Adjuvant systemic therapy for operable breast cancer

Increased autocrine production of insulin-like growth factor II (IGF-II) alters serum sensitivity of MCF-7 human breast cancer cell proliferation

Regulation of the growth of breast cancer cells is the result of a complex interaction between steroid hormones and growth factors, and in particular of oestrogen and insulin-like growth factors (IGF). Alteration of any one mitogenic component can affect the cell response to other pathways. Previous work has shown that increased autocrine production of IGF-II from a transfected inducible expression vector can result in reduced oestrogen sensitivity of growth of MCF-7 human breast cancer cells. This report describes alterations to non-oestrogen regulated pathways of cell growth following enhanced IGF-II expression in these transfected MI7 cells. Serum sensitivity of cell growth in the absence of oestrogen was found to differ between MI7 and untransfected MCF-7 cells, in that growth of MI7 but not MCF-7 cells was strongly inhibited by high serum levels. Increased serum had no effect on levels of IGF-II mRNA, IGFIR, IGFBP4 mRNA, or IGFBP secreted in MI7 cells. However, growth inhibition by serum in MI7 cells could be overcome by increasing levels of IGF-II in the serum or by removal of IGFBP onto polycarbonate membranes. Thus, the growth inhibition by serum in MI7 cells is concluded to result from the increased levels of IGFBP added with higher serum. This would support an inhibitory role for IGFBP on growth of breast cancer cells when cell growth is being driven by IGF pathways in the absence of oestrogen, and would suggest that cellular sensitivity to such factors can depend on levels of endogenous IGF production.

Interpectoral nodes in carcinoma of the breast: requiem or resurrection

Fifty-eight consecutive patients undergoing a modified radical mastectomy were subjected to complete dissection and pathological assessment of the interpectoral fascia and the group of lymph nodes it contains. The dissection was carried out in all patients, irrespective of whether they were palpable or not. Interpectoral nodes (IPNs) were anatomically present in 28 patients (48%) and were completely absent in 30 patients (52%). Ten patients were Stage I, 18 were Stage II, and 30 were Stage III. Of the 25% (15/58) of patients with microscopic metastasis, only 12/15 had palpable nodes; 66% (10/15) of patients had axillary and apical nodes positive. Significantly, two patients with negative nodes in the axillary and apical group had metastatic Rotter's nodes. Of the 15 patients with positive IPNs, nine had primary tumors located within the upper quadrants of the breast, whereas only five had tumors in lower quadrants and one had a centrally located tumor. The neurovascular bundle to the pectoralis major could be safely preserved in 93% (54/58) of patients. The incidence of impalpable nodes with microscopic metastasis and the evidence of exclusively metastatic interpectoral nodes with uninvolved axillary and apical nodes prompt the following conclusions: (1) interpectoral fascia and nodes should be mandatorily dissected in all patients irrespective of the nodes being palpable or not; (2) the dissection is anatomic and is associated with almost no additional morbidity; (3) the group of patients with IPNs positive and the axillary group negative, would benefit maximally from the IPN dissection. Similarly, this dissection in all other groups of patients would enable a more accurate staging and selection of therapeutic strategies.

The importance of interpectoral nodes in breast cancer

In a consecutive series of 73 patients undergoing a level III axillary clearance, interpectoral nodes were sought and, if palpable, excised. 18 interpectoral nodes were identified in 15 patients, 10 (14%) of whom had involved and 5 of whom had uninvolved interpectoral nodes. 7 of the 10 patients with involved interpectoral nodes also had axillary node involvement, but 3 patients had positive interpectoral nodes in the absence of involved axillary nodes. A comparison of patient and tumour characteristics in the groups of patients with and without interpectoral node involvement showed that patients who had involved interpectoral nodes were significantly younger and had significantly larger tumours. Interpectoral node involvement by breast cancer is not uncommon and these nodes can be involved in the absence of axillary nodal involvement. They should be looked for, and if identified, excised during axillary clearance.