In the present study, palatal cancers accounted for 8.66% of all oral malignancies. These findings are consistent with other studies (1, 2). In the current study, 56.43% of palatal cancers occurred in men and 43.56% in women (ratio: 1.29). In a study conducted by Aydil et al. (1), no sex predilection was evident. It is well-known that the commonest oral cancer is SCC (2, 11), but It is noteworthy to refer to Duzlu et al. (2) who found that a large number of SCC was detected in all sub-sites of the oral cavity except the hard palate. The present study considers salivary gland malignancies as the most common cancers of palate (47.19%) followed by epithelial cancers (36.3%), non-Hodgkin lymphoma, and sarcoma. This is in accordance with Aydil et al.’s (1) research, substantiating that 42.8% of the palatal cancers had salivary gland origin. SCC, melanoma, lymphoma, and sarcoma comprised 28.5%, 14.2%, 7%, and 7% of the malignancies in their series, respectively. Palate is the most common site for minor salivary gland tumor (1, 11, 12). Salivary gland neoplasms depict a heterogeneous group of tumors, with a broad range of microscopic types (13-15). In our series, AdCC and MEC were the commonest malignancies of salivary gland origin (77.6%) followed by adenocarcinoma NOS (8.4%) and PLGA (5.6%). Similar to the findings of this research, several studies reported that (AdCC) and (MEC) were the most common salivary gland carcinoma of palatal region (1, 8, 12, 16). In salivary gland carcinomas, the peak incidence was in the 4th to 7th decade almost equally. This is in agreement with Copelli et al.’s (8) study. Moreover, in salivary gland group, the male to female ratio was equal. However, there was a female predominance in MEC (F/M = 1.7) and a male predominance in AdCC (M/F = 2). Some reports revealed a male predominance (10, 17) and others depicted female predilection (18). Tian et al. (16) found that males were more frequently affected except in MEC. In the present research, certain tumors showed a female predilection, such as PLGA, clear cell carcinoma, and acinic cell carcinoma in contrast; some tumors, such as carcinoma ex PA and papillary adenocarcinoma revealed a male predilection. Palate is the most common site for PLGA. It occurs most frequently in the 6th and 7th decades of life and there is a female preponderance (19). In our series, the frequency of PLGA was low and comprised 5.5% of salivary gland malignancies of palate. This tumor demonstrates peak incidence in 6th decade and there was a female predilection (ratio: 1.66). Several reports indicated that PLGA was the third commonest malignancy of the minor salivary glands (10, 20-22). However, some indicated that this tumor is rare in minor salivary gland (8, 10, 16, 23). Interestingly, in two studies, PLGA was the commonest salivary gland malignancies (18, 24). Finally, one study demonstrated that the percentages of PLGA considerably differed by continent, ranging from 3.9% in Asia to 20% in Oceania (20). These differences may reflect diverse diagnostic criteria or actual geographic variations (16-18, 20).
In epithelial series, SCC comprised 83.63% of specimens followed by melanoma (10%). The male to female ratio was 1.39 and the peak incidence was in the 6th to 8th decades of life. Aydil et al. (1) also found that SCC is the second malignancy after salivary gland tumors in palate. Oral melanoma is rare and it accounts for only 0.5% of all oral malignancies, but palatal mucosa is the commonest location and there is a male predilection with the mean age of 65 years (25). In this study, melanoma comprised 3.6% of all palatal cancers with strong male predilection (ratio: 4.5) and old-aged group tendency.
According to several investigations, lymphomas consist of 1.5% to 8.8% of the oral malignancies. Palate is one of the most common sites of involvement for oral lymphoma (26). The prevalence of non-hodgkin lymphoma (NHL) increases from the 5th to 7th decades of life and has a male predilection. In the present research, lymphoma comprised 5.94% of palatal cancers. It should be noted that there is a male predominance (ratio: 2.6) and the most typical variant found was diffuse large B cell lymphoma (DLBL).
Head and neck sarcomas are extremely rare malignancies and they make about 4% - 10% of all sarcomas (27). Oral sarcomas show male preponderance with the average age of 42 years (28). Similar to previous reports, in the current research, sarcomas made about 2.3% of all palatal cancers with lower age tendency (under 40 years) and slight male predilection (ratio: 1.3).
It is worth mentioning that 3.9% of cancers occurred under 20 years and there was a male predilection (ratio: 1.4). In this age, group MEC was the most common type (50%) that is similar to a study carried out by Locati et al. (29).
One of the strengths of epidemiologic studies with large series is that due to the high sample size and data collection from different cities, reliable information about the lesions in the country is provided to the health services. However, it can be inferred that the great amount of information entry to this center has made the recording process a more cumbersome task. As a result, the patients’ detailed information such as clinical sign and symptoms have been excluded. In addition, we could not measure the survival rate of patients due to the lack of sufficient data.
In conclusion, salivary gland malignancies are the commonest cancers of palatal region followed by SCC. In this study, the prevalence of PLGA is similar to Asian countries. MEC is the most common cancer between young patients. As a final point, large series on the palatal cancers aid in recognizing the precise prevalence, demographic data, and histopathological variation, which may contribute to accurate diagnosis and better treatment of these malignancies.