Level IA Nodal Involvement in Parotid Cutaneous Squamous Cell Carcinoma

BACKGROUND: The frequency of Level IA metastasis in advanced cutaneous squamous cell carcinoma (cSCC) remains undefined yet determines the oncological safety of submental island flap (SIF) reconstruction. METHODS: A retrospective cohort study was performed on 131 adults who underwent parotidectomy and neck dissection, identified from the Sydney Head and Neck Cancer Institute database (2000-2025): 110 with parotid metastases and 21 with preauricular cSCC. The primary outcome was pathological Level IA involvement. RESULTS: Level IA involvement was identified in 4 patients (3.6%; 95% CI, 1%-9%), with an occult rate of 0% (95% CI, 0%-3.3%). This was significantly associated with extent of neck dissection, pathological nodal status and median nodal burden (all p ≤ 0.02). CONCLUSIONS: Level IA metastasis is uncommon in advanced cSCC and occurs exclusively in high-burden nodal disease. These findings support selective omission of Level IA dissection in the clinically node-negative neck and the oncological safety of SIF in well-selected patients.