Use of Screening Mammography to Detect Occult Malignancy in Autologous Breast Reconstructions: A 15-year Experience.

ABSTRACT

Purpose To examine how often screening mammography depicts clinically occult malignancy in breast reconstruction with autologous myocutaneous flaps (AMFs). Materials and Methods Between January 1, 2000, and July 15, 2015, the authors retrospectively identified 515 women who had undergone mammography of 618 AMFs and who had at least 1 year of clinical follow-up. Of the 618 AMFs, 485 (78.5%) were performed after mastectomy for cancer and 133 (21.5%) were performed after prophylactic mastectomy. Medical records were used to determine the frequency, histopathologic characteristics, presentation, time to recurrence, and detection modality of malignancy. Cancer detection rate (CDR), sensitivity, specificity, positive predictive value, and false-positive biopsy rate were calculated. Results An average of 6.7 screening mammograms (range, 1-16) were obtained over 15.5 years. The frequency of local-regional recurrence (LRR) was 3.9% (20 of 515 women; 95% confidence interval [CI] 2.2%, 5.6%); all LRRs were invasive, and none were detected in the breast mound after prophylactic mastectomy. Of the 20 women with LRR, 13 (65%) were screened annually before the diagnosis. Seven of those 13 women (54%) had clinically occult LRR, and mammography depicted five. Five of the six clinically evident recurrences (83%) were interval cancers. The median time between reconstruction and first recurrence was 4.4 years (range, 0.8-16.2 years). The CDR per AMF was 1.5 per 1000 screening mammograms (five of 3358; 95% CI 0.18, 2.8) after mastectomy for cancer and 0 of 1000 examinations (0 of 805 mammograms; 95% CI 0, 5) after prophylactic mastectomy. Sensitivity, specificity, positive predictive value, and false-positive biopsy rate were 42% (five of 12), 99.4% (4125 of 4151), 16% (five of 31), and 0.6% (26 of 4151), respectively. Conclusion The CDR of screening mammography (1.5 per 1000 screening mammograms) of the AMF after mastectomy for cancer is comparable to that for one native breast of an age-matched woman. Screening mammography adds little value after prophylactic mastectomy. © RSNA, 2018.