Bisphosphonates for Breast Cancer: Questions Answered, Questions Remaining

Analysis of orthopedic surgery of bone metastases in breast cancer patients

BACKGROUND

Breast cancer is the most common malignancy and the second leading cause of death in women. Because bone metastases are a common finding in patients with breast cancer, they are of major clinical concern.

METHODS

In 115 consecutive patients with bone metastases secondary to breast cancer, 132 surgical procedures were performed. Medical records and imaging procedures were reviewed for age, treatment of the primary tumor, clinical symptoms, surgical treatment, complications, and survival.

RESULTS

The overall survival of patients with metastatic breast cancer was dependent on the site and the amount of the metastases. Age was not a prognostic factor for survival. If the result of the orthopaedic surgery was a wide resection (R0) survival was significantly better than in the R1 (marginal resection - tumor resection in sane tissue) or R2 (intralesional resection) situation. Concerning the orthopaedic procedures there was no survival difference.

CONCLUSION

In conclusion a wide (R0) resection and the absence of pathological fracture and visceral metastases were predictive for longer survival in univariate analysis. Age and the type of orthopaedic surgery had no impact on survival in multivariate analysis. The resection margins lost significance. The standard of care for patients with metastatic breast cancer to the bone requires a multidisciplinary approach.

Oncologic emergencies

OBJECTIVES

To provide an up-to-date review of current literature on the pathophysiology, diagnosis, and management of five key malignancy-related complications: superior vena cava syndrome, malignant pericardial effusion, malignant spinal cord compression, hypercalcemia, and acute tumor lysis syndrome.

DATA SOURCES

Database searches and review of relevant medical literature.

DATA SYNTHESIS

Malignancy-related complications demand increased attention from intensivists due to their frequency and increasing cancer prevalence. Although such complications portend a poor prognosis, proper acute management can improve short-term outcomes by facilitating either definitive care of the underlying malignancy or the institution of appropriate palliative measures.

CONCLUSIONS

Knowledge of malignancy-induced complications in critically ill patients expedites the ability of the intensivist to properly manage them. Five complications commonly requiring emergency management are addressed in this review. Specifically, superior vena cava syndrome may warrant radiation, chemotherapy, vascular stenting, or surgical resection. Malignant pericardial effusion may require emergency pericardiocentesis if cardiac tamponade develops. Malignant spinal cord compression demands immediate spinal imaging, glucocorticoids, and either surgery or radiation. Hypercalcemia requires aggressive intravenous hydration and a bisphosphonate. Acute tumor lysis syndrome necessitates intravenous hydration, rasburicase, and management of associated electrolyte abnormalities.

Aging and osteoporosis in breast and prostate cancer

As people with cancer survive longer, and as the US population ages, skeletal effects of cancer treatment are becoming more pronounced. This is particularly true for breast and prostate cancer survivors because of the high average age of patients with these malignancies, the propensity of older adults in general toward the development of osteoporosis, and the wide use of therapeutic agents in these cancers that negatively impact bone health. Various therapies used in the treatment and prevention of cancer may cause decreases in bone mineral density and an increased risk of debilitating fracture, even in the absence of bone metastases. Aging is both a baseline risk factor in the development of osteoporosis and bony fracture, as well as a predictor of poor outcome after fracture. A variety of mechanisms may be responsible for the development of bone loss in patients with breast or prostate cancer. Cytotoxic chemotherapy may directly exert long-term toxic effects on bone. Chemotherapy and endocrine therapy can induce hypogonadism, leading to an increased rate of bone loss. The risk of skeletal events in older adults due to cancer therapy should be appreciated by all oncologists, geriatricians, and internists. The following review may serve as a guide to the skeletal side effects of cancer therapy in older adults with breast or prostate cancer, how to screen for treatment-related bone loss, and how to best prevent and/or treat skeletal events.

In vitro assessment of liposomal neridronate on MDA-MB-231 human breast cancer cells

Bisphosphonates have been used for decades in the standard therapy of bone-related diseases, including bone metastasis of various malignancies, and they might as well be toxic on early cancer cells themselves. In order to allow a better delivery of neridronate (a N-containing bisphosphonate with relatively poor activity), liposomes were evaluated in vitro on cancer cell lines (MDA-MB-231, U87-MG and Caco2). After chemical synthesis, this water-soluble molecule was encapsulated into liposomes containing DOPC:DOPG:Chol (72:27:1 molar ratio). The influence of neridronate (free or liposomal) on cell viability or proliferation after treatment was evaluated using the MTT method, as well as cell migration and invasion assays; these techniques showed a drastic improvement of the action of neridronate on MDA-MB-231 cells with an EC(50) 50 times lower when neridronate was encapsulated. Internalization of liposomes was followed by flow cytometry and fluorescence microscopy, demonstrating internalization via the endocytic pathway. Furthermore, since overexpression of matrix metalloproteinases (particularly MMP-2 and MMP-9) has been correlated to poor prognosis in many cancer types, detection of MMP expression is a satisfactory indication of the therapy efficiency and was then performed on treated cells. On MDA-MB-231 cells, MPPs expression was also significantly reduced by neridronate while entrapped in liposomes.

Electrolyte complications of malignancy

A thorough working knowledge of the diagnosis and treatment of life-threatening electrolyte abnormalities in cancer patients, especially hyponatremia, hypoglycemia, and hypercalcemia, is essential to the successful practice of emergency medicine. Although most minor abnormalities have no specific treatment, severe clinical manifestations of several notable electrolytes occur with significant frequency in the setting of malignancy. The treatment of life-threatening electrolyte abnormalities is reviewed here. Promising future treatments directed at the underlying physiology are also introduced.

Orthopedic surgery implications of breast cancer

Breast cancer is the most common malignancy and the second leading cause of death in women. The metastatic involvement of bone denotes disease progression and decreased survival. Controversy exists regarding the exact pathophysiologic mechanism of metastasis and the different pathways that determine an osteoblastic versus osteoclastic bone compromise. Several breakthrough advances in imaging techniques aid in the detection, staging and follow-up of bone metastases. Although usually responsive to hormonal therapy and pharmacologic interventions, skeletal metastases often require some type of surgical intervention. Orthopedic surgeons should establish an active role in the multidisciplinary treatment of patients with breast cancer.