Characteristics of tumours in the United Arab Emirates

Yasir Al Sarraj1, Satish Chandrasekhar Nair2, Ammar Al Siraj3 and Maher AlShayeb4

1, 4Ajman University of Science and Technology, Department of Oral and Maxillofacial , Post Box 346, United Arab Emirates 2Tawam Hospital- Johns Hopkins Medicine International Affiliate, Department of Academic Affairs-Medical Research, Post Box 15258, Al Ain, United Arab Emirates 3Mawi Medical Centre, Post Box 55510, Dubai, United Arab Emirates

Correspondence to: Satish Chandrasekhar Nair. Email: [email protected]

Abstract

Salivary gland tumours (SGT) are relatively rare cancers characterised by striking morphological diversity and wide variation in the global distribution of SGT incidence. Given the proximity to the head and neck structures, management of SGT has been clinically difficult. To the best of our knowledge, there are no epidemiological studies on SGT from the United Arab Emirates (UAE) or the Gulf Cooperation Council Countries (GCC). Patient charts (N = 314) and associated pathological records were systematically reviewed between the years 1998–2014. Predominance of benign (74%) compared with malignant (26%) SGT was observed. Among the 83 malignant SGT identified, frequency was higher in males (61%) than in females (39%) and peak occurrence was in the fifth decade of life. was the most common type of tumour (35%) followed by (18.1%) and acinar cell carcinoma (10.8%). A similar pattern of tumour distribution was seen in patients from GCC, Asian, and Middle East countries. This is the first report to address the distri- Research bution of salivary gland tumours in a multiethnic, multicultural population of the Gulf. The results suggest that the development of an SGT registry will help clinicians and researchers to better understand, manage, and treat this rare disease.

Keywords: , , Gulf, UAE

Published: 20/10/2015 Received: 09/06/2015 ecancer 2015, 9:583 DOI: 10.3332/ecancer.2015.583

Copyright: © the authors; licensee ecancermedicalscience. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

1 cally analysedusingtheSPSSprogramme(IBMStatistic 20). accordingly of neoplasm and from site which and the biopsy patients, was of taken. nationality gender,The histological age, specimens diagnosis, were reviewed histological by regarding the collected pathologist, staged, was and data ranked Corresponding gland. salivary the of pathologies biopsied or removed surgically with patients all for evaluated were data The region). maxillary the and , the of floor (the ,,buccalcavity,regions those inthelipandintra-oral included the minorglands gland whereas gland, andsublingual dibular were records subman gland, parotid the histopathological involved glands salivary major and The surgeon. a and pathologist clinical a with Technology.consultation in The authors the and by reviewed Science of University Ajman in Department Pathology the and ment Depart- Maxillofacial the at analysed further were which identified were gland salivary the of neoplasm primary with patients Eighty-three tion . The presentstudywasconductedfollowingapprovalfromthelocalcentralethicscommittee(AAMDHREC#12/13). sessing a National Insurance Card since 2012, although exemptions are made for rare-diseases and sub-specialty treatment such as radia date to until cases cancer of records 21,000 than more has from CCR and the countries, Gulf and the and hospital, UAE, Asia the the to within referred from are patients Africa Oncology Dhabi. Abu hospital, Joint Commission accredited, and a regional oncology referral centre until two years ago, still a referral centre for the emirates of 2014 until 1998 from years 25 over of period a for (CCR) Registry Cancer Comprehensive the from data pathological corresponding and conducted was records medical of Areview retrospective Materials andmethods followed bythesubmandibulargland,andpalatearemostoftenaffected by the SGT andthesublingualbeingleast common most the be to reported is adenoma pleomorphic SGT,although of types histological and incidence, distribution, site follows variation of [2]. Although, SGT predominantly arise in patients closer to 45 years of age, the sex ratio varies according to the tumour type. A wide range although genetic predisposition, viral infections, cigarette smoking, and exposure to environmental chemical hazards have been postulated observed been have SGT of distribution global the in differences epidemiological Striking fifth andsixthdecadesoflife,bothforexpatriatesnationals the year 2000 especially world, the East, over Middle all since Asia, from Europe expatriates and of Africa, number the in surge a witnessed have Dubai million at a ratio of 1:7 (UAE nationals to expatriates) followed soon cancer and disease, cardiovascular diabetes, namely diseases, Lifestyle-related lifestyle. in changes subsequent and urbanisation, swift growth, population to led prosperity years forty past the in gas natural and oil including resources, natural from wealth in increase significant a Emirates experienced Arab United the and Arabia, Saudi Qatar, Kuwait, Bahrain, Oman, of countries member (GCC) Council Cooperation Gulf The by theWorld HealthOrganisation(WHO)histologicalclassificationsystem,revisedin1999and2005[3] of SGT is also challenging for 0.4–13.5 cases per 100,000 people [1] types tumour different between and within diversity of morphological range by a striking characterised cancer rare relatively are tumours many different types of cells that can become malignant leading to many different types of salivary gland cancer. Globally, salivary gland glands Salivary gland tissues are distributed in the upper aerodigestive tract; the parotid, submandibular, and sublingual are the major salivary Introduction . These rare heterogeneous lesions with complex clinical and pathologic characteristics and dissimilar biological behaviour account behaviour biological dissimilar and characteristics pathologic and clinical complex with lesions heterogeneous rare These . [1] . Adenoid cystic carcinoma and mucoepidermoid carcinoma are the most common malignant SGT malignant common most the are carcinoma mucoepidermoid and carcinoma cystic Adenoid [2]. . The minor salivary glands are present in other sites such as , palate, tongue, oropharynx, etc. . Inter-rater reliability between the pathologists was assessed using Cohen’s kappa and was >0.80 was and Cohen’skappa using assessed was pathologists the between reliability Inter-rater [10]. [7]. With the rapidly increasing population, the region has seen an increase in the number of cancer deaths, especially in the [2] . The diversity of SGT lead to disagreements over histological nomenclature which were resolved in 1971 1971 in resolved were which nomenclature histological over disagreements to lead SGT of diversity . The [2] . Given the proximity to the various important head and neck structures, clinical management management clinical structures, neck and head important various the to proximity the Given . . The UAE is a multiethnic, multi-cultural nation with a population of almost eight almost of population a with nation multi-cultural multiethnic, a is UAE The [5]. [6]. Abu Dhabi, the capital and the largest among the seven emirates of the UAE, and . The CCR is located at Tawam Hospital, a 468-bed tertiary care-teaching tertiary 468-bed a TawamHospital, at located is CCR The [9]. . An oncology service is provided to UAE nationals and non-nationals pos- non-nationals and nationals UAE to provided is service [9]. oncology An [8]. 2 . The etiology of SGT are not clearly known clearly not are SGT of etiology The [1]. . [1] [2, . Salivary glands contain contain glands . Salivary ecancer [11statisti- was Data ]. . The , parotid The 7]. www.ecancer.org . This rise in rise This [4]. [2]. 2015,9:583 - -

Research Figure 1.Malignanttypesanddistributionofthevarioustumours inthemajorsalivarygland.Values expressedinpercentages. the MiddleEasternpopulation(excludingGCC). n = 11). (13.2%, Similar pattern Asia from of distribution and was seen Countries both for Cooperation and Gulf acinar cell the carcinoma (Figure from patients in common more was 12) = n (14.5%, carcinoma Mucoepidermoid information inthepatientmedicalrecordsorpathological(datanotshown). by followed stage 24), 3 (19.2%, = n = n 16), stage (28.9%, 1 (9.6%, 2 n = stage 8), and at stage 4 detected (4.8%, n were = 4). cancers Thirty-one most tumours (37%) criteria, were not staging staged because (AJCC) of incomplete Cancer on Committee Joint American Per (Figure (NOS) specified Primary sitescouldnotbedeterminedforfourofthecases. otherwise not adenocarcinoma, was observed tumour malignant only the gland, carcinomas sublingual mucoepidermoid the and In (46.7%) (19.8%). carcinomas cystic adenoid largely were tumours gland submandibular the contrast, stark In malignant tumour was mucoepidermoid carcinoma (39.7%) followed by acinar cell carcinoma (12.7%) and adenoid cell carcinoma (9.5%). duct carcinoma, etc. contributed to less than 5% to the total number of malignant SGT. Among the parotid gland tumours, the most frequent carcinoma cell (Table(10.8%) acinar and (18.1%) carcinoma cystic adenoid by followed was This tumours. all of (35%) approximately constituted and Histopathological distribution of the malignant salivary tumour indicated mucoepidermoid carcinoma was the most common type of tumour from 3–79years. widely ranged and females, and males between SGT for different statistically not 19, ± 41.9 and 5 ± 42.8 was deviation) standard (± age (n = 51) than in females 39% (n = 32). The peak occurrence of SGT was in the fifth decade of life both for males and females. The average tumours were not detected in the present study. Among the 83 cases identified, malignant SGT was observed (Tablegland sublingual more the in 1) = frequently (n and 15), = in (n glands submandibular the males by followed 63), = 61% (n glands parotid (Table gland tumour.gland salivary major benign the of majority Twenty-sixSGTtotal the of 83) salivary = primary (n malignant percent with presented gland tumours, predominance was for benign (74%) type (Table Review of medical and pathology records over a twenty-five year period collected 314 cases of salivary gland tumours. Among the salivary Results ). Each of the other type of tumours such as basal cell adenocarcinoma, follicular , , cell squamous lymphoma, follicular adenocarcinoma, cell basal as such tumours of type other the of Each 2). ), occurring unilaterally. The site of distribution data showed that the majority of the malignant SGT were in the in were SGT malignant the of majority the that showed data distribution of unilaterally.site occurring The 1), 39.7 Parotid 12.7 9.5 1). (64%) and Warthin’s tumour (24.9%) constituted 3 19.8 Submandibular 46.7 Sublingual 1.2 2). Lymphoma was high among ecancer ). Minor salivary gland salivary Minor 1). www.ecancer.org 2015,9:583 1).

Research observations fromastudyinvolvingcloselyrelatedMiddle Easternpopulation resembled range age and ratio gender The females. and males for both life, of decade fifth the was tumours gland salivary malignant for occurrence peak The combined). female and (male years 6.6 ± 42.4 to equal deviation standard and mean the with years, 79 to 3 from study,ranged study this in (39%). SGTfemales patients in the malignant than of of (61%) age proportion The males higher in a was there in Africa (46%) Uganda and (43%) Nigeria in Asia, (32%) China (38%), India (50%), Lanka Sri (32%), Jordan and (32%) Iran as such and countries Eastern Asian Middle other from reported than lower 26%, was study our in SGT malignant for frequency The the world[14–15 Denmark in than report WHO the with consistent (24.9%), tumour Warthin’s by followed tumours, gland salivary major benign Among the salivary gland tumours, predominance was for benign (74%) type. Pleomorphic adenoma (64%) constituted the majority of the 2008 in implemented was ‘my_file’in Arabic) means which Malaffi (or System formats. Information Apaper Hospital and electronic in both records, medical using (1998–2014) years twenty-five past the in tumours gland salivary of cases 314 reviewed study present The Discussion LYM =Lymphoma. ADC = Adenocarcinoma, SCC–SquamousCellCarcinoma,MEC=Mucoepidermoid ACC = Acinar CellCarcinomaand Figure 2.Distributionofmalignantsalivaryglandtumoursamongthemulti-ethnicpopulationUAE.Values expressedin%. ]. . Of note a predominance of benign SGT in the range between 60–80% have been reported from different parts of parts different from reported been have 60–80% between range the in SGT benign of predominance a note Of [13]. in theUAE. Table 1. Assessment ofmalignantsalivaryglandtumours 10.0 12.0 14.0 16.0 Female Male Minor salivarygland Parotid Malignant SGT Malignant salivaryglandtumours Benign salivaryglandtumours Total salivaryglandtumours (N=314) 0.0 2.0 4.0 6.0 8.0 8.4 ADC 4.8 7.2 4.8 SCC 0.0 GCC 2.4 Middle East 14.5 4 MEC 4.8 13.3 Asia 4.8 ACC [16–17 1.2 3.6 231 (74) 32 (39) 51 (61) 15 (18) 63 (76) 83 (26) n (%) 0 (0) 1 (1) ].

1.2 L 4.8 YM 1.2 , although this is lower is this although [12], ecancer www.ecancer.org [15–16 2015,9:583 . In our In ]. [7].

Research outlook andlessthan30%survivalbeyondtenyearspostdiagnosisofthetumours malignant salivary gland tumours 56.2%) and Asian (29.1 and 25.0%) nationalities. Prognosis studies indicate a 60–70% survival rate post diagnosis with stage 2 and stage 3 frequent malignant salivary gland tumour observed in our study. Predominance of stage 2 and stage 3 were seen among GCC (45.8% and spite of geographic isolation of the subpopulations from the Gulf and the practice of consanguineous marriages tion of mucoepidermoid carcinoma, adenoma, and acinar cell carcinoma were comparable between the population of the Gulf and Asia, in 31 patientsandpathologicalrecordsthenhadtobeexcluded. the in found was information staging incomplete where period the 2005, in WHO the by revision recent the to prior disease the of staging pathological inaccurate of possibility a be SGT,also the may There of systems. rarity information hospital the electronic given before diagnosis years earlier differential the the in with especially issues and reporting under from result could limitation this of Part years. 25 over of span a for tumours gland salivary malignant 83 only identify could we that fact the is foremost limitations, several has study Our Middle East [Iran (11%) and Jordan (7%)] compared to Congo (8%) and Uganda (9%) in Africa (25%) India and (22%) Lanka significantly Sri as was such countries carcinoma Asian in higher Mucoepidermoid carcinoma. cell acinar all and of carcinoma (35%) cystic adenoid approximately by constituted followed and tumours, tumour gland of salivary type common most the was carcinoma mucoepidermoid that showed study Our *NOS (Nototherwisespecified) Table 2.Histopathologicaldistributionofsalivarygland tumours (n=83). Carcinoma, undifferentiated, *NOS Carcinoma, *NOS Lymphoepithelial carcinoma Clear celladenocarcinoma,*NOS Synovial sarcoma,biphasic Polymorphous lowgradeadenocarcinoma Lymphoma, follicular, grade2 Squamous cellcarcinoma,lgcell,keratinising Eccrine adenocarcinoma Lymphoma, follicular, *NOS Basal celladenocarcinoma Epithelial–myoepithelial carcinoma Mixed tumour, malignant,*NOS Duct carcinoma,*NOS Carcinoma inpleomorphicadenoma Squamous cellcarcinoma,*NOS Adenocarcinoma, *NOS Squamous cellcarcinoma,keratinising,*NOS Lymphoma, malignant,largeB-cell Acinar cellcarcinoma Adenoid cysticcarcinoma Mucoepidermoid carcinoma [19–20 Salivary tumourtypes ]. Both GCC and Asians showed 50% frequency each for Stage 4 which has the poorest prognosis 5 . The frequency of mucoepidermoid carcinoma was lower in the in lower was carcinoma mucoepidermoid of frequency The [17]. Frequency 15 29 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 3 4 9 [19–20 ]. [16–17 Percentage 10.8 18.1 34.9 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 2.4 2.4 2.4 2.4 2.4 2.4 3.6 4.8 ]. Interestingly, the pattern of distribu [18]. Stage 2 was the most ecancer www.ecancer.org 2015,9:583 -

Research

References The UAEComprehensiveCancerRegistryisacknowledgedfordatasupportthisstudy. Acknowledgments This studywasnotsupportedbyfundingfromanysources. Funding support The authorsreportnoconflictofinterest. Conflicts ofinterest Both YAS andSCNcontributedequallytothisstudy. Author contribution document, manage,andtreatthisraredisease,globallyinthe Arabian Gulfregion. understand, better to help will registry tumour gland salivary a that the suggest results The address UAE. the in to tumours gland report salivary of first distribution the is diversity.This population high of regions Gulf, the or UAE the in tumours gland salivary malignant and head and neck structures, this makes clinical management of these cases difficult.the There have been to no epidemiological studies for benign proximity their given and tumours of group histopathologic heterogeneous highly a comprise tumours gland summary,salivary In Conclusion

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