Philip E. Castle

American Cancer Society, American Society for Colposcopy and Cervical Pathology, and American Society for Clinical Pathology screening guidelines for the prevention and early detection of cervical cancer

An update to the American Cancer Society (ACS) guideline regarding screening for the early detection of cervical precancerous lesions and cancer is presented. The guidelines are based on a systematic evidence review, contributions from 6 working groups, and a recent symposium cosponsored by the ACS, the American Society for Colposcopy and Cervical Pathology, and the American Society for Clinical Pathology, which was attended by 25 organizations. The new screening recommendations address age‐appropriate screening strategies, including the use of cytology and high‐risk human papillomavirus (HPV) testing, follow‐up (eg, the management of screen positives and screening intervals for screen negatives) of women after screening, the age at which to exit screening, future considerations regarding HPV testing alone as a primary screening approach, and screening strategies for women vaccinated against HPV16 and HPV18 infections. CA Cancer J Clin 2012.

American Cancer Society, American Society for Colposcopy and Cervical Pathology, and American Society for Clinical Pathology screening guidelines for the prevention and early detection of cervical cancer.

An update to the American Cancer Society (ACS) guideline regarding screening for the early detection of cervical precancerous lesions and cancer is presented. The guidelines are based on a systematic evidence review, contributions from 6 working groups, and a recent symposium cosponsored by the ACS, the American Society for Colposcopy and Cervical Pathology, and the American Society for Clinical Pathology, which was attended by 25 organizations. The new screening recommendations address age-appropriate screening strategies, including the use of cytology and high-risk human papillomavirus (HPV) testing, follow-up (eg, the management of screen positives and screening intervals for screen negatives) of women after screening, the age at which to exit screening, future considerations regarding HPV testing alone as a primary screening approach, and screening strategies for women vaccinated against HPV16 and HPV18 infections.

Human Papillomavirus Testing in the Prevention of Cervical Cancer

Strong evidence now supports the adoption of cervical cancer prevention strategies that explicitly focus on persistent infection with the causal agent, human papillomavirus (HPV). To inform an evidence-based transition to a new public health approach for cervical cancer screening, we summarize the natural history and cervical carcinogenicity of HPV and discuss the promise and uncertainties of currently available screening methods. New HPV infections acquired at any age are virtually always benign, but persistent infections with one of approximately 12 carcinogenic HPV types explain virtually all cases of cervical cancer. In the absence of an overtly persistent HPV infection, the risk of cervical cancer is extremely low. Thus, HPV test results predict the risk of cervical cancer and its precursors (cervical intraepithelial neoplasia grade 3) better and longer than cytological or colposcopic abnormalities, which are signs of HPV infection. The logical and inevitable move to HPV-based cervical cancer prevention strategies will require longer screening intervals that will disrupt current gynecologic and cytology laboratory practices built on frequent screening. A major challenge will be implementing programs that do not overtreat HPV-positive women who do not have obvious long-term persistence of HPV or treatable lesions at the time of initial evaluation. The greatest potential for reduction in cervical cancer rates from HPV screening is in low-resource regions that can implement infrequent rounds of low-cost HPV testing and treatment.

Guidelines for human papillomavirus DNA test requirements for primary cervical cancer screening in women 30 years and older

Given the strong etiologic link between high‐risk HPV infection and cervical cancer high‐risk HPV testing is now being considered as an alternative for cytology‐based cervical cancer screening. Many test systems have been developed that can detect the broad spectrum of hrHPV types in one assay. However, for screening purposes the detection of high‐risk HPV is not inherently useful unless it is informative for the presence of high‐grade cervical intraepithelial neoplasia (CIN 2/3) or cancer. Candidate high‐risk HPV tests to be used for screening should reach an optimal balance between clinical sensitivity and specificity for detection of high‐grade CIN and cervical cancer to minimize redundant or excessive follow‐up procedures for high‐risk HPV positive women without cervical lesions. Data from various large screening studies have shown that high‐risk HPV testing by hybrid capture 2 and GP5+/6+‐PCR yields considerably better results in the detection of CIN 2/3 than cytology. The data from these studies can be used to guide the translation of high‐risk HPV testing into clinical practice by setting standards of test performance and characteristics. On the basis of these data we have developed guidelines for high‐risk HPV test requirements for primary cervical screening and validation guidelines for candidate HPV assays.

Cervical cancer risk for women undergoing concurrent testing for human papillomavirus and cervical cytology: a population-based study in routine clinical practice

BACKGROUND Concurrent testing for human papillomavirus (HPV) and cervical cytology (co-testing) is an approved alternative to cytology alone in women aged 30 years and older. We aimed to assess the safety in routine clinical practice of 3-year screening intervals for women testing negative for HPV with normal cytology and to assess if co-testing can identify women at high risk of cervical cancer or cervical intraepithelial neoplasia grade 3 (CIN3) or worse over 5 years. METHODS We assessed the 5-year cumulative incidence, starting in 2003-05, of cervical cancer and CIN3 or worse for 331,818 women aged 30 years and older who enrolled in co-testing at Kaiser Permanente Northern California (Berkeley, CA, USA) and had adequate enrolment co-test results. Follow-up continued until Dec 31, 2009. We defined cumulative incidence to include prevalence at enrolment and incidence after enrolment. Prevalence at enrolment was defined as the ratio of women diagnosed with each outcome on the biopsy visit immediately after their enrolment screening visit to the total enrolled women. At screening visits only HPV test and Pap smear samples were collected, and at biopsy visits colposcopically directed biopsies were taken. To estimate post-enrolment incidence, we used Weibull survival models. FINDINGS In 315,061 women negative by HPV testing, the 5-year cumulative incidence of cancer was 3.8 per 100,000 women per year, slightly higher than for the 306,969 who were both negative by HPV and Pap testing (3.2 per 100,000), and half the cancer risk of the 319,177 who were negative by Pap testing (7.5 per 100,000). 313,465 (99.5%) women negative by HPV testing had either normal cytology or equivocal abnormalities. Abnormal cytology greatly increased cumulative incidence of CIN3 or worse over 5 years for the 16,757 positive by HPV testing (12.1%vs 5.9%; p<0.0001). By contrast, although statistically significant, abnormal cytology did not increase 5-year risk of CIN3 or worse for women negative by HPV testing to a substantial level (0.86%vs 0.16%; p=0.004). 12,208 (73%) of the women positive by HPV testing had no cytological abnormality, and these women had 258 (35%) of 747 CIN3 or adenocarcinoma in situ, [corrected] 25 (29%) of 87 cancers, and 17 (63%) of 27 adenocarcinomas. INTERPRETATION For women aged 30 years and older in routine clinical practice who are negative by co-testing (both HPV and cytology), 3-year screening intervals were safe because a single negative test for HPV was sufficient to reassure against cervical cancer over 5 years. Incorporating HPV testing with cytology also resulted in earlier identification of women at high risk of cervical cancer, especially adenocarcinoma. Testing for HPV without adjunctive cytology might be sufficiently sensitive for primary screening for cervical cancer. FUNDING Intramural Research Program of the US National Cancer Institute/NIH/DHHS, and the American Cancer Society.

Epidemiologic Profile of Type-Specific Human Papillomavirus Infection and Cervical Neoplasia in Guanacaste, Costa Rica

BACKGROUND Detailed epidemiologic studies of cervical type-specific human papillomavirus (HPV) infection in large populations are scarce. METHODS We recruited a population-based cohort in Guanacaste, Costa Rica. Participants were interviewed, screened for cervical neoplasia, and tested for >40 HPV types by use of MY09/11 L1 consensus primer polymerase chain reaction. We estimated the risk factors for infection and the associations between type-specific HPV infections and cervical intraepithelial neoplasia (CIN) and cancer in 8514 sexually active women who had not undergone a hysterectomy. RESULTS The overall HPV prevalence was 26.5%. The most common type was HPV-16 (3.6% of the population). HPV prevalence showed a U-shaped age-specific curve. Sexual behaviors were the main determinants of oncogenic and nononcogenic infections; age at first sexual intercourse was not independently associated with infection. Barrier contraceptive use was somewhat protective against infection. Oncogenic infections were strongly associated with risk of all grades of CIN and of cancer. Types 16, 18, and 58 were the most common in women diagnosed with CIN3 and cancer. Except for those that included HPV-16, multiple-type infections were associated with an increased risk (compared with that for single-type infections) of all grades of CIN and of cancer. CONCLUSIONS We confirmed the bimodal age pattern of HPV infection in Guanacaste and the sexually transmitted nature of both oncogenic and nononcogenic HPV types.

A prospective study of age trends in cervical human papillomavirus acquisition and persistence in Guanacaste, Costa Rica

BACKGROUND Cross-sectional human papillomavirus (HPV) DNA prevalence peaks at young ages, reflecting sexual acquisition and typically rapid clearance. In some populations, HPV prevalence demonstrates a second peak in older women. Longitudinal data may help to explain this second peak. METHODS We followed a population-based cohort of 7237 women in Guanacaste, Costa Rica, in which we had previously observed a second peak in the baseline HPV prevalence in older women. We tested for >40 HPV types by polymerase chain reaction. We analyzed age-specific patterns of acquisition and persistence 5-7 years after enrollment for individual HPV types. RESULTS At enrollment and follow-up, cross-sectional data revealed U-shaped age-specific HPV prevalence curves for virtually every type, with higher prevalences in the younger and older women than in the middle-aged women. Prospectively, acquisition of types decreased significantly as women aged (PTrend<.05, for both), with the highest peak in young women and a secondary minor peak in older women. Type-specific persistence of HPV increased with age (PTrend<.0001). Overall, HPV acquisition predominated at younger ages, whereas persistent infections gradually became more prominent with age (PTrend<.0001). CONCLUSIONS Newly apparent infections decreased, whereas persistence increased, with age; this latter tendency supports the utility of HPV screening in older women.

Rapid Clearance of Human Papillomavirus and Implications for Clinical Focus on Persistent Infections

Health professionals and the public need to understand the natural history of human papillomavirus (HPV) infections of the cervix to best use the information provided by new molecular screening tests. We investigated outcomes of 800 carcinogenic HPV infections detected in 599 women at enrollment into a population-based cohort (Guanacaste, Costa Rica). For individual infections, we calculated cumulative proportions of three outcomes (viral clearance, persistence without cervical intraepithelial neoplasia grade 2 or worse [CIN2+], or persistence with new diagnosis of CIN2+) at successive 6-month time points for the first 30 months of follow-up. Cervical specimens were tested for carcinogenic HPV genotypes using an L1 degenerate-primer polymerase chain reaction method. Infections typically cleared rapidly, with 67% (95% confidence interval [CI] = 63% to 70%) clearing by 12 months. However, among infections that persisted at least 12 months, the risk of CIN2+ diagnosis by 30 months was 21% (95% CI = 15% to 28%). The risk of CIN2+ diagnosis was highest among women younger than 30 years with HPV-16 infections that persisted for at least 12 months (53%; 95% CI = 29% to 76%). These findings suggest that the medical community should emphasize persistence of cervical HPV infection, not single-time detection of HPV, in management strategies and health messages.

American Cancer Society Guideline for Human Papillomavirus (HPV) Vaccine Use to Prevent Cervical Cancer and Its Precursors

The American Cancer Society (ACS) has developed guidelines for the use of the prophylactic human papillomavirus (HPV) vaccine for the prevention of cervical intraepithelial neoplasia and cervical cancer. These recommendations are based on a formal review of the available evidence. They address the use of prophylactic HPV vaccines, including who should be vaccinated and at what age, as well as a summary of policy and implementation issues. Implications for screening are also discussed.

A 2-Year Prospective Study of Human Papillomavirus Persistence among Women with a Cytological Diagnosis of Atypical Squamous Cells of Undetermined Significance or Low-Grade Squamous Intraepithelial Lesion

BACKGROUND Cervical cancer is caused by persistent infection with human papillomavirus (HPV). Most infections and associated lesions clear spontaneously. It is important to define the determinants and timing of clearance, so that viral persistence can be recognized and managed. METHODS We investigated HPV natural history among 4504 subjects from ALTS (Atypical Squamous Cells of Undetermined Significance/Low-Grade Squamous Intraepithelial Lesions Triage Study). A discrete-time Markov model was used to simultaneously describe the prevalence, incidence, and persistence of type-specific HPV infection over 24 months in women with equivocal or mildly abnormal cytological results. Interactions between multiple HPV types infecting the same woman were examined for incidence of new infection (after an HPV-16 infection) and persistence of a current infection within groups defined by phylogenetic relatedness or by carcinogenicity. RESULTS Ninety-one percent (95% credible interval [CI], 90%-92%) of prevalent HPV infections at enrollment cleared within 24 months. The probability that an infection would persist for a further 6 months increased with the duration of infection, from 37% (95% CI, 35%-39%) for a newly observed infection to 65% (95% CI, 61%-70%) for an infection that had already persisted for > or =18 months. No consistent evidence of interactions was found between multiple HPV types regarding the incidence of new infection after an HPV-16 infection or regarding persistence of current HPV infection. CONCLUSION Although virtually all HPV infections clear within 2 years, the remaining infections have a high potential for persistence and, by implication, progression to precancer and cancer. Once biological and behavioral determinants are controlled for, HPV infections with different types seem to be independent of each other.