Despite
a decline in most head and neck cancers during the past decade, the
incidence of a particular form of throat cancer is rising steeply,
according to a recent report in the British Medical Journal.
The
greatest concern? The type of cancer identified is related to the human
papilloma virus (HPV). Researchers say that sexual transmission of HPV
may explain the rise in cases. If that’s true, then add throat cancer –
in addition to cervical cancer – as a potentially deadly consequence of
HPV infection.
Head and neck cancer is widespread around the
world. There are about 640,000 new cases each year. The particular
cancer of concern is esophageal squamous cell cancer, which is
increasing only in the developed world. In the U.S., cases increased by
22% between 1999 and 2006 after being stagnant for the previous two
decades. The United Kingdom has recorded a dramatic 51% increase in
oro-pharyngeal cancer between 1989 and 2006. Much of it is attributed to
a rise in HPV-related cancers.
Evidence for the HPV link can be
found in biopsy studies of oro-pharyngeal cancers. HPV has been detected
in 60%-80% of recent biopsy samples in a U.S. study compared with 40%
in the previous decade. A Swedish study found a 70% rise in the
detection of HPV biopsies since the 1970s.
The emergence of
HPV-related oro-pharyngeal cancer is a relatively new phenomenon.
Fortunately, it carries a better prognosis than non-HPV cancers,
especially in non-smokers. It’s not understood why this cancer has
improved survival.
Other studies have established that the risk
of developing throat cancer is directly tied to the level of sexual
activity. For example, the risk is increased in those with a history of
six or more lifetime sexual partners, four or more lifetime oral sex
partners, and for men, an earlier start of sexual intercourse.
The
findings are likely to contribute to the debate over offering HPV
vaccines to young men and boys. Two vaccines are currently available and
approved for young women before they become sexually active – Cervarix
and Gardsil, which can prevent HPV infection. Studies will now be needed
to assess the cost-effectiveness of offering vaccines to boys.
HPV
is the most common sexually transmitted disease, affecting more than 20
million people each year. More than 100 strains of HPV are known to
exist, 30-40 of which are sexually transmitted. Virtually any skin to
skin contact, oral, genital or anal can transmit the virus. Unless they
develop skin or genital lesions, most infected individuals don’t know
that they’re infected with the virus.
The virus is usually
cleared by the immune system within 12-18 months and causes no further
harm. But certain high-risk strains may not clear and cause precancerous
lesions on the cervix. A Pap smear can detect these changes and can
lead to early and effective treatment. The potential link to oral and
throat cancers raises the issue of what kind of screening and
immunizations programs are appropriate to prevent this latest form of
the HPV scourge.
Source : http://www.lifescript.com/blogs/ed_geehr/health/oral_sex_turns_deadly.aspx
# Edward C. Geehr
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