Abstract
The internal mammary lymph node chain has been studied in patients with breast cancer by radioiosotope imaging. The technique enabled the study of lymph node function in an area inaccessible to clinical examination or lymphography.
Thirty-four patients with breast cancer have been studied by injecting the posterior sheath of the rectus abdominis muscle, in the subcostal region, with technetium-99m-labelled stannous phytate and subsequently imaging the anterior thorax. Lymph node metastases were diagnosed in 13 patients (38 per cent) in whom a suppressed uptake of the isotope by the internal mammary lymph nodes was observed. Eighteen patients (53 per cent) had normal scans and in 3 patients (9 per cent) the examination was technically unsatisfactory. Histopathological correlation of internal mammary node biopsy with the preoperative scan confirmed the scan findings in all but one case in which this was carried out. Radioassay of internal mammary lymph nodes confirmed that the agent was localized in them and that uptake was suppressed in the presence of metastases.
Twenty-three patients in this study underwent sequential scanning using first 99Tcm-labelled stannous phytate and subsequently 99Tcm-labelled antimony sulphide colloid. The latter agent was able to demostrate the anatomical presence of nodes when a suppressed uptake had initially been observed using 99Tcm-labelled stannous phytate.
Internal mammary lymphoscintigraphy may be of value in the preoperative of breast cancer.