Can an appointment-letter intervention increase pap smear screening in Samliem, Khon Kaen, Thailand?

Our objective was to assess the efficiency of an appointment-letter intervention aimed to increase uptake of cervical cancer screening in women between 35 and 65 years of age. From January, 2007, we randomly recruited 320 women, not screened for at least 5 years, from the Samliem inner-city community, Khon Kaen, Northeast Thailand. A total of 150 women 35, 40, 45, 50, 55, 60 and 65 years of age were assigned to the intervention group according to Thai National Cancer Institute's ( TNCI) strategy. A further 170 women between 36-39, 41-44, 46-49, 51-54, 56-59 and 61-64 years of age were assigned to the control group. Baseline interviews were conducted for all women in both groups by one of the researchers in January, who also provided culturally-sensitive health education emphasizing the need for screening. Then appointment letters were sent only to women in the intervention group in February, with the last date for an appointment being March 31st. In April of 2007, immediately post-intervention, screening-coverage interviews were performed in both groups for comparison. There was a significant increase in the Pap smear screening-coverage rate in the intervention group compared with the control group (44.67% vs. 25.88%, p=0.001). Therefore, the appointment-letter intervention produced a significant effect on increasing Pap smear coverage in this group of women.

Evaluation of primers and PCR performance on HPV DNA screening in normal and low grade abnormal cervical cells.

High risk human papillomaviruses (HR-HPVs) are associated with increased risk of normal cervical cells developing to dysplasia and cervical carcinoma. Therefore, HR-HPV DNA testing can predict an endpoint of cervical carcinogenesis that is earlier than the development of cervical abnormalities. Not only the sensitivity of methods but also the amount of HPV DNA are very important and might be parameters to distinguish HPV detection. In this study, we evaluated the effects of primer sets and the polymerase chain reaction (PCR) performance with low viral load samples with normal cervical cytology (140 samples) and mild dysplasia (140 samples) using two consensus primers MY09/MY11 and GP5+/6+. The PCR was performed with single and nested PCR. Positive samples with both primer sets were then HPV genotyped by dot blot hybridization. Results showed higher sensitivity of single PCR using primer GP5+/GP6+ than primer MY09/MY11. HPV DNA was detected in 15% (21 of 140)and 20.7% (29 of 140) of normal cervical samples, respectively. For mild dysplasia samples, HPV DNA was detected in 37.1% (52 of 140) with MY09/MY11 and 50% (70 of 140) using GP5+/GP6+. In normal cervical samples, the positivity rate was increased to 38.5% (54 of 140) by nested PCR using primer GP5+/6+, but only 2 mild dysplasia samples that were negative by single GP5+/6+ were positive by auto-nested PCR. These results suggested that, in low viral load samples, the sensitivity of HPV DNA detection depends not only on primer sets but also PCR performance. HPV 16 was the most common in mild dysplasia samples (20.8%), whereas HPV type 58 was found in 11.1%. This study suggested that nested PCR might be necessary for HPV DNA detection in cervical samples of women participating in cervical cancer screening.

Pap smear, colposcopy and biopsy findings at follow-up of Pap smear positive women in North-east Thailand.

As part of an ongoing project involving a large cohort in the Khon Kaen Province in the North-east of Thailand, a total of 236 women who had tested positive for a Pap smear at the initial recruitment and advised to seek medical attention were followed up after a mean period of 3.1 years. The 204 individuals who could be contacted were interviewed to determine treatments received and underwent a further Pap smear as well as colposcopy in 179 of the cases. On clinical advice, biopsies were also taken from 32 of these. Only 15% of the total of 204 had actually received therapy, the majority undergoing surgery (self-reported). Possible positive Pap smear results were obtained for 23.5%, with 6.4% having high grade squamous intraepithelial lesions (HGSILs) or squamous cell carcinoma (SCC) (one case). Comparison of the different testing modalities demonstrated 5.6% false negatives and 16.2 false positives for the Pap smear with colposcopy as the gold standard. Compared with biopsy findings, there were 21.8% and 40.6% false positives with Pap and colposcopy, respectively, but no false negatives. The present results point to good efficacy for the initial screening, since only 0.5% of the total population developed an SCC. However, judgement as to therapy should depend on a biopsy since there were considerable false positives with the other two modalities employed.

Risk factors and histological outcome of abnormal cervix with human papilloma infection in northeastern Thai-women.

This study aimed to investigate the histological outcome of cervix with human papillomavirus (HPV) infection and the association of risk factors with cervical intraepithelial neoplasia (CIN) and invasive cervical carcinoma (ICC) development in Northeast Thai women. The study population (n=210) comprised 71 cases of normal cervix, 71 cases of CIN and 68 cases of ICC. The histological outcome of HPV infection was determined for 9.5% of the study population. Increased risk factors for CIN were observed for more than one partner (odds ratio (OR)=3.75, p<0.05), history of sexually transmitted disease (STD) (OR=2.28, p<0.05), menarche under 14 years of age (OR=0.31, p<0.05) and partners' smoking history (OR=3.98, p<0.01). Increased risk for ICC was observed for those with a history of STDs (OR=0.14, p<0.01) and multiparity (OR=2.53, p<0.01). Age at first sexual intercourse was not a risk factor in this study population. Further studies with HPV-DNA tests should more precisely quantify the risks.

Selected risk factors, human papillomavirus infection and the p53 codon 72 polymorphism in patients with squamous intraepithelial lesions in northeastern Thailand.

Risk factors for cervical squamous intraepithelial lesions (SIL) including human papillomavirus (HPV) infection and the p53 codon 72 polymorphism were investigated in a case-control study with 103 cases and 105 controls in Northeastern Thailand. Increased risk for SIL was observed for age at menarche (odds ratio (OR) = 2.2; p< 0.005), age at the first sexual intercourse (OR=2.4; p< 0.05), number of sexual partners (OR=2.7; p< 0.005) and partners' smoking history (OR=2.3-3.2; p< 0.01). Prevalence of malignant type of HPV infection in the control and SIL groups was 18.1% and 60.2%, respectively. HPV infection significantly increased risk for SIL 6.8-fold (p< 0.001). HPV-16 infection was the commonest (31 out of 62 carriers) in SIL patients and highly associated with risk. The p53 codon 72 polymorphism was not identified as a genetic risk for SIL in this study, as demonstrated in Thai cervical cancer. Therefore, to prevent cervical neoplasia or HPV infection, inclusion of knowledge on sexual behavior and effects of smoking into public health programs is important and, at the same time, a nation-wide screening scheme for cervical abnormalities including HPV-typing is a high priority in Thailand.

Chromosome 3p alterations in northeastern Thai women with cervical carcinoma.

The purpose of this study was to determine the incidence of the loss of heterozygosity (LOH) among normal cervixes, cervical intraepithelial neoplasias (CINs) and invasive cervical cancers (ICCs). DNA samples (136) were obtained from 31 normal cervixes, 49 CINs and 56 ICCs. Four polymorphic microsatellite markers (D3S1300, D3S1351, D3S1478 and D3S4103) covering the chromosome 3p arm, were employed. LOH at one or more loci were identified in: 9/31 (8.1%) normal cervixes, 17/49 (14.6%) CINs and 26/56 (22.1%) invasive cancers. The incidence of the LOH at 3p varied for each locus and ranged from 5.6% for D3S1351 to the highest rate of 16.6% for D3S1300. We thus found that LOH of chromosome 3p can occur in normal cervixes and that incidences increase in CINs and ICCs. Deletion in the 3p14.2 (D3S1300) and 3p21.2 (D3S1478) regions might be an early event and, in fact, necessary for cervical cancer progression. The loss of function of tumor suppressor genes (TSGs) located in these regions may have a sequential effect in cervical cancer carcinogenesis.

Co-risk factors for HPV infection in Northeastern Thai women with cervical carcinoma.

HPV infection is the main cause of cervical cancer; however, factors that promote and maintain HPV infection are still unclear. This study was designed to search for factors responsible for the HPV infection in Northeastern Thai women. A total of 190 volunteers with a normal histopathologic appearance of cervix as controls (n=100) and with squamous cell cervical carcinoma (SCCA) (n=90) were the subjects. Variables of risk factors including sexual behaviors, history of reproduction, history of sexually transmitted diseases and smoking were conducted with self-report and direct interview. Number of sexual partners and smoking history increased the likelihood of high-risk HPV infection. Multiple sexual partners showed significantly higher 3.94-fold risk for HPV infection (95% CI = 1.82-8.82, p-value<0.001). Smoking history of partner increased the risk for HPV infection 3.03-fold (95%CI=1.42-6.58, p-value< 0.002). After OR were adjusted, significant difference was still observed in the number of sexual partners (p-value <0.0001) and smoking history of the partner (p-value<0.005). To decrease the incidence of cervical cancer, we should prevent HPV dissemination and be on the alert for having multiple sexual partners and a partner's smoking habit, which must be included in our public health planning.