Clinicopathological Evaluation of Neck Dissection Cases in Squamous Cell Carcinoma of Oral Cavity
The subjects were 209 patients with OSCC who underwent neck dissection in our department between 1996 and 2010.
The patients were 114 males and 95 females, and the mean age was 62.2 years. Regarding staging at the first examination, stage I was noted in 8 cases, II in 31 cases, III in 98 cases, and IV was observed in 72 cases. Neck dissection was performed simultaneously with the resection of the primary lesion at the first treatment in 175 cases, it was conducted for delayed neck metastasis in 31 cases, and for neck metastasis at the time of local recurrence in 3 cases.
Regarding pN classification, pN0 was noted in 110 cases, pN1 in 42 cases, and pN2 was observed in 57 cases. In pN (+) cases, the number of metastases was one in 42 cases, 2 in 25 cases, and more than 3 in 32 cases, and extracapsular spread was noted in 26 cases. Overall survival, disease-specific survival were calculated by the Kaplan-Meier method. The overall survival rate of all cases was 73.9%, and disease-specific survival rate was 79.0%. The survival rate was 89.7% in pN (-), and 66.6% in pN (+) cases, showing a significant difference (p<0.001). Furthermore, the survival rate in cases in which metastasis was noted was 82.3% in pN1 cases, 54.4% in pN2 cases, and it was significantly lower in pN2 than in pN1 cases (p<0.01). Regarding the number of pathological metastases and survival rate, the survival rate was 82.3% when the number was one, 63.8% when it was 2, and 45.1% when it was more than 3, and a significant difference was noted between when it was one and more than 2 (p<0.01), and between when it was less than 2 and more than 3 (p=0.01). Furthermore, cases with pathological extracapsular spread showed a significantly lower survival rate (p<0.001). Multivariate analysis using COX regression analysis revealed that extracapsular spread and metastatic progression to over level IV were factors significantly influencing the decrease in the survival rate. The survival rate was 19.2% in cases in which regional recurrence was noted, 86.2% in which no regional recurrence was present, and it was significantly lower in cases with regional recurrence (p<0.001). The recurrence rate was significantly higher in cases in which the number of pathohistological metastases was more than 4 (p<0.05).
In conclusion, the survival rate of cases in which metastasis was pathohistologically noted was low, and it was revealed that the presence of cervical recurrence was a factor markedly influencing the treatment results. Multivariate analysis clarified that the presence of extracapsular spread and metastatic progression to over level IV were factors influencing the survival rate. It was considered that positive postoperative adjuvant therapy is necessary for cases in which extracapsular spread noted, metastatic progression to over level IV is present, and the number of metastases is multiple, to improve the treatment results in cases of neck dissection.
Referrences: 1) Kowalski LP, Bagietto R, Lara JR, et al.: Prognostic significance of the distribution of neck node metastasis from oral carcinoma. Head Neck. 22:207-14. 2000. 2) Shingaki S, Nomura T, Takada M, et al.: The impact of extranodal spread of lymph node metastases in patients with oral cancer. Int J Oral Maxillofac Surg. 28:279-84.2003.