Cervical cancer develops in the lining of the cervix, the lower part of the uterus (womb) that enters the vagina (birth canal). This condition usually develops over time. Normal cervical cells may gradually undergo changes to become precancerous and then cancerous. Cervical intraepithelial neoplasia (CIN) is the term used to describe these abnormal changes. CIN is classified according to the degree of cell abnormality. Low-grade CIN indicates a minimal change in the cells and high-grade CIN indicates a greater degree of abnormality.
CIN may progress to squamous intraepithelial lesion (SIL; condition that precedes cervical cancer) or to carcinoma in situ (cancer that does not extend beyond the epithelial membrane). SIL is also classified as low-grade or high-grade. High-grade SIL and carcinoma in situ may progress to invasive carcinoma (cancer that has spread to healthy tissue).
Most (80–90%) invasive cervical cancer develops in flat, scaly surface cells that line the cervix (called squamous cell carcinomas). Approximately 10–15% of cases develop in glandular surface cells (called adenocarcinomas).
Incidence and Prevalence
Cancer of the cervix is the second most common cancer in women worldwide and is a leading cause of cancer-related death in women in underdeveloped countries. Worldwide, approximately 500,000 cases of cervical cancer are diagnosed each year.
Routine screening has decreased the incidence of invasive cervical cancer in the United States, where approximately 13,000 cases of invasive cervical cancer and 50,000 cases of cervical carcinoma in situ (i.e., localized cancer) are diagnosed yearly.
Invasive cervical cancer is more common in women middle aged and older and in women of poor socioeconomic status, who are less likely to receive regular screening and early treatment. In the United States, there is also a higher rate of incidence among African American, Hispanic, and Native American women.
Source : http://www.oncologychannel.com/cervicalcancer
