The origin of the five-year retrospective review of high-grade squamous intraepithelial lesion, or HSIL, in Pap tests is steeped in mystery. Why do we perform a retrospective review? Why five years? Is it useful? Is it important?
The five-year retrospective review of previous
negative Pap tests in a present HSIL is based on the premise that a
woman with an HSIL is an opportunity to identify those false-negative
Pap tests in someone who is a “high risk” patient. In other words, because the current Pap is HSIL, it offers an opportunity to identify an enriched population of negative cases that are quite likely to harbor a morphologic abnormality not detected on previous screening. From a quality improvement perspective, this is actually a theoretically potentially useful exercise. What better way to identify those patients who may have had an abnormality that was “missed” by routine screening and potentially identify systemic laboratory or individual issues that may have led to this “miss”?
So why do we stipulate a five-year retrospective
review? The simple answer is that it is the law. CLIA ’88 requires that a five-year retrospective review be performed whenever a current HSIL is detected. The regulation reads as follows: “For each patient with a current HSIL, adenocarcinoma, or other malignant neoplasm, laboratory review of all normal or negative gynecologic specimens received within the previous 5 years, if available in the laboratory (either on-site or in storage). If significant discrepancies are found that will affect current patient care, the laboratory must notify the patient’s
physician and issue an amended report (Fed Register. 2003(Jan
24): 5232 [42CFR493. 1274 (c) (3)]).”
This still leaves the question of why five years. There is no basis in science that five years is a magic number; five years is the length of time that laboratories are required to maintain slides from Pap tests according to CLIA regulations. Laboratories are required to maintain gynecologic cytology preparations for a minimum of five years. Therefore, these slides should always be available for review (Fed Register. 2003 (Jan 24): 7170 [42CFR493. 1105 (a) (7) (i) (A); 493. 1274(f)(2) through (f)(4)]).
What does this requirement mean in actuality?
Anytime a lab identifies a Pap test as having HSIL, all previous Pap
tests in the preceding five years that are “negative” must be reviewed.
If the preceding HSIL is presaged by four years of Pap tests demonstrating
a low-grade squamous intraepithelial lesion, or LSIL, those case are
not required by CLIA ’88 to be reviewed. If the woman has
five years of atypical squamous cells of undetermined significance,
or ASC-US, on Pap tests, these preparations likewise need not be reviewed.
However, any Pap test with the result negative for intraepithelial
neoplasm or malignancy, or NILM, during those five years must be reviewed.
For example, there is a current HSIL with two previous LSILs, one NILM, and one NILM with reactive changes and fungus; by regulation, the two NILM cases must be reviewed. The laboratory can stipulate the review of these LSIL or ASC-US cases as part of its quality assurance program. This would be a separate and reasonable part of a comprehensive QA program but is not mandated by law or as part of the cytology laboratory accreditation checklist. Similarly, the laboratory could add as part of its QA program a review of prior negative cases after the finding of CIN on a biopsy, but CLIA does not mandate it and the Laboratory Accreditation Program checklist does not require it.
The current CAP checklist indicates that any “new” HSIL requires a review of any previous negative Pap test in the preceding five years and all available “histologic reports” [CYP.07517:
Are all available (either on-site or in storage) previously negative
slides received within the past five years and histologic information
reviewed whenever a new high-grade squamous intraepithelial lesion
(moderate or severe dysplasia, carcinoma in situ, CIN 2 or 3) or malignant
gynecologic case is reported?].
This verbiage differs slightly from that in
the CLIA ’88 regulations. “Current” versus “new” is an interpretive variation. A cautious approach includes the review of all negative Pap tests in the previous five years in any patient with HSIL. If the patient is not a “new” patient
with HSIL, the previous review will be available in the QA material
of the lab and should not present additional problems. Another interpretive
variation that the CAP has added is to review histology reports at
the time previous NILM Pap tests are reviewed. Undoubtedly, the intent
of the checklist question was to try to identify those cases in which
the new HSIL was confirmed by biopsy.
So you have now identified a new HSIL in a patient,
the previous five years’ reports are reviewed, any previous NILM (or other Pap tests as dictated by the lab’s policy) are pulled for review, and the histology reports are reviewed. How should a laboratory proceed? It should document that the HSIL occurred, the negative slides were reviewed, and any clinically significant changes were reported in an amended report. Clinically significant changes are defined as those affecting current patient care—in
other words, changes worse than those seen in the current Pap test
or any concurrent biopsy. The original report should be amended only if
current patient care is affected. Thus, in most instances only a finding
of squamous cell carcinoma on a prior Pap would necessitate an amendment,
as the present HSIL is the clinically defined “worst case scenario.”
Remember that retrospective review is also “100 percent.” Because
the HSIL outcome is known, there is bias in the evaluation of the previous
negative slide. Though retrospective review is a valuable educational
tool, it cannot be used as a measure of individual performance. The
retrospective review does not represent the standard practice of Pap
test review. Unless the previous negatives are reviewed in a blinded
fashion, any discordant results of retrospective review cannot be interpreted
as poor or substandard performance. The retrospective review of NILM
when a current Pap test is HSIL is a QA measure that identifies those
scenarios in which HSIL may be overlooked in routine, regular screening.
How does the lab document a five-year retrospective
review? The retrospective review is required by CLIA and the CAP but
the mechanism for documentation is not specified. What shall we document?
Though QA documents are considered “protected” in many states, the
likelihood of legal discovery has not been tested in most of these
states. More importantly, QA documents have been reviewed successfully
in medicolegal circumstances in some states. When documenting reviews
of previous NILM Pap tests in a current HSIL, identify only the number
of previous Pap tests that were reviewed and the number of previous
Pap test results that were amended. Including the previous Pap result,
the review result, or a Pap test accession number is not required.
A simple checklist, identifying that the review was performed and the
number of Pap test results amended, is adequate for QA purposes.
So is “retrophobia” justified? The five-year lookback provides a mechanism to review negative cases at high risk for harboring true abnormalities. These reviews can provide information that can be used to improve laboratory performance as part of an overall QA program. Laboratories should, however, be careful about how they use these findings. All information discovered during retrospective review should be used in a positive manner. The review of NILM in a current HSIL should be educational, identifying those instances where HSIL may be overlooked. Retrospective review is a valuable QA method that should never be construed as the “usual” manner
of Pap test review. Likewise, the QA records of performing the five-year
retrospective review should indicate that the review was performed
and whether any changes were discovered that affect current patient
care, and they should not put the lab at inappropriate medicolegal
risk. Thus, retrospective review should inspire not a phobia but rather
quality in the cytology laboratory.
Dr. Moriarty, vice chair of the CAP Cytopathology Committee, is with AmeriPath Indiana, Indianapolis. Dr. Henry, a member of the CAP Cytopathology Committee, is with the Mayo Clinic, Rochester, Minn.