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Editorial Commentary

Recall Systems

The three fundamental components of cancer surveillance and prevention systems are Recruitment, Recall and Follow-up. Work is now in progress to develop the necessary policies and procedures for these components for the Ontario Cervical Screening Program scheduled to be formally launched on June 15, 2000 by Cancer Care Ontario.

Recruitment activities ensure that individuals in the eligible population enter the program for initial testing. Once that has occurred, a recall system brings participants back at appropriate intervals for retesting. Any identified abnormalities must be subject to a follow-up process to ensure that they are not overlooked.

In some respects, the most controversial of the three components is recall – requiring policy decisions on factors such as when to recall, who should be notified and what to do if the candidate cannot be located.

Since its inception in June, 1996, over three million cytology results have been registered in CytoBase, allowing characterization of the recall patterns in the absence of a formal screening program. Despite the fact that in 1996 laboratory participation was such that only half of the workload was captured in CytoBase and therefore the three year data underestimate the rate of recall, over 66% of individuals are known to have been rescreened within 36 months. The rescreen patterns following an initial normal result, depicted graphically in the charts, show that most women are retested at about 15 months. The time to recall decreases with increasing abnormality in the initial smear.

Because not all results are in CytoBase, it is not possible to ascertain the incidence of missed or inappropriately prolonged rescreens. However the data do provide information for the design of a recall system and permit estimates of the workload that may result.

The Ontario Cervical Screening Collaborative Group has recommended that if women have normal smears for three consecutive years, the appropriate rescreen interval is two years. It is therefore suggested that, in the initial implementation of the recall system, reminder notices should be sent at two and a half years with respect to those women who are not known to have been rescreened. Extrapolation of the CytoBase data indicates that approximately 10% of registered women will need to be recalled - this is in the order of 75,000 per year.

A second issue is the mechanism of notification. In order to support the doctor/patient relationship, recall notices will be forwarded to physicians rather than directly to women. It is believed that the tradeoff in maintaining continuity of care will be worth the effort of the office contacting the patient.

Until now, the system has relied on opportunistic screening. It is well known however, that a high proportion of cervical cancers arise in women who have not been screened at all. The full benefit of a recall system will thus be derived only in the presence of an effective recruitment program.

Currently about 90% of the results of cervical screening smears are registered in CytoBase. It is thus gratifying to see substantive progress in the implementation of a province wide cervical screening program with the goal of reducing the incidence of cervical carcinoma by 50%.