The effects of adding zoledronic acid to neoadjuvant chemotherapy on tumour response: exploratory evidence for direct anti-tumour activity in breast cancer.
BACKGROUND
Pre-clinical studies have demonstrated synergistic anti-tumour effects of chemotherapy (CT) and zoledronic acid (ZOL). Within the AZURE trial, designed to determine whether the addition of ZOL to neoadjuvant therapy improves disease outcomes, a subgroup received neoadjuvant CT. We report a retrospective evaluation comparing pathological response in the primary tumour between treatment groups.


METHODS
In total, 205 patients received neoadjuvant CT+/-ZOL (CT+ZOL, n=102; CT, n=103). The primary end point was pathologically assessed residual invasive tumour size (RITS) at surgery. Secondary end points were pathological complete response (pCR) rate and axillary nodal involvement. Following review of surgical pathology reports (n=195), outcome differences between groups were assessed adjusting for potential response modifiers.


RESULTS
Baseline characteristics and CT treatments were similar. In multivariate analysis, allowing for biological and clinical factors known to influence tumour response, the adjusted mean RITS in CT and CT+ZOL groups were 27.4 and 15.5 mm, respectively, giving a difference in means of 12 mm (95% confidence interval: 3.5-20.4 mm; P=0.006). The pCR rate was 6.9% in the CT group and 11.7% in the CT+ZOL group (P=0.146). There was no difference in axillary nodal involvement (P=0.6315).


CONCLUSIONS
These data suggest a possible direct anti-tumour effect of ZOL in combination with CT, warranting formal evaluation in prospective studies.
Academic Unit of Clinical Oncology, Weston Park Hospital, University of Sheffield, Sheffield, UK. r.e.coleman@sheffield.ac.uk
R E
RE
Coleman
M C
MC
Winter
D
D
Cameron
R
R
Bell
D
D
Dodwell
M M
MM
Keane
M
M
Gil
D
D
Ritchie
J L
JL
Passos-Coelho
D
D
Wheatley
R
R
Burkinshaw
S J
SJ
Marshall
H
H
Thorpe
D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy*; D004164:Diphosphonates / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007093:Imidazoles / Q000008:administration & dosage / Q000627:therapeutic use*; D008875:Middle Aged; D015999:Multivariate Analysis; D020360:Neoadjuvant Therapy; D018365:Neoplasm, Residual / Q000188:drug therapy; D000077211:Zoledronic Acid
D004164:Diphosphonates; D007093:Imidazoles; D000077211:Zoledronic Acid