Axillary lymph node staging in breast cancer: clinical value of single photon emission computed tomography-computed tomography (SPECT-CT) with 99mTc-methoxyisobutylisonitrile.
OBJECTIVE
To determine diagnostic accuracy of SPECT, CT and SPECT-CT in axillary lymph node (LN) staging in breast cancer (BC).


METHODS
Sixty consecutive patients with primary operable T1-3NxM0 BC were included in this study. All patients underwent SPECT-CT examination on Symbia-T16 scanner which consists of dual-head gamma camera combined with 16 slices diagnostic CT. SPECT-CT acquisition started 10-15 min after i/v injection of 740-1,000 MBq of 99mTc-MIBI. On CT images of axillary LN we analyzed following diagnostic signs: size (short axis more or less than 10 mm), shape (round or oval), cortical thickness and fat content (solid or with fat gate). Intensity of tracer uptake in axillary LN was classified as follows: grade (Gr) I-background, Gr II-slightly above background, Gr III-intense but below uptake in muscles, Gr IV-as high as in muscles. Histological examination of dissected LN was used as gold standard.


RESULTS
Various combinations of CT signs of axillary LN involvement demonstrated moderate diagnostic value with best results characterized by low (55 %) sensitivity (SEN), 97 % specificity (SP) and 83 % accuracy (AC). Intensive (Gr IV) uptake of 99mTc-MIBI in axillary LN characterized by low (55 %) SEN, high (100 %) SP and moderate (84 %) AC. Combination of CT and SPECT signs looks most promising especially when LN metastases were diagnosed in patients with enlarged solid LN or normal sized LN with Gr III-IV 99Tc-MIBI uptake. In these cases, SEN was equal to 75 %, SP-90 %, AC-85 %, only one of 5 patients with false negative results had metastases in more than 2 LN.


CONCLUSIONS
By combination of SPECT and CT data we can more accurately diagnose axillary LN invasion by breast cancer.
Department of Radiation Oncology and Nuclear Medicine, N.N. Petrov Institute Oncology, Leningradskaya 68, St Petersburg, 197758, Russia, krokon@mail.ru.
Sergey Nikolaevich
SN
Novikov
Pavel Ivanovich
PI
Krzhivitskii
Sergey Vasilevich
SV
Kanaev
Petr Vladimirovich
PV
Krivorotko
Nikolay Dmirievich
ND
Ilin
Ludmila Alexeevna
LA
Jukova
Olga Igorevna
OI
Ponomareva
D000328:Adult; D000368:Aged; D001365:Axilla; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000473:pathology; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed
D017256:Technetium Tc 99m Sestamibi