Multi-institutional Survey of Squamous Cell Carcinoma of the External Auditory Canal in Japan

Oncological outcomes of concurrent chemoradiotherapy with docetaxel, cisplatin, and 5-fluorouracil for locally advanced squamous cell carcinoma of the external auditory canal: A single-center study

BACKGROUND

Squamous cell carcinoma of the external auditory canal (EACSCC) is a rare condition. However, a standard treatment has not yet been established. We retrospectively evaluated the efficacy, adverse events, and feasibility of TPF-CCRT (concomitant chemoradiotherapy with docetaxel, cisplatin, and 5-fluorouracil) in patients with advanced EACSCC.

METHODS

Thirty-five consecutive patients with advanced EACSCC (T3, T4) initially treated with TPF-CCRT at Kobe University Hospital were included. T4 diseases with invasion of the brain, internal carotid artery, or internal jugular vein were classified as T4b, and those without these features were classified as T4a.

RESULTS

Five-year overall survival rates for T3 and T4 were 100% and 64.2%, respectively. A significant difference was observed between T4a and T4b (82.4% vs. 30%, p = 0.007). Five-year progression-free survival rates of T3, T4a, and T4b were 100%, 68%, and 20% (p = 0.022), respectively.

CONCLUSIONS

TPF-CCRT should be considered as a plausible treatment option for advanced EACSCC.

Analysis of Prognostic Factors For External Auditory Canal Carcinoma: A 22-Year Experience

OBJECTIVE

This study aimed to investigate the prognostic factors and treatment outcomes in patients with the external auditory canal (EAC) squamous cell carcinoma (SCC).

METHODS

All patients diagnosed with EAC SCC and treated with curative intent at a single tertiary institution were retrospectively reviewed over a 22-year period. Treatment modalities included surgery with adjuvant treatment or definitive radiotherapy. The primary endpoints were overall survival (OS) and disease-specific survival (DSS).

RESULTS

There were 51 patients in our cohort. The 5-year OS and DSS were 64.0% ± 7.0% and 72.0% ± 7.0% respectively. Patients in the surgical arm and RT arm showed no significant difference in OS, DSS, and LRFS (p = 0.075, 0.062, 0.058 respectively). Compared to other routes of spread within the temporal bone, pattern of posterior disease invasion (involving mastoid/sigmoid sinus) showed poorer OS and DSS on multivariate analysis (hazard ratio, HR4.34 and 5.88; p = 0.006 and 0.009). On multivariate analysis, the following factors were independently prognostic of poorer OS and DSS: Previous radiotherapy (HR 3.29 and 4.81, p = 0.021 and p = 0.029); Presence of facial nerve palsy (HR 3.80 and 7.63, p = 0.013 and p = 0.003); Posterior pattern of invasion (HR4.05 and 3.59, p = 0.013 and p = 0.043). Advanced modified Pittsburgh stage was not predictive of poor OS and DSS (HR1.17 and 1.17 E+5, p = 0.786 and p = 0.961).

CONCLUSION

Presence of previous radiotherapy, facial nerve palsy and posterior pattern of disease invasion were independent prognostic factors of poorer survival in patients with EAC SCC.

LEVEL OF EVIDENCE

4 Laryngoscope, 133:2203-2210, 2023.

Impact of Positive-Margin Resection of External Auditory Canal Squamous Cell Carcinoma

BACKGROUND

Positive-margin resection of external auditory canal squamous cell carcinoma (EAC-SCC) is still a major cause of recurrence. The aim of this study is to examine the clinical impact of positive-margin resection of EAC-SCCs.

METHODS

We retrospectively reviewed 40 surgical cases with en bloc temporal bone resection of EAC-SCC at a tertiary referral center from October 2016 to March 2022.

RESULTS

Two-year disease-specific, overall, and disease-free survival rates for all 40 cases reviewed were 85.2%, 88.85%, and 76.96%, respectively. En bloc resection with a negative margin significantly improved patient prognosis (p < 0.001). Positive-margin resection was observed in 9/40 cases (22.5%). Insufficient assessment of preoperative images was the cause in two of these cases. Postoperative lymph node metastasis and distant metastasis were observed in cases in which vascular, lymphatic duct or perineural invasion was found on postoperative pathological examination. In addition, three cases in which no vascular, lymphatic duct, or perineural invasion was found exhibited local recurrence during the follow-up period. Of the nine positive-margin resection cases, only two showed no postoperative recurrence.

CONCLUSIONS

Once positive-margin resections are confirmed, cases might have a high risk of tumor recurrence, even with the addition of postoperative adjuvant chemoradiotherapy.

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.

Reirradiation for Rare Head and Neck Cancers: Orbit, Auditory Organ, and Salivary Glands

We analyzed the efficacy and toxicity following reirradiation for locoregional recurrence of rare head and neck tumors. We retrospectively analyzed 17 patients who had received reirradiation for rare head and neck tumors. Primary tumor sites included nine ears (auditory organ), four salivary glands, and four orbits. The median follow-up time was 13.2 months for surviving patients. The median survival time was 12.6 months with one- and two-year survival rates of 53.1% and 44.3%, respectively. Nine out of 17 patients experienced local failure. The one- and two-year local control rates were 42.4% and 31.8%, respectively. The median survival times were 12.6, 5.3, and 11.0 months for orbit, auditory organ, and salivary glands, respectively. Three patients experienced grade 3 toxicity, including meningitis, brain necrosis, and facial nerve disorders. No grade ≥4 toxicities were observed. Reirradiation of rare head and neck tumors is feasible, with acceptable toxicity.

Treatment Outcome of External Auditory Canal Carcinoma: The Utility of Lateral Temporal Bone Resection

We examined the role of lateral temporal bone resection (LTBR) in the treatment of external ear canal (EAC) carcinoma between 2007 and 2018. The estimated 3-year disease-free survival (DFS) and disease-specific survival (DSS) according to the tumor stage and treatments were investigated in 36 patients with EAC squamous cell carcinoma. T stage classification according to the University of Pittsburgh staging system was as follows: 14 patients in T1, four patients in T2, nine patients in T3, and nine patients in T4. The 3-year DFS rate was 77.4% for T1 tumors, 100% for T2, 44.4% for T3 tumors, and 11.1% for T4 tumors (p < 001). The 3-year DSS rate was 100% for T1/T2 tumors, 87.5% for T3 tumors, and 11.1% for T4 tumors (p < 0.01). T1/T2 patients received mostly LTBR. Among nine T3 tumors, five patients (56%) received LTBR combined with preoperative chemotherapy and/or postoperative radiation (RT). Four of them had negative surgical margin and survived with no evidence of disease. The DFS of T3 patients who underwent concurrent chemoradiotherapy and LTBR was 0 and 80%, respectively (p = 0.048). For T1/T2 tumors, surgery achieved an excellent outcome. For T3 tumors, LTBR achieved negative surgical margin and showed good survival when combined with preoperative chemotherapy and/or postoperative RT. In contrast, the prognosis of T3 patients who could not undergo surgery was as poor as that of T4 patients. Therefore, in addition to subtotal temporal bone resection, LTBR-based treatment strategy may be a treatment option for limited cases of T3 patients.

Phase I trial of concurrent chemoradiotherapy with docetaxel, cisplatin and 5-fluorouracil (TPF-CRT) for locally advanced squamous cell carcinoma of the external auditory canal

PURPOSE

Chemoradiotherapy with docetaxel (DOC), cisplatin (CDDP), and 5-FU (TPF-CRT) for locally advanced external auditory canal cancer (EACC) has favorable oncological and functional outcomes. To establish TPF-CRT as a standard of care for advanced EACC, we conducted this study to determine the maximum tolerated (MTD) and recommended dose (RD) of DOC in TPF-CRT for locally advanced EACC.

METHODS

To determine the recommended (RD) and maximum tolerated dose (MTD) of DOC in TPF-CRT for EACC, a phase I trial was conducted using the standard "3 + 3" design for maximum dose finding. DOC was administered twice every 4 weeks, CDDP at 70 mg/m² and 5-FU at 700 mg/m²; patients were also receiving radiotherapy (66 Gy). Eight patients with T3 or T4 EACC were prospectively enrolled.

RESULTS

Two patients treated with DOC, 50 mg/m², and one out of six patients treated with DOC, 40 mg/m², had dose-limiting toxicities. Prolonged febrile neutropenia was observed in three patients. Grade 3 non-hematological toxicities were observed in only three patients. At study completion, six patients survived, five of whom were disease free.

CONCLUSION

The RD and MTD of DOC in TPF-CRT for locally advanced EACC are 40 mg/m² when doses of CDDP and 5-FU are 70 mg/m² and 700 mg/m², respectively.

Temporal bone carcinoma: testing the prognostic value of a novel clinical and histological scoring system

PURPOSE

Our group recently proposed the novel Padova prognostic scoring system for temporal bone carcinoma (TBSCC) that considers: the revised Pittsburgh staging system; radiological dura mater involvement; non-anterior spread (medial, inferior or posterior into the temporal bone and skull base) of T4 tumors; and histological grade. The aim of the present study was to validate this prognostic TBSCC scoring system in a case series selected from the literature.

METHODS

A search was run to identify studies on TBSCC reporting the variables included in our score for each patient. Then our system was applied to the data extracted.

RESULTS

Only two published investigations reported all the clinical and pathological data required for our scoring system. In one series from the Gruppo Otologico in Piacenza (Italy), a significantly higher recurrence rate (p = 0.008), shorter disease-free survival (DFS) (p = 0.001), higher disease-specific mortality (DSM) (p = 0.006), and shorter disease-specific survival (DSS) (p = 0.004) were associated with scores ≥ 5. Receiver operating curve (ROC) analysis showed an AUC of 0.804 for TBSCC recurrence, and 0.832 for DSM. In a series from Kyushu University Hospital (Japan), a significantly higher DSM (p = 0.018) and shorter DSS (p = 0.021) were associated with scores ≥ 5. ROC analysis showed an AUC of 0.812 for tumor relapse and 0.790 for DSM.

CONCLUSION

Our TBSCC Padova scoring system confirmed its validity when applied to the only two international TBSCC series providing the required data. These preliminary results need to be confirmed in a multi-center prospective setting.