Materials and Methods
In our clinic, to see the drainage from the breast to the axilla routinely on lymphoscintigraphy and to determine the number of increased uptake SLNs, first early then 2 hours later delayed imaging is performed. If the drainage area cannot be detected in the images and no increased uptake SLN is seen, new images are taken after some time if necessary but in the COVID-19 pandemic period it was decided by the surgical and nuclear medicine teams not to take delayed images in order to shorten the waiting time and hence reduce the risk of viral spread and transmission. After intradermal and 1 intraparenchymal or intra/peritumoral injection of 1mCi of 99m Tc labeled nanocolloid (Navidea Biopharmaceuticals, Dublin) to 4 quadrants around the lesion for the purpose of marking the SLN on the morning of the operation or one day before; early (dynamic-SPECT) and 2 hours later delayed (static) images are taken in the Nuclear Medicine unit. The patient is then taken into operation and intraoperative SLNs are searched with a gamma detector.
In both groups, number of lesion increased uptake observed in the lymphoscintigraphy, early/delayed increased uptake rate, SLN detection rate, sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV) of SLNB process, number of positive SLN, axillary dissection, axillary malignant lymph node, age, tumor characteristics (T stage, receptor status) and neoadjuvant therapy status were examined in patients. In the study the effect of taking delayed images on lymphoscintigraphy on SLN biopsy success was investigated.
Lymphoscintigraphy reports were examined by scanning electronic files. Micrometastatic lymph nodes were not included in the false negativity rate (FNR). The study protocol was approved by the ethics committee of our institution and the ethics committee approval number is 95/27.05.20.