R. Riccardi1,3, S. Patil1, R. S. Chamberlain1,2,3 1Saint Barnabas Medical Center,General Surgery,Livingston, NJ, USA 2University Of Medicine And Dentistry Of New Jersey,Newark, NJ, USA 3Saint George’s University,Grenada, Grenada, Grenada
Introduction: Worldwide statistics reveal that approximately 30% to 70% of female primary breast cancer patients will ultimately develop recurrence and succumb to metastases. The site of recurrence is intimately linked to survival, as visceral metastases patients generally succumb to disease early, while bone metastases patients can live years if properly treated. Advances in chemotherapy therapy drugs and regimens including the addition of targeted and immunotherapy therapy has yielded dramatic results in regards to prolonging survival for metastases to certain metastatic sites. This study aimed to patterns of metastatic spread among different age and ethnic groups and to more precisely determine metastatic site specific survival in metastatic breast cancer from a recent large nationwide cohort.
Methods: Data on all patients with breast cancer were abstracted from the Nationwide Inpatient Sample (NIS) database (2002-2009). Patients with MBC were identified using ICD-9 codes 1960-19889 (Table 1). Four ethnic groups (Caucasian, African American, Hispanic and Others), Two age groups (<50 years and >50 years) and two outcome groups (Alive and Dead) were compared for differences in metastatic patterns. Standard statistical methods were used for data analysis.
Results: 708,423 patients were analyzed for incidence of metastatic breast cancer. Overall metastases to axillary lymph nodes occurred in 24.3%, bone in 4.6%, and respiratory tract in 2.8%. Both lymph node and extralymphatic metastases were highest among African Americans compared to other ethnic groups. Similarly Hispanics had the highest percent of lymph node and extralymphatic metastases compared to Caucasians except for skin, peritoneum and adrenal metastases. Extra lymphatic metastases both to solid and hollow viscera were more common in patients < 50 years except for liver, brain and ovary. Mortality occurred in 32.9% of patients with metastases to the large intestine, 23.8% to the respiratory tract, 23.9% to the kidney, and 23.7% to the GIT NEC. On multivariate analysis metastases to inguinal lymph nodes, large intestine, liver, respiratory tract, brain, bone, peritoneum, skin, gastrointestinal tract NEC and to the thoracic lymph nodes was independently associated with increased mortality.
Conclusion: Metastatic breast cancer, especially extralymphatic metastases is more common in the younger population. Metastases to atypical sites like the inguinal LN and large intestine is associated with the highest mortality. Increased knowledge of metastatic site specific survival, should be useful to improve breast cancer staging (e.g., perhaps with the addition of M1bone, M1viscera, M1brain), and to better stratify clinical trial enrollment.
