[A Case of HER2-Positive Metastatic Breast Cancer Achieved a Complete Response to Paclitaxel and Trastuzumab in Combination with Pertuzumab in Fifth Therapy].

We report a case of HER2-positive metastatic breast cancer achieved a complete response(CR)to paclitaxel(PTX) and trastuzumab(HER) in combination with pertuzumab(PER) in 5th therapy. A 69-year-old woman was diagnosed left breast cancer and underwent mastectomy and sentinel lymph node biopsy in January 2011. Pathological examination revealed an invasive ductal carcinoma that was ER 0%, PgR 0%, HER2(3+), Ki-67 67% and node negative. Two years after the operation, she found multiple lung metastases in both lungs. She was administered drug treatment as HER2-positive metastatic breast cancer, but multiple lung metastases got worse after 4th treatment. Weekly PTX, trastuzumab and pertuzumab were administered as 5th therapy. After 2 months, lung metastases diminished significantly. After 44 courses of drug treatment, positron emission tomography computed tomography(PET-CT)scan revealed CR. She wanted to cease treatment, so she continues to get CT scan every half a year and the CR has been maintained.

[Clinical Practice of the Efficiency and Safety of Palbociclib in Patients with Metastatic Breast Cancer].

We aimed to examine the effects of palbociclib and neutropenia in patients with metastatic breast cancer(MBC). From December 2017 to December 2019, 18 patients with estrogen receptor(ER)-positive, human epidermal growth factor receptor 2(HER2)-negative MBC were treated with palbociclib for at least 1 cycle. The most common adverse event(AE) was neutropenia, which occurred in 83% of all cases. With cessation and dose reduction, none of the patients had Grade 4 neutropenia. Palbociclib used in the first- or second-line treatment of MBC showed a higher efficacy than when used as the third-line treatment, which was observed as a longer duration to stay on treatment and higher efficacy.