Do Resected Colorectal Cancer Patients Need Early Chest Imaging? Impact of Clinicopathologic Characteristics on Time to Development of Pulmonary Metastases

Abstract

INTRODUCTION: Among patients with colorectal cancer (CRC), the lung is the most common extra-abdominal site for distant metastasis. In many circumstances, pulmonary metastasectomy can improve survival and result in cure. However, practices for post-resection chest imaging vary widely, without data-driven rationale for timing. We aimed to identify clinicopathologic characteristics that may indicate a need for early follow-up imaging. METHODS: We retrospectively reviewed patients who underwent CRC resection and collected clinicopathologic details from patients’ medical records and prospectively maintained surgical databases (2000-2017). Patients were grouped according to development of pulmonary metastases (PM) and timing of PM diagnoses. Univariable and binomial logistic regression were performed to investigate odds ratio (OR) of PM diagnosis within 3 months of CRC resection. RESULTS: Of 1600 patients with resected CRC, 233 (14.6%) developed PM, with time to PM occurring at a median of 15.4 months following CRC resection. Univariable analyses revealed age, receipt of systemic therapy (neoadjuvant or adjuvant), lymph node ratio, lymphovascular and perineural invasion, and KRAS mutation as risk factors for PM. Further, multivariable regression showed neoadjuvant therapy (OR: 2.99, 95% Confidence Interval [CI]: 1.62-5.52, p < 0.001), adjuvant therapy (OR: 6.28, CI: 2.92-13.49, p < 0.001), lymph node ratio (OR: 28.91, CI: 5.25-159.16, p < 0.001), and KRAS mutation (OR: 5.19, CI: 2.83-9.50, p < 0.001) to predict PM within 3 months (Table). CONCLUSION: We identified specific clinicopathologic characteristics which predict development of PM within 3 months after primary CRC resection. Early surveillance in such patients may be considered to ensure timely identification and opportunity for intervention. Table. - Multivariable Logistic Regression of Factors Associated with Development of Pulmonary Metastasis Clinicopathologic characteristics Odds ratio (95% CI) p Value Age (Increasing) 0.98 (0.95-1.00) 0.066 Neoadjuvant Chemotherapy 2.99 (1.62-5.52) <0.001 Adjuvant Chemotherapy 6.28 (2.92-13.49) <0.001 Lymph Node Ratio (Increasing) 28.91 (5.25-159.16) <0.001 KRAS Mutated 5.19 (2.83-9.50) <0.001