Abstract
AimTo evaluate the clinical outcomes of metastatic colorectal cancer (mCRC) patients with oligometastases, oligoprogression, or local control of dominant tumors after stereotactic body radiotherapy (SBRT) and establish a nomogram model to predict the prognosis for these patients.Methods and MaterialsA cohort of 94 patients with 162 mCRC metastases was treated with SBRT at a single institution. Treatment indications were oligometastases, oligoprogression, and local control of dominant tumors. End points of this study were the outcome in terms of progression-free survival (PFS), overall survival (OS), local progression (LP), and cumulative incidence of starting or changing systemic therapy (SCST). In addition, univariate and multivariable analyses to assess variable associations were performed. The predictive accuracy and discriminative ability of the nomogram were determined by concordance index (C-index) and calibration curve.ResultsMedian PFS were 12.6 months, 6.8 months, and 3.7 months for oligometastases, oligoprogression, and local control of dominant tumors, respectively. 0-1 performance status, < 10 ug/L pre-SBRT CEA, and ≤ 2 metastases were significant predictors of higher PFS on multivariate analysis. Median OS were 40.0 months, 26.1 months, and 6.5 months for oligometastases, oligoprogression, and local control of dominant tumors, respectively. In the multivariate analysis of the cohort, the independent factors for survival were indication, performance status, pre-SBRT CEA, and PTV, all of which were selected into the nomogram. The calibration curve for probability of survival showed the good agreement between prediction by nomogram and actual observation. The C-index of the nomogram for predicting survival was 0.848.ConclusionsSBRT for metastases derived from colorectal cancer offered favorable survival and symptom palliation without significant complications. The proposed nomogram could provide individual prediction of OS for patients with mCRC after SBRT.
Highlights
Colorectal cancer (CRC) is a major cause of cancer-related deaths, with a 5-year survival rate of 64% [1]. 21% of patients are diagnosed with metastasis, and approximately 50% of patients with colorectal cancer in due course of time will develop distant metastasis, and the 5-year survival rate is less than 14% [1, 2]
There were a total of 94 patients and 162 lesions treated with stereotactic body radiotherapy (SBRT) in this paper. 42 patients were in oligometastases (OM) group, 19 patients were in oligoprogression (OP) group, and 33 patients were in local control of dominant tumors (LCDT) group
Performance status (0–1 vs 2–3, hazard ratio (HR) 1.86, 95%confidence interval (CI) 1.10–3.12, p = 0.020), pre-SBRT carcino-embryonic antigen (CEA) (< 10 ug/L vs > 100 ug/ L, HR 2.08, 95%CI 1.16–3.73, p = 0.013), number of metastases (≤ 2 vs > 2, HR 2.76, 95%CI 1.56–4.89, p = 0.001) still were significant factors for progression-free survival (PFS) (Table 2, Figure 1)
Summary
Colorectal cancer (CRC) is a major cause of cancer-related deaths, with a 5-year survival rate of 64% [1]. 21% of patients are diagnosed with metastasis, and approximately 50% of patients with colorectal cancer in due course of time will develop distant metastasis, and the 5-year survival rate is less than 14% [1, 2]. Local treatment can be used to reduce the burden of tumors to better control the disease, thereby improving the overall survival (OS). For patients with oligometastases of colorectal cancer, intensive treatment of metastases has improved OS [8, 9]. In surgically resected liver metastasis, the 5-year OS rate of CRC patients was between 50 and 60% [10,11,12]. Over the past two decades, extensive clinical experience has proved that SBRT is a non-invasive, high-precision technical method. It could deliver ablative treatments for different metastatic sites (liver, lung, brain, bone/spine, adrenal, lymphadenopathy, pancreas, etc.) [13,14,15] with little impact on acute quality of life. Many non-random studies of oligometastases with SBRT have achieved
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