Changing patterns of colorectal cancer metastases: A 10-year retrospective review

Abstract

3548 Background: Therapeutic advances for patients (pts) with metastatic colorectal cancer (CRC) have prolonged survival. Historically, bone and brain metastases have been uncommonly reported (6% and 1%, respectively). This study was undertaken to test the hypothesis that expanded treatment options are associated with an increased incidence of unusual sites of metastasis. Methods: Patients with metastatic CRC evaluated between 1993–2002 at Fox Chase Cancer Center were identified through the Tumor Registry. Medical records were abstracted to obtain: date of diagnosis, date of metastasis, site of primary malignancy (colon vs. rectum), therapeutic agents received, survival, and sites of metastatic disease. Results: The records of 1,021 patients were reviewed. Incidences of bone and brain metastases were 10.4% and 3%, respectively. Bone metastases were more common among pts receiving >1 active systemic agent (fluoropyrimidines, irinotecan, oxaliplatin, EGFR antibody, bevacizumab) compared to ≤1 (13% vs. 8.3%, p=0.017), and 3–5 compared to ≤2 (16% vs. 9.1%, p=0.008). Pts receiving irinotecan were more likely to develop bone metastases (13.2% vs. 8.3%, p=0.01), as were pts receiving oxaliplatin (16.9% vs. 9%, p=.003). Pts with rectal cancer were more likely to develop bone metastases than patients with colon cancer (16% vs. 8.6%, p=.001). Lung metastases were more common in patients with bone (64% vs. 38.7%, p<.0001) or brain (78.8% vs. 40.1%, p<.0001) involvement than in pts without. However, pts with bone or brain metastases were less likely to have liver metastases (67% vs. 81.3%, p<0.0001 for bone, 60.6% vs. 80.5%, p=0.01 for brain). Pts developing bone or brain metastases had a longer mean time from diagnosis to development of metastases (17.8 vs. 10.3 months, p<0.0001 for bone, 18.9 vs. 10.8 months, p=0.0036 for brain). Conclusions: These data demonstrate that the incidence of bone and brain metastases in pts with CRC is more common than previously reported, and is associated with receipt of multiple systemic treatments. As survival improves for this patient population, clinicians should be aware of the potential for metastasis in previously unusual sites. No significant financial relationships to disclose.