Different biological and prognostic breast cancer populations identified by FDG-PET in sentinel node-positive patients: results and clinical implications after eight-years follow-up.
BACKGROUND
Sentinel node (SN) biopsy is the standard method to evaluate axillary node involvement in breast cancer (BC). Positron emission tomography with 2-(fluorine-18)-fluoro-2-deoxy-D-glucose (FDG-PET) provides a non-invasive tool to evaluate regional nodes in BC in a metabolic-dependent, biomolecular-related way. In 1999, we initiated a prospective non-randomized study to compare these two methods and to test the hypothesis that FDG-PET results reflect biomolecular characteristics of the primary tumor, thereby yielding valuable prognostic information.


METHODS
A total of 145 cT1N0 BC patients, aged 24-70 years, underwent FDG-PET and lymphoscintigraphy before surgery. SN biopsy was followed in all cases by complete axillary dissection. Pathologic evaluation in tissue sections for involvement of the SN and other non-SN nodes served as the basis of the comparison between FDG-PET imaging and SN biopsy.


RESULTS
FDG-PET and SN biopsy sensitivity was 72.6% and 88.7%, respectively, and negative predictive values were 80.5% and 92.2%, respectively. A subgroup of more aggressive tumors (ER-GIII, Her2+) was found mainly in the FDG-PET true-positive (FDG-PET+) patients, whereas LuminalA, Mib1 low-rate BCs were significantly undetected (p = 0.009) in FDG-PET false-negative (FDG-PET-) patients. Kaplan-Meier survival estimates after a median follow-up of more than 8 years showed significantly worse overall survival for FDG-PET+ patients in node-positive (N+) patients (p = 0.035) as compared to N+/FDG-PET- patients, which overlapped with survival curves of N- and FDG-PET+ or - patients.


CONCLUSIONS
Our findings suggest that FDG-PET results reflect intrinsic biologic features of primary BC tumors and have prognostic value with respect to nodal metastases. FDG-PET false negative cases appear to identify less aggressive indolent metastases. The possibility to identify a subgroup of N+ BC patients with an outcome comparable with N- BC patients could reduce the surgical and adjuvant therapeutic intervention.
Breast Surgery Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. Electronic address: roberto.agresti@istitutotumori.mi.it.
Roberto
R
Agresti
Nuclear Medicine Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
Flavio
F
Crippa
Molecular Targeting Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
Marco
M
Sandri
Breast Surgery Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
Gabriele
G
Martelli
Molecular Targeting Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
Elda
E
Tagliabue
Nuclear Medicine Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
Alessandra
A
Alessi
Breast Surgery Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
Cristina
C
Pellitteri
Nuclear Medicine Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
Marco
M
Maccauro
Breast Surgery Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
Ilaria
I
Maugeri
Nuclear Medicine Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
Padovano
P
Barbara
Breast Surgery Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
Mario
M
Rampa
Breast Surgery Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
Alessandra
A
Moscaroli
Breast Surgery Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
Cristina
C
Ferraris
Pathology Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
Maria Luisa
ML
Carcangiu
Medical Oncology Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
Giulia
G
Bianchi
Breast Surgery Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
Marco
M
Greco
Nuclear Medicine Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
Emilio
E
Bombardieri
D000328:Adult; D000368:Aged; D001365:Axilla; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000000981:diagnostic imaging* / Q000473:pathology; D018275:Carcinoma, Lobular / Q000000981:diagnostic imaging* / Q000473:pathology; D015331:Cohort Studies; D005260:Female; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000473:pathology; D061305:Lymphoscintigraphy; D008875:Middle Aged; D009367:Neoplasm Staging; D015609:Organotechnetium Compounds; D049268:Positron-Emission Tomography; D011379:Prognosis; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D021701:Sentinel Lymph Node Biopsy; D055815:Young Adult
D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
Adjuvant treatment; Breast cancer; Positron emission tomography; Prognosis; Sentinel node biopsy; Surgery