Although the majority of patients has different pathways of lymphatic drainage from the ipsilateral breast and upper limb, in a small minority of patients the drainage pathway is through a common SLN. Such patients may be at increased risk of developing upper limb breast cancer-related lymphoedema after SLN biopsy.

It is not known why some women develop breast cancer-related lymphedema (BCRL) of the arm, whereas others having similar treatment do not. We speculated that increased uptake of protein into local blood may protect against BCRL. Sixteen women were given bilateral subcutaneous hand webspace injections of polyclonal immunoglobulin (HIgG), (99m)Tc-HIgG on one side and (111)In-HIgG on the other, before and 3 mo after axillary clearance surgery. The rates of clearance of activity from the depot (k) and accumulation in central blood (b(contra)) were measured using a scintillation probe and bilateral antecubital vein blood sampling, respectively. Activity accumulating in blood ipsilateral to the injected side, in excess of central blood activity (b(ipsi)) was also calculated as a measure of local vascular uptake. The k correlated with b(contra), but neither changed in response to surgery. However, b(ipsi) for injections of (99m)Tc-HIgG into the affected arm increased in all seven patients in whom data were available (0.018 +/- 0.006 to 0.038 +/- 0.007%/min; P < 0.05); indeed, in five of these seven, b(ipsi) paradoxically exceeded b(contra), and none developed BCRL at 3-yr follow-up. We conclude that uptake of protein into local blood and/or proteolysis increases after axillary surgery and may protect against BCRL.

Intradermally injected erythrocytes are able to detect and potentially quantify peripheral LVCs.

The aim of the project was to identify how lymphatic pathways are functionally arranged within the axilla (i.e., single linear chains, branching chains, and networks). We used ex vivo dual isotope radioassay of individual nodes resected at axillary lymphatic clearance surgery in breast cancer patients given simultaneous intradermal breast and intradermal hand injections (n = 15) or simultaneous intradermal breast and parenchymal breast injections (n = 15) of differentially labelled human immunoglobulin (Tc-99m-HIG and In-111-HIG). Nodes were ranked according to isotope content and activity-rank profiles constructed for each of the two injection sites. The majority of profiles following intradermal breast injection (17/30) were mono-exponential, consistent with a simple linear chain of nodes, with each node extracting a constant fraction of incoming HIG. In 15/17 of these, the accompanying profile from the alternative injection site was also mono-exponential and, in 11/15, essentially parallel. The profile appeared biphasic in 12/30 intradermal breast injections and of these 9/12 were accompanied by a biphasic profile (7/9 parallel) from the alternative injection site. In one patient, both profiles were polyphasic and parallel. Considering the respective shapes of paired profiles and whether the two injection sites shared the same first echelon nodes, functional lymph node arrangements are proposed. The commonest is a single linear chain, then a chain branching into two linear chains, and, least common, a network.

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