Incidental radiologic findings at breast cancer diagnosis and likelihood of disease recurrence

Abstract

Despite guidelines recommending against its routine use, perioperative imaging for distant metastases is frequently performed in newly diagnosed breast cancer patients, uncovering incidental findings of uncertain significance. We assessed the clinical significance of incidental findings by determining if their presence is associated with disease recurrence. A retrospective review of staging imaging was performed in patients with stage II or III invasive breast cancer diagnosed during 2008-2009 at a large academic medical center. Data related to perioperative imaging and disease recurrence were abstracted from the medical record. Kaplan-Meier curves and Cox proportional hazards models were used to assess the association between incidental findings and time to disease recurrence. A total of 169 of 340 patients (49.7 %) underwent staging evaluation for distant metastases (CT chest, abdomen, pelvis, bone scan, and/or PET-CT). Of these, 146 (86.4 %) had at least one suspicious or indeterminate finding. Follow-up studies were performed in 73 (43.2 %) patients. Nineteen patients were diagnosed with metastatic disease at diagnosis, 18 of whom had stage III disease. In patients without metastatic disease at diagnosis, 32 later developed recurrence. Non-calcified pulmonary nodules were associated with shorter time to disease recurrence (hazard ratio 2.51, 95 % CI 1.13-5.57, p = 0.02). Imaging for distant metastases frequently reveals indeterminate findings, most of which are not associated with disease recurrence. The association between pulmonary nodules and recurrence warrants validation in an independent cohort. Overall, these findings support current guidelines recommending against routine extent of disease evaluation in patients with newly diagnosed stage II breast cancer.

Keywords: Bone Scan; Breast Cancer; CT; Incidental Findings; PET; Staging.

Figure 1

Flow diagram of study population. ¹Patients with suspicious findings who did not undergo follow-up studies were determined to have metastatic disease based on initial staging imaging alone.

Figure 2

Findings on initial extent of disease evaluation. Distribution of normal, indeterminate, and suspicious findings for (A) CT chest, (B) CT Abdomen/Pelvis, (C) Bone Scan, and (D) PET-CT.

Figure 3

Time to disease recurrence. Kaplan Meier curves comparing time to disease recurrence between patients with and without (A) any indeterminate or suspicious finding (N=150) and (B) non-calcified pulmonary nodules on CT chest (N=136). Only patients without metastatic disease at diagnosis are included. Univariable log rank p-values are shown at the bottom right of each graph.

Figure 4

Time to disease recurrence by imaging modality or type of incidental finding. Forest plot depicting the association between time to disease recurrence and the presence of indeterminate or suspicious findings on specific imaging modalities (top section) or the presence of specific types of incidental findings (bottom section). Hazard ratios were adjusted using a multi-variable model to control for hormone receptor status, HER2 status, and stage.