Nuclear medicine imaging of breast cancer and regional lymph nodes

Abstract

The aim of this thesis was to explore the role of nuclear medicine in diagnosis of primary breast carcinoma and regional lymph node involvement. The introduction includes a review over nuclear medicine techniques currently under investigation.

Methods: In paper I, II, III and V patients were preoperatively investigated by scintimammography with 99m-Tc-Sestamibi. Ninety-six patients were imaged in prone position as a standard. All patients were routinely assessed by triple diagnosis (TD), i.e., physical investigation, mammography and fine-needle aspiration cytology. The results of TD had led to the decision that the patient was to be operated upon. Twenty-six patients were additionally imaged with single photon emission tomography (SPECT). Paper I, II and V evaluated Sestamibi uptake in breasts and paper III uptake in axillary lymph nodes. In paper IV detection of sentinel node (SN) in patients with breast carcinoma was studied. Lymphoscintigraphy with 99m-Tc-Nanocolloid, preoperative injection of Patent blue dye and peroperative use of gamma probe were applied on 75 patients.

Results and Implications: Scintimammography with 99m-Tc-Sestamibi showed a sensitivity of 84 % and specificity of 74 % (Paper II and V), which was not improved by the additional use of SPECT (Paper 1). The sensitivity of scintimammography in the detection of primary breast lesion depends on tumour size, site and histological features. Furthermore, also benign lesions showed increased Sestamibi uptake, which lead to false- positive findings. The method had unsatisfactory diagnostic accuracy in the detection of axillary lymph node metastases (Paper III). Complementary use of scintimammography to TD improved the sensitivity in diagnosing cancers, and was specialty valuable in patients with mammographically dense breast parenchyma (Paper V). The combined use of preoperative lymphoscintigraphy, injection of blue dye and the peroperatively use of a gamma probe resulted in a detection rate of SN of 92% in all patients. SN correctly predicted the axillary status in 96% of the cases and might therefore be a potential concurrent to axillary lymph node dissection (Paper IV).

Conclusions: Scintimammography can be recommended as a complementary method to TD, especially in patients with mammographically dense breasts. Biopsy of SN can be used instead of axillary lymph node dissection in selected patients.