Diagnostic ultrasound of the chest wall in the symptomatic patient after mastectomy

Lack of standardized imaging recommendations among mastectomy patients has led to variability in how recurrences are detected.

To describe the findings and assess the diagnostic efficacy of ultrasound in the evaluation of symptomatic post-mastectomy patients.

This single institution, retrospective study included 749 consecutive diagnostic chest wall ultrasound examinations performed in mastectomy patients, from January 2016 to June 2017. Chest wall ultrasound evaluated the mastectomy bed with or without reconstruction. Electronic health records were queried for the primary breast cancer histology prior to mastectomy, clinical symptoms prompting the diagnostic ultrasound, ultrasound findings, subsequent cytology and pathology, and follow-up data. Excluded were patients with a known recurrence, asymptomatic patients, and those with <2 years of clinical or imaging follow-up. Descriptive and comparative statistical analyses were performed.

Among the 749 ultrasounds performed, 58 malignancies were identified for a 7.7% (58/749) malignancy rate, with a median tumor size of 20 mm. Patients diagnosed with a malignancy most often presented with a palpable abnormality (79.3%, 46/58) or skin changes (13.8%, 8/58) and rarely with pain (1.7%, 1/58). Patients who underwent a biopsy yielding a benign result most often presented with a palpable abnormality (41.5%, 287/691), pain (25.6%,177/691), or postoperative swelling/suspected fluid collection (17.8%, 123/691). Diagnostic ultrasound yielded a 91.4% sensitivity (95% CI 81.0, 97.1), 96.1% specificity (95% CI 94.4, 97.4), 66.3% PPV₃ (95% CI 57.4, 74.1), and 99.3% negative predictive value (95% CI 98.3, 99.7) for cancer detection. There were 5 false negative ultrasound cases after a skin punch biopsy was performed due to clinically suspicious skin changes.

Chest wall ultrasound has a high sensitivity and negative predictive value for detection of breast cancer recurrence in symptomatic patients after mastectomy. Skin changes remain an important clinical manifestation of a cancer recurrence.