Nasopharyngeal Carcinoma in Oman and Malaysia: Is There Any Difference?

Abstract

We read the article titled ‘Nasopharyngeal Carcinoma in Oman: A descriptive analysis”, published in the May issue of the Oman Medical Journal (OMJ) with interest. The worldwide low incidence of the disease is reflected in the study whereby only 32 cases were identified within the nine-year period. On the contrary, nasopharyngeal carcinoma (NPC) is considered a common malignancy in Southeast Asia. This was made evident by data gathered in Malaysian Nasopharyngeal Carcinoma Database, which was established in 2008. Within the first seven months of establishing the database a total of 225 newly diagnosed NPC cases were identified. These figures illustrate the important difference, as NPC is known to be the third most common malignancy among Malaysian males, and the fourth among the total Malaysian population. Despite that, NPC is still the most common radio-curable cancer in Malaysia. Data from both countries show a similar prevalence in males and a bimodal distribution. However, the first peak occurs earlier among Southeast Asian patients in late childhood compared to young adulthood in Omani patients. Neck mass was the most common presentation, followed by nasal or ear complaints. These presenting features were also similar in pediatric patients. A striking feature noted was that no patients from the Omani population presented with cranial nerve involvement. It is a very important sign as the tumor is already in stage IV once the cranial nerve is involved. The cranial nerve involved varies, and the rate can be as high as 33% at presentation. Amongst the NPC patients worldwide, the abducens nerve was the most commonly affected by the tumor, and multiple cranial nerve involvement were seen amongst Malaysian patients. In both countries, the majority of the patients presented at a late stage (III or IV). Thus, the treatment of choice is concurrent chemoradiation, even though early NPC can be treated with radiotherapy alone and has fewer side effects. Prognosis wise, the T-classification, N-classification, stage, and cranial nerve involvement are the significant prognostic factors in determining the five-year overall survival. As clearly illustrated in the OMJ article, data analytical study is essential as it allows a multi-level comparison with different cohorts.

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