Purpose: In order to determine the initial treatment strategies for primary operable unicentric breast cancer, the possible relationships of the amplification of human epidermal growth-factor receptor-2 (HER-2), with age, menstrual status, tumor pathological size (pT), histopathological tumor type (HP) and kind of surgical treatment were studied.
Methods: Analysed were 301 patients treated initially by surgery in the period 2006-2009. HP tumor type, pT and HER-2 status (using firstly immunohistochemistry and then chromogenic in situ hybridization/CISH) were determined. The patients were divided into 2 subgroups according to the presence (CISH+)/absence (CISH-) of HER-2 amplification.
Results: Data on pT and HER-2 analyses were available for 293/301 (98.3%) patients with ductal (DC) and lobular carcinoma (LC). Amplification of HER-2 was found in 66 (21.9%) patients. No significant difference between the two subgroups regarding age (p=0.08), menstrual status (p>0.05) and kind of operation (p>0.05) was found. HP showed statistically significant difference between DC (55; 83.3%) and LC (11; 16.7%) patients with HER-2 amplification (p<0.01). Further HP analysis of the type of cancer within the pT category as a subgroup showed significantly higher frequency of HER-2 amplification in DC patients for pT1 (p<0.01) and in pT2 + pT3pN0 (p<0.05) compared with patients with LC.
Conclusion: This study showed a significantly higher incidence of HER-2 amplification in DC tumors, especially in pT1 and pT2, than in LC, which may influence the options in treatment strategies in primary unicentric operable DC type of breast cancer.