Incidental pulmonary nodules in oral squamous cell carcinoma - A retrospective cohort study

Incidental pulmonary nodules are frequently identified on staging imaging for oral cavity squamous cell carcinoma (SCC). These may represent metastases, lung primaries, or benign lesions. Existing risk stratification guidelines are not specific to head and neck cancer. This retrospective cohort study evaluated survival differences between patients with and without pulmonary nodules and explored follow-up imaging practices.

This single-centre retrospective cohort study included adults with oral mucosal SCC managed with curative intent between 2011 and 2018. Clinical, demographic, and radiographic data, including nodule characteristics and follow-up imaging, were extracted from electronic records. Primary outcomes were overall survival and metastatic disease-related death, analysed using Fisher's exact test, Kaplan-Meier survival with log-rank testing, and multivariable Cox regression.

Of 4563 clinic patients screened, 372 met inclusion criteria (mean age 58.3 years, 62.9% male). Pulmonary imaging was available in 84.1% of patients; among those with baseline thoracic imaging, pulmonary nodules were present in 25.6%, predominantly measuring < 6 mm and radiographically indeterminate. Pulmonary nodules were not independently associated with metastatic disease-related death or reduced overall survival within this cohort. Nodule size and multiplicity did not demonstrate statistically significant associations with metastatic disease-related death. Older age, nodal disease, and perineural invasion were independently associated with poorer survival.

Pulmonary nodules were common but were not independently associated with overall survival or metastatic mortality within this cohort. Established oncologic factors remained the dominant prognostic determinants. Small incidental pulmonary nodules identified on staging imaging should not, in isolation, alter curative treatment intent. Further prospective studies are required to clarify the prognostic significance of pulmonary nodules, particularly larger or radiologically suspicious lesions, and to determine the role of surveillance imaging strategies.