherapy: difference by histology

“…(12)(13)(14)16,17) Poor pulmonary function is a cause of medical inoperability, but we could not detect the influences of pulmonary function. Many other conditions are causes of medical inoperability.…”

“…This was a subsidiary analysis of prospective protocol-based studies of SBRT for stage I NSCLC; details of the SBRT studies were described previously. (16,17) In the studies, evaluation of tumor response using computed tomography (CT) was scheduled at 2, 4 and 6 months following SBRT. All patients underwent a pulmonary function test before SBRT.…”

“…Our methods of SBRT have been described in detail previously. (16,17) Briefly, CT images for treatment planning were obtained under normal breathing, and with breath holding during the expiratory and inspiratory phases. The clinical target volume (CTV) was defined as the visible gross tumor volume.…”

A phase I/II study on stereotactic body radiotherapy with real-time tumor tracking using CyberKnife based on the Monte Carlo algorithm for lung tumors

“…The incidence of grade 3 RP was extremely low in this study despite increases in the administered dose and large number of medically inoperable patients. Grade ≥2 severe pneumonitis was also relatively rare (10%); in other studies, the incidence of grade 2 or 3 RP was 11-39% [3,15,[26][27][28]. In the dose volume histogram analysis, V20 Gy (percentage of the lung minus the GTV volume receiving ≥20 Gy), V5 Gy, and the mean lung dose appeared to be suppressed at low levels despite dose increases, and this may have been due to decreases in the ITV owing to tracking.…”

Stereotactic Body Radiotherapy

“…The mixture of patient population (some with metastatic cancers) with varying degrees of comorbidities, differences in fractionation, and different clinical end points preclude exact comparison between studies. However, it has been shown in several retrospective studies that SBRT for primary lung tumors is more effective than conventionally fractionated treatment for medically inoperable patients (Blumgart and Fong 1995;Uematsu et al 1998;Hof et al 2003;Lee et al 2003;Onimaru et al 2003;Onishi et al 2004;Wulf et al 2004;Timmerman et al 2005;Baumann et al 2006;Fritz et al 2006;Hara et al 2006;Brown et al 2007;Pennathur et al 2007;Ricardi et al 2007;Scorsetti et al 2007;Baba et al 2010;Dunlap et al 2010). Local control is approximately 90% using various fractionations and total doses.…”