Disseminated Carcinomatosis of the Bone Marrow from Occult Breast Cancer Responding to a Sequence of Endocrine Therapy

Abstract

Patients with cancer of unknown primary (CUP) are generally treated with chemotherapy. Bone marrow involvement suggests an advanced stage, and CUP with disseminated carcinomatosis of the bone marrow (DCBM) appears to have a dismal prognosis. However, our case of CUP with DCBM was successfully treated with a sequence of endocrine therapy over a long period. A woman presenting with low back pain was found to have multiple bone metastasis without an identifiable primary tumor on imaging studies. Blood tests revealed anemia and thrombocytopenia. A bone marrow biopsy was performed and showed relatively uniform small cells, strongly positive for estrogen receptor and progesterone receptor expression. We considered chemotherapy to be risky due to bicytopenia and an aromatase inhibitor, letrozole, was initiated. The patient's symptoms and laboratory findings gradually improved and bone lesions almost disappeared on FDG-PET/CT after 1 year of treatment. After 2 years on letrozole, hemoglobin levels and platelet counts had been gradually decreasing. Although she had no symptoms and no significant changes were observed on a CT scan, disease progression was highly likely. Thus, second-line treatment with fulvestrant and palbociclib was commenced, and hemoglobin levels and platelet counts were restored to within the normal ranges. She currently continues to receive fulvestrant and palbociclib over a year later. CUP complicated with DCBM might be metastatic occult breast cancer, and endocrine therapy can be a valuable treatment option if tumors express hormone receptors.

Response and tolerability of palbociclib plus fulvestrant in breast cancer patient with bone marrow metastasis and cytopenia: A case report

“…Yamaguchi et al achieved response with palbociclib plus fulvestrant therapy in a patient with breast cancer with bone marrow metastases. (5) Although bicytopenia was present in our case report, we observed that dose…”

The Therapeutic Challenge of Disseminated Bone Marrow Metastasis From HR-Positive HER2-Negative Breast Cancer: Case Report and Review of the Literature

“…In contrast, ET, although less rapid than chemotherapy in obtaining a disease response, is better tolerated and has no hematological toxicity. Therefore, endocrine agents, from the point of view of toxicity, can be used safely in the treatment of BC with DCBM (34).…”

“…The patient was treated initially with letrozole and then with a combination of fulvestrant and palbociclib as second-line treatment, resulting in a response to treatment lasting more than 1 year. Palbociclib was initiated at a reduced dose (75 mg/day), being concerned about a possible exacerbation of pre-existing hematological toxicity (34).…”

Bone Marrow Carcinomatosis in a Stage IV Breast Cancer Patient Treated by Letrozole as First-Line Endocrine Therapy

“…Garufi et al [ 5 ] reported a case of a Stage IV BMC patient with Hb 7.5 g/dL and Plt 110,000/μL who achieved CR with a combination of CDK4/6 inhibitors and aromatase inhibitors as first-line endocrine therapy and continued treatment for 26 months. Yamaguchi et al [ 6 ] started letrozole monotherapy for 2 years for BMC in latent breast cancer, and pancytopenia improved. The patient was then treated with a combination of a CDK4/6 inhibitor and fulvestrant for second-line therapy [ 6 ].…”

“…Yamaguchi et al [ 6 ] started letrozole monotherapy for 2 years for BMC in latent breast cancer, and pancytopenia improved. The patient was then treated with a combination of a CDK4/6 inhibitor and fulvestrant for second-line therapy [ 6 ]. The present case had a similar course.…”