Determine role of selective mediastinal lymphadenectomy in staging non-small-cell lung cancer (NSCLC).
Sentinel lymph node (SLN) mapping was IRB-approved for 130 consecutive patients with clinical Stage I and Stage II NSCLC (study 7/00-4/04; 71 male, 59 female; ages 33-86 yr, median 64 yr). All patients had preoperative mediastinoscopic staging. Intraoperative SLN mapping was performed after the peritumoral area was injected subpleurally with either isosulfan blue dye, technetium 99-labeled sulfur colloid, or both. A handheld gamma detection probe was used to detect the “hottest” node in the lymphatic basin, and blue or “hot” nodes were designated as SLNs and removed for rapid frozen sectioning. Standard surgical resection included complete mediastinal node dissection.
Of the 130 patients, 79 (60%) had Stage I disease, 28 (22%) had Stage II disease, and 23 (18%) had Stage III disease. SLNs were identified in 105 patients (81%), 19 of whom had cancer in the SLN. Fourteen of the l9 patients with positive SLNs had mediastinal nodal metastasis: Occult N2 disease was seen in 9 patients with adenocarcinoma (diameter range 2.2-9 cm) and in 5 patients with squamous cell carcinoma (SCC) [diameter range 3.2–7.5 cm]. Of the l9 positive SLNs, 12 were the only site of metastasis. Of the 86 patients with tumor-negative SLNs, none had mediastinal nodal metastasis, and l3 had metastasis to segmental bronchial nodes. Of the 25 patients with undetected SLN, 19 had pN0 disease, and 6 had pN1 disease.
Good concordance was seen between SLN status and status of mediastinal nodes. Incidental (occult) N2 disease was seen only with adenocarcinoma >2 cm or SCC >3 cm in diameter.
Patients with negative SLNs and patients with either adenocarcinoma <2 cm or with SCC <3 cm in diameter may be spared the potential morbidity and additional operative time associated with complete mediastinal node dissection or systemic nodal sampling when staging NSCLC.
E.C. Saw, None.