Stereotactic body radiotherapy in pancreatic adenocarcinoma

Background:Stereotactic body radiotherapy(SBRT)in pancreatic cancer allows high delivery of radiation doses on tumors without affecting surrounding tissue.This review aimed at the SBRT application in the treatment of pancreatic cancer.Data sources:We retrieved articles published in MEDLINE/PubMed from January 2017 to December 2022.Keywords used in the search included:“pancreatic adenocarcinoma”OR“pancreatic cancer”AND“stereotactic ablative radiotherapy(SABR)”OR“stereotactic body radiotherapy(SBRT)”OR“chemoradiotherapy(CRT)”.English language articles with information on technical characteristics,doses and fractionation,indications,recurrence patterns,local control and toxicities of SBRT in pancreatic tumors were included.All articles were assessed for validity and relevant content.Results:Optimal doses and fractionation have not yet been defined.However,SBRT could be the standard treatment in patients with pancreatic adenocarcinoma in addition to CRT.Furthermore,the combination of SBRT with chemotherapy may have additive or synergic effect on pancreatic adenocarcinoma.Conclusions:SBRT is an effective modality for patients with pancreatic cancer,supported by clinical practice guidelines as it has demonstrated good tolerance and good disease control.SBRT opens a possibility of improving outcomes for these patients,both in neoadjuvant treatment and with radical intent.

Stereotactic body radiotherapy combined with sintilimab in patients with recurrent or oligometastatic hepatocellular carcinoma: A phase Ⅱ clinical trial

BACKGROUND Stereotactic body radiotherapy(SBRT)and programmed cell death 1 inhibitors have shown potential in treating hepatocellular carcinoma(HCC)in retrospective studies.AIM To evaluate the efficacy of combining SBRT with sintilimab for patients with recurrent or oligometastatic HCC.METHODS This trial involved patients with recurrent or oligometastatic HCC intravenously treated with SBRT plus sintilimab every 3 wk for 12 mo or until disease progression.The primary endpoint was progression-free survival(PFS).RESULTS Twenty-five patients were enrolled from August 14,2019,to August 23,2021.The median treatment duration was 10.2(range,0.7-14.6)months.SBRT was delivered at a median dose of 54(range,48-60)Gy in 6(range,6-10)fractions.The median follow-up time was 21.9(range,10.3-39.7)mo,and 32 targeted lesions among 25 patients were evaluated for treatment response according to the Response Evaluation Criteria in Solid Tumors version 1.1.The median PFS was 19.7 mo[95%confidence interval(CI):16.9-NA],with PFS rates of 68%(95%CI:52-89)and 45.3%(95%CI:28-73.4)at 12 and 24 mo,respectively.The median overall survival(OS)was not reached,with OS rates of 91.5%(95%CI:80.8-100.0)and 83.2%(95%CI:66.5-100.0)at 12 and 24 mo,respectively.The 1-and 2-year local control rate were 100%and 90.9%(95%CI:75.4%-100.0%),respectively.The confirmed objective response rate and disease control rate was 96%,and 96%,respectively.Most adverse events were graded as 1 or 2,and grade 3 adverse events were observed in three patients.CONCLUSION SBRT plus sintilimab is an effective,well-tolerated treatment regimen for patients with recurrent or oligometastatic HCC.

Hepatocellular carcinoma with child Pugh-A Cirrhosis treated with stereotactic body radiotherapy

AIM To evaluate the control, survival, and hepatic function for Child Pugh(CP)-A patients after Stereotactic body radiotherapy(SBRT) in hepatocellular carcinoma(HCC).METHODS From 2009 to 2016, 40 patients with Barcelona Liver Clinic(BCLC) stages 0-B HCC and CP-A cirrhosis completed liver SBRT. The mean prescription dose was 45 Gy(40 to 50 Gy in 4-5 fractions). Local relapse, defined as recurrence within the planning target volume was assessed with intravenous multiphase contrast computed tomography or magnetic resonance imaging every 4-6 mo after completion of SBRT. Progression of cirrhosis was evaluated by CP and Model for End Stage Liver Disease scores every 3-4 mo. Toxicities were graded per the Common Terminology Criteria for Adverse Events(v4.03). Median follow-up was 24 mo.RESULTS Forty-nine HCC lesions among 40 patients were analyzed in this IRB approved retrospective study. Median tumor diameter was 3.5 cm(1.5-8.9 cm). Six patients with tumors ≥ 5 cm completed planned selected transarterial chemoembolization(TACE) in combination with SBRT. Eight patients underwent orthotropic live transplant(OLT) with SBRT as a bridging treatment(median time to transplant was 12 mo, range 5 to 23 mo). The Pathologic complete response(PCR) rate in this group was 62.5%. The 2-year in-field local control was 98%(1 failure). Intrahepatic control was 82% and 62% at 1 and 2 years, respectively. Overall survival(OS) was 92% and 60% at 1 and 2 years, with a median survival of 41 mo per Kaplan Meier analysis. At 1 and 2 years, 71% and 61% of patients retained CPA status. Of the patients with intrahepatic failures, 58% developed progressive cirrhosis, compared to 27% with controlled disease(P = 0.06). Survival specific to hepatic failure was 92%, 81%, and 69% at 12, 18, and 24 mo. There was no grade 3 or higher toxicity. On univariate analysis, gross tumor volume(GTV) < 23 cc was associated with freedom from CP progression(P = 0.05), hepatic failure-specific survival(P = 0.02), and trended with OS(P = 0.10).CONCLUSION SBRT is safe and effective in HCC with early cirrhosis and may extend waiting time for transplant in patients who may not otherwise be immediate candidates.

Stereotactic body radiotherapy using Cyber Knife for locally advanced unresectable and metastatic pancreatic cancer

AIM: To evaluate the efficacy and toxicity of stereotactic body radiotherapy using Cyber Knife for locally advanced unresectable and metastatic pancreatic cancer.METHODS: From June 2010 to May 2014,25 patients with locally advanced unresectable and metastatic pancreatic cancer underwent stereotactic body radiotherapy.Nine patients presented with unresectable locally advanced disease and 16 had metastatic disease.Primary end-points of this study were overall survival,relief of abdominal pain,and toxicity.RESULTS: Fourteen patients were treated with a total dose of 30-36 Gy in three fractions and the remainder with 40-48 Gy in four fractions.Median follow-up was 11 mo(range: 2-25 mo).The median survival duration calculated from the time of stereotactic body radiotherapy for the entire group,the locally advanced group,and the metastatic group was 9.0 mo,13.5 mo,and 8.5 mo,respectively.Overall survival was 37% and 18% at one and two years,respectively.Abdominal pain relief was achieved within 2 wk of completing radiotherapy in the patients who received successful palliation(13 of 20 patients had significant pain).Five patients(20%) had grade 1 nausea,and one(4%) had grade 2 nausea.No acute grade 3+ toxicity was seen.CONCLUSION: Stereotactic body radiotherapy using the Cyber Knife system is a promising,noninvasive,palliative treatment with acceptable toxicity for locally advanced unresectable and metastatic pancreatic cancer.

Initial experience with stereotactic body radiotherapy for intrahepatic hepatocellular carcinoma recurrence after liver transplantation

BACKGROUND Graft hepatocellular carcinoma(HCC)recurrence after liver transplant is more frequently encountered.Graft hepatectomy is technically challenging and is associated with high morbidity.Stereotactic body radiation therapy(SBRT)has been shown to be safe and effective for the treatment of primary HCC.However,its role in HCC recurrence in a liver graft remains unclear.AIM To evaluate the safety and efficacy of SBRT for the treatment of graft HCC recurrence after liver transplantation.METHODS A retrospective study was conducted.From 2012 to 2018,6 patients with intrahepatic HCC recurrence after liver transplant were treated with SBRT at Queen Mary Hospital,the University of Hong Kong.The primary outcome was time to overall disease progression and secondary outcomes were time to local progression and best local response,as assessed with the Modified response Evaluation Criteria for Solid Tumours criteria.Patients were monitored for treatment related toxicities and graft dysfunction.RESULTS A total of 9 treatment courses were given for 13 tumours.The median tumour size was 2.3 cm(range 0.7-3.6 cm).Two(22%)patients had inferior vena cava tumour thrombus.The best local treatment response was:5(55%)complete response,1(11%)partial response and 3(33%)stable disease.After a median follow up duration of 15.5 mo,no local progression or mortality was yet observed.The median time to overall disease progression was 6.5 mo.There were 6 regional progression in the liver graft(67%)and 2 distant progression in the lung(22%).There was no grade 3 or above toxicity and there was no graft dysfunction after SBRT.CONCLUSION SBRT appears to be safe in this context.Regional progression is the mode of failure.

Advances of stereotactic body radiotherapy in pancreatic cancer

Pancreatic cancer（PCA） is one of the most aggressive tumors with few effective treatment modalities. It is the 4th and 7th leading cause of cancer death in the United States and China, respectively. At the time of diagnosis, only 20% of cases present with a resectable tumor, and about 40% with a locally advanced tumor that is considered unresectable. Even resected patients still have a poor prognosis, with an incidence of local recurrence ranging from 20% to 60%. It is also reported that up to 30% of PCA patients die from locally obstructive disease with few or no distant metastases. These findings have highlighted the importance of local radiation therapy in the treatment of PCA. As the role of conventional chemoradiotherapy remains controversial, the dawn of the pancreas stereotactic body radiation therapy（SBRT） era represents a potential paradigm shift in the management of PCA. SBRT delivers a higher biological effective dose to the tumor with sharp dose escalation in a shorter treatment time course. Pancreas SBRT is a novel therapeutic option to achieve local tumor control with minimal toxicity. Herein, we review the advancement of SBRT for PCA patients with different stages of pancreatic adenocarcinoma.

Partial and Full Arc Volumetric Modulated Arc Therapy in Lung Cancer Stereotactic Body Radiotherapy with Different Definitions of Internal Target Volume Based on 4D CT

Purpose: To investigate the feasibility of partial arc volumetric modulated arc therapy (VMAT) in lung cancer stereotactic body radiotherapy (SBRT), as well the volumetric and dosimetric effects of different internal target volume (ITV) definitions with 4D CT. Methods: Fourteen patients with primary and metastatic lung cancer underwent SBRT were enrolled. Full and partial arc VMAT plans were generated with four different ITVs: ITVall, ITVMIP, ITVAIP and ITV2phases, representing ITVs generated from all 10 respiratory phases, maximum intensity projection (MIP), average intensity projection (AIP), and 2 extreme respiratory phases. Volumetric and dosimetric differences, as well as MU and delivery time were investigated. Results: Partial arc VMAT irradiated more dose at 2 cm away from planning target volume (PTV) (P = 0.002), however, it achieved better protection on mean lung dose , lung V5, spinal cord, heart and esophagus compared with full arc VMAT. The average MU and delivery time of partial arc VMAT were 240 and 1.6 min less than those of full arc VMAT. There were no significant differences on target coverage and organ at risks (OARs) sparing among four ITVs. The average percent volume differences of ITVMIP, ITVAIP and ITV2phases to ITVall were 8.6%, 13.4%, and 25.2%, respectively. Conclusions: Although partial arc VMAT delivered more dose 2 cm out of PTV, it decreases the dose to lung, spinal cord, and esophagus, as well decreased the total MU and delivery time compared with full arc VMAT without sacrificing target coverage. Partial arc VMAT was feasible and more efficient for lung SBRT.

Stereotactic body radiotherapy for isolated paraaortic lymph node recurrence from colorectal cancer

AIM:To evaluate the efficacy and complications of stereotactic body radiotherapy in localized paraaortic lymph node recurrence from colorectal cancer.METHODS:From 2003 to 2009,7 patients with paraaortic lymph node recurrence(1-3 lesions)from colorectal cancer were treated with stereotactic body radiotherapy.Total gross tumor volumes ranged from 4 to 40 mL.The doses were escalated from 36 Gy/patient to 51 Gy/patient and were delivered in 3 fractions.RESULTS:One and 3 year overall survival rates were 100%and 71.4%,respectively,and median survival was 37 mo.GradeⅣintestinal obstruction was reported in 1 of 7 patients.This patient received 48 Gy in 3 fractions with a maximum point dose to the intestine of 53 Gy and V45Gy=3.6 mL.However,6 patients received an intestinal maximum point dose of<51 Gy and V45Gy of<1 mL,and did not develop any severe complications.CONCLUSION:This pilot study suggests selected paraaortic lymph node recurrence(1-3 closed lesions) that failed to respond to chemotherapy can be potentially salvaged by stereotactic body radiotherapy.

Challenges and opportunities of using stereotactic body radiotherapy with anti-angiogenesis agents in tumor therapy

Microvessels promote proliferation of tumor cells by delivering oxygen and nutrients, but rapid growth of tumors results in unmet demands for oxygen and nutrients, thereby creating a hypoxia microenvironment. Under hypoxic conditions, vascular endothelial cells（ECs） initiate the formation of immature and abnormal microvasculature. This results in leakage and tortuosity that facilitates tumor cell invasion, metastasis and resistance to cytotoxic treatment.Radiotherapy（RT） is a vital tumor treatment modality. Currently, more than 60% of patients with malignant tumors receive RT at certain points during their treatment. Hypoxia induced by abnormal microvessels can hamper the cytotoxic effect of ionizing radiation, particularly, stereotactic body radiotherapy（SBRT）. Anti-angiogenesis（AA） agents are known to reduce and renormalize microvessels in tumors, and hence alleviate hypoxia. The combination of AA agents with SBRT may have a synergistic role in inhibiting the growth of tumors. On the contrary, large doses of irradiation may affect tumor microvessels itself. In this review, we aim to clarify the relationship between SBRT and microvessel formation in tumors. In addition, we provide a retrospective analysis of the combination therapy involving SBRT and AA agents in preclinical and clinical practice to define its role in antitumor treatment.

Dosimetric Impact of Tumor Position and Lung Density Variations in Lung Stereotactic Body Radiotherapy

Purpose of this study was to evaluate the variation of the dose to gross tumor volume (GTV) related to tumor position and lung density for lung stereotactic body radiotherapy (SBRT) using a virtual phantom. The density of the equivalent lung surrounding the GTV (10 mm diameter) was defined as 0.10, 0.15, 0.25, 0.35, and 0.45 g/cm3. A planning target volume (PTV) was generated by adding a uniform 8 mm margin to the internal target volume (ITV). We defined that the 99% of the GTV should be covered by 100% of the prescribed dose using Monte Carlo (MC) calculation. The GTV structure was replicated from ITV to the PTV periphery at 1 mm intervals. Planned dose to the GTV was defined as the predicted dose in the replicated GTV structure. Simulated dose to the GTV was defined as the calculated dose in the replicated GTV structure taking into account the tumor position error. D99 of the planned dose to the GTV at the 8 mm shift position was 78.1%, 81.6%, 87.3%, 91.4% and 94.4% at equivalent lung densities of 0.10, 0.15, 0.25, 0.35, and 0.45 g/cm3, respectively. D99 of the simulated dose to the GTV at the 8 mm shift position was 96.9%, 95.3%, 94.2%, 95.1 % and 96.3% at equivalent lung densities of 0.10, 0.15, 0.25, 0.35, and 0.45 g/cm3, respectively. Planned dose to GTV is strongly dependent on lung density and tumor position errors, while simulated dose to GTV does not show any significant dependence.

Comparison of Stereotactic Body Radiotherapy Delivery Techniques for Early-Stage Lung Cancer Using Lung Toxicity Modeling

Purpose: Lung toxicity is a primary side effect in stereotactic radiotherapy (SBRT) for early-stage non-small cell lung cancer (NSCLC). We aimed to use a set of radiobiological models to evaluate and compare modern IMRT delivery techniques with three-dimensional conformal techniques for SBRT treatment of NSCLC in terms of lung toxicity, and aimed to compare the results from different radiobiologcal models. Methods: Ten early-stage NSCLC patients treated with SBRT were retrospectively selected. Five treatment plans were generated to deliver 50 Gy in five fractions to the planning target volume for each case: a helical tomotherapy (HT) plan, two three-dimensional cofnromal radiotherapy (3D-CRT) plans using 6-MV and 10-MV photon beams respectively, and two volumetric modulated arc therapy (VMAT) plans using one and two arc fields respectively. The lung RDV was calculated with three parallel functional sub-unit (FSU) models and two normal tissue complication probability (NTCP) models. Results: Both the HT and VMAT plans showed significantly higher contralateral mean lung dose and lower ipsilateral mean lung dose compared to the 3D-CRT plans. There was no statistically significant difference in terms of lung toxicities between the IMRT and 3D-CRT techniques using either the FSU models or the NTCP models. Based on both the FSU and the NTCP models, there was strong correlation between lung toxicity and the mean lung dose in SBRT treatment plans. Conclusions: Based on both the NTCP and parallel FSU models, both IMRT and traditional 3D-CRT delivery techniques could achieve comparable lung sparing inn SBRT treatment of early-stage lung cancer. However, the validity of the radiobiological model results should be checked by clinical data.

Lung Stereotactic Body Radiotherapy Using an Abdominal Compression System, “Air-Bag System”

We investigated respiratory tumor motion in lung stereotactic body radiotherapy (SBRT) with use of the “Air-Bag System”. 114 patients underwent four-dimensional (4D) computed tomography (CT) from October 2010 to April 2012. Gross tumor volume (GTV) was 8.1 ± 11.0 cc (range 0.3 - 77.5 cc). The tumor site was the upper and middle lobes in 62 cases, and lower lobe in 52 cases. The Air-Bag SystemTM consists of an inelastic air bag connected to a second smaller elastic air bag. The inelastic air bag is placed between the patient’s body surface and a HipFix and is secured by pressure adjustment via the elastic air bag. To assess respiratory tumor motion, the centroid of the tumor position is measured in the left-right, anterior-posterior, and caudal-cranial directions using the iPlan RT DoseTM treatment planning system. Respiratory tumor motion vector for patients with upper/middle and lower lobe tumors was 3.0 ± 2.2 mm (range, 0.4 - 11.7 mm) and 6.5 ± 4.6 mm (range, 0.4 - 22.0 mm) respectively, with this difference being significant (p < 0.05). Mean respiratory tumor motion for all patients was 0.9 ± 0.6 mm (range, 0.1 - 3.6 mm) in the left-right direction, 1.5 ± 1.1 mm (range, 0.1 - 5.7 mm) in the anterior-posterior direction, 4.1 ± 4.0 mm (range, 0.1 - 21.4 mm) in the caudal-cranial direction, and 4.7 ± 4.0 mm (range, 0.4 - 22.0 mm) overall. The Air-Bag System is expected to be provided an effective reduction in the motion of lung tumors.

The effects of stereotactic body radiotherapy on peripheral natural killer and CD3~+CD56~+ NKT-like cells in patients with hepatocellular carcinoma

Background: Both natural killer(NK) and CD3+CD56+ natural killer T(NKT)-like cells play critical roles in the antitumor response. This study aimed to explore the effects of stereotactic body radiotherapy(SBRT) on peripheral NK and NKT-like cells in patients with hepatocellular carcinoma(HCC), and to identify possible surface markers on these cells that correlate with the prognosis. Methods: Twenty-five HCC patients were prospectively enrolled in our study, and 10 healthy individuals were served as healthy controls. Flow cytometry was used to determine the counts and the percentages of peripheral NK and NKT-like cells, cells with certain receptors, and cells with intracellular interferon-γand TNF-α secretion at different time points, including time points of prior to SBRT, at post-SBRT, and 3-month and 6-month after treatment. The Kaplan-Meier method with the log-rank test was applied for survival analysis. Results: The peripheral NKT-like cells was increased at post-SBRT. Meanwhile, elevated levels of inhibitory receptors and reduced levels of activating receptors of NK cells were also observed in NK cells at post-SBRT, but the levels was not significantly different at 3-month and 6-month as compared with the baseline levels. Lower percentage of NKp30+ NK cells before SBRT and higher percentage of CD158b + NK cells after SBRT were associated with poor progression-free survival. In addition, higher percentage of CD3+CD56+ NKT-like cells was associated with a higher overall survival rate in HCC patients. Conclusions: SBRT has an apparent effect on both peripheral NK and CD3+ CD56+ NKT-like cells. Lower percentage of NKp30 + NK cells before SBRT and higher percentage of CD158b + NK cells after SBRT are correlated with poor patients' PFS. Higher percentage of CD3+ CD56+ NKT-like cells is associated with higher OS in HCC patients.

Hepatocellular carcinoma effective stereotactic body radiotherapy using Gold Anchor and the Synchrony system:Two case reports and review of literature

BACKGROUND Radiotherapy for hepatocellular carcinoma(HCC)is considered to have limited efficacy because of treatment intensity considering that the irradiated area includes the liver,which is highly radiosensitive.In this report,we present two cases in which tumor control by surgical resection,radiofrequency ablation,transcatheter arterial chemoembolization(TACE),and lenvatinib administration was difficult,but stereotactic body radiotherapy(SBRT)using the Synchrony system by Radixact?and Gold Anchor?(GA)was effective.CASE SUMMARY A 60-year-old man had a single 10-cm HCC in the right lobe.Viable lesions remained after TACE,and levels of alpha-fetoprotein and protein induced by vitamin K antagonists II(PIVKA-II)decreased and quickly re-elevated.We performed SBRT with GA.Three weeks after implantation,localized radiotherapy(SBRT;40 Gy/5 fractions)was performed using the Synchrony system by Radixact?.Four weeks later,the viable lesion had disappeared,and the PIVKA-II levels decreased.A 77-year-old man had a single 12-cm HCC in the right lobe.The patient experienced recurrence after hepatectomy.Further recurrence occurred after TACE,and we performed SBRT with GA.Because of the proximity of the HCC to the gastrointestinal tract,localized radiotherapy(SBRT;39 Gy/13 fractions)to the HCC was performed 3 wk after implantation using the Synchrony system by Radixact?.Four weeks later,the viable lesion had disappeared on computed tomography,and the PIVKA-Ⅱlevels decreased.CONCLUSION SBRT using the Synchrony system and GA can deliver a large dose accurately and safely,and could have a high therapeutic effect.

A phase I radiation dose escalation of stereotactic body radiotherapy for malignant lung tumors

Objectives: This Phase I study determines the maximum tolerated dose (MTD) of stereotactic body radiotherapy (SBRT) for lung tumors. Methods: Eli- gible patients had biopsy proven cancer with a maxi- mum tumor size ≤ 5 cm. Total doses were escalated from 40 to 48, then to 56 Gy, delivered in 4 equal fractions administered 2 to 3 times per week on an IRB approved protocol. SBRT was administered us- ing 5 to 9 fixed beam arrangements with CT loca- lization. Internal target volumes (ITV) were based on breath hold scans or 4D CT simulation. The planning target volume (PTV) was defined as the ITV with a uniform 5 mm expansion. Dose limiting toxicity (DLT) was defined as any grade 3 or higher toxicity using the Radiation Therapy Oncology Group (RTOG) common toxicity criteria (CTC). Results: Between April 2004 and February 2008, 18 patients received the prescribed treatment (40 Gy n = 6, 48 Gy n = 7, 56 Gy n = 5). Seventeen of 18 patients had non-small cell lung cancer (1 with rectal cancer), four of whom were treated for an oligometastasis. The median age of the patients was 68, while the median Karnofsky performance status was 90. The mean tumor size was 2.6 cm (range 0.9 to 4.5 cm). One grade 3 pulmonary event occurred (at 48 Gy dose level) immediately following treatment with the onset of fever and shortness of breath that responded to antibiotics. No other DLTs occurred. Conclusions: SBRT utilizing patient specific target volumes without gating appears safe. The maximum tolerated dose was not reached.

The efficacy of stereotactic body radiotherapy for patients with hepatocellular carcinoma

Objective:To evaluate efficacy of the stereotactic body radiotherapy for patients with hepatocellular carcinoma. Methods:Twenty-seven patients with hepatocellular carcinoma were treated by technique of stereotactic body radiotherapy. Planning of treatment was made and the prescribed dose was adjusted depending on the site of the tumor,clinical target volume(GTV),Kanofsky Performance and aim of treatment.Planning target volume received 50%–80%of the prescribed dose for 3.2–4.2 Gy per-fraction.Treatment total dose was 32–42 Gy(median dose 40 Gy)in daily fractions of 3.2–4.2 Gy for five fractions one week.Results:All the patients completed the planned radiotherapy.The tumor response rate was CR 25.9%,PR 55.6%,NR 18.59%;the response rate(CR+PR)was 81.5%.Half-year local recurrence-free survival rate was 75%;1-year local recurrence-free survival rate was 22%.There were no serious complications during radiotherapy and follow- up.Pain relieve rate in liver region was 83.3%.Conclusion:Stereotactic body radiotherapy can improve the local control and quality of life on the treatment of primary hepatic neoplasm while not increasing the treatment complication.

Delivered Dose Verification for Lung Cancer Stereotactic Body Radiotherapy Using Cone-Beam CT

Purpose: Verified the delivered dose distribution of lung cancer Stereotactic Body Radiotherapy (SBRT) using the cone-beam CT images. Methods: Twenty lung cancer patients who underwent SBRT with 100 CBCT images were enrolled in this study. Delivered dose distributions were recalculated on CBCT images with the deformed and non-deformed methods, respectively. The planned and delivered dose distributions were compared using the dose-volume histograms. Results: The delivered target coverage (V100) per patient inside target volume deviated on average were 0.83% ± 0.86% and 1.38% ± 1.40% for Pct vs. Pcbct and Pct vs. Pdcbct, respectively. The Conformity Index (CI) and Gradient Index (GI) showed a good agreement among the plans. For the critical organs, only minor differences were observed between the planned dose and the delivered dose. Conclusions: CBCT images were a useful tool for setup and dose delivery verification for lung cancer patients who underwent SBRT.

Observation on the Clinical Effect of Stereotactic Body Radiotherapy in Patients with Oligometastatic Tumors

Objective:To observe the efficacy and safety of stereotactic body radiotherapy(SBRT)in the treatment of extracranial oligometastases.Method:A retrospective analysis of 70 patients with extracranial oligometastasis of malignant tumors who underwent SBRT in our hospital(Shaanxi Provincial People’s Hospital)from January 2019 to December 2021 with≤5 metastases,≤3 metastatic organs,and metastases with diameters of≤5 cm.According to the clinical data of patients,the dose-fractionation mode of SBRT is mainly determined according to the pathology of the primary tumor,the location of the metastatic tumor,and the important structures around the tumor.The local control,survival and adverse reactions were observed.Results:A total of 219 oligometastatic lesions in 70 patients were treated with SBRT.The median follow-up time was 24 months(12-40 months).The local control rate(LCR)of all target lesions assessed 3 months after radiotherapy was 94.1%;the 1-,2-,and 3-year LCRs were 88.6%,74.6%,and 64.9%,respectively.The median progression-free survival(PFS)was 11.8 months(95%CI,8.9-14.7 months),and the 1-and 2-year PFS rates were 48.6%and 32.6%,respectively;the median overall survival(OS)was 31.9 month(95%CI 26.0-37.8 months),the 1-year OS rate was 84.3%.The local control time,PFS,and OS of patients with metastases≤3 cm were significantly better than those with metastases>3 cm,and the differences were statistically significant(P<0.05).Acute adverse reactions after SBRT treatment in oligometastatic patients were mainly bone marrow suppression and gastrointestinal reactions,with incidence rates of 48.98%and 30.61%,respectively;chronic adverse reactions were mainly pain(bone,muscle),radiation enteritis,and radiation pneumonitis,with incidence rates of 38.57%,30.00%,and 24.29%,respectively.The treatment-related adverse reactions were mainly grade 1,which were all improved after symptomatic treatment,except for one patient with bone metastases from lung cancer who had grade 4 myelosuppression.No grade 4 or 5 adverse events occurred in the other patients.Conclusion:The application of SBRT in the treatment of extracranial oligometastases is safe,effective,and has high tolerability.

Stereotactic body radiation therapy for non-small cell lung cancer:A review

Stereotactic body radiation therapy(SBRT) is the treatment of choice for medically inoperable patients with early stage non-small cell lung cancer(NSCLC). A literature search primarily based on PubMed electronic databases was completed in July 2018. Inclusion and exclusion criteria were determined prior to the search, and only prospective clinical trials were included. Nineteen trials from 2005 to 2018 met the inclusion criteria, reporting the outcomes of 1434 patients with central and peripheral early stage NSCLC. Patient eligibility,prescription dose and delivery, and follow up duration varied widely. Threeyears overall survival ranged from 43% to 95% with loco-regional control of up to 98% at 3 years. Up to 33% of patients failed distantly after SBRT at 3 years. SBRT was generally well tolerated with 10%-30% grade 3-4 toxicities and a few treatment-related deaths. No differences in outcomes were observed between conventionally fractionated radiation therapy and SBRT, central and peripheral lung tumors, or inoperable and operable patients. SBRT remains a reasonable treatment option for medically inoperable and select operable patients with early stage NSCLC. SBRT has shown excellent local and regional control with toxicity rates equivalent to surgery. Decreasing fractionation schedules have been consistently shown to be both safe and effective. Distant failure is common, and chemotherapy may be considered for select patients. However, the survival benefit of additional interventions, such as chemotherapy, for early stage NSCLC treated with SBRT remains unclear.

Stereotactic radiotherapy for prostate cancer:A review and future directions

Prostate cancer affects over 200000 men annually in the United States alone.The role of conventionally fractionated external beam radiation therapy (RT) is well established as a treatment option for eligible prostate cancer patients; however,the use of stereotactic body radiotherapy (SBRT) in this setting is less well defined.Within the past decade,there have been a number of studies investigating the feasibility of SBRT as a potential treatment option for prostate cancer patients.SBRT has been well studied in other disease sites,and the shortened treatment course would allow for greater convenience for patients.There may also be implications for toxicity as well as disease control.In this review we present a number of prospective and retrospective trials of SBRT in the treatment of prostate cancer.We focus on factors such as biochemical progression-free survival,prostate specific antigen (PSA) response,and toxicity in order to compare SBRT to established treatment modalities.We also discuss future steps that the clinical community can take to further explore this new treatment approach.We conclude that initial studies examining the use of SBRT in the treatment of prostate cancer have demonstrated impressive rates of biochemical recurrencefree survival and PSA response,while maintaining a relatively favorable acute toxicity profile,though long-term follow-up is needed.