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Cancer of the External Auditory Canal
Mette Nyrop, MD;
Aksel Grøntved, MD
Arch Otolaryngol Head Neck Surg. 2002;128:834-837.
ABSTRACT
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Objective To evaluate the outcome of surgery for cancer of the external auditory
canal and relate this to the Pittsburgh staging system used both on squamous
cell carcinoma and non–squamous cell carcinoma.
Design Retrospective case series of all patients who had surgery between 1979
and 2000. Median follow-up was 47 months (range, 2-148 months). Data on age,
sex, symptoms, TNM status, histopathological diagnosis, surgery, adjunctive
therapy, sequelae, recurrence, and status at follow-up were obtained.
Setting An ear, nose, and throat department in an ambulatory and hospitalized
care center.
Patients Ten women and 10 men with previously untreated primary cancer. Median
age at diagnosis was 67 years (range, 31-87 years). Survival data included
18 patients with at least 2 years of follow-up or recurrence.
Intervention Local canal resection or partial temporal bone resection.
Main Outcome Measure Recurrence rate.
Results Half of the patients had squamous cell carcinoma. Thirteen of the patients
had stage I tumor (65%), 2 had stage II (10%), 2 had stage III (10%), and
3 had stage IV tumor (15%). Twelve patients were cured. All patients with
stage I or II cancers were cured except 1 with adenoid cystic carcinoma. No
patients with stage III or IV cancer were cured. All recurrences developed
in patients with incompletely resected tumors.
Conclusions The outcome was related to the stage of disease, suggesting that the
Pittsburgh staging system is useful also in patients with non–squamous
cell carcinoma. Patients with early cancer benefited from a less aggressive
surgical approach, while survival was poor in patients with advanced cancer
with incompletely resected tumors despite adjuvant radiotherapy.
INTRODUCTION
CANCER of the external auditory canal is infrequent, with an incidence
of approximately 1 per million population per year.1
Because of difficulties in evaluating the temporal bone preoperatively, there
has been no generally used staging system of these tumors and therefore it
is difficult to compare the results of different groups. In 1990, Arriaga
et al2 from the University of Pittsburgh (Pa)
proposed a staging system for squamous cell carcinoma (SCC) of the external
auditory meatus, based on preoperative clinical examination and computed tomographic
(CT) findings. Some authors have used this staging system, which was revised
in 2000.3-5 There
is currently no generally accepted staging system for non-SCC tumors, so we
decided to use the Pittsburgh staging system also for patients with non-SCC.
Although surgery is nearly always performed, no consensus exists as
to the type of procedure that should be chosen. Some authors advocate en bloc
resection (eg, partial, subtotal, or total temporal bone resection)—the
extent of which is determined by preoperative imaging techniques.3 Others do not believe that the extent of the tumor
can be judged preoperatively and hence advocate that surgery should be guided
by intraoperative findings in a piecemeal manner. The morbidity and mortality
have been reported to be less when using this method.6-7
However, the extent of the recommended surgery varies, as does the use of
adjuvant radiotherapy.3-4,6-8
The aim of this study was to evaluate the results of surgically treated cancer
of the external auditory meatus at our department, which has a population
basis of approximately 1 million people.
PATIENTS AND METHODS
The records of all patients who had undergone surgery for cancer of
the external auditory meatus from January 1, 1979, to July 1, 2000, at our
department were retrospectively reviewed. Patients with carcinoma in situ
were not included. Age, sex, symptoms, TNM status at the time of operation,
histological diagnosis, and type and extent of surgery were recorded.
The operations were classified according to the definitions given by
Austin et al3: (1) Local
canal resection—removal of all or part of the cartilaginous external
canal and the skin of the external canal. Local canal resection may involve
removal of a portion (but not all) of the bony canal or removal of the tympanic
membrane. Local canal resection does not constitute an en bloc resection of
the external canal. Local canal resection was occasionally combined with mastoidectomy,
removal of incus and malleus, and/or parotidectomy, but in all local canal
resections some of the osseous external auditory canal was left. (2) Partial temporal bone resection—en bloc removal of
the entire external auditory canal (cartilaginous and bony part) through a
mastoid approach; the facial nerve is identified and the temporal bone contents
are removed lateral to the facial nerve (including the tympanic membrane with
the malleus and incus).3 This operation was
performed in 1 patient only.
Adjunctive therapy (postoperative irradiation, chemotherapy), sequelae,
recidivism, and status at follow-up were also recorded. Only patients with
at least 2 years of follow-up or recurrence were included in the survival
data. The criteria of the revised Pittsburgh staging system were used with
respect to T status and stage (for definitions, see Table 1). Even though the classification was originally devised
for SCC, we have now classified all cancers according to the system to make
our results more comparable to those of other groups. The results for SCC
and non-SCC are reported separately.
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Table 1. University of Pittsburgh TNM Staging System Proposed for External
Auditory Canal Squamous Cell Carcinoma2,5
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RESULTS
Twenty consecutive patients (10 women and 10 men) who had surgery for
cancer of the external auditory canal were included. All cases were previously
untreated primary cancers at inclusion. Initially, all patients had surgery.
Two patients had previously been irradiated in the ear region, 1 patient because
of a contralateral tonsillar cancer (6600 rad [66 Gy]; 11 years earlier) and
1 patient (6000 rad [60 Gy]; 28 years earlier) because of a hypophyseal adenoma.
Six patients (30%) had a history of previous chronic external otitis. The
median age at the time of diagnosis was 67 years (range, 31-87 years).
The most frequent presenting symptoms were otorrhea (9 patients), sensation
of occlusion of the ear (8 patients), and pain (7 patients). Itching and hearing
loss were present in 4 patients each. Only 1 patient had had bloody otorrhea.
The duration of symptoms at the time of referral was stated in 16 patients
and was 6 months (median) (25%-75% range, 2-7 months; total range, 1-72 months).
The histological diagnosis was SCC in 10 (50%) of the patients, basal
cell carcinoma in 4 (20%), adenoid cystic carcinoma in 3 (15%), adenocarcinoma
in 1 (5%), ceruminous carcinoma in 1 (5%), and malignant fibrous histiocytoma
in 1 (5%).
The patients were staged according to the Pittsburgh system (Table 1). Tomography of the temporal bone
or CT scanning was performed in 12 patients. In 8 patients the extent of the
tumor was judged from peroperative observations and histological examinations.
One patient had lymph node metastases (N1) at the time of surgery. None had
distant metastases.
One patient underwent partial temporal bone resection. The other patients
had local canal resection. The extent of a resection was determined by the
size and location of the tumor and in case of doubt, guided by frozen section
microscopy. If the tumor was located in the bony meatus and there was no macroscopically
bony involvement, bone was grinded away near the tumor. If necessary, further
resection (eg, mastoidectomy or parotidectomy) outside the meatus was performed
in a piecemeal manner (Table 2).
There was no perioperative mortality.
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Table 2. Summary of 20 Patients With Carcinoma of the External Auditory
Meatus*
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Peroperatively, in 9 of 10 patients with non-SCC, the surgery was macroscopically
thought to be complete. However, the final histopathological examination showed
that only 5 patients had negative margins (no cancer at the margins of the
resection). Among the 10 patients with SCC, surgery was thought to be complete
in 5 and incomplete in 5. These observations were confirmed by histopathological
examination. Hence, in 10 of the 20 patients, the surgery was complete (no
cancer at the margins of resection at histopathological examination). Postoperative
irradiation was given to all patients with incompletely resected tumors (5
non-SCC and 5 SCC). One patient (patient 15) was merely given irradiation
treatment toward her neck metastases due to earlier radiotherapy. One of the
patients with completely resected tumor received radiotherapy (patient 3).
Sequelae after the treatments were minor, and most frequently observed in
the patients treated with irradiation. Chronic otorrhea was observed in 7
patients. The patient who had partial temporal bone resection had conductive
hearing loss and trismus.
Two patients died of unrelated causes within 2 years after surgery and
were excluded from the survival data. The median duration of follow-up was
47 months (mean [range], 60.2 [2-148] months). Twelve patients (67%) (6 with
SCC and 6 with non-SCC) were cured. All 6 cases of recurrency developed in
patients with incompletely resected tumors (patients 5, 8, 9, 10, 16, and
18) (Table 2). Recurrence was
diagnosed 2 to 116 months (median [mean], 6 [24.5] months) after the operation.
Only 1 of 13 patients with stage I or II disease developed recurrence (metastases
in the lumbar spine), which occurred 10 years after the resection of an adenoid
cystic carcinoma. Among the 4 patients with incomplete resection of a stage
I or II cancer, only the patient with adenoid cystic carcinoma developed recurrence.
Four of 10 patients with SCC and 2 of 8 patients with non-SCC developed recurrence.
The stage-related cure rates are given in Table 3. At recurrence, 5 patients were treated with chemotherapy
(patients 5, 9, 10, 16, and 18), 2 underwent further operation (neck dissection
and resection in the aural region) (patients 5 and 8), and irradiation was
given to the patient with lumbar metastases (patient 16).
COMMENT
The main finding of this study is that local canal resection, guided
by the findings during surgery and aided by frozen section microscopy, is
a reasonable approach for cancer with limited involvement of the external
auditory canal (stages I and II). This procedure resulted in a cure rate of
92% without any significant morbidity. The only exception to cure was an adenoid
cyst carcinoma, suggesting that patients with this histological diagnosis
may warrant more aggressive treatment. In more advanced cancers (stages III
and IV) the same approach resulted in incomplete resections and recurrence
in every case despite postoperative radiotherapy. This indicates that a more
dramatic surgical approach should be used in the more advanced stages.
The results are comparable to most others regarding age and sex.1-4,8-9
This study has a higher proportion of stage I and II cancers, 75%, compared
with other studies using the same staging system (proportion of stage I and
II ranging from 33%-54%).3-4,10
The lack of a generally accepted staging system makes it difficult to
compare the results of different groups. Since this type of tumor is rare,
it is difficult for a single center to obtain sufficient experience. This
is probably one of the reasons why there are no randomized or controlled studies
(11 per a search of MEDLINE). Therefore, a standardized staging (and treatment)
system is particularly desirable for these tumors. In 1990, the Pittsburgh
group proposed a staging system for SCCs of the external auditory meatus based
on data from 39 patients of whom 33% had had a CT scan.2
Other authors have used this staging system.3-4,10
A minor revision was added in 2000.5 In the
present retrospective study that includes cases from the pre-CT era we classified
patients with cancer of the external auditory canal based on clinical and
CT findings according to the Pittsburgh classification, although CT was performed
in only 35% of the patients. We used this classification to make our data
comparable to these of other groups since in this infrequent disease with
a poor prognosis it is important that information from the usual small series
can be subjected to, for example, meta-analysis. This is also the reason why
we used the classification for the non-SCC of the external auditory canal
that is even more infrequent than SCC. Since the stage-related survival rates
for SCC and non-SCC in this study are similar, we find no contradictions to
apply the Pittsburgh staging system also on non-SCC of the external auditory
meatus. Due to the small numbers in the present study it was impossible to
determine, by multivariate analysis, if the staging system has independent
prognostic significance. Moody et al5 found
a direct correlation between the staging system and the 2-year survival rate.
In a meta-analysis, based on 26 publications with information on a total
of 144 patients,11 it was concluded that patients
with carcinoma confined to the external auditory canal had similar survival
rates, regardless of whether the operative procedure was mastoidectomy, lateral
temporal bone resection (defined as "removal of the osseous and cartilaginous
external auditory canal, incus and malleus"), or subtotal temporal bone resection
(as lateral temporal bone resection with "additional removal of the otic capsule");
furthermore, the addition of radiotherapy to lateral temporal bone resection
did not improve survival. If the disease extended into the middle ear, the
results of the meta-analysis suggested that survival of patients treated with
subtotal temporal bone resection was better than those treated with lateral
temporal bone resection or mastoidectomy.11
These conclusions are in accordance with those of the present study as detailed
below.
The mortality rates in the present study for the early stages (stage
I, 9% and stage II, 0%) are comparable or better than those reported by other
groups.3-6,10-11
Our mortality rates for the more advanced stages (stages III and IV, 100%)
are comparable to or worse than those of others.3-5,11-12
This is probably because none of our patients with advanced disease had tumor-free
margins after surgery. As found by Pfreundner et al,4
patients who had their tumors resected with free margins had a 5-year survival
rate of 100%, whereas the survival rate was only 66% in those where the tumor
had not been completely removed. Our data support this: All patients with
negative margins at surgery were cured. The overall recurrence rate among
patients with positive margins at surgery was 67% (25% in stages I and II;
and 100% in stages III and IV). Thus, our data suggest that for stage I and
II tumors, there is no reason to use large resection of the temporal bone,
as long as postoperative radiotherapy is given in case of incomplete resection.
The only exception to this may be in the case of adenoid cyst carcinoma. In
more advanced cancer, however, postoperative radiotherapy is not an alternative
to complete resection.
AUTHOR INFORMATION
Accepted for publication January 8, 2002.
Corresponding author and reprints: Mette Nyrop, MD, Department of
Oto-rhino-laryngology, Odense University Hospital, DK-5000 Odense, Denmark.
From the Department of Oto-rhino-laryngology, Odense University Hospital,
Odense, Denmark.
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