Role of Screening History in Clinical Meaning and Optimal Management of Positive Cervical Screening Results

BACKGROUND

Cervical cancer is caused by persistent human papillomavirus (HPV) infection. US consensus management guidelines for a positive cervical screening result typically focus on the current screening result only. A negative testing history may alter risk of the following positive screening results, caused by a new HPV infection, and therefore its optimal management.

METHODS

Women ages 30 years and older were screened with triennial HPV and cytology co-testing at Kaiser Permanente Northern California from 2003 to 2014. We estimated the subsequent 5-year risks of cervical intraepithelial neoplasia grade 3 or more severe diagnoses (CIN3+) in a cohort of 1 156 387 women following abnormal (atypical squamous cells of undetermined significance [ASC-US] or worse) cytology and/or positive HPV testing, when the test result followed 0 (n = 990 013), 1 (n = 543 986), 2 (n = 245 974), or 3 (n = 79 946) consecutive negative co-test(s). All statistical tests were two-sided.

RESULTS

Following 0-3 successive negative co-tests, 5-year CIN3+ risks following a positive HPV test decreased progressively from 7.2% (95% CI = 7.0% to 7.4%) to 1.5% (95% CI = 0.7% to 3.4%) (Ptrend < .001). Similarly, risks following an abnormal (ASC-US or worse) cytology result decreased from 6.6% (95% CI = 6.4% to 6.9%) to 1.1% (95% CI = 0.5% to 2.3%) (Ptrend < .001). Risks following low-grade squamous intraepithelial lesion, the risk threshold for referral to colposcopy in the United States, decreased from 5.2% (95% CI = 4.7% to 5.7%) to 0.9% (95% CI = 0.2% to 4.3%). Risks following high-grade squamous intraepithelial lesion or more severe, a specific marker for the presence of precancerous lesions, decreased from 50.0% (95% CI = 47.5% to 52.5%) to 10.0% (95% CI = 2.6% to 34.4%).

CONCLUSIONS

Following one or more sequential antecedent, documented negative co-tests or HPV tests, women with HPV-positive ASC-US or low-grade squamous intraepithelial lesion might have sufficiently low CIN3+ risk that they do not need colposcopy referral and might instead undergo 6-12-month surveillance for evidence of higher risk before being referred to colposcopy.

Impact of human papillomavirus vaccination on the clinical meaning of cervical screening results

Women previously vaccinated against human papillomavirus (HPV) type 16 and 18 are now reaching the age (21 years) at which cervical-cancer screening is recommended in the U.S. The impact of HPV vaccination on risks of cervical precancer following a positive and negative screen among women aged 21-24 years who just started routine cervical screening are not well described. Therefore, three-year absolute and relative (RR) cumulative risks of cervical intraepithelial neoplasia grade 2 or more severe diagnoses (≥CIN2) and grade 3 or more severe diagnoses (≥CIN3) were estimated for women undergoing cervical screening at Kaiser Permanente Northern California. Risks were estimated in women aged 21-24 years (n = 75,008) undergoing cervical screening since late 2006, 6 months after HPV vaccination became available; women were categorized vaccinated at ages <18, 18-20, and 21-24 years and compared to those who were unvaccinated. Three-year risks were estimated for normal, low-grade, and high-grade cytology results. Three-year risks of ≥CIN2 and ≥CIN3 for unvaccinated women following low-grade cytology were 10.89% for and 3.70%, respectively. By comparison, Three-year risks of ≥CIN2 and ≥CIN3 were 5.26% (RR = 0.48, 95%CI = 0.24-0.99) and 0.99% (RR = 0.27, 95%CI = 0.06-1.13), respectively, for women vaccinated under the age of 18 years. Three-year ≥CIN2 and ≥CIN3 risks were lower for those HPV vaccinated at younger age for any screening result (p_trend ≤ 0.01 for all comparisons). These data support initiating cervical screening at an older age or changing the management of a low-grade cytology result in women aged 21-24 years who were vaccinated against HPV younger than age of 18 years.

Clinical validation of the PCR-reverse dot blot human papillomavirus genotyping test in cervical lesions from Chinese women in the Fujian province: a hospital-based population study

Objective

To determine the clinical significance of the polymerase chain reaction (PCR)-reverse dot blot (RDB) human papillomavirus (HPV) genotyping assay in cervical cancer screening.

Methods

A total of 10,442 women attending the Fujian Provincial Maternity and Children's Health Hospital were evaluated using the liquid-based cytology (thinprep cytologic test [TCT]) and the PCR-RDB HPV test. Women with HPV infection and/or abnormal cytology were referred for colposcopy and biopsy. For HPV DNA sequencing, 120 specimens were randomly selected. Pathological diagnosis was used as the gold standard.

Results

Using the PCR-RDB HPV test, overall HPV prevalence was 20.57% (2,148/10,442) and that of high-risk (HR)-HPV infection was 18.68% (1,951/10,442). There was 99.2% concordance between HPV PCR-RDB testing and sequencing. In this studied population, the most common HR-HPV types were HPV-16, -52, -58, -18, -53, -33, and -51, rank from high to low. HPV-16, -18, -58, -59, and -33 were the top 5 prevalent genotypes in cervical cancer but HPV-16, -18, -59, -45, and -33 were the top 5 highest risk factors for cancer (odds ratio [OR]=34.964, 7.278, 6.728, 6.101, and 3.658; all p<0.05, respectively). Among 10,442 cases, 1,278 had abnormal cytology results, of which, the HR-HPV positivity rate was 83.02% (1,061/1,278). To screen for cervical cancer by PCR-RDB HPV testing, when using CIN2+, CIN3+, and cancer as observed endpoints, the sensitivity was 90.43%, 92.61%, and 94.78% and the negative predictive value (NPV) was 99.06%, 99.42%, and 99.78%, respectively. PCR-RDB HPV and TCT co-testing achieved the highest sensitivity and NPV.

Conclusion

For cervical cancer screening, the PCR-RDB HPV test can provide a reliable and sensitive clinical reference.

Evolution of cervical cancer screening and prevention in United States and Canada: implications for public health practitioners and clinicians

OBJECTIVE

Declines in cervical cancer incidence and mortality in Canada and in the United States have been widely attributed to the introduction of the Papanicolaou (Pap) test. This article reviews changes in screening and introduction of HPV vaccination.

METHOD

Sentinel events in cervical cancer screening and primary prevention through HPV vaccination in the US and Canada are described.

RESULTS

Despite commonalities, cervical cancer screening and prevention differ between the two countries. Canada has a combination of opportunistic and organized programs at the provincial and territorial level, while the US has opportunistic screening and vaccination systems. In the US, the HPV test along with the Pap test (co-testing) is part of national recommendations for routine cervical cancer screening for women age 30 and older. Co-testing is not being considered anywhere in Canada, but primary HPV testing is currently recommended (but not implemented) in one province in Canada.

CONCLUSION

Many prevention strategies are available for cervical cancer. Continued public health efforts should focus on increasing vaccine coverage in the target age groups and cervical cancer screening for women at appropriate intervals. Ongoing evaluation will be needed to ensure appropriate use of health resources, as vaccinated women become eligible for screening.

Physicians' intentions to change pap smear frequency following human papillomavirus vaccination

STUDY OBJECTIVE

We evaluated factors associated with physicians' intentions to perform Pap smears in human papillomavirus-vaccinated women.

DESIGN

Physicians were mailed a survey asking about intentions to change cervical cancer screening based on patients' human papillomavirus vaccination status.

PARTICIPANTS

A national sample of 1,738 Family Physicians, Internal Medicine Physicians, Pediatricians, and Obstetricians and Gynecologists was selected from the American Medical Association Physician Masterfile. Completed surveys were received from 1,118 physicians, of which 791 were included in the analyses.

MAIN OUTCOME MEASURES

Bivariate analyses compared physician, practice, and patient characteristics by intention change screening frequency. Significant variables were included in a multivariable logistic regression model.

RESULTS

Overall, 81.8% (n = 647) of physicians reported not planning to change Pap smear frequency for vaccinated women. Internal Medicine physicians were significantly more likely than Obstetrician/Gynecologists to report intentions to change frequency for vaccinated patients. Other factors significantly associated with the intention to change frequency were self-identification as a late adopter of new vaccines, a solo practice, and practicing primarily in a clinic or hospital-based setting.

CONCLUSIONS

Although it appears most clinicians understand that human papillomavirus vaccination should not alter current screening practices, there is a need to develop and evaluate interventions for physicians who are likely to change their screening pattern based on human papillomavirus vaccination receipt.

US physicians' intentions regarding impact of human papillomavirus vaccine on cervical cancer screening

BACKGROUND

US cervical cancer screening recommendations have not changed since the human papillomavirus (HPV) vaccine introduction in 2006, but epidemiological and cost-effectiveness studies indicate that recommendations will need to change for fully vaccinated women. We evaluated physician intentions regarding HPV vaccine's impact on future screening.

METHODS

A nationally representative sample of 1212 primary care physicians was surveyed in 2006-2007 (response rate: 67.5%). Our study included 1114 physicians who provided Pap testing. Questions covered Pap test screening practices and intentions regarding HPV vaccine's impact on screening. Distribution differences were assessed using chi(2) statistics; multivariate analyses were performed.

RESULTS

Overall, 40.7% (95% confidence interval (CI): 37.6-43.8%) of physicians agreed that the HPV vaccine will affect screening initiation, and 38.2% (35.0-41.5%) agreed that vaccination will affect screening frequency. Significant differences in responses were found by specialty; internists were more likely to agree that vaccination would impact screening than other specialties. Belief in the effectiveness of new screening technologies was associated with intention to change screening initiation (odds ratio (OR) = 1.66 (1.20-2.31)) and frequency (OR = 1.99 (1.40-2.83)). Adherence to current Pap test screening interval guidelines was associated with intention to change screening frequency (OR = 1.39 (1.01-1.91)).

CONCLUSIONS

Many providers anticipate adjusting screening for vaccinated women, but a significant group believes nothing will change or are unsure. The present study provides important baseline data on intentions in the period preceding widespread vaccine diffusion and may help explain current and future trends in practice patterns.

Current prophylactic HPV vaccines and gynecologic premalignancies

PURPOSE OF REVIEW

Studies of the human papillomavirus (HPV) vaccines, Cervarix and Gardasil provide strong evidence for the recommendation that HPV vaccines may minimize the incidence of cervical cancer over time.

RECENT FINDINGS

Both Cervarix and Gardasil provided more than 90% efficacy in preventing cervical intraepithelial neoplasia grade 2+ (CIN 2+) disease caused by HPV 16 and 18 in women 16-26 years who were seronegative and PCR-negative for HPV 16 and 18 at baseline. Cervarix provides more than 75% efficacy in independent cross-protection against persistent HPV 31 and 45, and 47% efficacy against HPV 33; whereas Gardasil offers 50% efficacy only against persistent HPV 31. A reduction in excisional therapies for CIN 2+ is nearly 70% for Cervarix, and 40% for Gardasil. Cervarix efficacy is documented to 6.4 years; Gardasil's to 5 years. Immunologically, Cervarix induces three to nine-fold higher peak-neutralizing antibody titers to HPV 16/18 than Gardasil, has significantly higher cervicovaginal mucus-neutralizing antibody presence than Gardasil, and significantly higher B memory cell response than Gardasil. Safety reports indicate injection site reactions for both Cervarix and Gardasil. Rare serious adverse events have been reported.

Impact of improved classification on the association of human papillomavirus with cervical precancer

Misclassification of exposure and surrogate endpoints of disease can obscure causal relations. Using data from the Atypical Squamous Cells of Undetermined Significance/Low-Grade Squamous Intraepithelial Lesion Triage Study (ALTS, 1997-2001), the authors explored the impact of exposure (human papillomavirus (HPV) detection) and endpoint (histologic cervical precancer) classification on their mutual association. Women referred into this study with an atypical squamous cells of undetermined significance Papanicolaou test with satisfactory results for all 4 HPV tests were included in this analysis (n = 3,215; 92.2%). HPV testing results were related to different definitions of cervical precancer, based on paired, worst 2-year histologic diagnoses, by calculating clinical sensitivity, specificity, and odds ratios. The authors found that HPV test sensitivity increased and specificity decreased with increasing certainty of cervical precancer, with HPV testing having the highest sensitivity (92%-98%) and lowest specificity (46%-54%) for consensus cervical intraepithelial neoplasia grade 3 (CIN 3). The overall accuracy of each HPV test, as measured by odds ratios, was greatest for consensus CIN-3 diagnoses, from 2- to 4-fold greater than for a less stringent precancer definition of any diagnosis of CIN 2 or more severe. In summary, there was convergence of greater certainty of carcinogenic HPV with greater certainty of a precancerous diagnosis, such that all 4 HPV tests almost always tested positive in women most likely to have cervical precancer. Finding increasingly strong associations when both test and diagnostic misclassification are reduced is a useful sign of "true association" in molecular epidemiology.

Pap testing and sexual activity among young women in the United States

OBJECTIVE

To understand whether and how recency of sexual activity is associated with Pap testing rates among young women.

METHODS

We analyzed data on self-reported receipt of Pap testing and initiation of sexual activity among young women and girls aged 15 to 24 years using the 2002 National Survey of Family Growth, an in-person, population-based survey of reproductive-aged men and women in the United States. The primary outcome was receiving a Pap test and its relationship to initiation of sexual activity. A multivariable model was used to predict the probability of having had a Pap test in the previous 12 months.

RESULTS

Thirty-three percent of the 2,513 women had never had sex. Of these, 13.9% had had a Pap test in the previous year. Sixty-seven percent of sexually-active women aged 15-24 reported receiving a Pap test (corresponding to 13.1 million tests). Approximately 59% women aged 15-20 years old who reported having initiated sexual activity in the previous 3 years also reported a Pap test in the previous year.

CONCLUSION

The current guidelines recommend screening 3 years after initiation of vaginal intercourse or at age 21, whichever is earlier. Contrary to the current guidelines, many young women who have not had sex or who initiated sex within the previous 3 years reported having had a Pap test. Assuming that the patterns observed in this study persist, there is an urgent need for education regarding the need to adhere to guidelines to reduce the burden of potentially unnecessary Pap tests in young women.

LEVEL OF EVIDENCE

III.

Uptake in cancer screening programmes

For cancer screening programmes to bring about reductions in mortality, a substantial proportion of the population must participate. Programmes with low uptake can be ineffective and can promote inequalities in health-service provision. Strategies to promote uptake are multifaceted, reflecting differences in the cancers targeted, invitees, health-service contexts, and the tests themselves. Accordingly, there is no universal approach. Strategies should accommodate the many factors that can influence uptake and should incorporate the need to promote informed choice. Screening has the potential to cause harm, and there is an ethical imperative to seek out strategies that provide balanced information on cancer screening. Further research is needed to assess newer approaches to promoting uptake, such as IT-based programmes, and to identify strategies that are balanced, self-sustaining, and affordable.

Age-appropriate use of human papillomavirus vaccines in the U.S

Cervical infections by approximately 15 cancer-associated (carcinogenic) human papillomavirus (HPV) genotypes cause virtually all cervical cancer and its immediate precursor lesions worldwide. Prophylactic vaccines against human papillomavirus (HPV) types HPV16 and HP18, which cause 70% of cervical cancer worldwide, hold great promise for reducing the burden of cervical cancer worldwide. However, current HPV vaccines prevent future infections and related cervical abnormalities and do not treat pre-existing HPV infections. In the U.S., HPV vaccine introduction should be considered in the context of a very successful cervical cancer screening program that has reduced the rates of cervical cancer by 75% or more. Thus, HPV vaccines will only prevent an incremental number of additional cervical cancers in the U.S. The introduction of HPV vaccines can also prevent other HPV-related sequelae, most importantly cervical intraepithelial neoplasia grade 2 or 3 (CIN2/3), which precede the development of cervical cancer and require clinical follow-up and treatment. Examining data from 7 clinical centers in the U.S., the median age of CIN2/3 is typically between 25 and 30 years of age in 2007; if screen-detected CIN2/3 develops on average 5-10 years after the causal infection is acquired, HPV vaccination will only prevent a significant proportion of CIN2/3 if it is given to women before the age of 26 and more so if given to women 18 and younger. It is increasingly evident that prophylactic HPV vaccines will provide the greatest public health or population benefit only when delivered to adolescent, mostly HPV-naive women.

Preventing cervical cancer : overviews of the National Breast and Cervical Cancer Early Detection Program and 2 US immunization programs

Three federal programs with the potential to reduce cervical cancer incidence, morbidity, and mortality, especially among underserved populations, are administered by the Centers for Disease Control and Prevention (CDC): the National Breast and Cervical Cancer Early Detection Program (NBCCEDP), the Vaccines for Children (VFC) Program, and the Section 317 immunization grant program. The NBCCEDP provides breast and cervical cancer screening and diagnostic services to uninsured and underinsured women. The VFC program and the Section 317 immunization grant program provide vaccines, including human papillomavirus (HPV) vaccine, to targeted populations at no cost for these vaccines. This article describes the programs, their histories, populations served, services offered, and roles in preventing cervical cancer through HPV vaccination and cervical cancer screening. Potential long-term reduction in healthcare costs resulting from HPV vaccination is also discussed. As an example of an initiative to vaccinate uninsured women aged 19-26 years through a cancer services program, a state-based effort that was recently launched in New York, is highlighted.

Cancer registries and monitoring the impact of prophylactic human papillomavirus vaccines: the potential role

The recent US Food and Drug Administration licensure of a prophylactic vaccine against oncogenic human papillomavirus (HPV) types 16 and 18, the first of its kind, poses unique challenges in postmarketing vaccine surveillance, especially in measuring vaccine effectiveness against biologic endpoints of HPV infection. Historically, the national system of population-based cancer registries in the US has provided high-quality data on cancer incidence and mortality for the most important biologic endpoints, namely, anogenital cancers and some oral cavity/oropharyngeal cancers. There also has been some data collection on cancer precursors; however, this activity has been inconsistent and of lower priority. Because effectiveness against HPV-associated cancers will not be measurable for several decades, strengthening and possibly expanding the capacity of registries to collect precancer data, which are earlier manifestations of infection, must be considered. Collecting type-specific data on HPV-associated precancers and cancers. While keeping in mind the current limitations of registry operations, they discuss resources that may be needed to implement and sustain these types of activities.