Cervical cancer risk increases with age. According to the National Cancer Institute, the median age for cervical cancer diagnosis between 2003 to 2007 was 48. Less than 15 percent of women under 35 are diagnosed with cervical cancer. Although rare, cervical cancer among young women is often characterized by an unusual cell type, greater invasiveness and a poorer prognosis.
Background
Cervical cancer is a cancer of cells between the vagina and uterus. According to the National Cancer Institute, more than 90 percent of cervical cancer is caused by infection with the human papilloma virus, or HPV.
Types of Cervical Cancer
Cervical cancer varies by the type of cells affected. The most common, accounting for 80 to 90 percent, is a squamous cell carcinoma. The second most common types, adenocarcinoma and adenosquamous carcinoma, account for approximately 10 percent of cases. Other cell types account for the rest.
Trends in Cervical Cancer
According to the American Cancer Society, since the mid-1950s there have been more than a 70 percent decrease in deaths attributable to cervical cancer. Early detection through Pap test screenings account for much of this decline. In spite of the declines in the overall incidence of cervical cancer, some studies have shown the decrease has been in the most common type --- squamous cell carcinomas. In contrast, there has been an increase in the incidence of adenocarinomas and adenosarcomas, which tend to have a poorer prognosis.
Younger Women
Although a less common type of cervical cancer, several studies document a considerable increase in the incidence of invasive cervical adenocarcinomas and adenosquamous carcinomas, despite the decrease in the overall incidence of cervical cancer, particularly among younger women.
A report by Lui and colleagues in the Canadian Medical Association Journal, for example, reviewed records in the Canadian Cancer registry over a twenty-year period. They found a significant increase in these cancers, particularly among younger women -- those aged 20 to 49 years. In fact, between 1970 and 1996, the risks of developing invasive adenocarcinoma and adenosquamous carcinoma of the cervix in the 20 to 34 year group trebled and in the 35 to 49 year age group doubled.
SEER Study
In 2007, a report based on NCI's Surveillance Epidemiology and End Results, or SEER, data, examined almost 31,000 patient records to determine whether the cell type of invasive cervical cancer was related to prognosis. The authors confirmed an increase in the incidence of adenocarcinomas and adenosarcomoas, a younger age at diagnosis and a poorer prognosis.
Conclusion
Some researchers speculate the increased incidence of invasive adenocarcinomas and adensquamous carcinomas among younger women is associated with a higher incidence of HPV infections. According to the SEER study researchers, although the causes of the increase remain unclear, the trends raise serious questions about the efficacy of current screening protocols. It also underscores the need for better means of identifying women who are at high risk and who might benefit most from HPV vaccinations.
References
- National Cancer Institute: Cervical Cancer.
- Biomedical Central: Prognostic Value of Histopathology and Trends in Cervical Cancer: A SEER Population Study: Vincent Vinh-Hung et al.: 2007.
- Canadian Medical Association Journal: Cervical Cancer: The Increasing Incidence of Adenocarcinoma and Adenosquamous Carcinoma in Younger Women: Shiliang Liu, Robert Semenciw and Yang Mao: 2001.
- University of Pennsylvania: Oncolink: Cervical Cancer: The Basics.
