THE PATTERN OF NASOPHARYNGEAL CARCINOMA IN SAUDI ARABIA: A DESCRIPTIVE EPIDEMIOLOGICAL STUDY OF DATA FROM SAUDI CANCER REGISTRY 2002-2013

Ibrahim G. Alghamdi and Ghanem M. Al-Ghamdi. 1. University of Al-Baha, College of Applied Medical Sciences, Saudi Arabia. 2. University of Al-Baha, College of Science, Saudi Arabia. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History

A total of 21 NPC cases were documented in the region of Baha by the SCR from 2002 to 2013. The overall CIRs of NPC among male and female Saudis living in Baha from 2002 to 2013 per 100,000 persons, were estimated at (0.7 and 0.4 Per 100,000 male/female). In addition, the overall age-adjusted incidence rates of NPC among male and female were estimated at (1.0 and 0.5 Per 100,000 male/female). However, there were no statistically differences in the rates of NPC between the region of Baha and other provinces of Saudi Arabia, except the region of Qassim and Riyadh, (F [12,143] = 6.848; P-Value < 0.05), among male Saudis in Qassim (95% CI: -2.4 --0.5), and in Riyadh (95% CI: -2.6 --0.2) (  Table 1:-The overall CIR and age-adjusted incidence rate of nasopharyngeal carcinoma among male and female Saudis in the region of Asir and Baha, from 2002 to 2013.

The Pattern of Nasopharyngeal Carcinoma in the region of Jazan and Najran:
A total of 49 NPC cases were documented in the region of Jazan by the SCR from 2002 to 2013. The overall CIRs of NPC among male and female Saudis living in Jazan from 2002 to 2013 per 100,000 persons, were estimated at (0.5 and 0.3 Per 100,000 male/female). In addition, the overall age-adjusted incidence rates of NPC among male and female were estimated at (0.6 and 0.4 Per 100,000 male/female). Furthermore, the region of Jazan recorded the lowest rates of NPC among male and female in Saudi Arabia. However, there were no statistically differences in the rates of NPC among the region of Jazan and other provinces of Saudi Arabia, except the region of Qassim and Riyadh, (F [12,143] = 6.848; P-Value < 0.05), among male Saudis in Qassim (95% CI: -3.2 --0.9), and in Riyadh (95% CI: -3.0 --0.6).
A total of 18 NPC cases were documented in the region of Najran by the SCR from 2002 to 2013. The overall CIRs of NPC among male and female Saudis living in Najran from 2002 to 2013 per 100,000 persons, were estimated at (0.6 and 0.2 Per 100,000 male/female). In addition, the overall age-adjusted incidence rates of NPC among male and female were estimated at (1.3 and 0.3 Per 100,000 male/female). However, there were no statistically differences in the rates of NPC between the region of Najran and other provinces of Saudi Arabia, except the region of Qassim and Riyadh, (F [12,143] = 6.848; P-Value < 0.05), among male Saudis in Qassim (95% CI: -2.6 --0.2), and in Riyadh (95% CI: -2.4 --0.1) (    Table 3:-The overall CIR and age-adjusted incidence rate of nasopharyngeal carcinoma among male and female   Table 4:-The overall CIR and age-adjusted incidence rate of nasopharyngeal carcinoma among male and female Saudis in the region of Madinah and Jouf, from 2002 to 2013.    Table 5:-The overall CIR and age-adjusted incidence rate of nasopharyngeal carcinoma among male and female Saudis in the region of Tabuk and Northern region, from 2002 to 2013.

The Pattern of Nasopharyngeal Carcinoma in the region of Riyadh and Makkah:
A total of 539 NPC cases were documented in the region of Riyadh by the SCR from 2002 to 2013. The overall CIRs of NPC among male and female Saudis living in Riyadh from 2002 to 2013 per 100,000 persons, were estimated at (1.6 and 0.6 Per 100,000 male/female). In addition, the overall age-adjusted incidence rates of NPC among male and female were estimated at (2.5 and 0.9 Per 100,000 male/female). However, there were statistically differences in the rates of NPC between the region of Riyadh and other provinces that mentioned in the above results, P-Value < 0.05.   Table 6:-The overall CIR and age-adjusted incidence rate of nasopharyngeal carcinoma among male and female Saudis in the region of Riyadh and Makkah, from 2002 to 2013.

The Pattern of Nasopharyngeal Carcinoma in the eastern region of Saudi Arabia:
A total of 213 NPC cases were documented in the eastern region by the SCR from 2002 to 2013. The overall CIRs of NPC among male and female Saudis living in the eastern region from 2002 to 2013 per 100,000 persons, were estimated at (1.0 and 0.3 Per 100,000 male/female). In addition, the overall age-adjusted incidence rates of NPC among male and female were estimated at (1.7 and 0.5 Per 100,000 male/female). However, there were no statistically differences in the rates of NPC between the eastern region and other provinces, except the region of Jouf among female Saudis, the results mentioned in the above results, P-Value < 0.05 (Table 7).  Table 7:-The overall CIR and age-adjusted incidence rate of nasopharyngeal carcinoma among male and female Saudis in the Eastern region, from 2002 to 2013.

Discussion:-
This is a descriptive epidemiological study of NPC among males and females Saudis from 2002 to 2013. It explores the pattern of NPC in all regions of Saudi Arabia, with focusing on the frequency number of cases, the CIR, and age-adjusted incidence rate stratified by gender, region, and year of diagnosis. The result of the study is based on the data recorded in the SCR from 2002 to 2013.
In this study, we have observed that the highest overall age-adjusted incidence rates of NPC among male Saudis were documented in the region of Qassim from 2002 to 2013. The most likely reason for this rising age-adjusted incidence rate is that most male Saudis living in the region of Qassim were more likely exposed to a specific risk factor that may less appear in other male Saudis living in other provinces of Saudi Arabia. However, two casecontrol studies should be conducted in the region of Qassim to identify the most important risk factors of NPC among male and female Saudis living in the region of Qassim. Figure 1, shows how one can identify the most important risk and protective factors for NPC among male and female Saudis living in the region of Qassim.
We have also observed that the highest overall age-adjusted incidence rates of NPC among female Saudis were documented in the region of Jouf from 2002 to 2013. The most likely reason for this rising age-adjusted incidence rate is that most female Saudis living in the region of Jouf were more likely exposed to a specific risk factor that may less appear in other female Saudis living in other provinces of Saudi Arabia. However, two case-control studies should be conducted in the region of Jouf to identify the most important risk factors of NPC among female and male Saudis living in the region of Jouf. Figure 2, shows how one can identify the most important risk and protective factors for NPC among female and male Saudis living in the region of Jouf.
From the above-mentioned result, it is very clear that the region of Jazan had the lowest overall age-adjusted incidence rates of NPC among male and female in Saudi Arabia, from 2002 to 2013. The most likely reason for this decreasing age-adjusted incidence rate is that most male and female Saudis living in the region of Jazan were more likely exposed to a specific protective factor that may does not appear in other male and female Saudis living in other provinces of Saudi Arabia. It means that the male and female Saudis living in the region of Jazan were sharing with each other the same protective factor of NPC. However, two case-control studies should be conducted in the region of Jazan to identify the most important protective factors of NPC among male and female Saudis living in the region of Jazan. Figure 3, shows how one can identify the most important risk and protective factors for NPC among male and female Saudis living in the region of Jazan.