Nancy E. Poitras

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.

Benchmarking CIN 3+ risk as the basis for incorporating HPV and Pap cotesting into cervical screening and management guidelines.

Objective In 2012, the US Preventive Services Task Force (USPSTF) and a consensus of 25 organizations endorsed concurrent cytology and human papillomavirus (HPV) testing (“cotesting”) for cervical cancer screening. Past screening and management guidelines were implicitly based on risks defined by Pap-alone, without consideration of HPV test results. To promote management that is consistent with accepted practice, new guidelines incorporating cotesting should aim to achieve equal management of women at equal risk of cervical intraepithelial neoplasia grade 3 and cancer (CIN 3+). Methods We estimated cumulative 5-year risks of CIN 3+ for 965,360 women aged 30 to 64 years undergoing cotesting at Kaiser Permanente Northern California over 2003 to 2010. We calculated the implicit risk thresholds for Pap-alone and applied them for new management guidance on HPV and Pap cotesting, citing 2 examples: HPV-positive/atypical squamous cells of undetermined significance (ASC-US) and HPV-negative/Pap-negative. We call this guidance process “benchmarking.” Results A low-grade squamous intraepithelial lesion result, for which immediate colposcopy is prescribed, carries a 5-year CIN 3+ risk of 5.2%, suggesting that test results with similar risks should be managed with colposcopy. Similarly, ASC-US (2.6% risk) is managed with a 6- to 12-month follow-up visit and Pap-negative (0.26% risk) is managed with a 3-year follow-up visit. The 5-year CIN 3+ risk among women with HPV-positive/ASC-US was 6.8% (95% confidence interval = 6.2%–7.6%). This is greater than the 5.2% risk implicitly leading to referral for colposcopy, consistent with current management recommendations that women with HPV-positive/ASC-US be referred for immediate colposcopy. The 5-year CIN 3+ risk among women with HPV-negative/Pap-negative results was 0.08% (95% confidence interval = 0.07%–0.09%), far below the 0.26% implicitly required for a 3-year return and justifying a longer (e.g., 5-year) return. Conclusions Using the principle of “equal management of equal risks,” benchmarking to implicit risk thresholds based on Pap-alone can be used to achieve safe and consistent incorporation of cotesting.

Five-Year Experience of Human Papillomavirus DNA and Papanicolaou Test Cotesting

OBJECTIVE: To estimate the 5-year age group–specific test positives for Pap tests and human papillomavirus (HPV) testing in a large, general screening population of women 30 and older. METHODS: Using data from Kaiser Permanente Northern California, a large health maintenance organization that introduced cotesting in 2003, we evaluated the cotesting results overall and by 5-year age groups. Women (n=580,289) who opted for and underwent cotesting (n cotests=812,598) between January 2003 and April 2008 were included in the analysis. Pap tests interpreted as atypical squamous cells of undetermined significance (ASC-US) or more severe were considered to be positive. Women were tested for carcinogenic HPV using an assay approved by the U.S. Food and Drug Administration. Binomial exact 95% confidence intervals (CIs) were calculated. RESULTS: Overall, 6.27% (95% CI 6.21–6.32%) of cotests were carcinogenic HPV positive, and only 3.99% (95% CI 3.94–4.03%) cotests had normal cytology and were carcinogenic HPV positive. By comparison, 5.18% (95% CI 5.13–5.23%) of cotests had ASC-US or more severe cytology, and 2.87% (95% CI 2.84–2.91%) of cotests had ASC-US or more severe cytology and were carcinogenic HPV negative. CONCLUSION: In a general screening population, concerns about excessive HPV test positives among women aged 30 years and older are not borne out. LEVEL OF EVIDENCE: III

The age-specific relationships of abnormal cytology and human papillomavirus DNA results to the risk of cervical precancer and cancer.

BACKGROUND: To estimate the relationship of human papillomavirus (HPV) detection and abnormal cytology with histologic diagnoses of cervical precancer and cancer. METHODS: From 2003 to 2008 we examined the HPV, cytology, and diagnostic results from almost one million cervical cancer screenings done on women aged 30 and older who were members in Kaiser Permanente Northern California, a large health maintenance organization that introduced cotesting in 2003. Women were screened using conventional Pap tests and a DNA test for a pool of 13 high-risk HPV genotypes. Women with HPV-positive atypical squamous cells of undetermined significance and other abnormal cervical cytology, independent of their HPV results, routinely underwent colposcopy. Results were stratified by 5-year age groups from 30 to 64. RESULTS: High-grade squamous intraepithelial lesions (HSIL), atypical squamous cells, cannot exclude HSIL (ASC-H), and atypical glandular cells were more strongly associated with cervical intraepithelial neoplasia grade 3 while low-grade squamous intraepithelial lesions (LSIL) and HPV-positive atypical squamous cells of undetermined significance were more strongly associated with cervical intraepithelial neoplasia grade 2 (CIN2). Cervical cancer was most commonly found in women with HSIL and atypical glandular cells cytology. Human papillomavirus–negative women with ASC-H cytology were at a reduced but significant risk of CIN2 or more severe (CIN2+) (10.6%) compared with HPV-positive women with ASC-H cytology. Human papillomavirus–negative women with LSIL were at a 4.0% risk of CIN2+, and among women 50 and older, at a 0.5% risk of CIN2+ with no cancers were diagnosed. CONCLUSION: Human papillomavirus testing may be useful for triage for colposcopic referral for LSIL cytology in older women but not for ASC-H cytology at any age. LEVEL OF EVIDENCE: II

Relationship of Atypical Glandular Cell Cytology, Age, and Human Papillomavirus Detection to Cervical and Endometrial Cancer Risks

OBJECTIVE: To quantify the age-specific and reproductive organ-specific cancer risk after an atypical glandular cell (AGC) cytologic interpretation in large clinic-based sample in which routine high-risk human papillomavirus (HPV) testing is conducted. METHODS: To estimate the absolute risk of cervical precancer, cervical cancer, and endometrial cancer in women with AGC cytology, we conducted a cross-sectional study of women with AGC cytology (n=1,422) in a large health maintenance organization that introduced high-risk HPV DNA testing into cervical cancer screening in 2003. Risks and binomial exact 95% confidence intervals (CIs) of cervical intraepithelial neoplasia grade 2 or more severe (CIN 2 or worse) and endometrial cancer were calculated. RESULTS: A total of 238 women with AGC cytology (16.7%, 95% CI 14.8-18.8%) were diagnosed with CIN 2 or worse, endometrial cancer, or other cancers. Among women aged 50 years or older, 420 high-risk HPV-negative women were at a 10.5% (95% CI 7.7-13.8%) risk of endometrial cancer, and 77 high-risk HPV-positive women were at a 10.4% (95% CI 4.6-19.4%) risk of cervical cancer and 0% (95% CI 0.0-4.7%) risk of endometrial cancer. CONCLUSION: High-risk HPV testing may distinguish between risk of endometrial cancer and cervical cancer in women with AGC cervical cytology, particularly in women aged 50 years or older. LEVEL OF EVIDENCE: III

Five-year risks of CIN 3+ and cervical cancer among women who test Pap-negative but are HPV-positive.

Objective Current US guidelines for cotesting recommend that the large numbers of women who test Pap-negative, but human papillomavirus (HPV)–positive, return in 1 year, and those who remain HPV-positive or have low-grade squamous intraepithelial lesion (LSIL) or worse Pap results be referred for colposcopy. However, the performance of these guidelines in routine clinical practice has not been evaluated. Methods We estimated cumulative 5-year risks of cervical intraepithelial neoplasia grade 3 or worse (CIN 3+) among 32,374 women aged 30 to 64 years with HPV-positive/Pap-negative cotest results at Kaiser Permanente Northern California during 2003 to 2010. Results The 5-year CIN 3+ risk after an HPV-positive/Pap-negative cotest result, which was found in 3.6% of women, was 4.5% (95% confidence interval [CI] = 4.2%–4.8%). The 5-year cancer risk was 0.34% (95% CI = 0.26%–0.45%), and half of the cases were adenocarcinoma. Overall, 48% of the women remained HPV-positive on return (median = 418 days after baseline), a percentage that varied little over ages 30 to 64 years. At the return after a baseline HPV-positive/Pap-negative result, almost every repeat cotest result predicted greater subsequent 5-year CIN 3+ risk than the same cotest result had at baseline (HPV-positive/LSIL, 9.2% vs 6.1%, p = .01; HPV-positive/atypical squamous cells of undetermined significance [ASC-US], 7.9% vs 6.8%, p = .2; HPV-positive/Pap-negative, 7.4% vs 4.5%, p < .0001; HPV-negative/LSIL,1.7% vs 2.0%, p = .8; HPV-negative/ASC-US, 2.9% vs 0.43%, p = .0005; HPV-negative/Pap-negative, 0.93% vs 0.08%, p < .0001). Conclusions Using the principle of “equal management of equal risks,” women testing HPV-positive/Pap-negative had a subsequent CIN 3+ risk consistent with risk thresholds for a 1-year return. However, on returning in approximately 1 year, about one-half of women will be referred for colposcopy because of continued HPV positivity or Pap abnormality. Clinicians should keep in mind that cotest results at the return after a baseline HPV-positive/Pap-negative finding are riskier than the same baseline cotest results in the general population, supporting intensified clinical management at return testing.

Five-year risks of CIN 3+ and cervical cancer among women with HPV testing of ASC-US Pap results.

Objective New screening guidelines recommend that human papillomavirus (HPV)–negative/atypical squamous cells of undetermined significance (ASC-US) results be considered as equivalent to HPV-negative/Pap-negative results, leading to rescreening in 5 years. However, despite ample data, the routine clinical performance of HPV testing of women with ASC-US has not been adequately documented. Methods We estimated 5-year risks of cervical intraepithelial neoplasia (CIN) 3+ and of cancer among 2 groups of women between 2003 and 2010 at Kaiser Permanente Northern California: 27,050 aged 30 to 64 years who underwent HPV and Pap cotesting and had an ASC-US Pap result and 12,209 aged 25 to 29 years who underwent HPV triage of ASC-US. Results Five-year risks of CIN 3+ and of cancer among women aged 30 to 64 years testing HPV-negative/ASC-US and among 923,152 women testing Pap-negative alone were similar although statistically distinguishable (CIN 3+, 0.43% vs 0.26%, p = .001; cancer, 0.050% vs 0.025%, p = .1). The increased risk of cancer after HPV-negative/ASC-US versus Pap-negative alone was confined to women aged 60 to 64 years (0.26% vs 0.035%, p = .3). Five-year risks of CIN 3+ and cancer among women with HPV-negative/ASC-US results were substantially higher than those among women testing HPV-negative/Pap-negative (CIN 3+, 0.43% vs 0.08%, p < .0001; cancer, 0.050% vs 0.011%, p = .003). For women aged 30 to 64 years testing HPV-positive/ASC-US, 5-year risks of CIN 3+ and cancer were slightly higher than those among 9,374 women with low-grade squamous intraepithelial lesion (LSIL) (CIN 3+, 6.8% vs 5.2%, p = .0007; cancer, 0.41% vs 0.16%, p = .04). Similar patterns were seen for women aged 25 to 29 years. Conclusions Women with HPV-negative/ASC-US had a similar risk as women testing Pap-negative alone but had a higher risk than women testing HPV-negative/Pap-negative. Based upon the principle of “equal management of equal risks,” our findings support the equal management of women with HPV-negative/ASC-US and those with Pap-negative alone, except for exiting women from screening because cancer risks at ages 60 to 64 years may be higher for women testing HPV-negative/ASC-US. Our findings also support managing HPV-positive/ASC-US and LSIL similarly.

Five-year risk of recurrence after treatment of CIN 2, CIN 3, or AIS: performance of HPV and Pap cotesting in posttreatment management.

Objective After excisional treatment, cervical intraepithelial neoplasia grade 2 or worse (CIN 2+) can recur. It is not clear how many negative posttreatment Pap or cotest results are needed to ensure adequate safety against CIN 2+ before returning to extended retesting intervals. Methods We observed 5-year risks of CIN 2+ for 3 follow-up management strategies after treatment (Pap-alone, human papillomavirus [HPV]-alone, and HPV/Pap cotesting) for 3,273 women aged 25 years and older who were treated for CIN 2, CIN 3, or adenocarcinoma in situ (AIS) between 2003 and 2010 at Kaiser Permanente Northern California. Results Five-year risks of recurrent CIN 2+ after treatment varied both by antecedent screening test result and the histology of the treated lesion. The risk ranged from 5% for CIN 2 preceded by HPV-positive/atypical squamous cells of undetermined significance or low-grade squamous intraepithelial lesion to 16% for CIN 3/AIS preceded by atypical glandular cells (AGC)/atypical squamous cells cannot rule out high-grade squamous intraepithelial lesion (ASC-H)/high-grade squamous intraepithelial lesion or worse (HSIL+) (p < .0001). However, after posttreatment negative tests, risks were lowered and similar regardless of antecedent screening test and histology of treated disease. The 5-year recurrent CIN 2+ risk after a negative posttreatment cotest (2.4%) was lower than that following a negative HPV test (3.7%, p = .3) or negative Pap result (4.2%, p = .1). Two negative posttreatment tests of each kind conferred slightly lower 5-year CIN 2+ risk than one (2 negative Pap tests vs. 1, 2.7% vs 4.2%, p = .2; 2 negative HPV tests vs. 1, 2.7% vs 3.7%, p = .7; 2 negative cotests vs. 1, 1.5% vs 2.4%, p = .8). The 5-year CIN 2+ risk after 2 negative cotests of 1.5% (95% confidence interval = 0.3%–7.2%) approached the 0.68% risk after a negative Pap test during routine screening. Conclusions Women with antecedent AGC/ASC-H/HSIL+ Pap results or those treated for CIN 3/AIS had a substantial risk of developing CIN 2+ posttreatment. On the basis of the principle of “equal management of equal risks,” after negative test results posttreatment, no subgroup of women achieved risk sufficiently low to return to 5-year routine screening. However, negative cotests after treatment provided more reassurance against recurrent CIN 2+ than either negative Pap tests or HPV tests alone.

Human Papillomavirus (HPV) Genotypes in Women with Cervical Precancer and Cancer at Kaiser Permanente Northern California

Background: The human papillomavirus (HPV) Persistence and Progression Cohort is a natural history study of carcinogenic HPV positive women. Here, we present the HPV genotypes found in first ∼500 cases of cervical intraepithelial neoplasia grade 3 (CIN3) or more severe disease (CIN3+) diagnosed at the study baseline. Methods: Women aged 30 and older were screened for cervical cancer using Pap smears and tested for carcinogenic HPV using Hybrid Capture 2 (HC2; Qiagen). We randomly selected women who tested HPV positive and were diagnosed with CIN3+ (n = 448) or without CIN3+ (<CIN3; n = 830). Residual cervical Pap specimens were HPV genotyped using a MY09/11 L1-targeted PCR method. Results: Among HC2-positive women, HPV16 (48.9%), HPV31 (9.2%), and HPV18 (8.5%) were the most common HPV genotypes in CIN3+. There was a decrease at older ages in the fraction of CIN3 (Ptrend = 0.006), adenocarcinoma in situ (AIS) (Ptrend = 0.08), and CIN3/AIS (Ptrend = 0.002) associated with HPV16. Compared to the other carcinogenic HPV genotypes in aggregate, HPV18 was strongly associated with CIN3+ in women with a normal Pap [odds ratio (OR) = 5.7, 95% CI = 1.2–26] but not in women with abnormal Pap (OR = 1.3, 95% CI = 0.74–2.3). Conclusions: HPV16 is more strongly associated with cervical precancer diagnosed in younger women (vs. older women). HPV18 infections were linked to precancerous lesions that were missed by cytology. Impact: The progression timeline of HPV16 differs from other carcinogenic HPV genotypes, which may impact the use of HPV16 detection in the management of HPV-positive women. Cancer Epidemiol Biomarkers Prev; 20(5); 946–53. ©2011 AACR.

Follow-up testing after colposcopy: five-year risk of CIN 2+ after a colposcopic diagnosis of CIN 1 or less.

Objective Most women referred for colposcopy are not diagnosed with cervical intraepithelial neoplasia grade 2 or worse (CIN 2+) but, nonetheless, are typically asked to return much sooner than their next routine screening interval in 3 to 5 years. An important question is how many subsequent negative Pap results, or negative Pap and human papillomavirus (HPV) cotest results, are needed before returning to an extended retesting interval. Methods We estimated 5-year risks of CIN 2+ for 3 follow-up management strategies after colposcopy (Pap-alone, HPV-alone, and cotesting) for 20,319 women aged 25 years and older screened from 2003 to 2010 at Kaiser Permanente Northern California who were referred for colposcopy but for whom CIN 2+ was not initially diagnosed (i.e., “women with CIN 1/negative colposcopy”). Results Screening results immediately antecedent to CIN 1/negative colposcopy influenced subsequent 5-year CIN 2+ risk: women with an antecedent HPV-positive/atypical squamous cells of undetermined significance (ASCUS) or low-grade squamous intraepithelial lesion (LSIL) Pap had a lower risk (10%) than those with antecedent atypical squamous cells cannot rule out HSIL (ASC-H; 16%, p < .0001) or high-grade squamous intraepithelial lesion or worse (HSIL+; 24%, p < .0001). For women with an antecedent HPV-positive/ASC-US or LSIL, a single negative cotest approximately 1 year after colposcopy predicted lower subsequent 5-year risk of CIN 2+ (1.1%) than 2 sequential negative HPV tests (1.8%, p = .3) or 2 sequential negative Pap results (4.0%, p < .0001). For those with an antecedent ASC-H or HSIL+ Pap, 1 negative cotest 1 year after colposcopy predicted lower subsequent 5-year risk of CIN 2+ (2.2%) than 1 negative HPV test (4.4%, p = .4) or 1 negative Pap (7.0%, p = .06); insufficient data existed to calculate the risk after sequential negative cotests for women with high-grade antecedent cytology. Conclusions Women with a CIN 1/negative colposcopy followed by negative postcolposcopy tests did not achieve sufficiently low CIN 2+ risk to return to 5-year routine screening. For women with antecedent HPV-positive/ASC-US or LSIL, a single negative postcolposcopy cotest reduced their risk to a level consistent with a 3-year return. For women with antecedent ASC-H or HSIL+, no single negative test result sufficed to reduce their risk to a level consistent with a 3-year return.