The same genital wart virus that causes the common form of cervical cancer also leads to a more unusual type of the disease, new research confirms.
In an analysis of eight international studies, researchers found that women who carried the human papilloma virus (HPV) were 81 times more likely to develop cervical adenocarcinoma - an uncommon form of cervical cancer - than women who were HPV-negative.
Most cases of cervical cancer are a type known as squamous cell carcinoma, and HPV is known to be the primary cause of this form of the disease. Only certain, “high risk” strains of HPV, however, can lead to cervical cancer.
The two strains most often linked to the common form of the cancer - HPV 16 and 18 - were also tied to most cases of cervical adenocarcinoma in the new study.
Importantly, the study authors say, this means that the two HPV vaccines expected to arrive on the market in the near future could prevent 86 percent of cervical adenocarcinomas worldwide.
In addition, lead study author Dr. Xavier Castellsague told Reuters Health, currently available HPV tests could catch nearly all cervical adenocarcinomas - which, compared with squamous cell cancers, are harder to detect with traditional Pap tests.
Castellsague, of the Institut Catala d’Oncologia in Barcelona, Spain, and his colleagues report the findings in the Journal of the National Cancer Institute.
The results are based on eight studies conducted in North Africa, South America and Southeast Asia that together included 167 women with cervical adenocarcinoma and 1,881 women who served as a comparison group.
Cervical samples were tested for HPV DNA, and 82 percent of the cancer patients were found to carry HPV 16 or 18.
Based on the findings, Castellsague and his colleagues estimate that available HPV tests could catch 98 percent of HPV-positive adenocarcinomas.
However, HPV DNA tests are not yet widely used, Castellsague said, and costs and lab resources will keep them out of reach in many parts of the world.
It’s the lack of routine screening with even traditional exams and Pap tests that allows cervical cancer to remain a major threat in poorer nations.
While the “tools” for preventing cervical cancer and deaths from the disease are here, an editorial published with the study notes, the next challenge will be in the logistics of using them.
Policymakers and public health professionals will have to figure out how to use these tests and vaccines in the “broadest, most rational and cost-effective manner,” write Drs. Allan Hildesheim, of the U.S. National Cancer Institute, and Amy Berrington de Gonzalez of Johns Hopkins University in Baltimore.
SOURCE: Journal of the National Cancer Institute, March 1, 2006.
Revision date: July 3, 2011
Last revised: by Sebastian Scheller, MD, ScD