Cervical cancer screening is done increasingly via an HPV test, slowly replacing the past gold-standard test, the Pap smear. Nevertheless, HPV tests have a high false positive rate, as 80% of US adults will be infected with HPV at least once in their lifetime. 90% of these infections are cleared within 1-2 years (WebMD), and do not advance to cervical cancer.

As such, many women will receive positive HPV  (and/or Pap) results, which leads to  repeated tests and follow-up colposcopies, to ensure infection clearance.  While most infections will clear, some women will develop a pre-cancerous condition, turning the ongoing testing period to a time fraught with fear of potential cervical cancer, even for the women  in whom the infection will  regress.

​

During a colposcopy test, the physician, or in some cases, a specialist or a gynaecological-oncologist, examines  the vagina and the cervix via a colposcope, which is a lighted magnifying device.  The physician searches these areas for lesions or other irregularities, which may be  pre-cancerous or cancerous.  In some cases, the physician uses acetic acid or iodine dies, to highlight suspicious areas. When deemed relevant, biopsy samples from suspicious  areas are collected and inspected by an expert pathologist.

​

As cervical cancer advances slowly, the above screening method is likely to identify pre-cancerous lesions, if performed according to the  recommendations of the medical community. Cervical cancer mortality rates decreased by 74% between 1955 and 1992 in the US due to increased screening and early detection using the Pap test (University of Maryland). Nevertheless, there are still many missed cases, and misdiagnosed patients in western countries and especially in developing countries.  

​

 

 

While the above-described screening process and subsequent testing procedures improved early detection of cervical cancer, resulting in significantly lower mortality rates, there are several limitations to the current screening  method. The Pap and HPV tests suffer from relatively high false positive and false negative rates. The Pap smear, for instance, suffers from a 10-20% false negative rate ( some studies quote the false-negative rate as high as 45%). This inaccuracy is usually attributed to imperfect sample collection, in which the infected area is missed or loss of some cells before they are transferred to the slide/tube, or as a result of a wrong diagnosis by the cytologist.  Each Pap test requires review of multiple slides and numerous cells.
The HPV test suffers from a 10% false negative rate attributed to imperfect cell collection, or to infection by an HPV strain, which is not  recognized by the HPV test.

Currently, colposcopy exams utilize acetic acid to visualize and identify suspicious areas, from which biopsies are taken.  However, most physicians  take multiple biopsies both from these abnormal areas, and randomly from all  quadrants of the cervix, in order to improve the chances of identifying cancerous areas.
 

In the majority of cases , the results of the colposcopy and the subsequent biopsies are normal. These statistics suggest that many unnecessary biopsies are performed every year, which is a major issue, in light of the fact that  biopsies are associated with discomfort, risk of infection, potential future fertility issues and delayed diagnosis, which causes the patient undue stress.
 

In the US, over 3 million Pap tests are found to be abnormal (~6% of all tests) annually.  Of these only 12,000 are diagnosed as cancer, annually, imposing a great burden on the medical system