Objectives:
Breast cancer is the most frequent female cancer. In some cases, a change in hormonal receptors and Her2neu status between primary tumors and relapsed tumors were reported.

Our aim is to determine if it is mandatory to repeat immunohistochemistry and if there are some factors that can predict change of status.



Methods:
A retrospective study about 46 patients with locoregional cutaneous or lymphatic relapse between 2015 to 2017. The patients were devided into 5 molecular subtypes:
Lumina A, Luminal B, Luminal B Her2; Her2 and triple negative subtype.

Results
The median age was 47-year-old (IQR 27-79). Mean histologic size was 4.56 cm (IQR 0.5-13). 34 patients were grade II of SBR. 54,34 %(25) of the patients had radical surgery associated to chemotherapy radiation therapy and hormonal therapy as initial treatment. A mean number of harvested metastatic lymph-nodes at initial surgery was 8.28 (0-36). 54,34 % (25) had their status changed. The highest ratio of status changes was observed with luminal A tumors73.33% (11/15). Whereas triple negative tumors have the lowest ratio 16.66% (1/6). We studied the impact of age, time to relapse and site of relapse on status change, but no statistical significance was found.

Conclusions:
Our results tend to prove the necessity of repeat immunochemistry. However, they failed to determine factors associated with higher risk of status change. Those results are to be taken with caution and further studies with bigger study population are mandatory.

IS RETESTING IMMUNOHISTOCHEMISTRY FOR BREAST CANCER LOCOREGIONAL RELAPSE MANDATORY? A 46 CASES STUDY.