Incidental detection of breast cancer by 68Ga-DOTATOC-PET/CT in women suffering from neuroendocrine tumours.
OBJECTIVE
Somatostatin receptor (sstr) imaging using 68Ga-DOTATOC-PET/CT in neuroendocrine tumors (NET) is promising, suggesting a more sensitive detection of lesions with a low sstr-expression. This is also important for other sstr positive tumors, especially breast cancer whose incidence and age-range is similar to that of NET.


METHODS
The PET/CT data of 33 consecutive women with NET (age: 33-78 years, mean 59) who underwent whole-body staging with 68Ga-DOTATOC was retrospectively analyzed for breast lesions. The data was read separately, side-by-side and as fused images. Focal tracer uptake in the breast was semiquantitatively analyzed by comparing the lesional SUVmax to normal breast tissue using Wilcoxon's rank sum test. Breast cancer lesions were compared visually to concomitant NET-lesions.


RESULTS
In six of 33 patients (18%) breast lesions were observed on the CT-scans and classified in four patients (12%) as suspicious. The same lesions also showed a pathological tracer uptake on the corresponding PET-scan, visually and semiquantitatively (p<0.01). Histological reevaluation of the suspicious lesions revealed two patients with NET metastases. Two patients had primary breast cancer with lower tracer uptake than concomitant abdominal NET-lesions. Breast cancer diagnosis resulted in a change of the therapeutic regimen.


CONCLUSIONS
68Ga-DOTATOC-PET/CT not only improves the staging of NET-patients, but also increases the chance to detect sstr-positive breast cancer. Although these lesions may show a lower tracer uptake than NET, they must not be overlooked or misinterpreted as metastases. Further imaging and clarification by histopathology is warranted, as the confirmation of a secondary malignoma has great impact on further therapeutic proceedings.
Elgeti
F
F
Klinik für Strahlenheilkunde CC6, Campus Virchow-Klinikum, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany. florian.elgeti@charite.de
Amthauer
H
H
Denecke
T
T
Steffen
I
I
Heuck
F
F
Stelter
L
L
Ruf
J
J
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000150:complications / Q000000981:diagnostic imaging*; D005260:Female; D005710:Gallium Radioisotopes; D006801:Humans; D033162:Incidental Findings; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000150:complications / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography; D011868:Radioisotopes; D014057:Tomography, X-Ray Computed
D005710:Gallium Radioisotopes; D011868:Radioisotopes