Real World Study On The Efficacy And Safety Of Stereotactic Radiotherapy For Liver And Lung Metastasis Of Colorectal Cancer

Background:Colorectal Cancer(CRC)is a common kind of gastrointestinal carcinoma.According to the Global Cancer Statistics 2020,colorectal cancer ranks the third in incidence and the second in mortality rate in the world.causing nearly 700,000 deaths worldwide every year.It is reported more than 20% patients were diagnosed m CRC(metastatic Colorectal Cancer)as soon as they were found having colorectal carcinoma.Liver and lung metastases account for more than 85% of colorectal cancer metastases.In 1995,Hellmann and Wiechselbaum introduced the term "oligometastatic tumor",which described that the disease was in an intermediate state between local and extensive metastasis due to the limited ability to metastasize,and had the potential to achieve local radical treatment after resection,which also provided theoretical support for radical local treatment of m CRC oligometastatic lesions.In the radical local treatment of oligometastases,surgical treatment is the most common and the most effective treatment,the cure rate can reach 60%.However,clinically,many m CRC patients with oligometastases lack the indications for surgery.Therefore,radiofrequency ablation and radiotherapy have been used to replace surgical treatment.Stereotactic body radiation therapy(SBRT)is defined by the American society of Radiation Oncology(ASTRO)as external radiation therapy,compared with traditional 3D-conformal radiotherapy(3D-CRT)and Intensity modulated Radiation Therapy(IMRT),SBRT can precisely deliver a single high-dose radiation of large incision to the target organ.Meanwhile,multiple studies have confirmed that SBRT can change the tumor immune microenvironment,so combined immunotherapy may improve the prognosis of patients.However,there are not enough studies on the efficacy and safety of SBRT in the treatment of liver and lung metastases of colorectal cancer.Therefore,this study aims to explore the efficacy and safety of stereotactic radiotherapy(SBRT)in the treatment of liver and lung metastases of colorectal cancer.Methods:The clinicopathological data of patients diagnosed with colorectal cancer with liver or lung metastasis and treated with SBRT in the First Affiliated Hospital of Nanchang University from August 2018 to April 2022 were collected and followed up to evaluate the efficacy and safety.Kaplan-Meier method was used to plot the survival curve.Cox proportional hazard regression model was used to analyze independent influencing factors of OS,LC and PFS.Results:1.Survival analysis: A total of 35 patients were included in this study,and by the end of follow-up,a total of 21(60%)deaths had occurred.The m OS of the whole group was 34.5 months(95%CI:26.8-42.2),and the 3-year OS rate was 45.1%(95%CI:26.9-63.3).Twelve patients(34.3%)were still recurrence-free,the m PFS of the whole group was 10.2 months(95%CI:7.6-12.8),and the 6-month PFS rate was 65.7%(95%CI:50-96.4).The m LC of the whole group was 9.5 months(95%CI:7.9-11.1)and the 6-month LC rate was 62.9%(95%CI:46.9-78.9).2.Prognostic analysis: univariate analysis showed that(1)radiotherapy target organs,oligo-extensive lesions,lymphocytes and SIRI were significantly correlated with the local control rate of patients;(2)Primary site location,lymphocyte and SIRI were significantly correlated with progression-free survival;(3)Primary resection,lymphocyte,NLR,and SIRI were significantly correlated with overall survival.COX proportional risk model was used to conduct multi-factor analysis respectively,and it was concluded that(1)high SIRI and target organs with extensive lesions were independent risk factors for LC in patients;(2)low lymphocytes,target organs with extensive lesions and high SIRI were independent risk factors for PFS in patients.(3)Unresected primary lesion,low lymphocyte,high NLR and high SIRI were independent risk factors for OS.3.Adverse reactions: No patients had grade 3 or 4 adverse events,which were as follows in order of occurrence frequency from high to low: Leukopenia(4 cases,11.4%),anemia(4 cases,11.4%),rash(4 cases,11.4%),radiation pneumonia(4 cases,11.4%),thrombocytopenia(2cases,5.7%),and abnormal liver function(2 cases,5.7%).Conclusions:1.Body stereotactic radiotherapy(SBRT)is effective and acceptable in the treatment of liver and lung oligometastases of colorectal cancer.2.Among inflammatory biomarkers,SIRI and NLR are independent factors for predicting the prognosis of SBRT in hepatic and pulmonary oligometastases of colorectal cancer.