Maxillary squamous cell carcinoma: an 11-year retrospective study of one regional cancer centre

Abstract

Intraoral maxillary squamous cell carcinoma (IOMSCC) tumours are comparatively rare compared to those occurring at other oral sites. This has resulted in limited studies regarding their pattern of local and regional behaviour. In a review of the IOMSCC cohort ( N = 39) at the study institution, IOMSCC was found to demonstrate a pattern of levels 1–3 nodal disease in the N+ neck at presentation (33.3%), with a total metastatic rate of 46.1%, which is similar to that for other intraoral sites. IOMSCC demonstrated metastatic potential to the contralateral neck, with 20% of patients progressing to present with disease. This seems to occur irrespective of midline involvement. On observation of the N0 group patients who did not have surgical treatment of the neck, the rate of progression to disease development was similar to those with N+ necks on presentation (38.5%). An ipsilateral selective neck dissection in the N0 cohort appeared to have resolved ipsilateral neck disease, but the disease rate in the contralateral neck, although numbers are small, was >20%. This clinical review suggests the use of level 1–3 ipsilateral neck dissection in treating the N0 patient for IOMSCC and may indicate a role for sentinel node biopsy in the management of the contralateral neck.

Intraoral maxillary squamous cell carcinoma (IOMSCC) tumours, defined in this study as tumours presenting originally on the intraoral maxillary alveolus, gingiva, and hard palate, are comparatively rare compared to those occurring at other oral sites. This has resulted in limited studies regarding their pattern of local and regional behaviour.

Historically published data have come from small cohorts, and a general consensus regarding the treatment of cervical lymphatics has been lacking. Recently published studies have been of multi-centre design and have suggested a selective neck dissection (SND) in the treatment of IOMSCC. However, due to centres having different protocols for IOMSCC management of the neck, there is a potential for error in interpreting the outcomes. There now seems to be a general consensus that IOMSCC should be managed like other oral SCC and that an elective neck dissection should be considered as part of their treatment.

Weiss et al. propose a 20% risk of occult metastasis as the threshold for elective surgical management of an at-risk neck in oral cancer. Recent publications have shown IOMSCC to be above this threshold.

Methods

The cases of 39 patients diagnosed with IOMSCC and treated from January 2001 to January 2012, were studied retrospectively. IOMSCC was defined as SCC arising from the palate or maxillary alveolus. Those that may have arisen from the maxillary sinus or buccal vestibule were excluded. Their treatment was discussed at a multidisciplinary team (MDT) meeting attended by head and neck consultants from surgery, radiology, pathology, and oncology. A contribution from other clinical but non-medical staff ensured optimization of the overall outcome.

Tumour staging at presentation was documented (cTNM), along with tumour site. The accuracy of the clinical findings was confirmed radiologically by primary tumour computed tomography (CT)/magnetic resonance imaging (MRI) and MRI neck studies (rTNM). A chest X-ray was included to assess concurrent chest pathology.

The sample of IOMSCC ( N = 39) was divided into those presenting with a positive neck (N+; n = 14) and those with a clinically negative neck (N0; n = 25). One patient in the positive neck group died before radiological staging and treatment was initialized, making this sample size 13. In comparing the N0 group ( n = 25), only patients who were fit for surgery were compared. Four patients were omitted from the observed N0 group because of co-morbidities.

Postoperative histological findings were used to confirm the clinical and radiological findings and to determine further treatment if necessary. Tumour staging according to the TNM system was documented. Pathological T4 tumours were treated with radiotherapy, 65 Gy over 6 weeks to the primary tumour site. Neck irradiation was given where there was a single lymph node with extracapsular spread, or in the presence of more than one lymph node with metastatic disease.

Patients were followed up in a joint head and neck clinic. Follow-up periods were as follows: year one, 4–6 weeks; year two, 8 weeks; year three, 3 months; year four, 6 months. Patients were given the option of being discharged at year 5.

During the study period, reconstruction of the maxillary defects was started. We therefore had two groups of patients with N0 necks: (1) those clinically N0 who had not undergone a staging neck (−SN), and (2) those with a histologically confirmed N0 neck (those who underwent a staging 1–3 neck (+SN) at the time of microvascular access). These two groups were used to compare the +SN in the N0 neck versus those −SN. The pattern of nodal spread and recurrence in the neck were documented and compared with the accuracy of radiological findings in IOMSCC.

Results

This was an 11-year retrospective study originally including 39 cases of IOMSCC. The study group of 39 patients analyzed included 18 males and 21 females with a mean age of 67.5 years. The clinical review period for the N0 necks ranged from 5 months to 87 months, with an average of 38 months.

Of the 39 cases, 10 (25.6%) presented with anterior maxillary disease and 29 (74.4%) had posterior disease. Thirteen (33.3%) patients had neck disease at presentation. It was noted that there was an inaccuracy with radiological T staging compared to pathological T staging. Forty percent of tumours that were originally staged as T1/2 with clinical and radiological examinations were upgraded to T4 on histology. Histologically it was noted that due to the thin mucosa, direct invasion into bone was the main reason for palatal and alveolar tumours.

In the nodal positive necks ( n = 13; Table 1 ), three (23.1%) were anterior tumours and 10 (76.9%) were posterior tumours. One hundred percent of anterior tumours and 80% of posterior tumours in the nodal positive neck presented as pathological T4 IOMSCC. A 1–3 nodal disease pattern of involvement was noted. There was one neck failure in the anterior maxilla group with disease representing in the contralateral neck only. Given the anatomical presentation it would have involved the midline. Forty percent of posterior tumours ( n = 4) had neck failure postoperatively, with two presenting with bilateral neck disease. These posterior tumours with contralateral neck disease did not cross or have midline involvement. Disease recurrence generally occurred during the first 6 months postoperatively even though they were treated with postoperative radiotherapy.

Table 1
Details of patients with IOMSCC and N+ neck who underwent a selective neck dissection.
Case no. Location of tumour in the maxilla Pathological stage a Pathological tumour grade b Location of neck disease Recurrent neck disease
1 Anterior T4N2a G3 Level 1, 2a, 3 Contralateral level 2
2 Posterior T4N2b G2 Level 1, 2b Bilateral 1–4
3 Posterior T4N2a G2 Level 1, 2a Level 1b
4 Anterior T4N2a G1 Level 1, 2a Nil
5 Posterior T4N2c G2 Level 2a Nil
6 Posterior T4N1 G2 Level 1 Nil
7 Anterior T4N1 G1 Level 1 Nil
8 Posterior T4N1 G2 Level 1 Nil
9 Posterior T1N2b G2 Level 1, 2a Nil
10 Posterior T4N2b G2 Level 1 Level 1
11 Posterior T4N2b G3 Level 1, 2a Nil
12 Posterior T2N2c G2 Level 1, 2b Bilateral level 3
13 Posterior T4N3 G1 Level 1, 2a Nil
IOMSCC, intraoral maxillary squamous cell carcinoma.

a TNM system.

b G1: well differentiated; G2: moderately differentiated; G3: poorly differentiated.

There were 25 clinically and radiographically negative necks. Seventeen patients had primary resections and had their necks observed, while eight had a level 1–3 SND.

In the observed neck group, 13 were medically fit for surgical treatment of the neck ( Table 2 ). It was this group of 13 that was used to compare with those that had a SND. The follow-up period for this group ranged from 6 to 87 months, with the average being 39.5 months. Five had neck failures (38.5%), which were staged clinically and radiographically as T1 but were re-staged on histology as T4 tumours. The presentations of the neck failures were ipsilateral ( n = 2) or bilateral ( n = 3). In the patients who progressed to presenting with neck disease, the prognosis was poor, with deaths occurring at 6, 16, 18, and 27 months. These patients with disease progression in the neck would have been treated with a level 1–4 neck dissection plus radiotherapy or palliative radiotherapy, as discussed in the MDT. One patient (20%) in this group had survived to 59 months and continues to remain disease-free.

Table 2
Details of patients with IOMSCC and N0 neck who did not undergo selective neck dissection.
Case no. Location of tumour in the maxilla Pathological stage a Pathological tumour grade b Excision margin Recurrent neck disease Follow-up period, months
1 Anterior T2 G1 Complete Nil 54
2 Posterior T2 G2 Complete Nil 34
3 Posterior T1 G1 Complete Nil 53
4 Posterior T4 G2 Complete Nil 30
5 Posterior T4 G2 Complete Level 1 and 2a 59
6 Anterior T2 G1 Complete Nil 67
7 Posterior T4 G3 Complete Bilateral right levels 1–3, left level 2a 16
8 Posterior T4 G1 <2 mm Level 1 18
9 Posterior T1 G1 Complete Nil 51
10 Posterior T4 G2 Complete Bilateral levels 1, 2a and b 27
11 Posterior T4 G2 Complete Bilateral and parapharyngeal 6
12 Posterior T1 G1 Complete Nil 12
13 Anterior T1 G1 Complete Nil 87
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Jan 19, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Maxillary squamous cell carcinoma: an 11-year retrospective study of one regional cancer centre
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