Early assessment with 18F-fluorodeoxyglucose positron emission tomography/computed tomography can help predict the outcome of neoadjuvant chemotherapy in triple negative breast cancer
Introduction
Triple-negative breast cancer (TNBC) accounts for 10–20% of invasive breast cancers and is characterised by the lack of oestrogen receptor (ER) and progesterone receptor (PR), and absence of HER2 over-expression [1], [2]. Patients with TNBC have a relatively poor outcome with higher relapse rates than those with other breast tumour types [1], [2]. However, these aggressive tumours have more intrinsic responsiveness to neoadjuvant chemotherapy (NAC) than ER-positive tumours. Also, TNBC patients with pathological complete response (pCR) after NAC have a good prognosis [3], [4]. Therefore, obtaining pCR for TNBC patients is an important clinical objective.
Positron emission tomography/computed tomography (PET/CT) with 18F-fluorodeoxyglucose (18FDG) is gaining importance for the staging of patients with large or locally advanced breast cancer [5], [6]. On the other hand, an early change in 18FDG uptake of the primary breast tumour (ΔSUVmax) is a potential predictive biomarker of response to NAC [7], [8]. Some teams suggested that 18FDG PET can also be used to predict response in axillary lymph nodes [9], [10]. Triple-negative tumours show high 18FDG uptake [11], [12]. Therefore, the TNBC subtype is probably ‘a good candidate’ to investigate response assessment with PET. The present prospective study investigated the ability of PET parameters (maximum standardised uptake value (SUVmax) at baseline, after two cycles of NAC, and ΔSUVmax) at early predicting pathological response and event-free survival (EFS) during NAC in a large series of TNBC patients. We also compared prediction offered by PET to that offered by baseline clinical or biological factors [3], [13].
Section snippets
Patients
From November 2007 to September 2012, 55 consecutive patients with clinical stage II or III breast carcinoma and a triple negative phenotype underwent 18FDG-PET/CT examination before starting NAC (PET1). Five of these patients had distant metastases identified at PET/CT and received treatment tailored to metastatic disease. The other 50 patients form the basis of the present study. All of them underwent a second 18FDG-PET/CT examination after the second cycle of chemotherapy (PET2). After
Results
One hundred 18FDG-PET/CT scans were performed in 50 M0 consecutive patients. Patients and tumour characteristics at baseline are summarised in Table 1.
At completion of NAC, breast-conserving surgery was performed in 21 women and mastectomy in 29. All patients had axillary lymph nodes dissection. Histopathology revealed pCR (pathological responders) in 19 patients (38%) while 31 (62%) had residual disease (non-pCR).
Discussion
Pathologic complete response is a surrogate end-point when TNBC patients are treated by neoadjuvant chemotherapy [3], [4]. In this prospective study of 50 women, the 3-year EFS was 100% in patients with pCR versus 51% [34.9-74.7] in those with residual tumour at surgery. We chose to present EFS data with follow-up from start of NAC, rather than disease free survival with follow-up from the date of surgery [15]. Indeed, trials with NAC often use EFS because patients are not disease-free at
Conflict of interest statement
None declared.
Acknowledgement
No external found was received in this study.
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