Skeletal metastases from breast cancer: pathogenesis of bone tropism and treatment strategy

Breast cancer (BC) is the most common female cancer worldwide with approximately 10 % of new cases metastatic at diagnosis and 20-50 % of patients with early BC who will eventually develop metastatic disease. Bone is the most frequent site of colonisation and the development of skeletal metastases depends on a complex multistep process, from dissemination and survival of malignant cells into circulation to the actual homing and metastases formation inside bone. Disseminated tumor cells (DTCs) can be detected in bone marrow in approximately 30 % of BC patients, likely reflecting the presence of minimal residual disease that would eventually account for subsequent metastatic disease. Patients with bone marrow DTCs have poorer overall survival compared with patients without them. Although bone-only metastatic disease seems to have a rather indolent behavior compared to visceral disease, bone metastases can cause severe and debilitating effects, including pain, spinal cord compression, hypercalcemia and pathologic fractures. Delivering an appropriate treatment is therefore paramount and ideally it should require interdisciplinary care. Multiple options are currently available, from bisphosphonates to new drugs targeting RANK ligand and radiotherapy. In this review we describe the mechanisms underlying bone colonization and provide an update on existing systemic and locoregional treatments for bone metastases.

Staging of primary breast cancer is not indicated in asymptomatic patients with early tumor stages

BACKGROUND

The routinely practiced staging for distant metastasis in patients with primary breast cancer has been increasingly questioned.

PATIENTS AND METHODS

Data from 742 patients with breast cancer who had completed staging (chest x-ray, liver ultrasound, and bone scan) were retrospectively analyzed. Present findings were transferred to a dataset of a voluntarily monitored benchmarking project by the West German Breast Center that included patient data of 179 breast cancer centers.

RESULTS

Routine staging examinations revealed in 1.2% (n = 9) distant metastasis and in 38.8% (n = 288) suspicious results. In total, 15 patients (2%) had distant metastases confirmed by additional diagnostics. The existence of distant metastases correlated with tumor size, nodal state, and lymphatic vessel spread. Tumor size and nodal state were independent predictors for disseminated disease. The risk of exhibiting distant metastases was 0.77% for patients with tumor stage pT1 pN1. Based on these findings, in 159,310 patients 41,728 chest x-rays, 43,950 liver ultrasounds, and 39,037 bone scans could have been avoided.

CONCLUSION

Asymptomatic patients with tumor stages ≤ pT1 pN1 do not benefit from staging of primary breast cancer. Suspending staging examinations for these patients could reduce cost without restricting oncologic safety.

Radiological staging in breast cancer: which asymptomatic patients to image and how

BACKGROUND

Approximately 4% of patients diagnosed with early breast cancer have occult metastases at presentation. Current national and international guidelines lack consensus on whom to image and how.

METHODS

We assessed practice in baseline radiological staging against local guidelines for asymptomatic newly diagnosed breast cancer patients presenting to the Cambridge Breast Unit over a 9-year period.

RESULTS

A total of 2612 patients were eligible for analysis; 91.7% were appropriately investigated. However in the subset of lymph node negative stage II patients, only 269 out of 354 (76.0%) investigations were appropriate. No patients with stage 0 or I disease had metastases; only two patients (0.3%) with stage II and < or =3 positive lymph nodes had metastases. Conversely, 2.2, 2.6 and 3.8% of these groups had false-positive results. The incidence of occult metastases increased by stage, being present in 6, 13.9 and 57% of patients with stage II (> or =4 positive lymph nodes), III and IV disease, respectively.

CONCLUSION

These results prompted us to propose new local guidelines for staging asymptomatic breast cancer patients: only clinical stage III or IV patients require baseline investigation. The high specificity and convenience of computed tomography (chest, abdomen and pelvis) led us to recommend this as the investigation of choice in breast cancer patients requiring radiological staging.