[Techniques of radiotherapy in so-called operable carcinoma of the breast]

The techniques of radiotherapy alone in carcinoma of the breast are determined by the possibilities of durable cure of the tumoral process using locoregional treatment. It seems undisputable that the risk of metastases at a distance from the tumor is related to the topographical as well as volum extension of lymph node involvement. Such risk is low with N-; it rapidly increases with lower axillary N+; it predominates with medial mammary N+; it becomes almost constant with upper axillary (subclavian) and supraclavicular N+. This explains why dose distribution should aim at curing, even at the price of some cosmetic or functional risk, tumoral lesions of the mammary gland, of the lower axillary area and, to a certain extent, of the medial mammary area. On the contrary, it is illusory to deliver an overdosage at ultrahigh dose-rates to the sub- and supraclavicular areas, where the chances for durable cure are almost nul if lymph nodes are invaded. This explains why curative radiotherapy alone appears only indicated in little developed cancers in their mammary (T1 or T2) as well as lymph node (N0 or N1 a) aspects. This also explains why such a responsability implies for the radiotherapist absolutely perfect technical conditions of spotting, centring and dose-measurements; careful protection of all healthy structures surrounding the target-volumes should, in particular, be obtained (for instance, accurate delimitation of beams, use of lead shields or even compensatory wedges should provide appropriate protection to the lung parenchyma, pectoral muscle, head of the humerus, laryngotracheal system). Finally, it is in the axillary area that the major technical hazards are encountered with: an insufficient dose is liable to cause lymph node recurrence, an excessive dose is liable to provoke irreversible muscular, articular, vascular or nervous sequelae. Provided a high level of technicity, it should be admitted to-day that a durable locoregional cure can be obtained in the vast majority of cases with but minimal tissue sequelae.