Low Rates of Intrapulmonary Local Recurrence After Laser Metastasectomy: A Single-Center Retrospective Cohort Study of Colorectal Cancer Metastases

<b>Objective:</b> Colorectal pulmonary metastasis is the most common resected metastatic disease of the lung. Pulmonary metastasectomy (PM) for colorectal oligometastases is a well-established intervention with curative intent. Local recurrence at the resection site in the lung is a problem, with an impact on survival. The use of a 1320 nm neodymium:yttrium aluminum garnet (Nd:YAG) laser causes the vaporization and coagulation at the resection line and thereby increases safety margins around the nodule. We aimed to evaluate the local recurrence rate after laser-assisted pulmonary metastasectomy (LPM) for colorectal metastases. <b>Methods:</b> We conducted a retrospective analysis of 49 patients treated with laser-assisted pulmonary metastasectomy for 139 metastatic nodules from colorectal cancer from 2010 to 2018. All nodules were resected using Nd:YAG 1320 nm laser, aiming for a safety margin of five mm. The minimum follow-up time after PM was 24 months. <b>Results:</b> Local intrapulmonary recurrence developed at 7 of the 139 (5.0%) resection sites in 5 of the 49 patients (10.2%). Microscopically incomplete resection was a significant risk factor for recurrence (<i>p</i> = 0.023). Larger nodule size (>12 mm) negatively impacted local recurrence (<i>p</i> = 0.024). Nodules larger or equal to 12 mm in size also lowered the patients' probability of survival by 67.29% (HR: 0.3271, 95% CI: 0.1265-0.846, <i>p</i> = 0.018). <b>Conclusions:</b> The rate of local recurrence at the resection site after LPM for colorectal metastases is low. Complete resection is a positive predictor of survival without local recurrence. Microscopic complete resection with the addition of vaporization and coagulation at the resection margin seems to be sufficient to prevent local recurrence. However, larger nodules may require larger safety margins.