Two birds with one stone: octreotide treatment for acromegaly and breast cancer.

Case Report A 74-year-old woman presented to the Breast Medical Oncology clinic for treatment of hormone receptor–positive, human epidermal growth factor receptor 2 (HER2) –negative, metastatic invasive lobular carcinoma (ILC). She was initially diagnosed in January 2007 with left breast ILC, which was estrogen receptor (ER) positive, progesterone receptor positive, and HER2 negative, when she presented with an ulcerating left breast mass. She underwent a left modified radical mastectomy and was found to have a pathologic stage T4N0 tumor. She received adjuvant chemotherapy with cyclophosphamide, methotrexate, and fluorouracil for six cycles followed by adjuvant therapy with exemestane at an outside hospital. Two years after the initiation of exemestane, she complained of bilateral hip and shoulder pain, and in April 2010, when a bone scan revealed multiple areas that were consistent with osseous metastasis, she presented to our center (M.D. Anderson Cancer Center) for additional treatment. The patient had a remote history of acromegaly that was treated with transsphenoidal resection in 1991, with no additional follow-up care. She also had a history of poorly controlled type 2 diabetes mellitus, hypertension, and osteoarthritis. On evaluation the patient was found to have numerous skin nodules that were suggestive of metastasis and features that were suggestive of acromegaly (Figs 1A and 1B). A biopsy of her skin nodules revealed metastatic carcinoma consistent with breast origin that was ER positive, progesterone receptor positive, and HER2 negative. A staging work-up with a computed tomography scan of the chest/abdomen and pelvis revealed diffuse bone, subcutaneous, intramuscular, pulmonary metastasis, and diffuse mediastinal lymphadenopathy. In June 2010, she was treated with fulvestrant and dasatinib as part of a clinical trial, and in October 2010, on disease progression in the lungs, she was withdrawn from the study. At that time, a magnetic resonance imaging scan of her pituitary revealed a residual subcentimeter adenoma or residual normal glandular tissue in the anterior sella, and measurements of insulin-like growth factor-1 levels (IGF-1) and growth hormone (GH) levels were elevated at 352 ng/mL (normal range, 64 to 188 ng/mL) and 6.45 ng/mL (normal range, 0.01 to 3.61 mL), respectively, thus confirming the diagnosis of active acromegaly. Treatment for her acromegaly was then initiated with the somatostatin analog octreotide in October 2010. With her consent, treatment with fulvestrant was reinitiated to determine whether treating the acromegaly would help overcome endocrine therapy resistance. She demonstrated a profound and durable response with the addition of octreotide. She experienced a significant clinical improvement with the partial or complete regression of her subcutaneous tumor nodules. She also had improvement in her bone pain. Nine months after octreotide initiation, her GH declined to a nadir of 0.67 ng/mL, although her IGF-1 levels did not respond appreciably and ranged between 346 and 390 ng/mL. Compared with her initial [F]fluorodeoxyglucose (FDG) positron emission tomography scan in June 2010, the positron emission tomography scan performed after octreotide treatment in January 2011 demonstrated a marked interval decline in the FDG-avid metastatic disease, as shown in Figures 2A and 2B. Cancer antigen 27-29 levels decreased from 929.2 U/mL to 299.6 U/mL after initiation of octreotide (Fig 3). After the significant response, the disease remained stable, but at 14 months the patient was found to have progression, with a malignant pericardial effusion that required a pericardiocentesis. Notably, the patient had also missed 5 months of octreotide treatment. During this period, the GH peaked at 1.84 ng/mL and IGF-1 rose to 447 ng/mL. Interestingly, the GH levels seemed to correlate with her disease course. The timing of cancer progression coincided with the