Treatment for T1-2 oral squamous cell carcinoma with or without perineural invasion: neck dissection and postoperative adjuvant therapy.
BACKGROUND
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.


METHODS
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.


RESULTS
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).


CONCLUSIONS
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.
Department of Otolaryngology, National Yang-Ming University, Taipei, Taiwan. sktai@vghtpe.gov.tw
Shyh-Kuan
SK
Tai
Wing-Yin
WY
Li
Muh-Hwa
MH
Yang
Shyue-Yih
SY
Chang
Pen-Yuan
PY
Chu
Tung-Lung
TL
Tsai
Yi-Fen
YF
Wang
Peter Mu-Hsin
PM
Chang
D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D037981:Neck Dissection; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000473:pathology / Q000601:surgery*; D009367:Neoplasm Staging; D010525:Peripheral Nerves / Q000473:pathology*; D011184:Postoperative Period; D011379:Prognosis; D015996:Survival Rate