Chlamydia Linked to Cervical Cancer Risk

New research in Scandinavia supports a link between the sexually transmitted disease chlamydia and cervical cancer, suggesting that women infected with certain types of chlamydia may be at heightened risk for malignancy.

Another common sexually transmitted disease, human papillomavirus or HPV, is the leading cause of cervical cancer, but data on chlamydia are much less clear.

The new findings, based on 128 women with invasive cervical cancer in Finland, Sweden and Norway, appear in Wednesday’s Journal of the American Medical Association.

Chlamydia and Cervical Cancer Linkage The findings “suggest that cervical malignancy should be added to the complications and costs associated with genital chlamydial infections,” Dr. Jonathan Zenilman of Johns Hopkins School of Medicine wrote in a JAMA editorial.

In some previous studies that found a link, HPV likely was the real culprit, but the current research strongly suggests there is an independent relationship between chlamydia and cervical cancer, Zenilman said.

The authors, led by Dr. Tarja Anttila of Finland’s National Public Health Institute, examined data on women diagnosed with cervical cancer at least a year after having blood tests during health exams.

Certain Chlamydia Strains Riskier Blood was measured for exposure to 10 different types of chlamydia. Three specific types were linked to cervical cancer, but one known as serotype G carried the highest risk. Women with that type of chlamydia were about 6.5 times more likely to develop cervical cancer than uninfected women.

The authors took into account the effects of HPV and smoking, another risk factor for cervical cancer.

How a bacterial infection such as chlamydia might cause cancer is unclear, the authors said, but they noted that other research has linked abnormal cell changes with the body’s inflammatory response to infection.

Unknown How Bacteria Increases Risk

In the editorial, Zenilman called the study intriguing but not conclusive since there may have been other behavioral or biological factors that contributed to the cancer risk. Still, Zenilman said, the findings may provide “additional justification for expanding chlamydial infection screening.”

Chlamydia is the most common bacterial STD in the United States, with between 4 million and 8 million new cases reported yearly. Unlike HPV, it can be treated with antibiotics, but many women have no symptoms and the disease can cause pelvic inflammatory disease and infertility.

About 13,000 cases of cervical cancer are diagnosed in the United States annually, and though Pap tests can detect many cases in early, treatable stages, it kills about 4,600 women each year.