A proposal for the treatment technique for the breast and regional lymph nodes in patients with conservatively operated neoplasms

: Adequate irradiation of regional lymph-nodes in selected patients seems to improve disease-free and over-all survival rates. Technically, regional lymph-nodes are generally treated separately (supra-infra clavicular, apex of axilla and internal mammary chain-IMC). About the treatment of the IMC nodes, there are two main problems: the identification of the individual target volume, and its correct irradiation. For the latter problem, the most employed solutions are: the inclusion of IMC in the tangential fields, the use of the direct or oblique electron beam for IMC alone. None of them is optimal regarding to the tolerance of adjacent critical organs and from a geometric and dosimetric point of view. In this paper we propose and discuss a modified method. The IMC nodes together with the breast are irradiated by a three field technique (two tangential photon beams and one oblique electron beam). Their arrangement allows to treat every part of the target by two fields, reducing the risk of hot and cold spots. This is obtained by extending the internal tangential photon beams to cover the electron beam. Wedges and different weights must be used to achieve an uniform dose distribution.