From the Guidelines
Carcinoma in situ and CIN III are not exactly the same, although they are closely related, with CIN III being a specific type of carcinoma in situ that occurs in the cervix. CIN III (Cervical Intraepithelial Neoplasia grade 3) is a specific type of carcinoma in situ that occurs in the cervix, as noted in the update on ASCCP consensus guidelines for abnormal cervical screening tests and cervical histology 1. Carcinoma in situ is a broader term that refers to an early stage of cancer where abnormal cells are present but confined to the tissue layer where they originated, without invasion into surrounding tissues. This condition can occur in many parts of the body, not just the cervix. Some key points to consider include:
- CIN III specifically describes severe dysplasia or pre-cancerous changes that affect the full thickness of the cervical epithelium, as discussed in the context of managing women with atypical glandular cells 1.
- Both conditions represent pre-invasive disease that has not yet spread beyond the basement membrane.
- Treatment for CIN III typically involves excisional procedures like LEEP (Loop Electrosurgical Excision Procedure) or cone biopsy to remove the abnormal tissue, with guidelines suggesting that ablation or diagnostic excision is acceptable for women with CIN 2,3 and satisfactory colposcopy 1.
- The distinction between carcinoma in situ and CIN III matters because while all CIN III is considered carcinoma in situ of the cervix, not all carcinoma in situ is CIN III, as carcinoma in situ can occur in other organs such as the skin, breast, or lungs.
- It's also important to note that CIN 3 is considered a cancer precursor, with about 12 percent of cases progressing to invasive cancer, 33 percent regressing, and the rest remaining CIN 3, highlighting the need for appropriate management and follow-up 1.
From the Research
Definition and Classification
- Carcinoma in situ (CIS) is often used interchangeably with Cervical Intraepithelial Neoplasia (CIN) III, as both terms refer to a precancerous lesion that has not invaded the basement membrane of the cervix 2.
- CIN III is a high-grade lesion that is considered to be a precursor to invasive cervical cancer, and it is often classified as stage 0 carcinoma 2.
Relationship between CIS and CIN III
- The terms CIS and CIN III are often used to describe the same condition, which is a precancerous lesion that has the potential to progress to invasive cancer if left untreated 3.
- Studies have shown that women with untreated CIN III are at high risk of developing invasive cervical cancer, highlighting the importance of timely and appropriate treatment 2, 3.
Treatment and Outcomes
- The standard treatment for CIN III is excisional therapy, which can be performed using various methods such as cold-knife conization or loop electrosurgical excision procedure (LEEP) 4, 5.
- Studies have shown that women who undergo excisional therapy for CIN III have a significantly lower risk of developing invasive cervical cancer compared to those who do not receive treatment 3, 6.
- The risk of invasive cervical cancer is particularly high for women who do not undergo excisional treatment, with a standardized incidence ratio (SIR) of 25.0 (95% CI: 12.0-46.0) compared to women who do receive treatment 3.