Nasopharyngeal carcinoma: differences in presentation between different ethnicities in the New Zealand setting

There is an elevated incidence of nasopharyngeal carcinoma (NPC) in the Maori and Pacific Island (MPI) population as well as the Asian population in New Zealand; however, no studies have been conducted to evaluate how the two populations differ in their clinical presentation according to the TNM stage.

A retrospective review was conducted of all patients presenting to the Auckland City Hospital ENT department with a newly diagnosed NPC between the years 1995 and 2007 inclusive. The patient's radiological and biopsy results were reviewed, and each patient was staged according to the TNM stage at presentation as per the revised 2002 American Joint Committee on Cancer staging criteria. The Fisher's exact test was used to compare the differences between ethnicities in the T and N stages of the disease at presentation; the Cochran-Armitage Trend test was used to look for statistically significant trends.

There was a statistically significant difference in T stage at presentation between MPIs and Asians (P < 0.0001), with a positive, statistically significant (P < 0.0001) trend indicating that MPIs present with greater T stage. A statistically significant difference in the N stage at diagnosis between MPIs and Asians, independent of the T stage, was found at stages T2 (P = 0.046) and T4 (P = 0.0083), with a statistically significant trend (T2 -P = 0.009; T4 -P = 0.026).

These results show that MPIs have a more advanced local NPC disease than Asians at presentation, and that for specific T stages, the nodal disease is also more advanced than that found in Asians.