Circulating tumour cell enumeration does not correlate with Miller–Payne grade in a cohort of breast cancer patients undergoing neoadjuvant chemotherapy

Sharon A. O’Toole1,2,3 · Cathy Spillane1,3 · Yanmei Huang1,2,3,4 · Marie C. Fitzgerald1,2,3 · Brendan Ffrench1 ·
Bashir Mohamed1,3 · Mark Ward1,3 · Michael Gallagher1,3 · Tanya Kelly1,3 · Cathal O’Brien5 · Carmel Ruttle1 ·
Anna Bogdanska2 · Cara Martin1,3 · Dorinda Mullen1,3 · Elizabeth Connolly3,6 · Sarah A. McGarrigle3,6 ·
John Kennedy3,7 · John J. O’Leary1,3

Received: 24 March 2020 / Accepted: 27 April 2020 / Published online: 6 May 2020 © The Author(s) 2020

Purpose The association between pathological complete response (pCR) in patients receiving neoadjuvant chemotherapy
(NAC) for breast cancer and Circulating Tumour Cells (CTCs) is not clear. The aim of this study was to assess whether
CTC enumeration could be used to predict pathological response to NAC in breast cancer as measured by the Miller–Payne
grading system.
Methods Twenty-six patients were recruited, and blood samples were taken pre- and post-NAC. CTCs were isolated using
the ScreenCell device and stained using a modified Giemsa stain. CTCs were enumerated by 2 pathologists and classified as
single CTCs, doublets, clusters/microemboli and correlated with the pathological response as measured by the Miller–Payne
grading system. χ2 or ANOVA was performed in SPSS 24.0 statistics software for associations.
Results 89% of patients had invasive ductal carcinoma (IDC) and 11% invasive lobular carcinoma (ILC). At baseline 85%
of patients had CTCs present, median 7 (0–161) CTCs per 3 ml of whole blood. Post-chemotherapy, 58% had an increase
in CTCs. This did not correlate with the Miller–Payne grade of response. No significant association was identified between
the number of CTCs and clinical characteristics; however, we did observe a correlation between pre-treatment CTC counts
and body mass index, p < 0.05.
Conclusions Patients with a complete response to NAC still had CTCs present, suggesting enumeration is not sufficient to
aid surgery stratification. Additional characterisation and larger studies are needed to further characterise CTCs isolated
pre- and post-chemotherapy. Long-term follow-up of these patients will determine the significance of CTCs in NAC breast
cancer patients.