Birth Control Pill Increases Risk of Cervical Cancer if HPV Positive: Eight earlier studies of 3,769 women from four continents pooled by WHO. 1,853 had cervical cancer, and 1,916 did not. Nearly all the women with cancer tested positive for HPV, while hardly any who were cancer-free had the virus. Nearly all sexually active women get HPV, but the immune systems of most eliminate it. However, some do not. Women who had taken the pill were no more likely than the others to be carriers of HPV. However, those infected with HPV who had used birth control pills for an accumulated total of five years were 3 times more likely to develop cervical cancer than HPV-infected women who had never taken the pill. The increased risk persisted for up to 14 years after stopping the contraceptives. Women who had taken the pill for 10 years were 4 times more likely to get the disease than those who had never taken it. Lancet (2002;359:1085-92). Worldwide, 360,000 women were diagnosed with cervical cancer in 1990. Of those, 190,000 died. Lifetime risk is 5% in parts of Africa, India, and Latin America, but only 1% in Europe and North America. Over 99% of women in Britain in whom cervical cancer is diagnosed test positive for DNA of HPV, an infection that affects a third of all women in their twenties. Cervical cancer strikes 12,900 American women each year and kills 4,400.

BCP Increases Risk: Cancer Research in Oxford reviewed 28 studies, covering around 12,500 women, which had looked at Pill use and cervical cancer. Women had a 10% increased risk of cervical cancer if they had taken the Pill for less than five years, 60% for five to nine years' use and double the risk if they had taken it for 10 years or more. True even if control for # partners, HPV, and smoking. Dr Amy Berrington. 4/4/03

HPV Persistance Reduced by B-12: Circulating vitamin B12 levels were inversely associated with HPV persistence (P for trend, 0.037) after adjusting for age, age at first intercourse, marital status, cigarette smoking status, race, and body mass index. In addition, women with circulating levels in the highest third (>493.2 pg/ml) of vitamin B12 were less likely to have a persistent infection (adjusted odds ratio = 0.4. Cancer Epidemiol Biomarkers Prev 2002 Apr;11(4):353-9

BCP, Multiple Pregnancies Increase if HPV Positive: Lancet (2002;359:1085-92). Women on the pill 5-9 years were 3 times more likely than non-users to develop cervical cancer. On the pill for more than 10 years were four times more likely. These risks did not vary with time since first or last use, or by age at first use. The study considered only women who were infected with HPV. Over 99% of women in Britain in whom cervical cancer is diagnosed test positive for DNA of HPV, an infection that affects a third of all women in their twenties. Lancet (2002;359:1093-101), confirmed the widespread belief that multiple pregnancies are another risk factor for cervical cancer. Women who tested positive for HPV and who had had seven or more full term pregnancies were 3.8 times more likely to develop the disease than infected nulliparous women. HPV positive women who had had more than five full term pregnancies and had taken the pill for more than five years ran nearly 12 times the risk of cervical cancer as HPV positive nulliparous women who had never taken the pill.

Cervical CA is the most common CA among women in developing countries. Lifetime risk is 5% in parts of Africa, India, and Latin America, & 1% in Europe and North America.

Every 5 Year Screening Expensive With Small Benefit: 348,419 Bristol women, and modeling of cases of cervical cancer and deaths with and without screening. For every 10,000 women screened from 1976 to 1996, 1564 had abnormal cytology, 818 were investigated, and 543 had abnormal histology; 176 had persistent abnormality for two years or more. In the absence of screening, 80 women would be expected to develop cancer of the cervix by 2011, of whom 25 would die. With screening, 10 of these deaths would be avoided. Comparison of cumulative abnormality rates with numbers expected to develop cancer in the absence of screening suggests that at least 80% of high grade dyskaryosis and of high grade dysplasia would not progress to cancer. The lifetime risk of having abnormal cytology detected could be as high as 40% for women born since 1960. Screening is labor and resource intensive. It involves treatment for many women not destined to develop invasive cancer. The increased intervention rate for cervical abnormality in England is due to change in practice, not a cohort effect, and is probably the reason for the marked fall in incidence and mortality during the 1990s. BMJ 2003;326:901