Lymph node metastasis pattern in recurrent and ipsilateral second primary oral squamous cell carcinoma

To examine the patterns of lymph node metastasis and associated risk factors in patients with recurrent tumors or ipsilateral second primary tumors (SPT), with the goal of providing insights for clinical diagnosis and management.

A retrospective analysis was conducted on patients who underwent radical surgery for oral squamous cell carcinoma (OSCC) and experienced tumor recurrence or ipsilateral SPT between January 2017 and March 2023. Comprehensive clinical and pathological data were collected at both the time of initial treatment and recurrent or ipsilateral SPT.

Most common primary OSCC sites were the tongue and buccal mucosa, while recurrent and ipsilateral SPT primarily occurred in the buccal mucosa. The lymph node metastasis rate for primary OSCC was 22.9%, increasing to 42.2% in recurrent and ipsilateral SPT (p < 0.001). Primary OSCC tended to metastasize to levels I-III, while recurrent and ipsilateral SPT more commonly metastasized to ipsilateral level V and contralateral level I. Multivariate logistic regression showed moderately and poorly tumor differentiation and T2 stage were significant risk factors for lymph node metastasis in primary OSCC. In recurrent and ipsilateral SPT, poorly differentiated tumors and T2 stage were similarly associated with increased lymph node metastasis. Both lymph node and distant metastases were significant prognostic risk factors in recurrent or ipsilateral SPT.

Recurrent and ipsilateral SPT exhibit a higher likelihood of lymph node metastasis compared to primary OSCC, particularly to ipsilateral level V and contralateral level I lymph nodes. This pattern of metastasis is strongly associated with a poorer prognosis.