HPV+ women smokers under greater threat of cervical cancer

Women who are both habitual smokers and also human papillomavirus type 16 (HPV-16) positive are at an increased risk of developing ‘cervical cancer in situ’ - a typical cancerous growth that affects the surface layer of the cervix, report researchers of a new study.

The study lead by Dr. Anthony S. Gunnell, a researcher at the Karolinska Institute in Stockholm, Sweden, reports 14 times higher vulnerability among women smokers tested positive for HPV16, to develop cervical cancer.

Though, previous studies have been continuously linking smoking and the human papillomavirus(HPV) infection with greater susceptibility of developing cervical cancer, the current study looks into the possible relationship between the two.

Cervical cancer is a malignancy of the cervix which is particularly marked by vaginal bleeding at advanced stage.

Being completely asymptomatic in early stages, the early detection of cancer becomes difficult. It is the second most common cancer infecting women worldwide with more than 80 percent cases reported in developing countries.

However, still an estimated 10,000 cases are reported annually in United States, of which a third die.

Regular and frequent Pap smear’s are recommended to increase the possibility to identify premalignant changes on a cervix. If detected early, it can be treated without impairing fertility.

According to most scientific studies, human papillomavirus (HPV) infection is responsible for more than 90 percent of the cases of cervical cancer. Of the 19 known strains, 7 most common types of HPV - 16, 18, 31, 33, 42, 52 and 58. Of these types 16 and 18 being the most common cause of the cervical cancer.

The Sewdish study randomly shortlisted 738 women from a database of 146,104 women who underwent cervical screening in the region between 1969 and 1995. While, 375 women subjects showed signs of precancerous cervical lesions the remaining 363 were healthy women.

The findings published in the November issue of Cancer Epidemiology, Biomarkers & Prevention reported "synergistic" relationship between heavy smoking and high levels of a specific strain of HPV.

Women smokers who were also carriers of HPV-16 infection reported 14 times higher probability of cervical cancer risk than current smokers who were tested negative for the infection.

While, high HPV-16 levels only raised the risk of cervical cancer by six times among nonsmokers.

Though researchers are not clear as to why smoking increases the risk of cervical cancer among women, but both smoking and HPV infection are known to affect molecules known as cytokines, which control tumor growth.

Meanwhile healthcare companies are making a continuous effort to develop vaccination to fight the fatal HPV strains. Merck & Co.’s, Gardasil - vaccine against four strains of HPV got FDA approval in June this year.

Cervarix, another drug developed by Glaxosmithkline which shows 100 percent effectiveness in preventing HPV strains 16 and 18 is likely to get FDA approval by year end.