SURGICAL MANAGEMENT OF T1 AND T2 LESIONS WITH OUTCOMES

Takashi Nakagawa,1 Takayuki Sueta,1 Kazuki Nabeshima2

Departments of Otorhinolaryngology and Head & Neck Surgery1 and Pathology2, Fukuoka University, School of Medicine, Fukuoka, Japan

Introduction

T1 or T2 lesion of squamous cell carcinoma (SCC) of the temporal bone is defined to be limited to the inside of the external auditory canal by the Pittsburg T-staging system.1 It is an early stage and good outcomes in survival ratio were reported by several authors.2,3 However, there is no consensus in operative procedure. The necessity of neck dissection remains to be demonstrated. Factors which affect outcomes have not been discussed yet. We have checked these points from outcomes in our facilities.

Method

We treated 56 patients with squamous cell carcinoma of external auditory canal (EAC) and middle ear. Settings were Kyushu University Hospital from January 1998 to March 2006 and Fukuoka University Hospital from April 2006 to March 2011. Mean age was 65 years (ranged between 41 and 93 years). There were 31 male and 26 female patients. Cases of a follow-up period of more than 12 months were included in the study. Patients who died of the disease were not included. Mean follow-up period was 37 months. Numbers of cases: T1N0 = one; T1N1 = none; T2N0 = 12; T2N1 = three; T3N0 = seven; T3N1 = two; T4N0 = 20; T4N1 = 11. Twenty-nine percent (n = 16) had lymph-node metastasis. There was only one case of T2N1M1.

Treatment strategy was determined by the extent of the tumor, evaluated by both CT and MRI before treatment. Fig. 1 shows the treatment strategy of our facilities at which the first author worked as a final decision maker of strategy for each patient.

Using the method of lateral temporal bone resection, the cartilaginous region including the cavum conchae of the auricle and the EAC, the bony part of the EAC and the tympanic membrane with the bony annulus were resected at the lateral side of the facial nerve. Upper neck dissection was in most cases added to the surgical procedure.

Using subtotal temporal bone resection, the facial nerve, inner ear, and internal auditory canal were sacrificed. The posterior and middle cranial fossa dura, sigmoid sinus, internal jugular vein, bulb and internal carotid artery were preserved. Modified neck dissection up to the skull base with total parotidectomy was commonly performed. As a consequence, the lesion inside the middle ear and the soft tissue containing lymph-flow draining from primary lesion down to the lower neck were totally removed.

Results

In 2006, we reported that disease-specific survival rate of the T1, T2, T3 and T4 lesions were 100%, 100%, 83% and 39%, respectively.3 Including the previous six years, the disease-specific survival rates for 13 years were summarized (Fig. 2). The five-year survival rate of T3 and T4 was 89% and 52%, respectively. However, the five-year survival rate of T1 and T2 decreased to 68% and was lower than that of T3. Although treatment strategy was maintained during 12 years, the number of cases of T1 and T2 was roughly three times that of the previous report.

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Fig. 1. Treatment strategy of temporal bone squamous cell carcinoma. Extent of tumor was evaluated by both CT and MRI before any treatment.

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Fig. 2. Disease-free survival rate for T stage.

Fig. 3 shows details of T1 and T2 cases. Four patients died of the disease in the follow-up period of 16, 18, 18 and 37 months. Markers of epithelial-mesenchymal transition (EMT) in the SCC tumor cells were examined in seven out of 16 cases. Three out of four patients who died of the disease were included in the study. Vimentin was positive and laminin was diffusely stained in all cases.

Discussion

We reported the outcome of our treatment strategy for temporal-bone SCC from 1998 to 2010. Characteristics of our strategy are pre-operative chemo-radiotherapy to control minor lesion of surgical margin and as surgical procedure en-bloc dissection with neck dissection. The strategy works for operative cases in an advanced stage. Five-year survival rate of T3 and T4 elevated to 89% and 52%. However, the survival rate of early-stage cases decreased to that of a T3 stage case.

As shown in Fig. 1, when a patient did not agree with our strategy, we modified the protocol and usually selected a less invasive treatment. Patients’ freedom of choice may modify the results. The disease-free survival rate was re-calculated by picking up on 46 cases which followed our treatment strategy. Early-stage, T3 and T4 cases were 83%, 100% and 55%, respectively. Although the survival rate of early-stage cases elevated over 80%, inversion still existed.

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Fig. 3. Details of T1 and T2 cases DOD labeled ‘died of disease’.

One of the reasons for inversion could be the different extent of neck dissection beside temporal bone resection. All regional lymph nodes with soft tissue including the parapharyngeal space were salvaged with T3 lesion by sacrificing the facial nerve. This procedure was not performed to the T2 lesion because of avoiding facial nerve palsy. Like in other head-and-neck cancers, lymph-node metastasis can be a poor prognostic factor for early stage. Cases 1, 10 and 16 had node metastasis as shown in Fig. 3. Several lymph-node metastases were found at parotid and upper neck in case 1. The patient agreed to a total parotidectomy by sacrificing the facial nerve even though facial nerve palsy was not pre-operatively found. The patient survived for a year. In case 16, a single lymph-node metastasis was found in the upper neck. Treatment of choice was neck dissection without parotidectomy and the patient survived for five years without recurrence. However, case 4 refused parotidectomy in spite of lymph-node metastasis at the deep lobe of the parotid gland and chose chemotherapy combined with immunotherapy. The patient died 18 months after the onset of the disease.

These experiences also suggested a validity of the high survival ratio of T3 cases treated by our strategy. Modified neck dissection up to the skull base with total parotidectomy consequently salvages all soft tissue containing lymph-flow draining from primary lesion down to the lower neck. It indicated that neck dissection was the treatment of choice lymph-node metastasis was found. Although it should depend on each patient’s own decision, we should not be reluctant to select total parotidectomy with sacrificing facial nerve for a case with lymph node metastasis in the deep lobe of the parotid gland.

There is also the possibility that pre-operative chemo-radiotherapy might not be effective to microlesion of lymph-node metastasis. An insufficient neck dissection for early-stage cases lowered the survival ratio. Sugimoto and colleagues suggested that EMT in tumor cells can be an indicator of poor prognosis in temporal bone SCC.4 Vimentin is one of the intermediate filament proteins expressed in mesenchymal cells related to EMT. Laminin is one of the proteins in the basal lamina. The translational activation of laminin during EMT was one of the prognostic factors of cancer. Our examination of immunostaining showed that vimentin was positive and laminin was diffusely stained in all early-stage DOD cases. It may suggest that an aggressive treatment strategy should be proposed when the biopsy specimen shows diffusion by laminin staining and vimentin-positivety. It could also be possible that a less invasive therapy might be selected when the immuno-pathological examination shows no lymph-node metastasis. Further study is necessary to investigate these options.

References

1.Arriaga M, Curtin HD, Takahashi H, Hirsch BE, Kamerer DB. Staging proposal for external auditory meatus carcinoma based on preoperative clinical examination and computed tomography findings. Ann Otol Rhinol Laryngol 99:714–721, 1990

2.Moody SA, Hirsch BE, Myers EN. Squamous cell carcinoma of the external auditory canal: an evaluation of a staging system. Am J Otol 21;582–588, 2000

3.Nakagawa T, Kumamoto Y, Natori Y, Shiratsuchi H, Toh S, Kakazu Y, Shibata S, Nakashima T, Komune S. Squamous cell carcinoma of the external auditory canal and middle ear: an operation combined with preoperative chemoradiotherapy and a free surgical margin. Otol Neurotol 27:242–249, 2006

4.Sugimoto H, Ito M, Hatano M, Kondo S, Suzuki S, Yoshizaki T. Roles of epithelial-mesenchymal transition in squamous cell carcinoma of the temporal bone. Otol Neurotol 32:483–487, 2011


Address for correspondence: Takashi Nakagawa, tnakgawa@fukuoka-u.ac.jp

Cholesteatoma and Ear Surgery – An Update, pp. 133–136

Edited by Haruo Takahashi

2013 © Kugler Publications, Amsterdam, The Netherlands