Why Not All Cervical Precancer Progresses To Cancer

The HPV virus causes cervical cancer. You get it sexually or through skin to skin contact. If you have an HPV infection that doesn't resolve on it's own, then it's more likely to persist and become cervical cancer. But not just any HPV infections will do this, it has to be due to the infection of a high risk HPV virus, like HPV 16, which then stays and transforms the cell. Then if the cell's growth is unchecked the tissue will change into precancer called CIN or Cervical Intraepithelial Neoplasia. So if HPV virus causes pre-cancer, and much precancer will eventually become more severe, called CIN 3,  why doesn’t all CIN 3 progress to cancer? We know now that it is the way the HPV virus behaves in your system that determines whether it will progress to cancer. Cancer is more likely to be triggered when the HPV virus genes E6/7 are turned on. The newest way to figur find and treat them. And if you don’t treat the patient who has both the advanced CIN and the activated HPV genes, then she is most likely to be the one who will get cancer. For most gynos this means treating all CIN 3 prenvents cancer. Since we think the colposcopic microscope test of your cervix is most likely to find CIN 3, we rely on this most heavily to determine who to treat. At least 1/3 of CIN 3 are colposcopically invisible. Age, screening history and which type of HPV effects the accuracy of colposcopy according to the research by Stolar et al In J Cancer 2011, 128: 1454-62. Once you have CIN 3 if it is treated then you are likely to be cured, in fact just getting colposcopy helps as about 1/3 times the biopsy cures the CIN 3.  Other factors as to whether you are going to progress to cervical cancer have to do with your immune system: do you smoke, have you had this a long time without getting treated, and other factors that your individual provider can discuss.