HPV16 Antibodies Strongly Increase Throat Cancer Risk, Can Develop Decades Before Diagnosis

The presence of antibodies against human papillomavirus type 16 (HPV16) strongly increases the risk of throat cancer and can develop between 6 to 40 years before diagnosis, according to a new study published in Annals of Oncology.

In the United States, the majority (70%) of oropharyngeal squamous cell carcinoma (OPSCC) cases are attributed to infection with HPV16 and cases of HPV16-associated throat cancer are increasing worldwide. Other risk factors include smoking and alcohol use.

For the study, the researchers examined data from 743 patients with throat cancer compared with a control group of 5814 individuals without cancer. Prior to any diagnosis of cancer, patients provided at least 1 blood sample, which was tested for antibodies against HPV16 cancer-causing E6 protein. Multiple samples were provided by 111 patients over a period of up to 40 years.

According to the study, the median time between first blood sample collection and a diagnosis of OPSCC was approximately 11 years.

In the control group, only 0.4% of individuals had HPV antibodies compared with 26.2% in patients with OPSCC. The presence of antibodies in white individuals prior to diagnosis was significantly higher than in black individuals (27.2% versus 7.7%), indicating a 98.2-fold increase in the risk of OPSCC and a 17.2-fold increase, respectively.

The researchers noted that this may partly explain better survival rates for white individuals compared with black individuals with throat cancer. HPV16-associated throat cancers tend to respond better to treatment than cancers that are not associated with the infection, according to the study.

The study also showed that HPV16 antibodies appeared more in individuals aged between 40 and 80 years, with the median age of 52 years old and median age of diagnosis at 62 years.

“We also found that people diagnosed in more recent calendar years were more likely to have HPV antibodies, which is consistent with what we know about the increase in the proportion of throat cancers that are due to HPV16,” lead study author Aimée Kreimer, PhD, senior investigator at the Division of Cancer Epidemiology and Genetics, National Cancer Institute, said in a press release. “Although there were some people with HPV antibodies detected prior to 1995, this was relatively rare.”

Changes in sexual practices and a decrease in tonsillectomy rates could be the reason for increasing incidence of HPV16-driven throat cancer in recent decades, the researchers explained.

Although HPV16 antibodies could be a way to identify high-risk individuals, the study authors concluded that further research should delineate the next steps in the screening process for potentially identifying pre-malignant lesions, as well as alternative ways for reducing risk of OPSCC.

“In other words, there is a long way to go before this biomarker can be used in clinical practice,” Mattias Johansson, PhD, a cancer epidemiologist at the International Agency for Research on Cancer, said. “While vaccination against HPV holds promise in preventing HPV-related cancers, we will not see resulting reduction in throat cancers for several decades.”

References

Antibodies Against HPV16 Can Develop up to 40 Years Before Throat Cancer is Diagnosed and Mark a 100-fold Increase in Risk in White People [news release]. European Society for Medical Oncology. https://www.esmo.org/Press-Office/Press-Releases/Annals-Oncology-Antibodies-HPV16-Throat-Cancer-Risk. Accessed June 12, 2019.

Kreimer AR, Ferreiro-Iglesias A, Nygard M, et al. Timing of HPV16-E6 antibody seroconversion before OPSCC: findings from the HPVC3 consortium. Annals of Oncology. 2019. https://doi.org/10.1093/annonc/mdz138