Stereotactic body radiation therapy in centrally and superiorly located stage I or isolated recurrent non-small-cell lung cancer

Abstract

Purpose: To evaluate the efficacy and adverse effects of image-guided stereotactic body radiation therapy (SBRT) in centrally/superiorly located non-small-cell lung cancer (NSCLC).

Materials and methods: We delivered SBRT to 27 patients, 13 with Stage I and 14 with isolated recurrent NSCLC. A central/superior location was defined as being within 2 cm of the bronchial tree, major vessels, esophagus, heart, trachea, pericardium, brachial plexus, or vertebral body, but 1 cm away from the spinal canal. All patients underwent four-dimensional computed tomography-based planning, and daily computed tomography-on-rail guided SBRT. The prescribed dose of 40 Gy (n = 7) to the planning target volume was escalated to 50 Gy (n = 20) in 4 consecutive days.

Results: With a median follow-up of 17 months (range, 6-40 months), the crude local control at the treated site was 100% using 50 Gy. However, 3 of 7 patients had local recurrences when treated using 40 Gy. Of the patients with Stage I disease, 1 (7.7%) and 2 (15.4%) developed mediastinal lymph node metastasis and distant metastases, respectively. Of the patients with recurrent disease, 3 (21.4%) and 5 (35.7%) developed mediastinal lymph node metastasis and distant metastasis, respectively. Four patients (28.6%) with recurrent disease but none with Stage I disease developed Grade 2 pneumonitis. Three patients (11.1%) developed Grade 2-3 dermatitis and chest wall pain. One patient developed brachial plexus neuropathy. No esophagitis was noted in any patient.

Conclusions: Image-guided SBRT using 50 Gy delivered in four fractions is feasible and resulted in excellent local control.

Fig. 1

SBRT in a lesion close to the left hilum and pulmonary artery achieved a complete response without grade 2 or higher toxicity. Priority was given to avoid critical structures when it conflicted with target coverage conformity.

Fig. 2

Computed tomography images showing SBRT in a lesion close to the brachial tree achieved a complete response without grade 2 or higher toxicity. (A.) Before SBRT. PA: pulmonary artery; RLB: right lower bronchus. (B.) Isodose distribution. (C.) Complete clinical response (CR) 1 year after SBRT. (D.) Dose-volume histogram. More than 95% of the gross tumor volume plus a 3-mm set-up uncertainty received 50 Gy, while 95% of the CTV received 40 Gy because of brachial tree sparing. The brachial tree received <40 Gy.

Fig. 3

SBRT resulted in brachial plexus neuropathy in one patient. (A.) A lesion close to the brachial plexus. (B.) Isodose distribution. (C.) Dose-volume constrains showed 20% of the brachial plexus received ≥ 40 Gy.