The added value of whole-body magnetic resonance imaging in the management of patients with advanced breast cancer

Abstract

This study investigates the impact of whole-body MRI (WB-MRI) in addition to CT of chest-abdomen-pelvis (CT-CAP) and 18F-FDG PET/CT (PET/CT) on systemic treatment decisions in standard clinical practice for patients with advanced breast cancer (ABC). WB-MRI examinations in ABC patients were extracted from our WB-MRI registry (2009-2017). Patients under systemic treatment who underwent WB-MRI and a control examination (CT-CAP or PET/CT) were included. Data regarding progressive disease (PD) reported either on WB-MRI or on the control examinations were collected. Data regarding eventual change in treatment after the imaging evaluation were collected. It was finally evaluated whether the detection of PD by any of the two modalities had induced a change in treatment. Among 910 WB-MRI examinations in ABC patients, 58 had a paired control examination (16 CT-CAP and 42 PET/CT) and were analysed. In 23/58 paired examinations, additional sites of disease were reported only on WB-MRI and not on the control examination. In 17/28 paired examinations, PD was reported only on WB-MRI and not on the control examination. In 14 out of the 28 pairs of examinations that were followed by a change in treatment, PD had been reported only on WBMRI (14/28; 50%), while stable disease had been reported on the control examination. In conclusion, WB-MRI disclosed PD earlier than the control examination (CT-CAP or PET/CT), and it was responsible alone for 50% of all changes in treatment.

Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1. Impact on treatment: Overall and subgroup analyses.

The flowcharts in this picture illustrate how often the imaging outcomes motivated changes of treatment in our cohort, with a distinction between the cases of PD reported only on WB-MRI and those in which PD was reported on both examinations (WB-MRI and the control examination). The first flowchart includes all 58 paired examinations (overall analysis). Separate analyses are shown for specific subgroups in the following flowcharts, including analyses of all 16 paired examinations in which WB-MRI was paired to CT-CAP, all 42 paired examinations in which WB-MRI was paired to PET/CT and all 19 paired examinations performed in ILC patients. Abbreviations: PD = progressive disease; SD = stable disease.

Fig 2. Nodal recurrence or progression to metastatic disease?

36 years old woman with locally advanced ductal breast cancer, after surgery (pT1 N1a M0), local radiation therapy and adjuvant chemotherapy. While under endocrine treatment, an axillary nodal recurrence is diagnosed (histologically proven). In the suspicion of distant metastases, the patient underwent FDG-PET/C. Coronal FDG-PET MIP (a) showed uptake in left axillary lymph nodes (white arrowhead), with no other finding suspicious for metastases. WB-MRI was performed 15 days later: DWI b-900 MIP (b) confirmed the left axillary lymph node metastases (white arrowhead), and detected metastases in bone (left iliac bone, right sacral wing; black arrows), in liver (II and VI segments; white arrows), in lymph nodes (right parasternal, left internal mammary, hepatic hilar, para-aortic and lumbar; red arrows) and in subcutaneous parasternal tissues (black arrowhead). Normal areas of high signal can be seen in cervical and pelvic lymph nodes, brain, spinal cord, spleen, kidneys and in bilateral ovarian cysts. The PD reported at WB-MRI determined a change in treatment from Letrozole to capecitabine, vinorelbine and cyclophosphamide, with additional radiation therapy on bone lesions.

Fig 3

In the same pair of examinations of Fig 2, axial fused FDG-PET/CT showed non-specific FDG uptake in the pelvic bones (a). T1 weighted axial image from WB-MRI showed a suspicious bone lesion in the left iliac bone (arrow in b), which was hyperintense on b-900 DWI images (arrow in c) with low ADC values (d).

Fig 4

In this picture, taken from the same examination of Figs 2 and 3, two different examples of high signal intensity findings in DWI b-900 MIP (a) are illustrated. (b) B-900 DWI images reveal two new hyper intense lesions in the left liver lobe (arrows). (c) In the correspondent ADC map, the lesions (arrows) show low values, which suggest high cellularity, making them suspicious for metastases. (d) B-900 DWI images show bilateral pelvic masses with high signal intensity (arrowheads). (e) The correspondent ADC maps shows the absence of impeded diffusion within the masses, that represent follicular ovarian cysts.

Fig 5. Peritoneal carcinosis undetected at PET/CT.

Patient with locally advanced ductal breast carcinoma (pT2, N2a, M0) after surgery and 4 cycles of chemotherapy, under endocrine therapy. After suspicious rise in CA15-3 the patient underwent FDG-PET/CT, which showed no suspicious uptake and was reported as negative for distant metastases. Sagittal MIP (a) showed non-specific FDG uptake in the ascending colon and tracer excretion in the urinary tract. Pelvic axial cross-section of the FDG-PET/CT (b) and the co-registered CT image (c) did not show any suspicious uptake or measurable lesion.

Fig 6

In the same patient of Fig 5, the paired WB-MRI showed thickening of the peritoneum in the right pelvis, which was hyper-intense in DWI b-900 sagittal MIP (a) and DWI axial b-900 images (arrow in b), with corresponding reduced ADC values (c). Axial T1 and T2 images confirmed the presence of a suspicious thickening of the right pelvic peritoneum and mesorectal fascia (arrows in d and e). No significant fluid collection can be seen. Other benign high signal intensity areas in the MIP image (a) include salivary glands, spinal cord, silicon breast implant, spleen, kidneys, small bowel and a bartholin’s gland cyst. The PD reported at WB-MRI determined a change in treatment from Letrozole to Fulvestrant.