BACKGROUND
Thailand was one of the first Asian countries to be affected by the epidemic of human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS). Furthermore, Thailand possesses a national cancer surveillance system based upon regional cancer registries.

METHODS
Data from five population-based cancer registries, covering one-fifth of the national population, were used to study trends in the incidence of malignancies related to HIV/AIDS in Thailand during the period 1989–2001.

RESULTS
Although the incidence of Kaposi sarcoma (KS) increased slightly from 1989–1991 to 1995–1997, KS remains a very rare malignancy in Thailand compared with other countries in which the prevalence of HIV/AIDS is much lower. The authors reported a marked increase in the incidence of non-Hodgkin lymphoma (NHL), and particularly high-grade/diffuse NHL. However, the largest increases in incidence were noted among individuals age = 55 years and in regions with a relatively low prevalence of HIV/AIDS.

CONCLUSIONS
The rarity of KS presumably reflected the low prevalence of the causative agent (i.e., KS-associated herpesvirus) in the Thai population. The increasing incidence of NHL may be related to the AIDS epidemic, although a similar increase is observed in many countries worldwide and is not specifically linked to the HIV/AIDS epidemic. Cancer 2004. © 2004 American Cancer Society.