Perineural invasion of the lower alveolar nerve by oral cancer: a follow-up study of 12 cases

Japanese clinical practice guidelines for oral cancer, 2023

The Japanese Society of Oral Oncology and Japanese Society of Oral and Maxillofacial Surgeons have jointly developed clinical practice guidelines for oral cancer (oral squamous cell carcinoma) to improve and standardize the quality of oral cancer treatment in Japan. The first, second, and third editions were published in 2009, 2013, and 2019, respectively, and the 2023 edition was recently developed. In the development of the 2023 edition, 60 clinical questions (CQs) were listed. Systematic reviews following the GRADE approach were performed for 11 of these CQs. This article outlines the 2023 edition and describes the most relevant guidelines and CQs for the diagnosis, treatment, follow-up, and supportive care of oral cancer patients in Japan.

Perineural Invasion Is a Significant Prognostic Factor in Oral Squamous Cell Carcinoma: A Systematic Review and Meta-Analysis

(1) Objectives: This systematic review and meta-analysis aimed to summarize current evidence regarding the prognostic role of perineural invasion (PNI) in patients with oral squamous cell carcinoma (OSCC). (2) Methods: We searched Cochrane Central, ProQuest, PubMed, Scopus, Science Direct, and Web of Science, using relevant keywords to identify eligible articles. Two independent reviewers conducted two-stage screening, data extraction, and quality assessment. The risk of bias was assessed using the Newcastle-Ottawa Scale (NOS) criteria. All analyses were performed using comprehensive meta-analysis (CMA; version 3.3.070) software. (3) Results: The study included 101 published articles encompassing 26,062 patients. The pooled analyses showed that PNI was associated with significantly worse overall survival (OS; HR = 1.45, 95% CI: 1.32-1.58; p < 0.001), worse disease-specific survival (DSS; HR = 1.87, 95% CI: 1.65-2.12; p < 0.001), and worse disease-free survival (DFS; HR = 1.87, 95% CI: 1.65-2.12; p < 0.001). Similarly, both local recurrence-free survival (LRFS) and regional recurrence-free survival (RRFS) were worse in patients with PNI (HR = 2.31, 95% CI: 1.72-3.10, p < 0.001; and HR = 2.04, 95% CI: 1.51-2.74, p < 0.001), respectively. The random-effect estimate of three studies demonstrated that the presence of PNI was associated with worse failure-free survival (FFS; HR = 2.59, 95% CI: 1.12-5.98, p < 0.001). (4) Conclusions: The current evidence suggests that PNI can be used as an independent predictor of the prognosis for patients with OSCC. The presence of PNI was associated with worse OS, DFS, DSS, FFS, and with recurrence. Asian patients and patients with extra-tumoral or peripheral PNI invasion were associated with worse prognosis.

Malignant cell infiltration in the peripheral nervous system

The peripheral nervous system can be affected by malignancies involving different mechanisms. Neoplastic nerve lesion by compression, invasion, and infiltration is rare and occurs in particular in leukemia (neuroleukemiosis) and lymphoma (neurolymphomatosis). Its occurrence is much rarer in cancer, and even less so in sarcoma. The neoplastic infiltration of peripheral nerves by solid tumors is characterized by specific topographical sites such as the base of the skull, the ear, nose and throat region, and the cervico-brachial plexus as well as the lumbar and sacral plexus. Rarely malignant invasion affects the cranial nerves of the face where it can spread centripetally. Autonomic nerves and ganglia can also be affected. The retrograde spread of cancer in nerves is a bad prognostic sign. The clinical diagnosis is determined by tumor type, the pattern of involvement, and often pain.

The role of tumor invasion into the mandible of oral squamous cell carcinoma

PURPOSE

The aim of this study was to determine the prognostic impact of the extent of bone invasion in patients undergoing mandibulectomy for oral squamous cell carcinoma (OSCC), and to evaluate the relation between clinicopathologic parameters and outcome.

METHODS

Nine hundred and eighty-two patients presented with OSCC and 334 were treated surgically by some form of mandibular excision. Treatment included marginal, rim, or segmental mandibulectomy depending on the clinical and radiological observation of the mandible and suspected bone invasion. Kaplan-Meier plots and univariate log-rank test and multivariate Cox proportional hazards regression models were used to determine the association between possible predictor variables and survival time.

RESULTS

After controlling for age, tumor and nodal stage, UICC stage, type of reconstruction, which were independent predictors of survival, type of mandibulectomy was significantly associated with survival in the univariate analysis (P = 0.038), whereas bone invasion was not in both univariate and multivariate analysis. The rate of bone invasion detected after marginal mandibulectomy was 15.5%, in rim resections 50%, and segmental mandibulectomy at 84.7%. Recurrence of OSCC was found to be associated with overall survival (P = 0.039).

CONCLUSIONS

If bone invasion is identified histologically in a resected specimen, the prognosis is not worsened and additional surgery need not be undertaken in adequately resected margins. Although the mandible should be preserved if feasible, the choice of treatment should always provide safe resection margin. The high rates of unsuspected bone invasion found in this study should be kept in mind in patients with OSCC close to the mandible.

Minor salivary gland squamous cell carcinoma of the lower lip demonstrating striking perineural invasion

Squamous cell carcinomas (SCC) of minor salivary gland origin are extremely rare. We present an unusual case of a 29-year-old female patient who presented with a well-differentiated SCC of minor salivary gland origin arising in the lower lip. Wedge resections of the lip, including bilateral mental nerve excision, were required to clear the tumor because of striking pathological evidence of perineural invasion distant from the primary tumor site.

Perineural invasion of the major and minor nerves in laryngeal and hypopharyngeal cancer

OBJECTIVE: To investigate the perineural invasion in patients with squamous cell carcinoma of the larynx and hypopharynx.

STUDY DESIGN: A prospective study of patients with laryngeal and hypopharyngeal squamous cell carcinoma who underwent total or partial laryngectomy.

METHODS: Patients with squamous cell carcinoma of the larynx and pyriform sinus who underwent laryngectomy between 2002 and 2006 in the ENT Clinic of Cluj-Napoca were investigated for histopathological identification of perineural invasion.

RESULTS: The present study included 256 patients. Perineural invasion was present in 86 cases out of the 256. Perineural invasion was detected in the major nerves of only one case out of 219 patients who had undergone total laryngectomy. The difference between the mean disease-free survival of patients with or without perineural invasion of the minor nerves was statistically significant (Mann-Whitney U test, P = 0.000102). The local recurrence rates in the cases with or without perineural invasion were significantly different (log-rank test, P = 0.00001).

CONCLUSION: Major nerves do not constitute a way of spreading in the squamous cell carcinoma of the larynx and hypopharynx, whereas minor nerves remain a potential one.

Perineural tumor spread

Perineural spread (PNS) refers to the extent of tumor cells or other nonneoplastic lesions along the tissues of the nerve sheath, its overall incidence ranges from 2.5% to 5%. PNS is more frequently associated with carcinoma arising from minor or major salivary glands (more often adenoid cystic carcinoma), mucosal or cutaneous squamous cell carcinoma, basal cell carcinoma, melanoma, lymphoma, and sarcoma. Although PNS was previously associated with worsening prognosis, increasing evidence shows that cure is possible. Therefore, radiologists must be aware of the relevant cranial nerve anatomy and thoroughly scrutinize not only the nerves close to the primary tumor site but also the whole neural pathways that can be accessed by PNS. Equally critical is knowledge of the radiologic appearance of perineural tumor extension and the best imaging strategies to detect PNS.

Patterns of mandibular invasion by gingival squamous cell carcinoma

PURPOSE

This study examined patterns of invasion of lower gingiva cancer into the mandible. Our goal was to clarify the most common routes for gingival squamous cell carcinoma to enter and spread within the mandible.

PATIENTS AND METHODS

The subjects were 176 patients with lower gingival squamous cell carcinoma who underwent mandibulectomy; all tumors were examined histopathologically. The method of mandibulectomy was decided on the basis of conventional plain radiographic and computed tomographic findings.

RESULTS

The tumor extended to the periosteum in 33%, to the cortical bone in 23%, and to the bone marrow in 9% of the patients who underwent mandibular resection. The remaining 35% of our patients had no evidence of mandibular invasion.

CONCLUSION

The area of bone resorption on preoperative clinical and radiographic examinations often disagreed with the extent of mandibular invasion on histopathologic examination.

Mandibular invasion of lower gingival carcinoma in the molar region: its clinical implications on the surgical management

The spread pattern of a tumour and its extent in the mandible are important in the management of gingival cancer. Sixteen patients with gingival squamous cell carcinoma (SCC) involving the mandible in the molar region were included in this study. Resection specimens of the mandibular bone and adjacent cancer were histologically analysed to identify the type and characteristics of invasion and were compared with the radiological features. Our results showed that the actual width of invasion was underestimated to a greater extent than the actual depth of invasion. For horizontal aspects, four dentate cases had horizontal intramedullary spread underneath intact mucosa or cortical bone extended from the main foci of tumour that infiltrated through the occlusal surface. For vertical aspects, nerve invasion took place in only one of 16 specimens, while five cases showed downward infiltration beyond the inferior alveolar canal without nerve involvement, so that the pattern of tumour spread was mostly transmedullary rather than perineural in previously non-irradiated cases. These cases with deep infiltration showed the infiltrative type of invasion in the dentate mandible. And when the tumour was related with previous dental extractions or curettage, it tended to be more extensive than what was predicted from an imaging point of view. These pathological and clinical features affecting the tumour spread should be considered in the management of gingival SCC in the molar region.