Postoperative Radiotherapy for pT1- and pT2-Classified Squamous Cell Carcinoma of the External Auditory Canal

Cindy H Nabuurs; Wietske Kievit; Charles René Reinier Leemans; Conrad F G M Smit; Michiel W M van den Brekel; Robert J Pauw; Bernard F A M van der Laan; Jeroen C Jansen; Martin Lacko; Weibel W Braunius; Chunfu Dai; Xunbei Shi; Giovanni Danesi; Jan Bouček; Daniele Borsetto; Shavran Gowrishankar; Romain Kania; Clément Jourdaine; Thijs T G Jansen; Jolanda Derks; Tim Dijkema; Robert P Takes; Henricus Dirk P M Kunst

doi:10.3390/cancers16234026

Postoperative Radiotherapy for pT1- and pT2-Classified Squamous Cell Carcinoma of the External Auditory Canal

Cancers (Basel). 2024 Nov 30;16(23):4026. doi: 10.3390/cancers16234026.

Authors

Cindy H Nabuurs^{1

2}, Wietske Kievit^{1

2

3}, Charles René Reinier Leemans⁴, Conrad F G M Smit⁴, Michiel W M van den Brekel⁵, Robert J Pauw⁶, Bernard F A M van der Laan^{7

8}, Jeroen C Jansen⁹, Martin Lacko¹⁰, Weibel W Braunius¹¹, Chunfu Dai¹², Xunbei Shi¹², Giovanni Danesi¹³, Jan Bouček¹⁴, Daniele Borsetto¹⁵, Shavran Gowrishankar¹⁵, Romain Kania¹⁶, Clément Jourdaine¹⁶, Thijs T G Jansen^{1

2}, Jolanda Derks¹, Tim Dijkema¹⁷, Robert P Takes^{1

2}, Henricus Dirk P M Kunst^{1

2

10}

Affiliations

¹ Department of Otorhinolaryngology and Head and Neck Surgery-Academic Alliance Skull Base Pathology Radboudumc & MUMC+, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands.
² Rare Cancers, Radboud Institute for Health Sciences, 6525 EZ Nijmegen, The Netherlands.
³ Department of Health Evidence, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands.
⁴ Department of Otolaryngology-Head and Neck Surgery, Amsterdam University Medical Centers, VU University, 1081 HV Amsterdam, The Netherlands.
⁵ Department of Head and Neck Surgery and Oncology, Netherlands Cancer Institute-Antoni van Leeuwenhoek, 1066 CX Amsterdam, The Netherlands.
⁶ Department of Otorhinolaryngology and Head and Neck Surgery, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands.
⁷ Department of Otorhinolaryngology and Head and Neck Surgery, University Medical Center of Groningen, University of Groningen, 9713 GZ Groningen, The Netherlands.
⁸ Department of Otorhinolaryngology Head and Neck Surgery, Haaglanden Medical Center, 2512 HH The Hage, The Netherlands.
⁹ Department of Otorhinolaryngology and Head and Neck Surgery, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands.
¹⁰ Department of Otorhinolaryngology and Head and Neck Surgery-Academic Alliance Skull Base Pathology Radboudumc & MUMC+, Maastricht University Medical Center, 6229 HX Maastricht, The Netherlands.
¹¹ Department of Head and Neck Surgical Oncology, University Medical Center, Utrecht Cancer Center, 3584 CG Utrecht, The Netherlands.
¹² Department of Otology & Skull Base Surgery, Eye Ear Nose & Throat Hospital, Fudan University, Shanghai 200437, China.
¹³ Department of Otorhinolaryngology and Skull Base Microsurgery-Neurosciences, Azienda Socio Sanitaria Territoriale Papa Giovanni XXIII, 24127 Bergamo, Italy.
¹⁴ Department of Otorhinolaryngology, Head and Neck Surgery, The First Faculty of Medicine, Charles University in Prague, University Hospital Motol, 150 06 Prague, Czech Republic.
¹⁵ Department of Otorhinolaryngology, Head and Neck Surgery, Cambridge University Hospitals NHS Foundation Trust, Cambridge CB2 0QQ, UK.
¹⁶ Department of Head and Neck Surgery, Lariboisière University Hospital, 75010 Paris, France.
¹⁷ Department of Radiation Oncology, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands.

Abstract

Background: There is no consensus regarding the indication for postoperative radiotherapy (PORT) for T1- and T2-classified squamous cell carcinoma (SCC) of the external auditory canal (EAC) even with negative surgical margins. This study aimed to evaluate whether PORT provides additional benefits for these cases.

Methods: We collected retrospective data from fourteen international hospitals, including resected pT1- and pT2-classified EAC SCC with negative surgical margins.

Results: A total of 112 early-stage radically resected EAC SCC were included, with 48 patients receiving PORT. The 5-year DFS of T1- and T2-classified EAC SCC treated with PORT was not statistically significantly different (92.9% and 76.9%, respectively) compared to the group treated without PORT (100% and 90.9%, respectively; p-values of 0.999 and 0.526, respectively). EAC SCC treated with PORT more frequently exhibited perineural and angioinvasive growth. Eighteen patients experienced side effects related to radiotherapy, of which one patient developed osteoradionecrosis.

Conclusions: Our study suggests that PORT for early-stage radically resected EAC SCC should only be considered in selected cases with perineural, infiltrative growth or angioinvasive growth, and with a close margin. This approach helps mitigate the negative impact on quality of life and the risk of side effects associated with radiotherapy.

Keywords: disease-free survival; radiotherapy; squamous cell carcinoma; temporal bone; treatment.

Grants and funding

This work represents independent research supported by the Department of Otorhinolaryngology and Head and Neck Surgery, Radboud University Medical Center. JB was supported by the Ministry of Health of the Czech Republic (grant NU21-08-00280).