Effect of primary tumor location and tumor size on the response to radiotherapy for liver metastases from colorectal cancer

Abstract

Abstract. Metastatic liver tumors (MLTs) from colorectal cancer (CRC) are often treated with stereotactic body radiation therapy (SBRT). The present study aimed to examine the predictive factors for response of MLTs to SBRT. A total of 39 MLTs from 24 patients with CRC were retrospectively analyzed. Radiotherapy for MLT was typically performed with a prescribed dose equivalent to a biologically effective dose (BED) 10 of 100 Gy. The median follow-up period was 16 months (range, 5-64 months). The median prescribed dose and total BED 10 were 56 Gy (range, 45-72 Gy) and 97.5 Gy (range, 71.7-115.5 Gy), respectively, in a median of 8 fractions (range, 4-33 fractions). The 1-and 2-year local control rates were 67.2 and 35.9%, respectively. For patients with MLT treated with ablative SBRT (BED 10 ≥100 Gy in ≤5 fractions), the 1-and 2-year local control rates were 83.3 and 62.5%, respectively. Univariate analysis showed that primary tumor location (left-sided colon), maximum tumor diameter (≤30 mm) and ablative SBRT (BED 10 ≥100 Gy in ≤5 fractions) were significantly associated with improved local control (P=0.0058, P=0.0059 and P=0.0268, respectively). Multivariate analysis showed that tumor diameter was significantly associated with improved local control (P=0.0314). In addition, patients who received ablative SBRT had significantly prolonged overall survival times compared with those treated with non-ablative SBRT (P= 0.0261). To conclude, tumors ≤30 mm that can be treated with ablative SBRT are associated with good local control rates. The primary tumor location may affect the radiosensitivity of MLTs. IntroductionPatients with colorectal cancer (CRC) often have metastases at initial presentation or during follow-up (1,2). The liver is one of the most frequent sites of metastasis (1,2). Newly developed chemotherapeutic agents, including targeted therapies, have improved the progression-free and overall survival times of patients with metastatic CRC (3,4). There is also evidence supporting the benefit of surgery to treat metastases from CRCs, with surgery improving overall survival time (5-7). The prolonged survival times of patients have highlighted the importance of local therapy for CRC and limited metastatic disease. In patients who are unfit for surgery, alternative local therapeutic approaches, including radiofrequency ablation (RFA), are available to treat liver metastases; these approaches are minimally invasive and can achieve good local control (8,9). However, their indication is currently limited to relatively small tumors that are located far away from critical structures (8,9).Modern radiotherapeutic techniques, including intensity-modulated radiation therapy (IMRT) and stereotactic body radiation therapy (SBRT), have recently become more frequently utilized to curatively treat limited metastatic tumors (10-14). SBRT, also termed stereotactic ablative radiation therapy, is a proven curative treatment for medically inoperable small tumors in the lung and liver; it delivers highly conformal radiation in a ...

Prediction of Colon Cancer Stages and Survival Period with Machine Learning Approach

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Stereotactic Body Radiation Therapy for Liver Tumors: Current Status and Perspectives

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