Cervical cancer in the asian pacific-epidemiology, screening and treatment.
Squamous cell carcinoma (SCC) of the cervix continues to be a major problem in many areas of the Asian-Pacific, particularly in the Indian subcontinent and Papua New Guinea, and to a lesser extent in South-East Asia, Korea and Mongolia. In contrast, levels in the developed countries of the region are low, as is also the case for the Muslim countries of Western Asia, and mainland China. Incidence generally mirrora associated mortality, although with some exceptions reflecting facilities and infrastructure for early detection. Over the last 25 years there has been a marked decrease in incidence rates across most of the Asian Pacific, although less pronounced in India than elsewhere, and there are exceptions where the incidence is on the increase. The predominant risk factor is well established to be persistent infection with a high risk 'oncogenic' type of human papilloma virus (HPV), along with multiple partners, other sexually transmitted diseases and smoking. Consumption of vegetables, in contrast, appears to be protective. Hormonal factors may also play some role. Modifying factors may either impact on neoplasia by directly influencing the processes underlying carcinogenesis, or indirectly by affecting persistence of viral infections. For primary prevention, avoidance of repeated infections and smoking, as well as a high antioxidant intake may be beneficial. Vaccines against HPV also have promise for the future, but a better understanding of the mechanisms underlying spontaneous clearance of both infection and cervical intraepithelial neoplasia (CIN) of different grades is also essential for optimal intervention. For screening, the choice of whether the PAP smear, HPV testing or some form of visual inspection are utilized depends on the resources which are available, all approaches having their own advantages and disadvantages, but with similar sensitivity and specificity. One complication is the increase in adenocarcinoma of the cervix which has been reported in some countries, for which risk factors and most effective screening may differ from the SCC case. A focus on high risk groups like sex workers might be warranted where financial and technical support are limited. If cervical intraepithelial neoplasias are detected then cryotherapy or the loop electrosurgical excision procedure (LEEP) are effective for their removal. Control of cancer of the cervix, however, demands that a comprehensive approach to screening and management is adopted, necessitating major training of personnel and provision of appropriate resources.