A young woman with a breast mass: What every internist should know
Case continues: Seven years later, metastases in the spine
The patient achieves a complete remission. She is seen for a routine visit 7 years after diagnosis. She now reports mid-back pain that has worsened over the last 2 months. A bone scan reveals diffuse metastatic disease in the spine and in both humeral bones. CT of the chest, abdomen, and pelvis is negative for visceral metastases. Bone marrow aspiration and biopsy study show marrow infiltration by adenocarcinoma that stains positive for estrogen receptors and negative for HER2. The patient otherwise feels well and has no other symptoms.
WHAT TREATMENT FOR METASTATIC BREAST CANCER?
6. What should you now do for our patient?
- Discuss end-of-life care and refer her to a hospice program
- Educate the patient that no options for treatment exist and recommend enrolling in a phase I clinical trial
- Refer her to an oncologist for consideration of chemotherapy
- Refer her to an oncologist for consideration of endocrine treatment
She should be referred to an oncologist for consideration of endocrine treatment.
The most common sites of breast cancer metastases are the bones, followed by the liver and lungs. Metastatic breast cancer almost always is incurable. However, treatment can palliate symptoms.
Although a randomized trial of treatment vs best supportive care has never been done, many believe that treatment may improve survival. 40 The median survival of patients treated with standard therapy is about 3 years if the breast cancer is estrogen-receptor-positive and 2 years if it is estrogen-receptor-negative, but survival rates vary widely from patient to patient.41,42
Standard therapy or enrollment in a clinical phase II or III trial is indicated for this patient before considering enrollment in a phase I clinical trial or supportive care alone.
Endocrine therapy is the first-line therapy in women with estrogen-receptor-positive metastatic breast cancer. Postmenopausal women usually receive an aromatase inhibitor first.43,44 Response to endocrine therapy usually takes weeks to months but may last for several years.
Premenopausal women with estrogen-receptor-positive breast cancer also receive ovarian ablation therapy (oophorectomy or chemical ovarian ablation) with gonadotropin-releasing hormone agonists.
In addition, most patients with bone involvement are treated with high doses of intravenous bisphosphonates, which can reduce skeletal complications.45
Chemotherapy is reserved for patients with estrogen-receptor-negative breast cancer and those with cancer that progresses despite treatment with multiple antiestrogen agents. The time to response when chemotherapy is used is quicker, but the duration of response is usually shorter, lasting on average less than 1 year.37
Trastuzumab (Herceptin), a monoclonal humanized murine antibody to the extracellular domain of the HER2 protein, is indicated in patients with HER2-overexpressing tumors.46,47
STABLE 2 YEARS LATER
The patient was started on letrozole and a bisphosphonate, zolendronic acid (Zometa). Ovarian ablation was initiated with goserelin (Zoladex) given monthly. A bone scan performed 2 months after starting treatment showed improvement in bony metastases. She also noted significant improvement in pain. Her disease remains stable 2 years after starting endocrine therapy.
