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Background: Breast and ovarian cancers are predominant female cancers with increasing prevalence. The purpose of this study was to estimate the population attributable risks (PARs) of breast and ovarian cancer occurrence based on the relative risks (RRs) of modifiable reproductive factors and population-specific exposure prevalence.Methods: The PAR was calculated by using the 1990 standardized prevalence rates, the 2010 national cancer incidence with a 20 year lag period, the meta-analyzed RRs from studies conducted in the Korean population for breast cancer, and the meta-analyzed RRs from a Korean epithelial ovarian cancer study and a prior meta-analysis, and ovarian cancer cohort results up to 2012. For oral contraceptive and hormone replacement therapy use, we did not consider lag period.Results: The summary PARs for modifiable reproductive factors were 16.7% (95% CI 15.8-17.6) for breast cancer (2404 cases) and 81.9% (95% CI 55.0-100.0) for ovarian cancer (1579 cases). The modifiable reproductive factors included pregnancy/age at first birth (8.0%), total period of breastfeeding (3.1%), oral contraceptive use (5.3%), and hormone replacement therapy use (0.3%) for breast cancer and included breastfeeding experience (2.9%), pregnancy (1.2%), tubal ligation (24.5%), and oral contraceptive use (53.3%) for ovarian cancer.Conclusions: Despite inherent uncertainties in the risk factors for breast and ovarian cancers, we suggest that appropriate long-term control of modifiable reproductive factors could reduce breast and ovarian cancer incidences and their related burdens by 16.7% and 81.9%, respectively. [ABSTRACT FROM AUTHOR]

Background In the Republic of Korea, cancer is the most common cause of death, and cancer incidence and mortality rates are the highest in East Asia. As alcoholic beverages are carcinogenic to humans, we estimated the burden of cancer related to alcohol consumption in the Korean population. Methods The cancer sites studied were those for which there is convincing evidence of a positive association with alcohol consumption: oral cavity, pharynx, esophagus, colon, rectum, liver, larynx and female breast. Sex- and cancer-specific population attributable fractions (PAF) were calculated based on: 1) the prevalence of alcohol drinkers among adults ≥20 years of age in 1989; 2) the average daily alcohol consumption (g/day) among drinkers in 1998; 3) relative risk (RR) estimates for the association between alcohol consumption and site-specific cancer incidence obtained either from a large Korean cohort study or, when more than one Korean study was available for a specific cancer site, meta-analyses were performed and the resulting meta-RRs were used; 4) national cancer incidence and mortality data from 2009. Results Among men, 3% (2,866 cases) of incident cancer cases and 2.8% (1,234 deaths) of cancer deaths were attributable to alcohol consumption. Among women, 0.5% (464 cancer cases) of incident cancers and 0.1% (32 deaths) of cancer deaths were attributable to alcohol consumption. In particular, the PAF for alcohol consumption in relation to oral cavity cancer incidence among Korean men was 29.3%, and the PAFs for pharyngeal and laryngeal cancer incidence were 43.3% and 25.8%, respectively. Among Korean women, the PAF for colorectal cancer incidence was the highest (4.2%) and that for breast cancer incidence was only 0.2%. Avoiding alcohol consumption, or reducing it from the median of the highest 4th quartile of consumption (56.0 g/day for men, 2.80 g/day for women) to the median of the lowest quartile (28.0 g/day for men, 0.80 g/day for women), would reduce the burden of alcohol-related cancers in Korea. Conclusions A reduction in alcohol consumption would decrease the cancer burden and a significant impact is anticipated specifically for the cancers oral cavity, pharynx, and larynx among men in the Republic of Korea. [ABSTRACT FROM AUTHOR]

Background: Little is known about the natural history of human papillomavirus (HPV) infection in Asian women. Methods: A follow-up study was conducted, with exfoliated cervicovaginal cells self-collected from, and questionnaires administered to 197 female students, aged 17-26 years, who had been already examined one and half years before. The presence of 25 HPV types was evaluated by a polymerase chain reaction-based assay. Results: The acquisition of new infection for any HPV type among 171 female students at risk who were negative at baseline, 60% of whom had remained as virgins, was 17.5% (95% confidence interval [CI]: 11.8-23.2). Among individual types, HPV16, 18 and 35 showed the highest rate of new infection. Women who had had first sexual intercourse (OR = 2.9; 95% CI: 1.0-8.8), or had changed sexual partners (OR = 2.9; 95% CI: 0.9-9.3) during the follow-up period showed a higher risk of new HPV infection than women who had remained virgins since baseline. The rate of new infection also tended to be higher in those who started, or continued smoking during the follow-up period, than in nonsmokers. Clearance of HPV infections since baseline examination was 80.6% (95% CI: 67.6-93.5), and did not differ between high-risk and low-risk HPV types or between single- and multiple-type infections. Conclusion: This study shows that the acquisition of new HPV infection among young women in the Republic of Korea is high and also the clearance is frequent. Self-collection of cervicovaginal cells is applicable to follow-up studies that include virgins. [ABSTRACT FROM AUTHOR]

A cohort was established for evaluation of cancer risk factors in Sancheong-gun, Gyeongsangnam-do, Korea. As one of the cohort studies, stools of 947 residents (403 males and 544 females, age range: 29-86 years) were screened for Clonorchis sinensis eggs using both Kato-Katz method and formalin-ether sedimentation technique. The overall egg positive rate of C. sinensis was 37.7% and individual EPG (eggs per gram of feces) counts ranged from 24 to 28,800. Eight egg positive residents voluntarily joined a process of collection of the passed worms after praziquantel treatment. A total of 158 worms were recovered from 5 of the 8 treated persons, ranged from 3 to 108 in each individual. The worms were 15-20 mm x 2-3 mm in size, and showed brown-pigmented, red, or white body colors. This is the first collection record of C. sinensis adult worms from humans through anthelmintic treatment and purgation. The adult worms of C. sinensis may be paralyzed by praziquantel and then discharged passively through bile flow in the bile duct and by peristaltic movement of the bowel. [ABSTRACT FROM AUTHOR]

Cervical cancer in South Korea Since 1980, Korea has had a national tracking system for major cancers, which includes site-specific and regional tracking. The database for national cancer incidence is estimated to be 95% complete. Cervical cancer is the fourth most common cancer in Korean women. With an AAR of 15.5 in 2001, it is less common than cancers of the stomach, breast, and colon/rectum. Between 1993 and 2001, the curves for age-specific incidence of uterine cancer fell, with this trend most marked among women 50-70 years of age (Figure 5). Almost 40% of malignant cervical cases are being detected in situ, before they become invasive. For women diagnosed with cervical cancer during the period 1995-2001, 6.6% died within 12 months. Almost 80% survived for at least 5 year There are local variations in the incidence and mortality of cervical cancer. Morphologically, the majority of tumours (~ 80%) are of squamous cell origin; however, during the 10 years from 1993, there was a growing proportion of adenocarcinomas (6.9% in 1993; 10.4% in 2001). The 5-year survival rate for adenocarcinomas (74.3%) is less than that for SCC (81.4%). Epidemiology and risk factors Key factors associated with a lower risk of cervical cancer in Korean women are [120] (i) no family history, (ii) no/few children, (iii) marriage, (iv) late first sex, (v) circumcision. In a review of HPV types in Busan for the IARC HPV International Prevalence Survey, the seropositivity of antibodies to HR-HPV (types 16, 18, 31, 33, and 58) was 19.8% among sexually active women 20-74 years of age. The most common types were HPV 70, HPV 33, and HPV 16 [121]. All seven women with HSIL lesions on cytology tested positive for HR-HPV. Busan HPV prevalence study in young women This trial was undertaken by the Korea National Cancer Center with the Unit of Field and Intervention Studies in the International Agency for Research on Cancer, in 2002, to determine at what age women become sexually active, exposed to HPV-DNA, and then seropositive for HPV 16 and HPV 18. It also provided an opportunity to assess willingness to participate in future HPV vaccine trials. Students 16-26 years of age attended a health education class and were asked to complete a survey. They provided a blood sample and either a vaginal (self-collected) or penile (physician-collected) swab. Among 672 females, 15.2% tested positive to HPV, 9.4% of whom tested positive to a high-risk type. Among this latter group, there was a high frequency of infection with multiple strains. Among males 8.7% tested positive for HPV [122]. The risk for infection clearly rose with the number of lifetime sexual partners. Among this group of 1100 university students, 64% of men and 58% of women said they would be willing to participate in a trial for HPV vaccines. Cervical cancer screening in Korea Since 1988, medical insurance beneficiaries have received a Pap smear for cervical cancer check as part of their general health checkup. In 1999, the National Screening Program began covering Medicaid patients' screens for stomach, breast, and cervical cancers. Since this time, coverage has been expanded and about 50% of insured patients are currently included. The current recommendation is that all women > 30 years of age should have a Pap smear every 2 years. Participation in cervical screening in 2002 was 15.6% and 10.8% in 2003. Incorporation of HPV testing into the screening process may improve sensitivity and allow the screening interval for many women to be extended. [ABSTRACT FROM AUTHOR]