Robotic brachytherapy and sublobar resection for T1 non-small cell lung cancer in high-risk patients

Sublobar lung resection and brachytherapy seed placement is gaining acceptance for T1 non-small cell lung cancer (NSCLC) in select patients with comorbidities precluding lobectomy. Our institution first reported utilization of the da Vinci system for robotic brachytherapy developed experimentally in swine and applied to high-risk patients 5 years ago. We now report seed dosimetrics and midterm follow-up.

Eleven high-risk patients with stage IA NSCLC who were not candidates for conventional lobectomy underwent limited resection of 12 primary tumors. To reduce locoregional recurrence, (125)I brachytherapy seeds were robotically sutured intracorporeally over resection margins to deliver 14,400 cGy 1 cm from the implant plane. Patients were followed with dosimetric computed tomography scans at 30 +/- 16 days. Survival and sites of recurrence were documented.

Resected tumor size averaged 1.48 +/- 0.38 cm (range, 1.1 to 2.1 cm). Perioperative mortality was 0% and recurrence was 9% (1 of 11 [margin recurrence at 6 months with resultant mortality at 1 year]). Follow-up duration was 31.82 +/- 17.35 months. Dosimetrics confirmed 14,400 cGy delivery using 24.21 +/- 4.6 (125)I seeds (range, 17 to 30 seeds) over a planning target volume of 10.29 +/- 2.39 cc(3). Overall, 84.1% of the planning target volume was covered by 100% of the prescription dose (V100), and 88.2% was covered by 87% of the prescription dose (V87), comparable to open dosimetric data at our institution. Follow-up imaging confirmed seed stability in all patients.

Robotic (125)I brachytherapy seed placement is a feasible adjuvant procedure to reduce the incidence of recurrence after sublobar resection in medically compromised patients. Tailored robotic seed placement delivers an exact dosing regimen in a minimally invasive fashion with equivalent precision to open surgery.