What is the follow-up for Cervical Intraepithelial Neoplasia (CIN) grade 1, mild cervical dysplasia?

From the Guidelines

The follow-up for CIN-1 (mild cervical dysplasia) typically involves repeat HPV testing and/or Pap smear in 12 months rather than immediate treatment. For most patients, CIN-1 will resolve spontaneously without intervention as the immune system clears the underlying HPV infection 1. If follow-up testing remains abnormal after 12 months, colposcopy may be repeated. If CIN-1 persists for 2 years or progresses to higher-grade lesions, treatment options like loop electrosurgical excision procedure (LEEP), cryotherapy, or laser therapy may be considered.

• Key considerations in managing CIN-1 include:
  • The high likelihood of spontaneous regression
  • The risks of unnecessary procedures that could affect future pregnancy outcomes
  • The importance of regular follow-up to monitor for potential progression to higher-grade lesions
• Patient factors to consider during the observation period include:
  • Avoidance of tobacco use, as smoking impairs immune function and increases risk of persistence or progression
  • Regular follow-up, as approximately 10% of CIN-1 cases may progress to higher-grade lesions if left unmonitored
• The decision to treat persistent CIN-1 should be based on patient and provider preferences, with consideration of the potential benefits and risks of treatment 1.
• A diagnostic excisional procedure is recommended if the colposcopic examination is unsatisfactory, the endocervical sampling contains CIN, or the patient has been previously treated 1.

From the Research

Follow-up of CIN-1 Mild Cervical Dysplasia

• The follow-up of CIN-1 mild cervical dysplasia typically involves a strict follow-up with colposcopy and treatment in case of persistence or progression of the abnormalities 2.
• The risk of cancer is extremely low, and a conization is not necessary in an asymptomatic woman with a LSIL/ASC-US pap smear in case of CIN-1, even if the squamocolumnar junction is not entirely visualized 2.
• The rate of progression of a CIN-1 to a CIN-3 or more severe lesion is less than 9% in the two years following the initial diagnosis 2.
• A CIN-1 is associated with a risk of evolution to a CIN-2 or more severe lesion that is not markedly more important than the risk associated with a LSIL/ASC-US pap smear while the colposcopy is normal or the biopsy is negative 2.

Management Strategies

• The management of CIN-1 involves a follow-up with cytology and/or HPV testing at 12 months, and a repeat control is necessary at 18 months if the results are positive or persisting ASC-US/LSIL 2.
• A single negative cotest approximately 1 year after colposcopy predicts a lower subsequent 5-year risk of CIN-2+ than 2 sequential negative HPV tests or 2 sequential negative Pap results 3.
• Two negative posttreatment tests of each kind confer slightly lower 5-year CIN-2+ risk than one, and the 5-year CIN-2+ risk after 2 negative cotests approaches the risk after a negative Pap test during routine screening 4.

Natural History of CIN-1

• The natural history of CIN-1 shows that a low rate of progression, suggesting it may be reasonable to prolong the screening interval in women with CIN-1 5.
• At 6 months, 49% of patients with CIN-1 regress to normal, 45% have persistent low-grade, and 7% progress to high-grade lesions 5.
• At 12 months, of those with negative pathology at 6 months, 80% remain negative, 16% demonstrate low-grade, and 4% progress to high-grade lesions 5.