Cancer free survival after CIN treatment: comparisons of treatment methods and histology

Cervical cancer is one of the most lethal cancers among women worldwide. Women are treated and followed-up in several different manners. Long-term studies of cancer or death risks after different methods of treatment or after different initial histology are scarce.

A retrospective cohort study with 7466 women treated of CIN between 1974 and 2001 in Helsinki University Hospital followed-up until the end of 2003. The Cox model was used to determine differences in cancer free or overall survival between women treated of CIN with different methods or after different initial grade of CIN.

Twenty-two cases of invasive cervical cancer (ICC) and 57 cases of CIN 3 after treatment of CIN were observed. There were no statistically significant differences in ICC free survival between different treatment methods or initial grade of CIN. In CIN 3 free survival, the hazard ratios for the 57 cases of CIN 3, when cold knife coagulation (CKC) was set as the reference, were 0.22 for laser, 0.55 for cryotherapy and 0.31 for LEEP. In CIN 3+ (CIN 3 or ICC) free survival, the hazard ratios of 79 CIN 3+ cases (CKC reference) were 0.25 for laser, 0.50 for cryotherapy and 0.27 for LEEP. There were no differences in overall survival between different grades of initial CIN.

The CKC seems to be the least favorable in terms of both further cancer and CIN 3 risk. The follow-up has to be well organized because the post-treatment cancer risk is independent of the initial grade of CIN.