To investigate whether routine cervical screening using human papillomavirus (HPV) and cytology co-testing effectively identifies women with endometrial (EC) or ovarian (OvC) cancer.

In 2003, Kaiser Permanente Northern California implemented triennial co-testing in women aged ≥30 years. Index screening results (n = 2,385,729) were linked to subsequent EC (n = 3434) and OvC (n = 1113) diagnoses from January 1, 2003 to December 31, 2017. EC were categorized as type 1 or 2, and, selectively, EC and OvC diagnoses were stratified on whether symptoms were present at the time of the co-test. Fractions and absolute risks of EC or OvC of each co-testing result were calculated.

Most EC (82.18%) and OvC (88.68%) were preceded by a negative HPV and negative cytology co-test. More EC were preceded by atypical squamous cells of undetermined significance (ASC-US) or more severe (ASC-US+) cytology and negative HPV test (n = 290) (8.44% of EC) compared to a negative cytology and a positive HPV test (n = 31) (0.89% of EC) (p < 0.001). The absolute risk of any EC diagnosis following ASC-US+ and negative HPV test was 0.48%. Atypical glandular cells (AGC) cytology and a negative HPV result preceded 6.92% of any EC diagnosis, with an absolute risk of 4.02%, but preceded only 1.13% of type 2 EC cases, with an absolute risk of 0.24%, in asymptomatic women. AGC cytology and a negative HPV result preceded 1.44% of OvC, with an absolute risk of 0.28%.

Abnormal cervical screening tests, even AGC cytology, rarely precedes and poorly predict women with EC or OvC.