Sites of invasion of cancer of the external auditory canal predicting oncologic outcomes

Treatment outcome and prognostic factors of external auditory canal squamous cell carcinoma: A retrospective study in a tertiary center

Objective

Squamous cell carcinoma (SCC) of the external auditory canal (EAC) is a rare malignancy with various treatment strategies and outcomes. The purpose of this study was to evaluate the clinical characteristics and survival outcomes and identify prognostic factors in patients with SCC of EAC.

Methods

Twenty-one patients with SCC of EAC treated in a single tertiary center between 2009 and 2021 were retrospectively reviewed and analyzed. The modified Pittsburgh classification system was applied for staging. Factors associated with survival were identified by univariate survival analysis.

Results

The mean age at diagnosis was 61 years (range: 41-79 years). Early-stage (T1 + T2) accounts for 38.1% of the series and advanced-stage (T3 + T4) accounts for 61.9%. Eighteen (85.7%) patients underwent primary surgery with curative intent. The 5-year overall survival rate of the 21 patients was 67.4%. Tumor invasion to the otic capsule, eustachian tube, sigmoid sinus, and dura were associated with poor prognosis in univariate analysis (p = .046; .008; .027; and .08, respectively).

Conclusions

Factors predictive of less favorable survival include the history of COM, tumor invasion to the otic capsule, eustachian tube, sigmoid sinus, and dura. It is important to make a precise and systemic preoperative evaluation of disease extent.

Level of Evidence

4.

Risk Factors for Locoregional Recurrence and Distant Metastasis in 143 Patients with Adenoid Cystic Carcinoma of the External Auditory Canal

AIMS

Adenoid cystic carcinoma (ACC) grows slowly and is characterised by potential recurrence and metastasis to distant organs. This study aimed to evaluate the risk factors for locoregional recurrence (LRR) and distant metastasis in patients with ACC of the external auditory canal (EAC).

MATERIALS AND METHODS

Demographic, pathological, therapeutic and survival data of 143 patients with EAC ACC were reviewed in this study. Univariate and multivariate Cox proportional hazard regression analyses were carried out to determine the risk factors for LRR and distant metastasis. Factors associated with overall survival after LRR and distant metastasis were also analysed.

RESULTS

During a median follow-up of 49 months, 31 of 143 patients were observed with LRR and 34 developed distant metastasis. Bone invasion and histological subtype were independent risk factors for locoregional recurrence-free survival. T stage and LRR were independent risk factors for distant metastasis-free survival. Salvage surgery and adjuvant radiotherapy or chemoradiotherapy for LRR resulted in better survival, whereas extrapulmonary metastasis and LRR were associated with a higher risk of poor survival after distant metastasis.

CONCLUSION

Patients with distant metastases, especially those with LRR, are at significant risk of poor prognosis. Our findings emphasise the importance of long-term regular follow-up and recommend surgical intervention with radiotherapy for recurrent EAC ACC.

Treatment outcomes of the external auditory canal and temporal bone malignancy with dura invasion

Objectives

This study aimed to evaluate the characteristics and surgical outcomes of patients with external auditory canal (EAC) and temporal bone (TB) malignancy with dura invasion.

Methods

The medical records of patients with EAC and TB malignancy with dura invasion were retrospectively reviewed. Survival outcomes (overall survival [OS], disease-specific survival [DSS], recurrence-free survival [RFS], and distant metastasis-free survival [DMFS]) were analyzed using the Kaplan-Meier method.

Results

A total of eight patients were included in this study. The median age at diagnosis was 49.5 years (range 12-74 years). The median follow-up periods were 46.5 months. Histologically, four out of eight patients were diagnosed with squamous cell carcinoma (SCC; 50%). The 2-year OS and DSS rates of all patients were 62.5%, and those of EAC SCC patients were 50% and 66.7%, respectively; while the 2-year RFS and DMFS rates of all patients were 37.5%. There was one local recurrence at the resection site (12.5%), two regional neck nodal recurrences (25%), and two distant metastases (25%). Dura resection and duroplasty areas were not involved in the local recurrence case.

Conclusion

In EAC and TB cancer with dura invasion, radical surgery with dura resection may show similar survival outcomes to previous studies without recurrence at the dura resection site.Level of evidence: IV.

[Current status of the diagnosis and treatment of temporal bone squamous cell carcinoma]

Temporal bone squamous cell carcinoma, which is rare in the clinical setting, is the most common type of temporal bone malignancy. Its rarity makes the staging, the way of temporal bone resection, the management of parotid gland and cervical lymph node, and the application of radiotherapy and chemotherapy still controversial.There is no unanimous consensus and guideline about it to date at home and abroad.This paper reviewed the recent advance in the diagnosis and treatment of temporal bone squamous cell carcinoma in the hope of providing some help and reference for the management of the disease.

A rapid and durable response to larotrectinib in a patient with NTRK fusion-positive secretory carcinoma originating from the external auditory canal

For decades, no clear consensus existed on the standard treatment option for malignant tumors of the external auditory canal, an extremely rare disease. Here we report the case of a 55-year-old female patient with secretory carcinoma that originated from the left external auditory canal. Magnetic resonance imaging (MRI) at baseline showed that the tumor had extended to the medulla oblongata despite surgical and radiation treatments for more than 20 years from the initial diagnosis. Based on the results of a next-generation sequencing test of a formalin-fixed paraffin-embedded surgical specimen indicating that the tumor harbored ETV6–NTRK3 fusion, the patient was enrolled in a global basket study of larotrectinib, an oral selective tropomyosin receptor kinase (TRK) inhibitor. Three weeks after the start of larotrectinib treatment, MRI showed only small remnants of the tumor in the medulla oblongata and the patient’s headache before the treatment had disappeared. Subsequent MRI after 12 weeks of treatment confirmed the complete disappearance of the tumor. The patient repeated grade 2 flu-like symptoms related to treatment, but did not experience any other grade 2 or worse treatment-related adverse events. TRK inhibitors, such as larotrectinib, exert potent antitumor activity against neurotrophic tyrosine receptor kinase (NTRK) fusion-positive tumors in a tumor-agnostic manner. To the best of our knowledge, this is the first report on NTRK fusion-positive secretory carcinoma of the external auditory canal, and this report provides a valuable insight into the management of the extremely rare but now treatable malignancy.

Evaluation of subclasses for T4-classified squamous cell carcinoma of the external auditory canal

Background

T4‐classified squamous cell carcinoma (SCC) of external auditory canal (EAC) can potentially involve different anatomical structures, which could translate into different treatment strategies and survival outcomes within one classification. Our aim is to evaluate the clinical added value of T4‐subclasses proposed by Lavieille and by Zanoletti.

Methods

Retrospective data, including patients with primary operated cT4‐classified EAC SCC, was obtained from 12 international hospitals. We subclassified according to the T4‐subclasses. The treatment strategies, disease‐free survival (DFS) and overall survival per subclass were calculated.

Results

A total of 130 T4‐classified EAC SCC were included. We found commonly used treatment strategies per subclass according to Lavieille and the DFS seems also to differ per subclass. Subclass according to Zanoletti showed comparable treatment strategies and survival outcomes per subclass.

Conclusion

Our study suggests that the subclass according Lavieille might have added value in clinical practice to improve care of T4‐classified EAC SCC.