Cervical Intraepithelial Neoplasia: Overview and More

Cervical intraepithelial neoplasia (CIN), also known as cervical dysplasia, is the abnormal growth of cells (neoplasia) or lesions on your outer cervix lining (intraepithelial). CIN can be detected through your routine pap smear exam and is most commonly caused by one of the 100 subtypes of human papillomavirus (HPV).

CIN is also considered “premalignant” cancer, because having CIN is a risk factor for developing cervical cancer at a later time. Depending on your age, risk factors for cervical cancer, and health condition, treatment protocols can vary. 

Cervical Intraepithelial Neoplasia (CIN) Symptoms

Cervical intraepithelial neoplasia can happen without you knowing it, because there are typically no symptoms. This is why getting routine pap smears is so important—only a pap smear will show the abnormal cells.

Further classification will occur after the diagnosis to specify the amount of tissue affected. The three grade levels of CIN include:​​

• Low-grade neoplasia (CIN 1) involves about one-third of the thickness of the epithelium.
• CIN 2 refers to abnormal changes in about one-third to two-thirds of the epithelial layer.
• CIN 3 (the most severe form) affects more than two-thirds of the epithelium.

Causes

Cervical intraepithelial neoplasia is most commonly caused by variations of HPV (i.e., HPV16 and HPV18) infecting a woman’s reproductive tract. The World Health Organization says these two HPV types (16 and 18) cause 70% of cervical cancers and precancerous cervical lesions.

Some risk factors also increase your likelihood of coming into contact with HPV, but you should know it’s a pretty common virus. Estimates say more than three-quarters of all sexually active women will become infected with HPV at some point in their lifetime.

Additional risk factors include:

• Age (approximately 50% of HPV infections occur in girls and women between ages 15 to 25)
• Smoking cigarettes
• Taking immunosuppressant drugs 
• Having unprotected sex
• Having sex with multiple people
• Sexual activity before age 18

You can help protect yourself against HPV infection by getting vaccinated.

Diagnosis

If your pap smear results show abnormal cells, your doctor or doctor’s office will contact you to discuss next steps. While this is an understandably upsetting experience, precancerous cells don’t typically become cancerous for years, if at all.

The next step is often to get an actual look at what’s happening via colposcopy so your doctor can examine the cervix area under a microscope. 

The colposcopy can be completed in your doctor’s office and can also be used to examine for:

• Growths or lesions
• Inflammation
• Warts

From here, your doctor can decide if they need to take a biopsy or whether or not close monitoring (more frequent pap smears) is enough for now. DNA testing may also be done to see if you have a high-risk form of HPV.

If your HPV status is unknown, be aware that screening guidelines do recognize HPV testing as a method of detecting and preventing CIN and cervical cancer (in women age 30 and over). Getting tested is a part of determining your overall risk and what treatment method is most suitable.

Treatment

Treatment may not be necessary in cases of low-grade CIN 1 because the underlying infection often resolves on its own. For higher-grade disease, the cells may need to be destroyed or removed to keep them from multiplying or mutating years from now.

If you have a more severe grade of CIN (2 or 3), treatment options include:

• Cone biopsy to remove abnormal tissues; used for both therapeutic and diagnostic purposes
• Cryotherapy (cold therapy) to freeze and remove abnormal tissues
• Laser therapy or laser ablation to destroy abnormal cells
• Loop electrosurgical procedure (LEEP), which uses an electricity-heated, thin, wire loop to remove abnormal tissue from the cervix

Research on alternative treatments or potential contributing factors that can be manipulated for therapeutic reasons is also being conducted.

One such study looked at how the presence or absence of Lactobacillus spp. (a common probiotic) altered the vaginal environment. Lower levels were associated with lower disease regression rates in 12- and 24-month follow-ups, suggesting some link which needs further examination.

Prognosis 

The prognosis of CIN will depend upon two factors:

• The level of severity of abnormal cell coverage on your cervix upon discovery from pap smear. This is why detecting these cells as early as possible is best (the cells have less opportunity to multiply or mutate). 
• Your ability and willingness to follow the ASCCP recommendations

A Word From Verywell

It can be scary when you get a pap smear back with abnormal results, but most of the time there is nothing to worry about. Especially when discovered early on, the risk of these cells developing into cancer is fairly low.

Still, leaving something like this untreated is not recommended. You can protect yourself by making pap smears part of your healthcare routine and by following through with your doctor’s recommendations.