Differences in lymph drainage between swollen and non-swollen regions in arms with breast-cancer-related lymphoedema

Recent research indicates that the pathophysiology of breast-cancer-related lymphoedema (BCRL) is more complex than simple axillary lymphatic obstruct ion as a result of the cancer treatment. Uneven distribution of swelling (i nvolvement of the mid-arm region is common, but the hand is often spared) i s puzzling. Our aim was to test the hypothesis that local differences in ly mphatic drainage contribute to the regionality of the oedema. Using lymphos cintigraphy, we measured the removal rate constant, k (representing local l ymph flow per unit distribution volume, V-D), for Tc-99m-labelled human imm unoglobulin G in the oedematous proximal forearm, and in the hand (finger w eb) in women in whom the hand was unaffected. Tracer was injected subcutane ously, and the depot plus the rest of the arm was monitored with a gamma -r adiation camera for up to 6 h. V-D was assessed from image width. Contralat eral arms served as controls. k was 25% lower in oedematous forearm tissue than in the control arm (BCRL, -0.070 +/-0.026%(.)min(-1); control, -0.093 +/-0.028%(.)min(-1); mean +/-S.D.; P=0.012) and V-D was greater. In the non -oedematous hand of the BCRL arm, k was 18% higher than in the control hand (BCRL, -0.110 +/-0.027%(.)min(-1); control, -0.095 +/-0.028%(.)min(-1); P= 0.057) and 59% higher than forearm k on the BCRL side (P=0.0014). V-D did n ot differ between the hands. Images of the BCRL arm following hand injectio n showed diffuse activity in the superficial tissues, sometimes extending a lmost to the shoulder. A possible interpretation is that the hand is spared in some patients because local lymph flow is increased and diverted along collateral dermal routes. The results support the hypothesis that regional differences in surviving lymphatic function contribute to the distribution of swelling.