Cervical Carcinoma and Sexual Behavior: Collaborative Reanalysis of Individual Data on 15,461 Women with Cervical Carcinoma and 29,164 Women without Cervical Carcinoma from 21 Epidemiological Studies

Abstract

High-risk human papillomavirus (HPV) types cause most cervical carcinomas and are sexually transmitted. Sexual behavior therefore affects HPV exposure and its cancer sequelae. The International Collaboration of Epidemiological Studies of Cervical Cancer has combined data on lifetime number of sexual partners and age at first sexual intercourse from 21 studies, or groups of studies, including 10,773 women with invasive cervical carcinoma, 4,688 women with cervical intraepithelial neoplasia grade 3 (CIN3)/carcinoma in situ, and 29,164 women without cervical carcinoma. Relative risks for invasive cancer and CIN3 were estimated by conditional logistic regression. Risk of invasive cervical carcinoma increased with lifetime number of sexual partners (P for linear trend <0.001). The relative risk for z6 versus 1 partner, conditioned on age, study, and age at first intercourse, was 2.27 [95% confidence interval (95% CI), 1.98-2.61] and increased to 2.78 (95% CI, 2.22-3.47) after additional conditioning on reproductive factors. The risk of invasive cervical carcinoma increased with earlier age at first intercourse (P for linear trend <0.001). The relative risk for age at first intercourse V14 versus z25 years, conditioned on age, study, and lifetime number of sexual partners was 3.52 (95% CI, 3.04-4.08), which decreased to 2.05 (95% CI, 1.54-2.73) after additional conditioning on reproductive factors. CIN3/carcinoma in situ showed a similar association with lifetime number of sexual partners; however, the association with age at first intercourse was weaker than for invasive carcinoma. Results should be interpreted with caution given the strong correlation between sexual and reproductive factors and the limited information on HPV status.

Epidemiological and Histological Profile of Cervical Cancer in Cameroon: About 2078 Cases

“…Cervical squamous cell carcinoma risk is 1.5 times higher in current smokers than in people who have never smoked [14]. Cervical cancer risk is almost three times higher in women who had 6 or more sexual partners, compared to those who had only one [15]. [17].…”

“…However, many young women become infected with multiple types of human papilloma virus, which then can increase their risk of getting cervical cancer in the future. Early age at first intercourse is consistently found to be a risk factor in most of the early epidemiological studies of cervical cancer [15] [20]. Cervical cancer risk is double in women who first had sexual intercourse at the age of 14 or less, compared to those who did at 25 or more [15].…”

“…Early age at first intercourse is consistently found to be a risk factor in most of the early epidemiological studies of cervical cancer [15] [20]. Cervical cancer risk is double in women who first had sexual intercourse at the age of 14 or less, compared to those who did at 25 or more [15]. The importance of early age at first coitus lies in the fact that intercourse introduces a carcinogenic agent (HPV infection) to the cervical epithelium, which is most susceptible during adolescence [20].…”

Age-Group Differences in Human Papillomavirus Types and Cofactors for Cervical Intraepithelial Neoplasia 3 among Women Referred to Colposcopy

“…A pooled analysis of international case-control studies found that smoking was associated with similar 2-fold greater odds of both carcinoma in situ and invasive cervical cancer among HPV positive women, and found no evidence of age-group differences in the effects of smoking with invasive and in situ cases combined(24). Our selection of candidate cofactors for CIN3+ was informed by the larger body of literature on invasive cervical cancer, which has identified associations with age at first full-term pregnancy and number of full-term pregnancies(23), lifetime number of sexual partners(25), hormonal contraceptive use(26), and smoking (24, 27). It is important to consider cofactors for CIN3+ because precancerous lesions are the target of screening activities, and cofactors for this endpoint might differ from those for invasive cancers because of the timing of exposures, the portion of the pathophysiologic process affected by the risk factor, the age of cases, or differences in control selection.…”

Time since first sexual intercourse and the risk of cervical cancer

“…2 Early age at first sexual intercourse (AFI) is an important risk factor for cervical cancer. 3 Other risk factors include lifetime number of sexual partners, 4 tobacco use 5 hormonal contraceptives, 6 young age at first full-term pregnancy and number of full-term pregnancies. 7 …”