In Reply.—Drs Khoury, Vogelzang, and Fink state that the College of American Pathologists 10-year retention period for tissue (presumably paraffin blocks) is insufficient and propose changing it to 20 years. Although the current retention period is already much longer than the 2 years required by the Clinical Laboratory Improvement Amendments of 1988 (42 CFR 493.1105), the authors argue that this is still “relatively short” and that patients would benefit from a longer period. Institutions can always choose to keep blocks longer than the minimum retention period, but before the College can mandate a longer period for all laboratories, the value of that change must be balanced with the added burden it represents.
The authors base their proposal on 5 patients who were ineligible for a small phase I trial because their blocks were no longer available. As most clinical trials enroll patients within 10 years of diagnosis, this situation would seem to be very uncommon. Changing the retention period to 20 years on this basis would result in a substantial incremental increase in the cost of storage for all laboratories that would likely benefit only a few patients.
The authors do not address the issue of storage conditions, but the quality of paraffin-embedded material stored under routine conditions for more than 10 years is often unknown. The quality of RNA, for instance, has been shown to decrease significantly after 10 years.1 If prolonged storage of paraffin blocks reduces their value for some types of testing, the relative benefit of this proposed change is diminished even further.
Anticipating objections to a blanket requirement to store all blocks for 20 years, the authors offer 2 alternatives, neither of which is realistic. The first—a separate 20-year storage interval for cancer cases—is impractical. Busy histology laboratories must have an efficient daily work flow process to ensure that patient care needs are met and that errors are avoided. Having to establish a process to sort through and segregate blocks sometime after the pathologist has determined which ones contain cancer would be an enormous (and new) burden on histology laboratories. The second alternative—requiring institutions to locate every patient after 10 years and involve them in the decision to discard their material—is simply not credible.
Before mandating changes as significant as the ones proposed, a much clearer demonstration of value is needed. If, as seems most likely, very few patients would benefit from the proposed change, the substantial increase in resources needed would merely represent another unfunded mandate for laboratories without sufficient justification.