Added value of dedicated axillary hybrid 18F-FDG PET/MRI for improved axillary nodal staging in clinically node-positive breast cancer patients: a feasibility study

Abstract

PurposeTo investigate the feasibility and potential added value of dedicated axillary 18F-FDG hybrid PET/MRI, compared to standard imaging modalities (i.e. ultrasound [US], MRI and PET/CT), for axillary nodal staging in clinically node-positive breast cancer.MethodsTwelve patients with clinically node-positive breast cancer underwent axillary US and dedicated axillary hybrid 18F-FDG PET/MRI. Nine of the 12 patients also underwent whole-body PET/CT. Maximum standardized uptake values (SUVmax) were measured for the primary breast tumor and the most FDG-avid axillary lymph node. A positive axillary lymph node on dedicated axillary hybrid PET/MRI was defined as a moderate to very intense FDG-avid lymph node. The diagnostic performance of dedicated axillary hybrid PET/MRI was calculated by comparing quantitative and its qualitative measurements to results of axillary US, MRI and PET/CT. The number of suspicious axillary lymph nodes was subdivided as follows: N0 (0 nodes), N1 (1–3 nodes), N2 (4–9 nodes) and N3 (≥ 10 nodes).ResultsAccording to dedicated axillary hybrid PET/MRI findings, seven patients were diagnosed with N1, four with N2 and one with N3. With regard to mean SUVmax, there was no significant difference in the primary tumor (9.0 [±5.0] vs. 8.6 [±5.7], p = 0.678) or the most FDG-avid axillary lymph node (7.8 [±5.3] vs. 7.7 [±4.3], p = 0.767) between dedicated axillary PET/MRI and PET/CT. Compared to standard imaging modalities, dedicated axillary hybrid PET/MRI resulted in changes in nodal status as follows: 40% compared to US, 75% compared to T2-weighted MRI, 40% compared to contrast-enhanced MRI, and 22% compared to PET/CT.ConclusionsAdding dedicated axillary 18F-FDG hybrid PET/MRI to diagnostic work-up may improve the diagnostic performance of axillary nodal staging in clinically node-positive breast cancer patients.

PET/MRI in Breast Cancer

“…One study evaluated the impact of dedicated axillary PET/MRI on axillary nodal status in 12 patients with clinically positive axillary nodal disease. In that study, axillary PET/MRI changed nodal status in 40% of patients compared with ultrasound, in 40% of patients compared with contrast‐enhanced MRI, and in 22% of patients compared with PET/CT …”

Is the whole larger than the sum of the parts? Integrated PET/MRI as a tool for response prediction

“…The impact of FDG PET/CT on oncologic management decisions has also been presented [15]. Recently, the value of integrated PET/MRI on initial staging and therapy decision-making has been demonstrated [16,17].…”

Towards de-escalation of axillary management after neoadjuvant chemotherapy in breast cancer

“…A variety of methods are used to target the pathologically proven positive lymph node: marking with a clip pre-NST followed by placing an iodine seed or wire in the clipped node post-NST 7,[33][34][35]37 and primary marking with an iodine seed, clip, charcoal, or electromagnetic reflector. 36,38 Also, the time of marking the lymph node pre-NST differs: either immediately at time of FNAC/CNB, 7,33,34,37 at a second appointment once metastatic burden of the punctured lymph node is confirmed by the pathologist 35,36 or even at both occasions. 38 Currently, further research has to define which combination procedure is most accurate, patient-friendly, and cost-effective.…”

“…Therefore, we decided to include these studies, 7 in total, in the qualitative analysis. 7,[33][34][35][36][37][38] See Table 4.2 for detailed characteristics of these studies. In this table, we have included results of a study by our own research group (manuscript submitted).…”

“…A feasibility study reported that this technique may improve the diagnostic performance of the standard work-up for axillary staging in cN+ patients. 36 Future research has to determine if this may also apply for axillary staging in cN+ patients after neoadjuvant chemotherapy. Our group is currently applying for funding for the OPTIMA trial.…”