Oral cancer

Oral cancer is part of a group of cancers called head and neck cancers. Oral cancer can develop in any part of the oral cavity or oropharynx. Most oral cancers begin in the tongue and in the floor of the mouth. Almost all oral cancers begin in the flat cells (squamous cells) that cover the surfaces of the mouth, tongue, and lips. These cancers are called squamous cell carcinomas.

When oral cancer spreads (metastasizes), it usually travels through the lymphatic system. Cancer cells that enter the lymphatic system are carried along by lymph, a clear, watery fluid. The cancer cells often appear first in nearby lymph nodes in the neck.

Cancer cells can also spread to other parts of the neck, the lungs, and other parts of the body. When this happens, the new tumor has the same kind of abnormal cells as the primary tumor. For example, if oral cancer spreads to the lungs, the cancer cells in the lungs are actually oral cancer cells. The disease is metastatic oral cancer, not lung cancer. It is treated as oral cancer, not lung cancer. Doctors sometimes call the new tumor "distant" or metastatic disease.

NEW YORK (Reuters Health) - Human papillomavirus (HPV) infection from oral sex may have increased rate of tonsillar cancer, a study from Sweden hints.

Reports from both the US and Finland have documented a rise in the incidence of tonsillar cancer. This occurred in the absence of any increase in smoking or alcohol consumption, two well-known causative factors for the malignancy. This led Dr. Eva Munck-Wikland, from the Karolinska Institute in Stockholm, and colleagues to look for other epidemiologic trends that might explain the growing incidence of tonsillar cancer.

HPV is known to be associated with tonsillar cancers. Whether an increase in HPV-positive cases drove the recent increase in incidence, however, was unclear.

In their study, reported in the International Journal of Cancer, the investigators found that the incidence of tonsillar cancer rose by 2.8-fold in Sweden during the study period, 1970 to 2002. Cases of the disease in women rose by 3.5-fold, while cases in men increased by 2.6-fold.

At the same time, the proportion of HPV-positive cases of tonsillar cancer increased 2.9-fold, the report indicates. In the 1970s, 23.3 percent of cases were HPV-positive compared with 68 percent in 2000 to 2002.

This may be related to patterns of sexual behavior, with high-risk HPV-16 infections, not uncommon in the genital area, also becoming more common in the mouth due to an increase in oral sex, Munck-Wikland and colleagues note

They hypothesize that an "epidemic" of HPV infection in the oral cavity, due to changed sexual habits, "may contribute to the significant increase in incidence of tonsillar cancer."

If HPV does, in fact, cause tonsillar cancer, it might stimulate interest in developing a vaccine for preventing the malignancy, they suggest.

SOURCE: International Journal of Cancer, December 1, 2006.