DART-bid: dose-differentiated accelerated radiation therapy, 1.8 Gy twice daily: high local control in early stage (I/II) non-small-cell lung cancer.

BACKGROUND: While surgery is considered standard of care for early stage (I/II), non-small-cell lung cancer (NSCLC), radiotherapy is a widely accepted alternative for medically unfit patients or those who refuse surgery. International guidelines recommend several treatment options, comprising stereotactic body radiation therapy (SBRT) for small tumors, conventional radiotherapy ≥ 60 Gy for larger sized especially centrally located lesions or continuous hyperfractionated accelerated RT (CHART). This study presents clinical outcome and toxicity for patients treated with a dose-differentiated accelerated schedule using 1.8 Gy bid (DART-bid). PATIENTS AND METHODS: Between April 2002 and December 2010, 54 patients (median age 71 years, median Karnofsky performance score 70%) were treated for early stage NSCLC. Total doses were applied according to tumor diameter: 73.8 Gy for < 2.5 cm, 79.2 Gy for 2.5-4.5 cm, 84.6 Gy for 4.5-6 cm, 90 Gy for > 6 cm. RESULTS: The median follow-up was 28.5 months (range 2-108 months); actuarial local control (LC) at 2 and 3 years was 88%, while regional control was 100%. There were 10 patients (19%) who died of the tumor, and 18 patients (33%) died due to cardiovascular or pulmonary causes. A total of 11 patients (20%) died intercurrently without evidence of progression or treatment-related toxicity at the last follow-up, while 15 patients (28%) are alive. Acute esophagitis ≤ grade 2 occurred in 7 cases, 2 patients developed grade 2 chronic pulmonary fibrosis. CONCLUSION: DART-bid yields high LC without significant toxicity. For centrally located and/or large (> 5 cm) early stage tumors, where SBRT is not feasible, this method might serve as radiotherapeutic alternative to present treatment recommendations, with the need of confirmation in larger cohorts.