Experience in managing a large-scale rescreening of Papanicolaou smears and the pros and cons of measuring proficiency with visual and written examinations.

Experiences in a large-scale interlaboratory rescreening of Papanicolaou smears are detailed, and the pros and cons of measuring proficiency in cytology are discussed. Despite the additional work of the rescreening project and some psychological and technical problems, it proved to be a useful measure of the laboratory's performance as a whole. One problem to be avoided in future similar studies is the creation of too many diagnostic categories. Individual testing and certification have been shown to be accurate predictors of proficiency. For cytology, such tests require a strong visual component to test interpretation and judgment skills, such as by the use of glass slides or photomicrographs. The potential of interactive videodisc technology for facilitating cytopathologic teaching and assessment is discussed.

Retrospective evaluation of gynecologic cytodiagnosis. II. Interlaboratory reproducibility as shown in rescreening large consecutive samples of reported cases.

Two laboratories exchanged and rescreened a large sample of cases with cervicovaginal smears they had consecutively accessioned to examine the reproducibility of gynecologic cytodiagnosis under optimum conditions. At least a "working agreement" (diagnoses within +/- 1 category on a ten-category scale) was achieved in diagnoses of normal, benign reaction and squamous abnormality (from minimal dysplasia though invasive cancer) in 18,859 cases (96.8%), of endometrial abnormality in 21 cases (42%) and of "unsatisfactory" in 99 cases (20.7%). Larger differences occurred in greater than or equal to 30% of cases except in the categories of "normal" and "benign reaction," reaching a maximum of 82% for moderate dysplasia. Reexamining 382 cases decreased disagreement by category to the 20% to 65% range only in the five categories of dysplasia plus carcinoma in situ. Agreement was not predicated on the presence of endocervical cells or squamous metaplasia; the basis for "unsatisfactory" calls was not uniform. Comparison of the laboratories' diagnoses with referee diagnoses or, on 178 cases, with tissue diagnoses also demonstrated differences in diagnostic criteria.

Cervical cancer occurrence in Memphis and Shelby County, Tennessee, during 25 years of its cervical cytology screening program.

This review of the cytologic history of 430 women with histologically proved invasive cancer of the uterine cervix indicates that several significant subgroups can be defined. One major subgroup consists of 142 patients or 33% of the total group in whom invasive cancer developed within 1 to 5 years, with an average of 2.6 years, after one or more negative cytologic findings. This appears to be a significant proportion of the occurrence of invasive cervical cancer and warrants consideration in the recommendation of screening intervals. The second major subgroup, consisting of 88 patients (20.5%), had a delay in diagnosis averaging 9.9 years after the first abnormal cytologic finding. In some of these patients either the cytologic examination results reverted to negative for a period or the biopsy material did not confirm the cytologic abnormalities. The disease progressed to invasion. These findings appear to bear out the importance of close follow-up of patients with any abnormal cytologic finding in the intraepithelial neoplasia category even though intermittent cytologic studies may appear negative.

Retrospective evaluation of gynecologic cytodiagnosis. I. Reproducibility using an experimental diagnostic scale.

A system for the exchange of specimens between two independent laboratories ("A" and "B") was designed to enable them to review a consecutive series of one another's gynecologic smears. Another cytopathologist "refereed" diagnoses differing beyond agreed limits and examined all smears called carcinoma in situ or a more severe lesion by either laboratory. A ten-numeral gradient nomenclature scale was developed to code all cytodiagnoses for data processing. This analysis of the reproducibility of the experimental diagnostic system is based on all participants' examination of 100 selected specimens, half contributed by reviewing laboratory A and half by reviewing laboratory B, with the target value of each specimen established by the contributor. Intralaboratory reproducibility, expressed by a correlation coefficient (r), ranged from 0.78 to 0.93. After adjusting for straightforward squamous-cell lesions, r ranged from 0.88 to 0.91. Intralaboratory agreement +/- 1 scalar category, defined as a "working consensus," ranged from 77% to 84%. Interlaboratory correlation ranged from r = 0.74 to 0.94. Adjustment for squamous-cell lesions exerted less effect than it had on intralaboratory reproducibility. Interlaboratory agreement within one category ranged from 58% (laboratory B reviewing specimens contributed by laboratory A) to 92% (referee examining specimens contributed by laboratory B). Initially, laboratory A tended to classify a given specimen higher on the scale than did laboratory B and the referee, but as the study progressed, both laboratories tended to converge toward a more congruent diagnostic position, with referee greater than A greater than B. The level of discrimination attained by all participants validates use of this system to compare a larger series of diagnoses.