Diagnostic value of cytology in detecting human papillomavirus-independent cervical malignancies: A nation-wide study in Korea

Background: Human papillomavirus (HPV) independent cervical malignancies (HPV-IDCMs) have recently been classified by the World Health Organization (WHO) 5th edition. These malignancies have historically received limited attention due to their rarity and the potential for evasion of HPV-based screening. Methods: We retrospectively reviewed 5, 854 biopsy-confirmed cervical malignancies from 22 institutions over 3 years (July 2020-June 2023). Histologic classification followed the WHO guidelines. HPV independence was confirmed by dual negativity for p16 and HPV; discordant cases (p16-positive/HPV-negative) underwent additional HPV testing using paraffin-embedded tissue. Cytological results were matched sequentially to histological confirmation. Results: The prevalence of HPV-IDCM was 4.4% (257/5, 854) overall and was 3.6% (208/5, 805 cases) among primary cervical malignancy. Patient age of HPV-IDCM was 29 to 89 years (median, 57.79). Its histologic subtypes included primary adenocarcinoma (n = 116), endometrial adenocarcinoma (n = 35), squamous cell carcinoma (n = 72), metastatic carcinoma (n = 14), carcinoma, not otherwise specified (n = 10), neuroendocrine carcinoma (n = 3), and others (n = 7). Among 155 cytology-histological matched cases, the overall and primary Pap test detection rates were 85.2% (132/155) and 83.2% (104/125), respectively. The interval between cytology and histologic confirmation extended up to 38 months. Conclusions: HPV-IDCMs comprised 3.6% of primary cervical malignancies with a high detection rate via cytology (83.2%). These findings affirm the value of cytological screening, particularly in patients with limited screening history or at risk for HPV-independent lesions, and may guide future screening protocols.