Interval cancer developing within 3 years after recall to assessment: a review of the South East Wales cases

Objective

To review interval cancers developing after initial recall in the mammographic screening programme in South East Wales.

Methods

Interval cancer data were collected from patient records where the women had been recalled to assessment at the last screening visit.

Results

A total of 206 patients developed interval cancer following a normal assessment result over a 3-year period; 169 patient records were available for analysis. Fifty-six patients (33%) had false negative results on screening mammogram. Seventy-one cases (41%) were true interval cancers, nine (6%) were occult and 34 (20%) were unclassified. Of 56 false negative results, 53 were assessed for the same area and three for a different area. Patients were assessed for microcalcification (14 cases), asymmetric density (22 cases), mass (six cases), spiculate density (two cases) and distortion (nine cases). Six patients had either biopsy or cyst aspiration. Almost 90% of the interval cancers were invasive cancer. Thirty patients (55%) developed interval cancer between 12 and 24 months after screening.

Conclusion

Assessment for glandular asymmetry and micro-calcification should include biopsy in more cases.