Lymphoscintigraphy in breast cancer patients - comparison of peritumoural and intradermal injection

Aim of this study was to determine whether the sentinel lymph nodes (SLNs) can be accurately identified in breast cancer patients with intradermal inj ection of the radiotracer above the primary tumour in comparison to peritum oural injection. Methods: In 45 women with breast cancer we performed lymph oscintigraphy on two separate days. We injected Tc-99m nanocolloid on the f irst day peritumourally, and on a separate day intradermally. The results o f both investigations using different injection sites were compared in orde r to determine the number and location of SLNs. Results: The SLN identifica tion rate using peritumoural injection was 71% (32 of 45 patients) and 96% (43 out of 45 patients) using intradermal injection. In 62% (28 of 45 patie nts) the number and location of the SLNs were identical. In 97% (31 of 32 p atients) in whom a SLN was detected using peritumourol injection, the same SLNs reappeared with intradermal infection. There were no false negative fi ndings with the peritumoural administration of tracer whereas the intraderm al administration approach resulted in a faire negative rate of 13%. Conclu sion: In women with breast cancer the reproducibility of lymphoscintigraphy using peritumoural and introdermal injection sites was 62%. The intraderma l injection modality enables the detection of a SLN in patients where the p eritumoural injection failed but it has the disadvantage of a higher false negative rate in comparison to the peritumoural injection technique.