Prospective observational study: cervical cancer smears
Does incidence vary after several negative smear results at different ages?
Cervical screening has effectively reduced the number of women diagnosed with and dying from cervical cancer in most developed countries. The smear test is the most widely used screening tool. It aims to detect premalignant cells, which can then be treated, preventing cancer. A sample of cells is scraped from the cervix of the uterus and examined by microscope. The study of cells is called cytology. Cervical cytology identifies abnormal cells, which need investigation; it does not provide definitive diagnosis. Diagnosis should be based on microscopic analysis of cervical tissue (known as histology).
Ideally, cervical screening should be repeated every 3-5 years. With longer intervals a woman might develop cancer from a lesion that was not detectable when she was last screened. With shorter intervals new lesions since her last screen are less likely to be important. Much of cancer screening remains controversial because of the balance between the benefits