The effect of definitive irradiation on local control and disease free survival in breast cancer

The prognostic factors important in determining local regional control or failures can be divided into two groups. The first, the intrinsic factors, relate to the initial inherent condition of the tumor, that is, the tumor labeling index, progesterone receptors, the degree of involvement of the lymph nodes in the area, the size of the tumor, etc. The second, extrinsic factors, relate to type and adequacy of treatment. The presentation demonstrates (a) that the most critical factors in determining failure and patterns of failure are the intrinsic factors, that is, histologic grade tumor labeling index, number of nodes involved, progesterone receptors and size, and (b) that the adequacy of treatment affects failure and patterns of failure in patients treated. This paper shows that adequate radiation reduces local recurrence and, consequently, increases the survival rate, it also demonstrates that inadequate radiation will lead to increased local recurrence and decreased survival. The factors involved in determining the adequacy of irradiation are discussed.