Correlation of cytotechnologists' parameters with their performance in rapid prescreening of papanicolaou smears

[New strategies for the prevention and control of cervical cancer in Chile.]

OBJECTIVE

To discuss cervical cancer (CC), Human PapillomaVirus (HPV),CC control program and propose alternatives for Chile.

MATERIALS AND METHODS

We analyzed the national program of CC 1966-2015 and the clinical CC guideline 2015-2020;HPV prevalence in women and in cases of CC; HPV infection and serology; the self-vaginal sample; the accuracy and cost-effectiveness of screening with HPV versus Papanicolaou,and triage options among HPV-AR positives.

RESULTS

600 women die of CC each year in Chile, mainly from low resources. Papanicolaou coverage is <70%; Papanicolaou sensitivity is much lowerthan HPV test.Change from Papanicolaou to HPV test is cost-effective. Since 2015, girls under 13 have been vaccinated against HPV.

CONCLUSIONS

.There are the technical and economic conditions for a substantial improvement of CC in Chile: replacement of the Papanicolaou by HPV; screening every five years, with the option of self-sampling, and triage based on HPV 16/18 or Papanicolaou typing.

Pap smears with glandular cell abnormalities: Are they detected by rapid prescreening?

BACKGROUND

Rapid prescreening (RPS) is one of the quality assurance (QA) methods used in gynecologic cytology. The efficacy of RPS has been previously studied but mostly with respect to squamous lesions; in fact, there has been no study so far specifically looking at the sensitivity of RPS for detecting glandular cell abnormalities.

METHODS

A total of 80,565 Papanicolaou (Pap) smears underwent RPS during a 25-month period. A sample was designated as "review for abnormality" (R) if any abnormal cells (at the threshold of atypical squamous cells of undetermined significance/atypical glandular cells [AGC]) were thought to be present or was designated as negative (N) if none were detected. Each sample then underwent full screening (FS) and was designated as either R or N and also given a cytologic interpretation.

RESULTS

The final cytologic interpretation was a glandular cell abnormality (≥AGC) in 107 samples (0.13%); 39 of these (36.4%) were flagged as R on RPS. Twenty-four patients (33.8%) out of 71 who had histologic follow-up were found to harbor a high-grade squamous intraepithelial lesion or carcinoma; 13 of those 24 Pap smears (54.2%) had been flagged as R on RPS. Notably, 11 AGC cases were picked up by RPS only and not by FS and represented false-negative cases; 2 of these showed endometrial adenocarcinoma on histologic follow-up.

CONCLUSIONS

Pap smears with glandular cell abnormalities are often flagged as abnormal by RPS, and this results in a sensitivity of 36.4% (at the AGC threshold). Most importantly, some cases of AGC are detected on Pap smears by RPS only, and this demonstrates that RPS is a valuable QA method.

NILM Pap slides from women 30 years of age and older with positive high-risk HPV DNA. Focused rescreening prior to report issuance, an enhanced quality control measure

OBJECTIVES

Clinical Laboratory Improvement Amendments of 1988 (CLIA '88) regulations specify that at least 10% of negative Papanicolaou (Pap) slides be rescreened as a quality control (QC) measure. With incorporation of human papillomavirus (HPV) DNA testing into screening guidelines for women aged 30 years or older, a population of patients exists who are HPV positive as well as negative for intraepithelial lesion or malignancy (NILM).

METHODS

In this 9-month retrospective review with follow-up, 26,501 women 30 years of age and older underwent liquid-based Pap screening with concomitant high-risk HPV DNA testing at CellNetix Pathology and Laboratories, Seattle, WA. Of these women, 1,096 (4.1%) were originally interpreted by cytotechnologists as NILM with HPV DNA positivity.

RESULTS

On rescreening, 13.9% (152/1,096) of patients were upgraded to atypical squamous cells and higher, with 2.8% being upgraded to low-grade squamous intraepithelial lesion (LSIL) and higher. Historical routine QC measures from the same period showed that 0.3% of cases were upgraded to LSIL and higher, representing a statistically significant increase in the detection of cases with LSIL and higher (χ(2) two-tailed P < .0001).

CONCLUSIONS

Focused rescreening of this enriched subpopulation of patients who are NILM and high-risk HPV DNA positive enhances QC. An inherent potential bias in study design is recognized because results of DNA testing were, by definition, known at the time of rescreening result interpretations.

Rapid prescreen of cervical liquid-based cytology preparations: results of a study in an academic medical center

A rapid prescreening or rapid rescreening method for quality assurance in cervical cytology has been used in Europe and in Canada but has not been accepted in the United States. The rapid prescreen method was tested in a cytology laboratory that serves an academic medical center with a high-risk population for cervical cancer. For a period of 3 months, a tray of 20 sequentially numbered Surepath™ liquid-based preparations, randomly selected from the cervical cytology daily workload, were each prescreened in a random fashion for 1 minute. Experienced cytotechnologists performed the rapid prescreen. Results were recorded as negative, further review needed, or epithelial cell abnormality, category specified. The 20 cervical cytology preparations were then replaced in their same position in the daily workload for routine screening performed by another cytotechnologist. Final interpretation was by a cytopathologist as requested or required by Clinical Laboratory Improvement Amendments of 1988. The rapid prescreen data was tabulated and compared with data for a similar time period using the laboratory's normal quality assurance program. Seven hundred and twelve cases underwent rapid prescreen. Six hundred and forty-two were interpreted as negative. Twenty-six cases were interpreted as low-grade squamous intraepithelial lesion (LGSIL) or higher. Forty-four cases were classified as needing further review. For the 642 negative cases by rapid prescreening, routine screening reported 537 as negative and 105 as either abnormal or needed cytopathologist review. The error rate for the rapid prescreen is 50 of 712 (7.0%); for LGSIL and above 19 of 712 (2.6%). Of the 105 abnormal cases or those submitted for cytopathologist review, 31 were interpreted as atypical squamous cells of undermined significance (ASCUS), 41 cases as reactive/repair, 17 as LGSIL, 4 as unsatisfactory, 1 as atypical squamous cells, cannot rule out high-grade squamous intraepithelial lesion (ASC-H), 8 as the presence of endometrial cells in a women aged >40, 1 as malignant melanoma, and 2 as within normal limits with the presence of Actinomyces. The laboratory's routine quality assurance program selects cases, 10% of initially interpreted negative cases plus any gynecologic cytology on patients with a prior abnormal cervical cytology, or history of cervical epithelial cell abnormality. This quality assurance program averages 29% of cases, 4,045 of a total of 13,767, in 2008. Thirty-seven (0.9%) cases were detected in this rescreen (ASCUS, 16 cases; LGSIL, 13 cases; 1 high-grade squamous intraepithelial lesion; 4 ASC-H; and 3 atypical glandular cells of undetermined significance). Eliminating ASCUS cases, eight significant cases were detected, with an error rate of 0.2%. In this cytology laboratory, the rapid prescreen did not prove as reliable as routine quality assurance program for cervical cytology cases.

Effectiveness of rapid prescreening and 10% rescreening in liquid-based Papanicolaou testing

Although rapid prescreening (RPS) has been shown to be an effective quality control procedure for detecting false-negative conventional Papanicolaou (Pap) tests, RPS has not been widely implemented in the United States. In our laboratory, cytotechnologists performed RPS in 3,567 liquid-based Pap tests: 1,911 SurePath (BD Diagnostics-TriPath, Burlington, NC) preparations that were manually screened and 1,656 ThinPrep Pap tests (Hologic, Bedford, MA) that were imaged using the ThinPrep Imaging System (Hologic). We compared the sensitivity of RPS, 10% rescreening (R-10%), and routine screening (RS). In contrast with previously published findings, we found that RS + RPS did not improve screening sensitivity compared with RS + R-10%. These results support the following hypotheses: (1) Higher baseline RS sensitivity as a result of Pap test diagnoses standardization implemented for quality improvement purposes decreases the performance impact of RPS. (2) R-10% and RPS quality assurance methods detect diagnostic failures caused by different types of cognitive errors.

Quality Improvement in Cytology: Where Do We Go From Here?

Context.—Cytology is a success because of the many quality controls used to ensure the accuracy of its results. Nevertheless, additional information is becoming available to the cytologist, often from untraditional sources, and the best way to use that information to improve the quality of cytology is not yet known.

Objective.—To review ways to use new information to improve the quality of cytology.

Data Sources.—Review of relevant literature.

Results.—Information contained in many sources can be used in new ways to improve the quality of cytology. These include the timing of cytologic and histologic correlation, electronic medical records, workload information, prior aspirations, and molecular tests.

Conclusions.—To maintain their high standard of excellence, cytologists should seek to define the most appropriate way to incorporate this new information into their interpretation of individual cases.

ASC/SIL ratio for cytotechnologists: A survey of its utility in clinical practice

The atypical squamous cell to squamous intraepithelial lesion (ASC/SIL) ratio for cytotechnologists (CTs) may correlate with screening sensitivity in some laboratory settings. Whether this ratio can be applied to other laboratory settings is not known. We conducted a survey of nine cytology laboratories and correlated the ASC/SIL ratio of individual CTs with other laboratory characteristics. The ASC/SIL ratio for individual CTs varied from 0.6 to 4.5 (mean: 1.9, median: 1.5). The ASC/SIL ratio within individual laboratories varied up to 567%; 25/78 (32%) CTs had an ASC/SIL ratio of less than 1.5, though only three of nine laboratories had more than one CT with a ratio this low. Laboratories that used 100% location guided screening (ThinPrep Imaging System) were much less likely to have a CT with a ratio <1.5 (1/20, 5%) than laboratories that never used location guided screening (14/34, 42%; P = 0.004). In addition, the normalized variance of these same laboratories that used location guided screening was significantly lower than those that did not (normalized standard deviation 0.32 vs. 0.55, P = 0.004). The ASC/SIL ratios did not correlate with laboratory volume, individual workload, or type of specimen preparation (conventional vs. liquid based). The ASC/SIL ratio for CTs varies widely between and within laboratories, and may correlate with the use of location guided screening. Very low ASC/SIL ratios are unusual, and CTs with low ratios may warrant further evaluation.

Does the time of day or weekday affect screening accuracy? A pilot correlation study with cytotechnologist workload and abnormal rate detection using the ThinPrep Imaging System

BACKGROUND

Workload is extensively regulated in gynecologic cytology. However, sensitive monitors of excessive workload are not available.

METHODS

We measured the variation in abnormal (atypical squamous cells [ASC], low-grade squamous intraepithelial lesion [LSIL], and high-grade squamous intraepithelial lesion [HSIL]) rates for 4 cytotechnologists (CTs) among different days of the week and at different times during the day while they were performing primary screening with the ThinPrep Imaging System.

RESULTS

Three of 4 CTs detected significantly less abnormal cases on 1 day of the week than another (1 Monday, 2 Friday). Two of those CTs detected significantly fewer total abnormal cases in the afternoon than in the morning; this was strongly correlated with increased speed in the afternoon and decreased detection of ASC cases. HPV + rates for ASC cases dropped as the abnormal rate dropped. The third CT detected significantly fewer ASC cases in the morning; this was counterbalanced by an increase detection of LSIL cases, suggesting a shift in diagnostic threshold between the AM and PM. The difference in abnormal detection rates between morning and afternoon correlated with a false-negative fraction of 0.96.

CONCLUSIONS

There are significant differences in detection rates of abnormal cases between days of the week and the morning and afternoon. Correlating abnormal rates and workload between the morning and afternoon may represent a sensitive way to detect excessive workload. Because individual CTs may have different responses to workload and no overall pattern emerged, data on their workload and performance need to be tracked individually.

Surrogate indicators of sensitivity in gynecologic cytology: can they be used to improve the measurement of sensitivity in the laboratory?

Background:

Measuring the sensitivity of screening in gynecologic cytology in real life is problematic. However, other quality measures may correlate with sensitivity, including the atypical squamous cells (ASC)/squamous intraepithelial lesion (SIL) ratio. Whether these other measures can function as “surrogate indicators” for sensitivity and improve the assessment of sensitivity in the laboratory is not known.

Materials and Methods:

We compared multiple quality measures with true screening sensitivity in a variety of situations.

Results:

The abnormal rate, ASC rate, and ASC/SIL ratio were all highly correlated (r =.83 or greater) with sensitivity when the overall laboratory sensitivity was low (85%) but became less correlated (.64 or less) or uncorrelated when the screening sensitivity was higher (88% or 95%, respectively). Sensitivity was more highly correlated with the abnormal rate than the ASC/SIL ratio at low screening sensitivity. While thresholds could be set that were highly sensitive and specific for suboptimal screening, these thresholds were often less than one standard deviation away from the mean.

Conclusion:

The correlation of the abnormal rate and the ASC/SIL ratio with sensitivity depends on overall sensitivity. Standards to define minimum screening sensitivity can be defined, but these standards are relatively narrow. These features may limit the utility of these quality measures as surrogates for sensitivity.

ASC/SIL Ratio for Cytotechnologists: A surrogate marker of screening sensitivity

The atypical squamous cell/squamous intraepithelial lesion (ASC/SIL) ratio has been used as a surrogate quality control tool for specificity and uncertainty for cytopathologists. Whether this ratio is useful for cytotechnologists is not known. During an 8-month period, the sensitivity of screening for 11 cytotechnologists was determined using rapid prescreening. The ASC/SIL ratio for each cytotechnologist was correlated with the screening accuracy for each. Screening sensitivity varied from 50.5% to 97.7%, and the ASC/SIL ratio varied from 0.87 to 4.49. The mean screening sensitivity for cytotechnologists with ASC/SIL ratios less than 1.5 was significantly less than that of cytotechnologists whose ASC/SIL ratio was more than 3.0 (67% vs 95%; P = .021). In the absence of more accurate quality control data, an ASC/SIL ratio less than 1.5 for a cytotechnologist may be a surrogate marker for inadequate screening sensitivity.

Measuring the significance of workload on performance of cytotechnologists in gynecologic cytology: a study using rapid prescreening

BACKGROUND

Workload is extensively regulated and often used as a measure of quality in gynecologic cytology. Whether workload correlates with the sensitivity of screening in gynecologic cytology is not known.

METHODS

The sensitivity of gynecologic cytology screening was measured over an 8-month period using the result of full screening coupled with the results of rapid prescreening. Sensitivity results were then correlated with daily workload volumes and the experience level of individual cytotechnologists.

RESULTS

Rapid prescreening had an average sensitivity of 41.9% for atypical squamous cells of undetermined significance (ASCUS) and above. Full screening had a corrected sensitivity of 82.2% for ASCUS and above. Rapid prescreening increased the sensitivity of the laboratory to 89.9%. The sensitivity of full screening was significantly different between cytotechnologists (79.2% vs 99%, P < .001), but was not correlated with years of experience, sensitivity of rapid prescreening, or workload (all P > .05). When sensitivity and workload were examined on a monthly basis, there was no significant difference between sensitivity either as a group or individually at the highest and lowest workloads (P > .40 for all).

CONCLUSIONS

Screeners sensitivity in gynecologic cytology appears to be unrelated to the experience level of individual cytotechnologists or to their workload at the levels examined.