Significance of the relative size of a breast tumor in deciding the method of surgical treatment.

Aim: In the surgical treatment of breast cancer there are basically two options: radical and breast-sparing surgery. The main criterion in deciding the mode of treatment is the absolute size of the primary tumor. The purpose of this study was to analyze the relative size of a breast tumor as a prognostic factor and to establish boundary values of the relative tumor size for breast-sparing or radical surgery.

Methods: The relative volume of the breast tumor was analyzed in 200 female patients treated at the Zagreb University Hospital for Tumors. All patients were diagnosed with ductal invasive carcinoma and underwent radical surgery.

Results: The study found the correlation between the relative volume of the tumor and tumor grade (r = 0.805, P = 0.24) and between the relative volume of the tumor and the involvement of regional lymph nodes (r = 0.493, P = 0.14). These correlations confirmed the possible prognostic value of the relative size of a breast tumor.

Conclusions: Three percent is the boundary value of the relative volume of a tumor at which its biological potential changes and the pathohistological level of a tumor and the number of affected lymph nodes increases. The relative size of 3% could therefore be considered a boundary value in making a decision about the method of surgical treatment (breast-sparing or radical surgery). For tumors with a relative size of less than 3%, breast-conserving surgery is recommended for its lesser malignant potential and the possibility of performing wide extirpation (extirpation 1-2 cm from the tumor margin), regardless of the size of the breast.