Right dominance in the incidence of external auditory canal squamous cell carcinoma in the Japanese population: Does handedness affect carcinogenesis?

Laterality and otorhinolaryngology: a review

BACKGROUND

Laterality of paired organs involves the function of the eyes, ears, hands and feet. Whilst most people have a right-handed preference, about 10 per cent are left-handed. Similarly, the right eye is usually preferred to the left. Medicine is both taught and practised for those with right hand and eye preference, and left-handed medical students and doctors must negotiate the right-handed world.

OBJECTIVE

This brief review looks at society's attitudes, medical training and the practice of otolaryngology in the UK towards laterality and handedness.

METHOD

Literature review.

RESULTS

Studies suggest that left-handers are more versatile and so are more ambidextrous. Conversely, this may result in problems when a right-hander tries to undertake a procedure with the non-dominant hand.

CONCLUSION

Cultures and attitudes are changing towards those who are left-handed. Left-handed surgeons may encounter difficulties in the clinical environment throughout their training.

Biological and genetic characterization of a newly established human external auditory canal carcinoma cell line, SCEACono2

Squamous cell carcinoma of the external auditory canal (EACSCC) is an extraordinarily rare and aggressive malignant disease. Establishment of EACSCC cell line with robust molecular characteristics is essential for the basic and translational research of EACSCC. Here, we show the newly established EACSCC cell line SCEACono2, derived from a patient with well-to-moderately differentiated EACSCC. We analyzed histologic and genetic features of SCEACono2 hiring multiple experiments, including next-generation sequencing (NGS). Immunocytochemical staining of SCEACono2 showed positivity of p53 and SCC1/2. Furthermore, SCEACono2 exhibited a unique characteristic that cytokeratin, vimentin as well as cancer stem cell markers (CD44, CD133, ALP and Oct3/4) were positive. SCEACono2 had an ability to form tumors at the temporal lesion xenograft nude mice model. NGS revealed that SCEACono2 harbored the somatic mutations of TP53 (p.G245S) and NOTCH1 (p.A465T). RNA-seq and downstream bioinformatics analysis revealed significant enrichment of genes involved in inflammation and cell adhesion in SCEACono2 compared to SCC-9 and HSC-4. STR profiling indicated no evidence of cross-contamination. In conclusion, SCEACono2 could serves as a promising and robust research resource of EACSCC in vitro and in vivo.

Association of gene mutations with clinicopathologic features in patients with external auditory canal squamous cell carcinoma

BACKGROUND

External auditory canal squamous cell carcinoma (EACSCC) is a rare form of malignant tumor. Due to the extremely limited understanding of the genomic landscape in EACSCC, the association between gene mutations and clinicopathologic features remains unclear. This study aimed to explore somatic gene mutations associated with the clinicopathological features in patients with EACSCC, and to identify the candidate gene mutations for predicting survival outcome in EACSCC.

METHODS

Twenty-two tissue samples obtained from patients with EACSCC were analyzed for genetic mutations based on targeted next-generation sequencing and genetic expression based on IHC staining to investigate the driver of tumorigenesis and/or the candidates of genes for predicting clinical outcome in EACSCC.

RESULTS

Gene alterations were most frequently observed in TP53 (59.1%), followed by CREBBP (9.1%). TP53 mutations showed significant correlation with T classification (P = 0.027) and p53 expression phenotype (P < 0.001). The 5-year overall survival (OS) rates for EACSCC patients with TP53 mutations and wild-type TP53 were 45.0% and 75.0%, respectively. Multivariable analysis using the Cox proportional hazards model demonstrated that TP53 mutations were independent predictors of OS rates for EACSCC patients (P = 0.007).

CONCLUSION

This study has suggested that TP53 mutations have potential for use as a biomarker for identifying individuals at high risk of developing tumors and for predicting survival outcome in EACSCC. IHC staining for p53 might play a useful role as screening tool for detecting TP53 mutations in patients with EACSCC.

Analysis of the epidermal growth factor receptor/phosphoinositide‐dependent protein kinase‐1 axis in tumor of the external auditory canal in response to epidermal growth factor stimulation

Objectives

The epidermal growth factor receptor (EGFR) is related to the invasion and metastasis of external auditory canal (EAC) squamous cell carcinoma (SCC). The phosphoinositide‐dependent protein kinase‐1 (PDPK1) accelerates tumor cell growth through anti‐apoptotic signaling under the influence of downstream EGFR‐mediated signaling pathways. In this study, we investigated the EGFR/PDPK1 axis in the EAC under EGF stimulation.

Methods

We confirmed EGFR and PDPK1 expression in human EACSCC specimens immunohistochemically. We next transfected the EGF expression vector in the mouse EAC and then conducted a PDPK1 inhibitory experiment. Immunohistochemical analysis was performed in the mouse EAC, using anti‐EGF, anti‐EGFR, anti‐PDPK1, and anti‐Ki67 antibodies. Immunohistochemical analysis of cleaved caspase‐3 and terminal deoxy(d)‐UTP nick end labeling (TUNEL) detection assays were also performed for the assessment of apoptosis in the inhibitory experiment.

Results

Immunohistochemical analysis revealed overexpression and colocalization of EGFR and PDPK1 in human EACSCC specimens. The growth of a protuberant tumor was observed in the mouse EAC in which EGF expression vector was transfected, and EGF, EGFR, PDPK1, and Ki67 labeling indexes (LIs) were significantly increased. PDPK1 inhibition then induced normal epithelial appearance in the EAC. Moreover, EGF, EGFR, PDPK1, and Ki67 LIs were decreased, and cleaved caspase‐3 and TUNEL LIs were increased in the EAC.

Conclusion

We demonstrated the possibility that PDPK1 plays an important role in EACSCC.

Level of Evidence: NA.

Programmed Death-Ligand 1 Expression and Tumor-Infiltrating Lymphocytes in Temporal Bone Squamous Cell Carcinoma

OBJECTIVES/HYPOTHESIS

The tumor immune microenvironment in temporal bone squamous cell carcinoma (TBSCC), including the programmed death-ligand 1 (PD-L1) expression and tumor-infiltrating lymphocytes (TILs), has not been established.

STUDY DESIGN

Retrospective cohort study.

METHODS

We performed immunohistochemistry analyses to retrospectively analyze 123 TBSCC cases for PD-L1 expression and TILs and their prognostic significance. We also evaluated the prognostic correlations between these immunomarkers and the therapeutic responses to chemoradiotherapy (CRT).

RESULTS

PD-L1 expression (≥1%) was detected in 62 (50.4%) TBSCC cases and was significantly associated with worse prognosis: progression-free survival (PFS), P < .0001; overall survival (OS), P = .0009. A high density of CD8⁺ TILs was significantly associated with better prognosis (PFS, P = .0012; OS, P = .0120). In contrast, a high density of Foxp3⁺ TILs tended to be associated with an unfavorable prognosis (PFS, P = .0148; OS, P = .0850). With regard to the tumor microenvironment subtypes defined by CD8⁺ TILs and PD-L1 expression, the CD8^low /PD-L1⁺ group showed significantly worse prognosis. Among the 36 neoadjuvant CRT-treated cases, PD-L1 expression was significantly associated with worse OS (P = .0132). Among the 32 CRT-treated cases without surgery, a high density of CD8⁺ TILs tended to be more highly associated with complete response to CRT compared to a low density of CD8⁺ TILs (P = .0702).

CONCLUSIONS

These results indicate that the evaluation of the tumor immune microenvironment may contribute to the prediction of prognoses and the selection of an individualized therapeutic strategy for patients with TBSCC.

LEVEL OF EVIDENCE

4 Laryngoscope, 2021.

Case Series and Systematic Review of Treatment Outcomes for Auricular Pseudocysts

OBJECTIVE

Auricular pseudocyst (AP: intracartilaginous cyst, endochondral AP, cystic chondromalacia, and benign idiopathic cystic chondromalacia) is a benign condition of unknown etiology. This report systematically reviews the published demographics, treatment protocols, and outcomes of AP between the various medical disciplines, and compares the findings to a theretofore-unreported 12-patient cohort. Primary outcome measure was AP complete resolution without recurrence.

DATA SOURCE

A systematic literature search of "MEDLINE" via "PubMed" and "Google Scholar" was performed in June, 2020. The 12 new patients were enrolled between January 2016 and December 2020.

STUDY SELECTION

Seventy-four papers met the study inclusion criteria and provided data on sex distribution, surgical approach and outcome, performance of approaches according to medical specialty, and recurrence rates of the reported AP populations.

DATA EXTRACTION

The appropriateness and study design quality were independently assessed by two reviewers.

DATA SYNTHESIS

The primary outcome was therapeutic success. A comparative analysis was also performed on the same extracted information that was retrieved from the medical files of the 12 new patients (10 men, 2 women, average age 24 yrs, range, 17-38).

CONCLUSIONS

AP is not uncommon. In line with the published literature, incision and curettage with excision of the anterior pseudocystic wall (deroofing) resulted in a recurrence rate of less than 17% with good cosmetic outcome among all 12 patients. Aspiration alone was associated with increased recurrence rates. Deroofing emerged as the preferred modality, with good cosmetic outcome and reduced recurrence rate. It was usually performed by otolaryngologists, while dermatologists used more conservative approach more frequently. Incision and drainage combined with compression reduces risk of recurrence.

A retrospective analysis of radiotherapy in the treatment of external auditory canal carcinoma

External auditory canal carcinoma (EACC) is a rare disease. The current study aimed to evaluate the clinical outcomes of patients treated with external beam radiotherapy (EBRT) for EACC. The present study retrospectively reviewed 34 consecutive patients treated for EACC with EBRT between February 2001 and January 2019 at the University of Tokyo Hospital. Clinical staging was performed according to the modified Pittsburgh classification. Of all the included patients, seven patients were in the early stages (I or II) and 27 in the advanced stages (III or IV) of EACC. A total of 16 patients underwent EBRT and surgery (S+RT) pre- and/or postoperatively, while 18 patients underwent definitive radiotherapy (dRT). The median prescribed doses for the S+RT and dRT groups were 66 and 70 Gy, respectively. The median follow-up period for all patients was 22.4 months (range, 2-205 months). The 5-year overall survival rates of the S+RT and dRT groups were 66.7 and 45.1%, respectively. The progression-free survival rate at 5-year was 55.6% (95% confidence interval: 36.5-71.1%) for the entire cohort. A total of 14 patients experienced disease relapse after treatment, consisting of 11 locoregional recurrences and three distant metastases. The current study revealed the clinical outcomes of EBRT for EACC.

Genetic landscape of external auditory canal squamous cell carcinoma

External auditory canal squamous cell carcinoma (EACSCC) is an extremely rare and aggressive malignancy. Due to its rarity, the molecular and genetic characteristics of EACSCC have not yet been elucidated. To reveal the genetic alterations of EACSCC, we performed whole exome sequencing (WES) on 11 primary tumors, 1 relapsed tumor and 10 noncancerous tissues from 10 patients with EACSCC, including 1 with a rare case of synchronous bilateral EACSCC of both ears. WES of the primary tumor samples showed that the most frequently mutated gene is TP53 (63.6%). In addition, recurrent mutations in CDKN2A, NOTCH1, NOTCH2, FAT1 and FAT3 were detected in multiple samples. The mutational signature analysis of primary tumors indicated that the mutational processes associated with the activation of apolipoprotein B mRNA‐editing enzyme catalytic polypeptide‐like (APOBEC) deaminases are the most common in EACSCC, suggesting its similarity to SCC from other primary sites. Analysis of arm‐level copy number alterations detected notable amplification of chromosomes 3q, 5p and 8q as well as deletion of 3p across multiple samples. Focal chromosomal aberrations included amplifications of 5p15.33 (ZDHHC11B) and 7p14.1 (TARP) as well as deletion of 9p21.3 (CDKN2A/B). The protein expression levels of ZDHHC11B and TARP in EACSCC tissues were validated by immunohistochemistry. Moreover, WES of the primary and relapsed tumors from a case of synchronous bilateral EACSCC showed the intrapatient genetic heterogeneity of EACSCC. In summary, this study provides the first evidence for genetic alterations of EACSCC. Our findings suggest that EACSCC mostly resembles other SCC.

Squamous cell carcinoma of the temporal bone: A current review

OBJECTIVES

The rarity of temporal bone squamous cell carcinoma (TBSCC) precludes a clear understanding of the disease and approach to its management. This review provides general background on the disease and discusses the current and emerging oncologic and rehabilitative management options.

DATA SOURCES

PubMed literature review.

METHODS

A review of the current literature was conducted to assess and collate up-to-date information regarding TBSCC management.

RESULTS

TBSCC is a rare and aggressive disease arising in the ear canal, temporal bone, or extratemporal sites. Prior radiation, chronic ear disease, or habitual ear picking may contribute to primary disease development. Because the symptoms of TBSCC and benign otologic disease are similar, TBSCC diagnosis may be delayed, allowing the tumor time to spread throughout the anatomically intricate temporal bone. The extent of the disease is determined based on imaging and is usually staged with the Pittsburgh Staging System. Temporal bone resection with parotidectomy and neck dissection is the current standard of care. Survival is generally good for early disease and poor for advanced disease, but chemotherapy is emerging as a promising treatment option. Auditory rehabilitation with osseointegrated hearing aids is recommended at initial oncologic resection.

CONCLUSIONS

The knowledge of and outcomes for TBSCC have improved with time, but because of the aggressive nature of the disease and the anatomic intricacy of the temporal bone, TBSCC treatment is complex and should be delivered by a multidisciplinary team. Inter-institutional collaboration may accelerate research for this rare disease.

LEVEL OF EVIDENCE

5.

Management of Temporal Bone Malignancy in Ireland

Objectives  Lateral temporal bone malignancy remains a challenging rare disease. We report 17 years of multidisciplinary care of these tumors with univariate and multivariate analyses of key prognostic indicators for consideration in contemporary oncological management. Design  This is a retrospective cohort study. Setting  This is set at a tertiary referral center. Participants  All patients presenting with histopathologically newly diagnosed cases of temporal bone malignancy between 2000 and 2017 were included. Main Outcome Measures  The main outcome measures are disease-specific and recurrence-free survival rates. Results  In this study, 48 cases of temporal bone malignancy were diagnosed. Median age at diagnosis was 69 years (range: 5-88). Fourteen patients were female. Squamous cell carcinoma was the predominant malignancy in 34 cases (71%). Surgical treatment was undertaken in 37 patients. Mean length of follow-up was 32 months (range: 0.7-117). Overall 5-year disease-specific survival was 52.4%, while overall 5-year recurrence-free survival was 53.5%. On univariate analysis, significantly worse survival was seen in females ( p  = 0.008), those with distant metastatic disease ( p  = 0.041), and in middle ear involvement ( p  = 0.012) with no difference for involvement of the external auditory canal ( p  = 0.98) or mastoid ( p  = 0.78). Only middle ear involvement remained significant on multivariate analysis. Conclusion  A wide variety of malignant pathology may present in the temporal bone. Recurrence-free survival is equivalent to international data; however, this figure is low. This emphasizes the need to treat these tumors appropriately with radical resection, where possible, at first presentation. Therefore, multidisciplinary surgical input is recommended. Middle ear involvement was a negative prognosticator for disease-specific and recurrence-free survivals.