Chemotherapy-Resistant Breast Cancer and Carcinomatous Pleuritis Successfully Treated with Abemaciclib plus Letrozole Therapy

A 78-year-old woman was examined in the outpatient department with a chief complaint of swelling of the left breast. Examination confirmed a 10 cm mass in the left breast as along with edema and redness of the skin, following which a diagnosis of invasive micropapillary carcinoma was made after biopsy. The CT imaging showed left chest wall invasion, multiple axillary lymph node metastases, and left carcinomatous pleuritis. Since this a case of advanced breast cancer, we initiated treatment with bevacizumab plus paclitaxel. After 8 months, her medication was changed to eribulin, owing to progression of the cancer, which continued even up to 4 months. We then initiated abemaciclib plus letrozole therapy as the third treatment. We observed tumor reduction and clearing of pleural effusion with no serious adverse events, and continued her therapy for 11 months before the cancer progressed. We report a case of chemotherapy-resistant breast cancer and carcinomatous pleuritis in an older adult patient for which abemaciclib plus letrozole therapy was effective.

 

Comments：

Invasive micropapillary carcinoma is a rare type of breast cancer that is often associated with a poor prognosis. The presence of chest wall invasion, axillary lymph node metastases, and carcinomatous pleuritis suggests an aggressive disease that is resistant to conventional treatments.

Bevacizumab plus paclitaxel is a common first-line treatment for advanced breast cancer. However, the progression of the disease after 8 months of treatment indicates resistance to this regimen. Eribulin is a microtubule inhibitor that is often used as a second-line therapy in patients who have progressed after receiving anthracycline and taxane-based chemotherapy. Unfortunately, the disease continued to progress even with eribulin therapy.

Abemaciclib plus letrozole is a combination therapy that has been shown to improve progression-free survival in patients with hormone receptor-positive, HER2-negative advanced breast cancer. This regimen was effective in reducing the tumor size and clearing the pleural effusion in this patient. It is encouraging to see that the patient tolerated the therapy well with no serious adverse events.

It is important to note that each patient is unique, and treatment plans should be tailored to their individual needs and preferences. Close monitoring of the disease progression and regular follow-up with the treating oncologist are essential to ensure timely adjustments to the treatment plan.

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