Journal of Islamabad Medical & Dental College (JIMDC); 2015:4(1):3-7
Original Article
Morphological Pattern and Management Options for Salivary Gland Malignant Tumors among Local Population of Rawalpindi Nadir Mehmood1, Nazim M Khan2, Naeem Zia3, Hina Dilruba K4, Qasim M Khan5, Irmaghana B6, Asif Zafar Malik7 1 Assistant Professor, 3Associate Professor, 4 Senior Registrar, Dept of Surgery, Rawalpindi Medical College, Rawalpindi 2 Assistant Professor of Surgery, Rawal Institute of Health Sciences, Islamabad 5 Postgraduate Trainee, Dept Of General Medicine, Rawalpindi Medical College, Rawalpindi 6 & 7Al-Nafees Medical College, Islamabad gland tumors, Parotid tumors.
Abstract Objective:
Introduction
To evaluate the morphological pattern and management options for salivary gland malignant tumors in local population.
Salivary gland tumors (SGT) consist of a group of heterogeneous lesions with complex clinico-pathological characteristics and distinct biological behaviors, most of them arising in the parotid gland.1 Salivary gland malignancies account for 3–6 % of head and neck cancers and 0.3 % of all malignancies.2 The reported incidence according to some epidemiological studies was reported 0.2–9.7.3 Bicellular stem cell theory holds that tumors arise from 1 of 2 undifferentiated stem cells. Excretory stem cells give rise to squamous cell and mucoepidermoid carcinomas (MEC), while intercalated stem cells give rise to pleomorphic adenomas, oncocytomas, adenoid cystic carcinomas, adenocarcinomas, and acinic cell carcinomas.4,5 In the multicellular theory, each tumor type is associated with a specific differentiated cell of origin within the salivary gland unit. Squamous cell carcinomas arise from excretory duct cells, pleomorphic adenomas arise from the intercalated duct cells, oncocytomas arise from the striated duct cells, and acinic cell carcinomas arise from acinar cells.4,5 The latest 2005 WHO classification of salivary gland carcinomas includes 24 different subtypes that present with distinct clinical characteristics and pathological behaviors.6 Investigations include FNAC, Ultrasound, CT and MRI scans. Nevertheless, none of these tools provide definitive information regarding the nature and the precise histology of a parotid mass. Mainstay of treatment is surgery for all benign and malignant salivary gland neoplasms.7 The extent of resection is based on tumor histology, tumor size, grade and location, invasion of local structures, and the status of regional nodal basins. Beahrs and Adson (1958) eloquently described the relevant anatomy and surgical technique of current parotid gland surgery.8 Most tumors of the parotid (approximately 90%) originate in the superficial lobe. Superficial parotid
Patients and Methods: This cross sectional observational study was carried out in the Department of Surgery, Benazir Bhutto Hospital Rawalpindi from Jan. 2010 to Oct. 2013. Patients of all ages and both genders, diagnosed as malignant salivary gland cancers were included in the study. Benign and recurrent salivary gland tumors were excluded from the study. All the patients were diagnosed and staged on the basis of patient’s FNAC and CT scans reports according to WHO guidelines. Results: Out of 67 patients with salivary gland tumors, fifteen were diagnosed as malignant and most commonly involved gland was parotid gland. Adenocarcinoma was the most common (33.3%) tumor found. All patients with parotid tumors underwent total parotidectomy with facial nerve sacrifice in 3 patients. 12 patients underwent modified neck dissection. Primary closure was possible in 4 patients and in 11 patients a reconstructive procedure was performed. Postoperatively, seven patients (4 transient and 3 permanent) developed facial palsy. All patients received post operative radiotherapy. Conclusion: Frequency of malignancy among salivary glands was 22% and mostly it involved the major salivary glands especially the parotid gland (60%). Adenocarcinoma was the most common malignant tumor. All 15 malignant salivary gland tumors were managed with surgical excision and postoperative radiotherapy. Primary closure was possible in only 4 patients and remaining 11 patients required a reconstructive procedure. Key Words:
Adenocarcinoma,
Malignant salivary
Corresponding Author Dr Nadir Mehmood Email:
[email protected] Received: April 23rd 2015; Accepted: June 12th 2015
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Journal of Islamabad Medical & Dental College (JIMDC); 2015:4(1):3-7 lobectomy is the minimum operation appropriate for malignancies confined to the superficial lobe, those that are low grade, those less than 4 cm in greatest diameter, tumors without local invasion, and those without evidence of regional node involvement. If the tumor is high-grade or >4 cm in greatest diameter, or lymph node metastasis is identified, a complete total parotidectomy should be performed. If the facial nerve or its branches are adherent to or directly involved by the tumor, they must be sacrificed. However, a pathologic diagnosis of malignancy must be confirmed intraoperatively prior to sacrificing facial nerve branches. In cases of locally advanced parotid cancer, complete resection may require the performance of an extended total parotidectomy which can include adjunct procedures such as mandibulectomy, skin resection, infratemporal fossa dissection, and skull base or temporal bone resection. Neck dissection should be performed when malignancy is detected in the lymph nodes pre- or intraoperatively. Other indications for functional neck dissection include tumors >4 cm in greatest diameter, high-grade, locally invading, recurrent and deep lobe tumors. Every effort should be made to preserve the facial nerve function.9 The consensus of opinion is that a functionally intact nerve should be preserved if there is no intraoperative finding of direct macroscopic nerve invasion.10 The rationale for this is that resection of an intact nerve has not been shown to improve local disease control.11 The options for wound closure in the presence of a skin or soft tissue deficit include skin grafting, cervicofacial flap, trapezius flap, pectoralis flap, deltopectoral flap, and microvascular free flap. General indications for postsurgical radiation therapy include tumors >4 cm in greatest diameter, tumors of high grade, tumor invasion of local structures, lymphatic invasion, neural invasion, vascular invasion, tumor present very close to a nerve that was spared, tumors originating in or extending to the deep lobe, recurrent tumors following re-resection, positive margins on final pathology, and regional lymph node involvement. Although chemotherapy alone does not improve survival rates, the integration of radiation and chemotherapy has been shown to increase local control. Chemotherapy improves radiotherapy efficacy through its radio-sensitizing ability, and at the same time provides adjuvant systemic therapy against distant micro-metastasis.12 The major determinants of survival are histology and clinical stage. Poor prognostic factors include high grade, neural involvement, positive margins, locally advanced disease, advanced age, associated pain, regional lymph node metastases, distant metastasis, and accumulation of p53 or c-erbB2 oncoproteins.1 The present study was conducted to evaluate the morphological patterns and management options for salivary gland malignant tumors in a local population.
Materials and Methods This cross sectional observational study was carried out at the Department of Surgery, Benazir Bhutto Hospital Rawalpindi from Jan. 2010 to Oct. 2013. Patients of all ages and both gender, diagnosed as having malignant salivary gland cancers were included in the study. Benign and recurrent salivary gland tumors were excluded from the study. Study design was approved from ethical committee and written consent was signed from each patient. A thorough history, meticulous clinical examination, routine hematological and biochemical investigations were done in all the patients. All patients were diagnosed and staged on the basis of FNAC and CT scan reports according to WHO guidelines. MRI scan was not performed routinely due to unavailability of the equipment at the institution. Preanesthesia fitness was taken for all patients. Postoperatively, patients were followed up 3 monthly for first year and 6 monthly for next two years and annually thereafter. Data was recorded on a written proforma which was entered and statistical analysis was done on SPSS 16.
Results During the study period, 67 patients presented with salivary gland tumors. Their age ranged between 3 months to 70 years and the mean age of 48.7 years. The male to female ratio was 1:1.2.After investigations, 15 (22%) out of these 67 patients were diagnosed as having malignant salivary gland tumors. Adenocarcinoma was the most common 5 (33.3%) histological variety found. The breakdown of malignant salivary tumors is shown in table1. Malignancy was confirmed preoperatively in 14 patients. In one patient it was a histopathological surprise. Out of 15 malignant cases, 9 (60%) patients had parotid lesions, Submandibular 4 (26.6%), sublingual and minor salivary glands 1(6.6%) each. All the patients presented with a swelling in the area of the affected salivary gland, only 4 (26.6%) had associated pain. Three patients (20%) had facial nerve paralysis. On physical examination, 11 (73.3%) patients had palpable cervical nodes. The duration of symptoms ranged from 3 months to 10 years with a mean of 2 years delay in presentation. Patients with malignant parotid tumors underwent total parotidectomy with facial nerve sacrifice in 3 (20%) patients. Postoperatively, 7 (46.6%) patients (4 transient and 3 permanent) had facial nerve paralysis. Permanent facial palsy resulted from sacrifice of facial nerve during radical parotidectomy. The patients with transient palsy had full recovery of facial nerve functions within 3 months of the surgery. About 12 (80%) patients underwent ipsilateral modified neck dissection. Primary closure was possible in 4 (26.6%) patients and in 11 (73.3%) patients a reconstructive procedure was performed (Table 2). All patients received post operative radiotherapy.
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Journal of Islamabad Medical & Dental College (JIMDC); 2015:4(1):3-7 Out of 15 malignant cases, 9 (60%) patients had parotid lesions, submandibular 4 (26.6%), sublingual and minor salivary glands 1(6.6%) each. Data of this study indicated that the most common site of occurrence for salivary gland tumors was parotid (60%). Majority of our malignant tumors involved major salivary glands (93.3%). Laishram et al16 showed similar results of 91.34% involvement by major salivary glands and parotid being involved in 59.09% cases. Torabinia and Khalesi17 reported as parotid being commonest site of malignancy. Our results also showed that two thirds (10/15) of our malignant cases were diagnosed as adenocarcinoma, MEC or adenoid cystic carcinoma. Rest one third (5/15) was evenly distributed among acinic cell carcinoma, malignant melanoma, lymphoma, secondary tumor and squamous cell carcinoma. Most studies15,16,18 claim MEC to be the most common salivary malignant tumor. However, most common type in our patients was adenocarcinoma (33.3%) followed by MEC (20%) and then adenoid cystic carcinoma (13.3%). Relatively small number of patient sample in our study could be the cause of this difference. Parotid tumors typically (>80%) manifest as a painless lump in the pre-auricular region and approximately 30% of patients describe pain associated with the mass.25 Pain most likely indicates peri-neural invasion, which greatly increases the likelihood of malignancy. 7-20% of patients with malignant parotid tumors present with facial nerve weakness or paralysis which indicate a poor prognosis.
Table: 1 Types of Tumors (n=15) Types of Tumors Adenocarcinoma
No. of Cases 5
Percentage
Mucoepidermoid
3
20%
Adenoid cystic carcinoma
2
13.3%
Acinic cell carcinoma
1
6.6%
Malignant melanoma
1
6.6%
Lymphoma
1
6.6%
Secondary tumor
1
6.6%
Squamous cell carcinoma
1
6.6%
33.3%
Table: 2 Choice of Flaps for Reconstruction (n=11) Choice of Flap
No. of Cases
Percentage
Delto-pectoral flap
4
36.3%
Pectoralis flap
3
27.2%
Cervico fascial flap
3
27.2%
Cervico pectoral flap
1
9.0%
Discussion Salivary gland tumors account for only 3% of all tumors in the body and it is estimated that about 1% of all head and neck malignant neoplasms arise in the salivary glands.14 The age of studied patients ranged between 3 months to 70 years with the mean age was 48.7 years. This figure is close to mean ages reported by Sarfraz15 (48.02 years), Laishram16 (46.8 years), Torabinia17 (52 years), and Musani18 (42 years). Current results also showed that there was a slight female predominance with a male to female ratio of 1:1.2 and this finding is comparable most of the studies which also show a female predominance.17-19 However, Otoh et al.20 and Tian et al.1 have reported more male predilection in salivary gland neoplasms in Nigeria and China. Review of literature shows that the tumors originating in the parotid glands account for approximately 70% of the cases and
