Clinical Analysis of En Bloc Resection for Advanced Temporal Bone Squamous Cell Carcinoma

Abstract

Objective En bloc and margin-negative surgical resection seems to offer the best prognosis for patients with temporal bone squamous cell carcinoma (TB-SCC). In this study, we summarize the outcomes of surgical cases of advanced TB-SCC (T3-T4) that were managed in two institutions, with an accompanying description of the surgical procedure that was utilized: modified subtotal temporal bone resection (STBR), which involves the en bloc removal of the temporal bone including or transecting the otic capsule. Design This is a case series study with chart review. Setting The study was conducted at two academic tertiary care medical centers. Participants Chart information was collected for all patients who underwent surgical resection of advanced TB-SCC between July 1998 and February 2019. The resulting dataset contained 43 patients with advanced TB-SCC who underwent en bloc resection during the review period. Tumor staging followed the modified Pittsburgh classification. Disease-specific survival (DSS) rates were calculated according to the Kaplan-Meier method. Main Outcome Measure This study shows disease-specific 5-year DSS rate. Results The 5-year DSS rate of the cases who underwent en bloc resection was 79.7%. En bloc lateral temporal bone resection was employed in a total of 25 cases (DSS: 79.0%). En bloc modified STBR was utilized in 18 cases (DSS: 81.7%). Conclusion En bloc margin-negative resection is a reliable treatment strategy for advanced TB-SCC. Modified STBR can be a treatment option for TB-SCC without marked posterior extension.

Keywords: skull base; squamous cell carcinoma; subtotal temporal bone resection; temporal bone.

Fig. 1

Surgical procedure. ( A ) Osteotomy range. The osteotomy lines for lateral temporal bone resection and modified STBR are indicated by white and yellow dotted lines, respectively. ( B ) Craniotomy and osteotomy lines for modified STBR. ( C ) The anterior osteotomy line (red dotted line) is created through the glenoid fossa. ( D ) The posterior osteotomy line (yellow dotted line) is created through the mastoid cavity. ( E ) Exposure of the infero-posterior aspects of the jugular bulb. ( F ) The medial osteotomy line, which is shown in B with an orange dotted line, is created from the middle cranial fossa. ( G ) The venous wall of the jugular bulb is separated from the jugular fossa. ( H ) The final surgical view after modified STBR. A., artery; CN, cranial nerve; EAC, external auditory canal; IAC, internal auditory canal; ICA; internal carotid artery; IJC, internal jugular vein; JB, jugular bulb; M., muscle; STBR, subtotal temporal bone resection; SS, sigmoid sinus; TM, temporal muscle.

Fig. 2

Preoperative and postoperative images of a representative case. ( A ) Preoperative CT. ( B ) Preoperative fluoro-deoxyglucose positron emission tomography. ( C, D ) Postoperative CT. The postoperative three-dimensional reconstruction model is shown in the upper right corner of D. CT, computed tomography; EAC, external auditory canal.

Fig. 3

Kaplan–Meier curves. ( A, B ) Disease-specific survival curves for all advanced temporal bone squamous cell carcinoma cases who were treated, stratified according to T status ( A ) and treatment modality (en bloc resection versus other) ( B ). ( C ) Disease-specific survival curves for the en bloc resection group, stratified according to T status. ( D ) Disease-specific survival curves for cases treated with lateral temporal bone resection and modified subtotal temporal bone resection.