Human papillomavirus infection among patients with cervical cancer in Cambodia

Cervical cancer is the second-most common cancer among Cambodian women, with an estimated 1274 new cases and 670 deaths annually. On October 5, 2023, the Cambodian government introduced HPV vaccination for 9-year-old girls into the country's national immunization schedule. The optimal strategy for this nascent vaccination campaign, and the expected effects thereof, depend on a robust understanding of HPV epidemiology in Cambodia. To this end, we conducted a retrospective, observational, cross-sectional study of HPV infection among patients with cervical cancer at Calmette Hospital in Phnom Penh, Cambodia.

Fifty specimens of formalin-fixed, paraffin-embedded cervical tumor tissue selected from archival specimens of biopsies performed at Calmette Hospital between April 2019 to March 2020 were analyzed using next-generation sequencing to detect HPV types present in each sample. Forty-seven samples of non-cancerous cervical tissue were selected for comparison from archival specimens of non-oncological hysterectomies performed at Cambodia's National Maternal and Child Health Center between January 2020 to March 2021 and analyzed using PCR, gel electrophoresis, and p16 immunohistochemistry to detect the presence of HPV infection in each sample. Those that tested positive for HPV underwent next generation sequencing to detect which HPV subtypes were present in each sample.

HPV-16/18 were detected in 83.3% of cervical cancer specimens, and HPV-58 was detected in 11.9%. Multiple HPV subtypes were detected in 2.4% of cancer specimens. Neither HPV-16 nor - 18 differed statistically in observed prevalence from either those rates reported for all Asia or globally. The observed prevalence of HPV-58 was not dissimilar between Cambodia and Asia, however Cambodia's prevalence of HPV-58 was substantially higher than the global rate. HPV DNA was detected in 0/47 control specimens.

This is the first study of HPV type prevalences among patients with cervical cancer in Cambodia, providing epidemiological data that is crucial for assessing and optimizing the country's vaccination policy. Results suggest that the efficacy of current vaccination strategy should not be hindered by any outsized prevalence of non-vaccine type HPV.