Natsuko Sawai

Decision analysis and treatment threshold in a management for the N0 neck of the oral cavity carcinoma

The optimal method of management of clinical N0 neck in squamous cell carcinoma of the oral cavity remains controversial. We used decision analysis to determine the current optimal strategy in comparison with observation of the neck and elective neck dissection. A total of 165 previously untreated patients with N0 classification were investigated. Probabilities of each recurrence were calculated and probabilities of being cured in each event were substituted with the 5-year overall survival calculation with Kaplan-Meier method. A sensitivity analysis was performed to determine the optimal threshold for treatment of the N0 neck. The threshold of N0 neck was calculated using the formula with putting the three probabilities of being cured. In this study the threshold was estimated at 44.4%. N0 neck of squamous cell carcinoma of the oral cavity should be observed if the probability of occult metastasis is less than 44.4%. Proper calculation of three probabilities of being cured in each institution will make a decision of the optimal method of clinical N0 neck by using the threshold formula.

Risk factors for distant metastasis in squamous cell carcinoma of the oral cavity.

PURPOSE This study aimed to identify risk factors for distant metastasis (DM) in patients with squamous cell carcinoma of the oral cavity. MATERIALS AND METHODS A retrospective analysis of 516 patients with squamous cell carcinoma of the oral cavity from 1986 through 2009 was performed. DM was classified as 2 types based on whether patients had locoregional failure (LRF). The frequency and clinicopathologic risk factors for the 2 types of DM were evaluated separately using univariate χ(2) tests and multivariate logistic regression models. Overall survival was evaluated with the Kaplan-Meier method and compared by the log-rank test. RESULTS Fifty-four patients (10%) developed DM, 16 with isolated DM and 38 with DM with LRF. The 5-year survival rate from a DM diagnosis in patients with isolated DM was 13%, significantly higher than the rate of those with DM with LRF (0%; log-rank test, P < .05). Multivariate analysis indicated unique risk factors and common risk factors for the 2 types of DM. The common factors were nonsurgical treatment and the presence of pathologic positive nodes. The unique factors for isolated DM were histologic grade G3 and the later treatment period (after 1998). Conversely, the unique factor for DM with LRF was extracapsular spread. CONCLUSION The risk of isolated DM development after 1998 was 2.6 times higher than that before 1997. Histologic grade G3 and the presence of pathologic positive nodes may play a causative role in isolated DM.

Preventable Sternocleidomastoid Muscular Atrophy after Neck Dissection

Background: Modified radical neck dissection (mRND) [preserving the sternocleidomastoid muscle (SCM) and the spinal accessory nerve] and supraomohyoid neck dissection have become common surgical procedures for treating head and neck cancer. Postoperative severe asymmetry of the neck and severe atrophy of the SCM, however, have been demonstrated. Methods: Using computed tomographic images, cross-sectional areas of the SCMs were measured in 99 patients with carcinoma of the oral cavity who underwent unilateral mRND or supraomohyoid neck dissection. An asymmetry index was used. Results: Innervation to the SCM was preserved in 91 patients. The spinal accessory nerve and the innervation were sacrificed in 3 patients; the innervation was repaired in 5 patients. Sacrifice of innervation to the SCM resulted in extremely severe asymmetry. Repair of the innervation prevented severe asymmetry in 40%. Preservation of the innervation prevented severe asymmetry in 75% at the middle portion of the neck and in 56% at the lower portion after mRND. Conclusion: Preserving innervation to the SCM and gentle handling of the nerve during neck dissection could prevent severe asymmetry after neck dissection.

Management for the N0 Neck of SCC in the Oral Cavity

The oral cavity is the most predominant location in the head and neck region for primary malignant tumors, and more than 90 % cancer consists of squamous cell carcinoma (SCC).(Shah and Patel 2003) SCC has a high propensity to early and extensive lymph node metastases. Regarding cancer stage distribution at diagnosis, regional spread is more frequent in cancers of oral cavity and pharynx compared to other cancers, including such as prostate, breast, lung and bronchus, and colorectum (Figure 1).(Jemal et al. 2010) Therefore, clinicians for cancers of the oral cavity and pharynx have to regard regional metastasis as most important. Advanced SCC of the oral cavity has regional metastasis frequently, and even in small tumors (T1 or T2) has a relatively high propensity of regional lymph node