A therapeutic approach to roentgenographically occult squamous cell carcinoma of the lung

The significance of limited resections, including wedge resection and segmentectomy, remains controversial because of their curability rates. In the current study, the objective was to determine a strategy for the treatment of patients with roentgenographically occult bronchogenic squamous cell carcinoma (ROSCC) based on the pathologic findings from 184 patients with ROSCC who underwent resection.

In Miyagi Prefecture, 1422 patients with lung carcinoma were diagnosed during a mass screening program between 1982 and 1995. Among them, 236 patients had ROSCC, and 184 patients with ROSCC underwent pulmonary resection followed by systemic lymph node dissection.

Pathologically, only 0.9% of the ROSCCs that were within the range of endoscopic visibility were revealed to have lymph node involvement, whereas 13% of patients with extracartilage invasion had lymph node involvement. Early ROSCC, which means ROSCC that is limited within the cartilaginous layer and is without lymph node involvement, comprised 90% of ROSCCs that measured <10 mm in longitudinal extension, comprised 77% of ROSCCs that measured 10-29 mm in longitudinal extension, and comprised 33% of ROSCCs that measured >30 mm in longitudinal extension. Eighty-nine percent of the tumors with lymph node involvement had extracartilaginous invasion. The 3-year survival rate of patients after undergoing photodynamic therapy was 100% when their tumor was regarded as early ROSCC (i.e., within 10 mm in longitudinal extension and within the range of endoscopic visibility). To date, 18 patients with ROSCC underwent segmentectomy, and all of these patients are alive without tumor recurrence. The incidence rate of multiple lung carcinomas, including synchronous and metachronous tumors, in patients with ROSCC was 22%.

The authors concluded the following: 1) Patients with lesions that are within the range of endoscopic visibility and that measure <10 mm in longitudinal extension are candidates for photodynamic therapy. 2) Patients with lesions that are beyond the range of endoscopic visibility or that measure >10 mm in longitudinal extension are candidates for segmentectomy as long as intraoperative examination shows a tumor free bronchial stump and negative lymph nodes 11-13. 3) Patients with lesions that show bronchial obstruction or extrabronchial invasion should undergo standard resection.