Squamous cell carcinoma of the external auditory canal: two cases treated with high dose rate 192Ir remote afterloading system (RALS).

We report two cases of early-stage external auditory canal cancer treated by intracavitary irradiation with a high dose rate (HDR) 192Ir remote afterloading system (RALS) for preoperative treatment. A 6-Fr catheter for the HDR 192Ir remote afterloader, fixed by a plastic earplug, was inserted into the external auditory canal in two cases (case 1, T2N0M0; case 2, T1N0M0). The total intracavitary radiation dosages were 50 Gy (10 Gy/2 Fr/wk for 5 wks) for case 1, and 42 Gy (15 Gy/5 Fr/wk for 3 wks) for case 2. No external irradiation was given in either case. Surgical resection was performed in both cases, three to four weeks after irradiation. Histopathological examination confirmed the post-irradiation changes of necrosis, hyalinosis, and calcification, although vivid cancer cells remained. In preoperative irradiation of external auditory cancer, this method, although limited to treating early-stage cancers, may be a modality of choice for its efficacy and less severe side effects.