Cervical cancer is one of the most common malignancies in women, and is second only to breast cancer in its incidence and mortality. According to the International Federation of Gynecology and Obstetrics, the 5 year survival rate for cervical cancer is 91% when discovered in early stages. Unfortunately, the survival rate drops to 15% and lower, when diagnosed at a late stage. While persistent HPV infection is known to be the central causative factor in squamous cell carcinoma of the cervix, HPV infection is common and most women clear the disease without developing cancer, so that HPV tests cannot be the sole predictor of cervical cancer.
In developed countries, routine screening programs for cervical cancer are common practice. These involve primarily screening of cervical smears using Pap staining. Since it came into use more than 50 years ago, the Pap test has greatly reduced the incidence of cervical cancer in these countries. Over 300 million Pap tests are performed annually world wide. Despite its success and wide use, the Pap test suffers from major drawbacks; mostly in low sensitivity and a high rate of false positive as well as false negative results; difficulties in automation; and constant reliance on expert cytological analysis of results. The limitations exerted in the current screening methods highlight the unmet medical need for effective screening tools towards early identification of cervical cancer in developed countries and in developing countries, which have 80% of the newly identified world wide cervical cancer cases, with practically no effective screening tools.
Recently, new HPV vaccines have been released to the market. The proposed large scale vaccination programs in many countries demonstrate the awareness to the fact that cervical cancer can and should be irradiated, but at the same time have raised serious questions with regard to the limitations of these current vaccines. Even if effective vaccination will be made available, in both developed and developing markets, it is estimated that screening programs for cervical cancer will continue for many years, until full coverage of the population with all high risk strains is achieved, and until a few generations have passed and all women will be effectively vaccinated. Thus, effective tools for screening cancer will be of need for several decades.
