Treatment for T1-2 Oral Squamous Cell Carcinoma with or Without Perineural Invasion: Neck Dissection and Postoperative Adjuvant Therapy
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Although perineural invasion (PNI) has been a poor prognostic factor for head and neck cancers, few studies have focused on oral squamous cell carcinoma (OSCC). The independent significance of PNI in early T1-2 OSCC and the benefit of treatment modification based on PNI status have not been assessed. This study investigated the role of PNI in T1-2 OSCC patients, with focus on the controversial issues of neck management and postoperative adjuvant therapy.
PNI status was re-reviewed under hematoxylin and eosin staining in tumors of 307 consecutive T1-2 OSCC patients. Oncologic and survival outcomes were analyzed by univariate and multivariate analyses.
PNI was identified in 84 (27.4%) patients, correlating with several established poor prognostic factors. In multivariate analysis, PNI remained an independent predictor for neck metastasis, neck recurrence, and a worse 5-year disease-specific survival. Elective neck dissection contributed to a significantly better 5-year disease-specific survival only in cN0 patients with PNI-positive tumors (P = 0.0071) but not in those with PNI-negative tumors (P = 0.3566). In low-risk patients who were treated by surgery alone, including neck dissection, the 5-year disease-specific survival rates were almost the same in those with PNI-positive tumors and those with PNI-negative tumors (92.0 vs. 92.9%; P = 0.9104).
Elective neck dissection is indicated for cN0 patients with PNI-positive tumors for the efficacy of improving disease-specific survival as well as neck control. However, low-risk PNI-positive patients who undergo neck dissection do not need postoperative adjuvant therapy, because the residual risk from PNI is minimal.
We thank the Clinical Research Core Laboratory, Taipei Veterans General Hospital, for technical assistance. This work was supported in part by National Science Council of Taiwan (grant number NSC 98-2314-B-010-013-MY3), and Taipei Veterans General Hospital (grant numbers V98C1-169, V99C1-117, V100C-090).
Conflict of interest
The authors declare no conflict of interest.
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