Stereotactic body radiotherapy for patients with oligometastases from colorectal cancer: risk-adapted dose prescription with a maximum dose of 83-100 Gy in five fractions

Five-Fraction Radiosurgery Using a Biologically Equivalent Dose of a Single Fraction of 24 Gy for a 3-cm Parasagittal Para-Central Sulcus Brain Metastasis From Adenocarcinoma of the Cecum

An isolated single brain metastasis (BM) is an extremely rare manifestation of failure in patients with cecal adenocarcinoma (CAC). Total en bloc resection (while preserving function) of a 3-cm BM involving both the primary motor and sensory cortexes presents a conundrum: achieving long-term local control and safety of such a BM is also challenging for stereotactic radiosurgery (SRS). We describe the case of a 3.1-cm BM from CAC in the left parasagittal para-central sulcus region, which was treated using five-fraction SRS with a biologically effective dose (BED) of 81.6 Gy. In the SRS, the gross tumor volume (GTV, 7.14 cm3) was defined based on computed tomography (CT)/T1/T2 matching (enhancing lesion 11.66 cm3), and 98.7% of the GTV (CT/T2 mass) was covered with 43.6 Gy (58% isodose) using volumetric-modulated arcs. The maximum tumor response was partial (19.7% of the prior GTV) and sustained for 15.2 months, leaving minor neurological symptoms. However, the patient developed neurological worsening at six months, attributed to adverse radiation effects with a CT/T1/T2 mismatch, for which medical management, including the addition of bevacizumab (BEV), was effective for one year. Multi-fraction SRS with a high marginal and internal BED and sequential systemic therapy, including BEV, can be a minimally invasive, efficacious, and durable treatment option for a large CAC-BM involving the central sulcus. Early co-administration of BEV following SRS, dose escalation to the GTV boundary, and more than five fractions of SRS may be considered to improve the efficacy and safety further.

Stereotactic ablative body radiotherapy with a central high dose using CyberKnife for metastatic lung tumors

BACKGROUND

The CyberKnife system features a robotically-positioned linear accelerator to deliver real-time image-guided stereotactic ablative body radiotherapy (SABR). It achieves steep dose gradients using irradiation from hundreds of different directions and increases the central dose of the gross tumor volume (GTV) without increasing the marginal dose to the planning target volume. We evaluated the effectiveness and safety of SABR with a central high dose using CyberKnife for metastatic lung tumors.

METHODS

A total of 73 patients with 112 metastatic lung tumors treated with CyberKnife were retrospectively analyzed. Local control, progression-free survival, and overall survival were calculated using the Kaplan-Meier method. The median age was 69.2 years. The most common primary sites were the uterus (n = 34), colorectum (n = 24), head and neck (n = 17), and esophagus (n = 16). For peripheral lung tumors, the median radiation dose was 52 Gy in 4 fractions, whereas for centrally located lung tumors, it was 60 Gy in 8-10 fractions. The dose prescription was defined as 99% of the solid tumor components of the GTV. The median maximum dose within the GTV was 61.0 Gy. The GTV and planning target volume were enclosed conformally by the 80% and 70% isodose lines of the maximum dose, respectively. The median follow-up period was extended to 24.7 months; it was 33.0 months for survivors.

RESULTS

The 2-year local control, progression-free survival, and overall survival rates were 89.1%, 37.1%, and 71.3%, respectively. Toxicities of grade ≥ 2 were noted as grade 2 and 3 radiation pneumonitis in one patient each. The two patients with grade 2 or higher radiation pneumonitis had both received simultaneous irradiation at two or three metastatic lung tumor sites. No toxicity of grade ≥ 2 was observed in patients with metastasis in one lung only.

CONCLUSIONS

SABR with a central high dose using CyberKnife for metastatic lung tumors is effective with acceptable toxicity.

TRIAL REGISTRATION

Number: 20557, Name: Stereotactic ablative radiotherapy using CyberKnife for metastatic lung tumor, URL: http://www.radonc.med.osaka-u.ac.jp/pdf/SBRT.pdf , Date of registration: April 1, 2021 (retrospectively registered), Date of enrollment: May 1, 2014.

Stereotactic body radiation therapy for metastatic lung metastases

Although systemic therapy is standard management for patients with metastatic disease, several recent reports have indicated that an addition of local therapies including stereotactic body radiation therapy (SBRT) for patients with oligometastatic disease (OMD) could improve survival. The lung is the most common site of distant metastasis from many solid tumors, and the strategy of SBRT, such as dose-fraction schedules, timing, etc., would be different depending on the type of primary tumor, location, and patterns of OMD. This review describes the role of SBRT with curative-intent for patients with pulmonary OMD for each of these variables. First, differences according to the type of primary tumor, for which many studies suggest that SBRT-mediated local control (LC) for patients with pulmonary OMD from colorectal cancer (CRC) is less successful than for those from non-CRC tumors. In addition, higher dose-fraction schedules seemed to correlate with higher LC; hence, different SBRT treatment strategies may be needed for patients with pulmonary OMD from CRC relative to other tumors. Second, differences according to location, where the safety of SBRT for peripheral pulmonary tumors has been relatively well established, but safety for central pulmonary tumors including pulmonary OMD is still considered controversial. To determine the optimal dose-fraction schedules, further data from prospective studies are still needed. Third, differences according to the patterns of OMD, the number of metastases and the timing of SBRT whereby 1–5 lesions in most patients and patients with synchronous or metachronous OMD are considered good candidates for SBRT. We conclude that there are still several problems in defining suitable indications for local therapy including SBRT, and that further prospective studies are required to resolve these issues.

Role of stereotactic body radiotherapy in multidisciplinary management of liver metastases in patients with colorectal cancer

In the treatment of colorectal cancer patients with distant metastases, the development of new anticancer agents has considerably prolonged progression-free survival. Such survival benefits attributed to chemotherapy have increased the relative significance of local therapy in patients with limited metastases. The liver is recognized as the most common site of metastasis of colorectal cancer because of the intestinal mesenteric drainage to the portal veins. Hepatic resection of isolated liver metastases of colorectal cancer is the only option for a potential cure. However, hepatic metastases are resectable in only approximately 20% of the patients. For remaining patients with high-risk resectable liver metastases or those who are unfit for surgery, less invasive, local therapies including radiation therapy (stereotactic body radiation therapy, SBRT) may have a potential role in treatment. Although the local control rate of SBRT for colorectal liver metastases has room for improvement, its less-invasive nature and broad indications deserve consideration. Future research should include SBRT dose escalation or the selection of patients who benefit from local ablative therapies. SBRT may offer an alternative, non-invasive approach for the treatment of colorectal liver metastases in a multidisciplinary treatment strategy.

Novel Clinically Weight-Optimized Dynamic Conformal Arcs (WO-DCA) for Liver SBRT: A Comparison with Volumetric Modulated Arc Therapy (VMAT)

PURPOSE

To evaluate the feasibility of shortening the duration of liver stereotactic radiotherapy (SBRT) without jeopardizing dosimetry or conformity by utilizing weight-optimized dynamic conformal arcs (WO-DCA) as opposed to volumetric modulated arc therapy (VMAT) for tumors away from critical structures.

METHODS

Nineteen patients with liver metastasis were included, previously treated with 50 Gy in 4 fractions with VMAT technique using two partial coplanar arcs of 6 MV beams delivered in high-definition multi-leaf collimator (HD-MLC). Two coplanar partial WO-DCA were generated on Pinnacle treatment planning system (TPS) for each patient; and MLC aperture around the planning target volume (PTV) was automatically generated at different margins for both arcs and maintained dynamically around the target during arc rotation. Weight of the two arcs using optimization method was adjusted between the arcs to maximize tumor coverage and protect organs at risk (OAR) based on the RTOG-0438 protocol.

RESULTS

The WO-DCA plans successfully "agreed" with the standard VMAT for OAR (liver, spinal cord, stomach, duodenum, small bowel, and heart) and PTV (Dmean, D98%, D2%, CI, and GI), with superior mean quality assurance (QA) pass rate (97.06 vs 93.00 for VMAT; P < 0.001 and t = 8.87). Similarly, the WO-DCA technique additionally reduced the beam-on time (3.26 vs 4.43; P < 0.001) and monitor unit (1860 vs 2705 for VMAT; P < 0.001) values significantly.

CONCLUSION

The WO-DCA plans might minimize small-field dosimetry errors and defeat patient-specific VMAT QA requirements due to the omission of MLC beam modulation through the target volume. The WO-DCA plans may additionally enable faster treatment delivery times and lower OAR without sacrificing target doses in SBRT of liver tumors away from critical structures.

Oligometastasis scoring system for predicting survival of patients with colorectal liver metastasis after hepatectomy

BACKGROUND

Oligometastasis, the presence of a small number of resectable metastatic tumors, usually has favorable outcomes. Here we examined whether the novel oligometastatic score (OLGS), which divides the number of colorectal liver metastases (CRLMs) by the time from colorectal resection to liver recurrence, better predicts CRLM patient survival than the commonly used clinical risk score.

METHODS

A total of 143 patients who underwent curative hepatectomy for CRLMs between 2007 and 2018 were analyzed. We investigated their clinical characteristics and outcomes using OLGS.

RESULTS

Of the 143 CRLM patients, 70 had synchronous CRLMs and 73 had metachronous CRLMs. Patients with metachronous CRLMs were divided into OLGS-low (n = 59) and OLGS-high (n = 14) subgroups. The 5-year overall survival (OS) rates after hepatectomy differed significantly between the subgroups (p < .001). In the multivariate Cox model, a high OLGS was an independent predictor of 5-year OS (p < .001), and the hazard ratio (HR) of the OLGS-high group (HR = 7.171) was higher than that of the high clinical risk score group (HR = 4.337).

CONCLUSION

The OLGS, a simple and handy scoring system, better predicts the 5-year OS of patients with CRLMs after hepatectomy and warrants prospective validation.

Multi-Institutional Retrospective Analysis of the Outcomes of Proton Beam Therapy for Patients With 1 to 3 Pulmonary Oligometastases From Various Primary Cancers

Purpose

Our purpose was to evaluate the efficacy of proton beam therapy (PBT) in patients with 1 to 3 pulmonary oligometastases from various primary cancers in Japan.

Methods and Materials

This multi-institutional retrospective survey included 118 patients with 141 metastatic lung tumors from miscellaneous primary cancers, across 6 Japanese institutions, and involved the analyses of local progression-free rate (LPF), distant progression-free rate, progression-free survival rate, cause-specific survival rate, and overall survival rate (OS). Treatment-induced adverse effects of grade ≥2 were evaluated according to the Common Terminology Criteria for Adverse Events (version 4.0). Cox proportional hazards regression models were used in univariable analysis and multivariable analysis (MVA) for the identification of the prognostic factors of LPF and OS.

Results

The median follow-up duration from the time of PBT was 25.5 months. The major primary disease sites included colorectal cancer (42.4%), lung cancer (11.9%), head and neck cancer (8.5%), and kidney cancer (8.5%). For years 1, 2, and 3, LPFs were 92.2%, 86.3%, and 78.4%; distant progression-free rates were 59.1%, 44.1%, and 34.0%; progression-free survival rates were 49.6%, 31.7%, and 24.2%; cause-specific survival rates were 83.4%, 72.5%, and 64.8%; and OS rates were 79.0%, 67.8%, and 59.6%, respectively. Eight patients developed acute adverse effects (grade ≥2). Ten patients developed radiation pneumonitis (grade 2) as a late adverse effect. None of the patients developed severe late toxicity (grade ≥3). Colorectal cancer as the primary disease was the only prognostic factor associated with LPF that remained independently significant in the MVAs performed using 3 sets of parameters (hazard ratio [HR], 3.31-4.76 in 3 MVA sets). In the MVA, the significant prognostic factors for OS were performance status (HR, 2.78; 95% confidence interval, 1.01-7.67) and total tumor volume (HR, 1.01; 95% confidence interval, 1.00-1.02).

Conclusions

PBT provides promising outcomes for pulmonary oligometastasis with acceptable toxicities.

Stereotactic body radiotherapy prolongs the progression-free survival and delays the change of systemic therapy regimen in patients with lung oligoprogressive metastatic colorectal cancer

PURPOSE

To analyze the effect of stereotactic body radiotherapy (SBRT) on colorectal cancer (CRC) patients with lung oligoprogression (OP).

METHOD

Patients with lung OP from CRC treated by SBRT at our center were included in this retrospective analysis. The progression-free survival (PFS), change of systemic therapy (CST), local control (LC), and overall survival (OS) were analyzed. Cumulative incidence was used to report CST, and the Kaplan-Meier method was used to evaluate PFS and LC.

RESULTS

A total of 17 patients with 38 lung OP lesions treated by SBRT from October 2012 to December 2018 were involved. All patients had undergone radical resection for primary CRC and administered with standard systemic therapy regimens (seven for the first line and 10 for the second line). Among them, nine (52.9%) had received targeted therapy before SBRT, 14 (82.4%) patients underwent chemotherapy, and 12 received targeted therapy after SBRT. Six patients (35.3%) underwent CST after a median time of 5.2 months (range: 1.7-27.5 months). The median follow-up was 9.9 months, and the 1-year OS rate for all patients was 73.5%. Progression was observed in of 14 of 17 patients (82.4%), and the 6-month PFS for all patients was 25.9%. Univariate analysis indicated that only targeted therapy before SBRT was a beneficial prognostic indicator for 6-month PFS (P = .026) and N-PFS (P = .013). The 1-year LC for all 38 lesions was 77.8%, and during and after SBRT, no grade 3 or higher toxicities were observed.

CONCLUSION

SBRT combined with systemic therapy made partial CRC patients with lung OP avoid the progress within 6 months and delayed the need for CST to 5.2 months, and targeted therapy before SBRT was a positive indicator of PFS.

Analyses of local control and survival after stereotactic body radiotherapy for pulmonary oligometastases from colorectal adenocarcinoma

This study is a subset analysis of a retrospective multicenter study performed in Japan and its purpose was to investigate the effectiveness of stereotactic body radiotherapy (SBRT) for pulmonary oligometastases from colorectal cancer. Local control (LC), freedom from further metastases, relapse-free survival and overall survival (OS) after SBRT were retrospectively analyzed. The Kaplan-Meier method was used to estimate lifetime data and the log-rank test was performed as univariate analyses. The Cox proportional hazards model was applied in multivariate analyses. Data for 330 patients with 371 tumors were used for analyses. The median follow-up period was 25.0 months. The 3-year LC, freedom from further metastases, relapse-free survival and OS rates were 64.9, 34.9, 24.9 and 63.4%, respectively. The results of multivariate analyses showed that a higher LC rate was associated with no history of local therapy for oligometastases (P = 0.01), SBRT without concurrent chemotherapy (P < 0.01), type B calculation algorithm (P < 0.01) and higher biological effective radiation doses (≥115 Gy, P = 0.04). A longer OS was associated with no history of local therapy for oligometastases (P = 0.04), a more recent period of SBRT (2010-15, P = 0.02), tumor located in the upper or middle lobe (P < 0.01) and higher biological effective radiation doses (≥115 Gy, P = 0.01). In conclusion, OS after SBRT was good, but LC rate was relatively low. The use of high biological effective radiation doses can improve both LC and OS outcomes.

Analyses of the local control of pulmonary Oligometastases after stereotactic body radiotherapy and the impact of local control on survival

Background

Successful local therapy for oligometastases may lead to longer survival. The purpose of this multicentre retrospective study was to investigate factors affecting the local control (LC) of pulmonary oligometastases treated by stereotactic body radiotherapy (SBRT) and to investigate the impact of LC on survival.

Methods

The inclusion criteria included 1 to 5 metastases, the primary lesion and other extrathoracic metastases were controlled before SBRT, and the biological effective dose (BED₁₀) of the SBRT was 75 Gy or more. The Cox proportional hazards model was used for analyses.

Results

Data of 1378 patients with 1547 tumours from 68 institutions were analysed. The median follow-up period was 24.2 months. The one-year, 3-year and 5-year LC rates were 92.1, 81.3 and 78.6%, respectively, and the 1-year, 3-year and 5-year overall survival rates were 90.1, 60.3 and 45.5%, respectively. Multivariate analysis for LC showed that increased maximum tumour diameter (p = 0.011), type A dose calculation algorithm (p = 0.005), shorter overall treatment time of SBRT (p = 0.035) and colorectal primary origin (p < 0.001 excluding oesophagus origin) were significantly associated with a lower LC rate. In the survival analysis, local failure (p < 0.001), worse performance status (1 vs. 0, p = 0.013; 2–3 vs. 0, p < 0.001), oesophageal primary origin (vs. colorectal origin, p = 0.038), squamous cell carcinoma (vs. adenocarcinoma, p = 0.006) and increased maximum tumour diameter (p < 0.001) showed significant relationships with shorter survival.

Conclusions

Several factors of oligometastases and SBRT affected LC. LC of pulmonary oligometastases by SBRT showed a significant survival benefit compared to patients with local failure.

Stereotactic Body Radiotherapy for Pulmonary Oligometastasis from Colorectal Cancer

BACKGROUND/AIM

A retrospective study was conducted to evaluate the safety and efficacy of stereotactic body radiotherapy (SBRT) for pulmonary oligometastasis from colorectal cancer (CRC).

PATIENTS AND METHODS

Patients with pulmonary oligometastasis from CRC who were treated with SBRT between April 2010 and October 2018 were enrolled in this study. All patients underwent SBRT using Cyberknife® with a dose of 54-60 Gy in 3 fractions to 99% of the clinical target volume. The treatment efficacy was evaluated by the local control (LC) and overall survival (OS) rates. The toxicity was evaluated using the National Cancer Institute's Common Terminology Criteria for Adverse Events version 4.0.

RESULTS

Twenty-six lesions in 20 patients were treated with SBRT. The median follow-up duration was 19 months (range=6-98 months). Local recurrence occurred in 6 of 26 lesions with a median follow-up of 12 months. The 2-year LC and OS rates were 65.8% and 88.6%, respectively. No patient developed ≥ grade 2 toxicity in the lung and other sites.

CONCLUSION

Although very high doses were delivered to the tumors with SBRT, the LC of pulmonary metastasis from CRC was not satisfactory when compared to that for stage I primary non-small cell lung cancer reported in the literature.

Local control by salvage stereotactic body radiotherapy for recurrent/residual hepatocellular carcinoma after other local therapies

Background: To clarify local control by salvage stereotactic body radiotherapy (SBRT) for recurrent/residual hepatocellular carcinoma (HCC) compared with initial definitive SBRT for local treatment-naïve HCC.Material and methods: We retrospectively investigated HCC patients that received SBRT between July 2005 and December 2017. We classified HCC tumors as the initial definitive SBRT group (Arm-1; initial definitive SBRT, Arm-2; initial definitive planned SBRT following transarterial chemoembolization (TACE)) and salvage SBRT group (Arm-3; salvage SBRT for recurrent/residual tumors after TACE, Arm-4; salvage SBRT for recurrent/residual tumors after radiofrequency ablation (RFA), Arm-5; salvage SBRT for recurrent/residual other than Arm-3 or Arm-4). Local control was evaluated by mRECIST.Results: We reviewed 389 HCC tumors of 323 patients treated by 35-40 Gy/5 fr. The median follow-up time for local recurrence of tumors was 34.8 months (range, 6.5-99.2). The cumulative local recurrence rates at 3 years of Arm-1-5 were 1.4% (95% CI, 0.3-4.4%), 5.0% (95% CI, 1.6-11.5%), 12.4% (95% CI, 5.7-21.9%), 14.8% (95% CI, 3.3-34.3%) and 7.3% (95% CI, 1.9-18.0%), respectively. The cumulative local recurrence rates at 3 years of initial definitive treatment and salvage treatment groups were 2.8% (95% CI, 1.1-5.6%) and 11.1% (95% CI, 6.3-17.3%), respectively (p=.004). On multivariate analysis, salvage treatment and the tumor diameter were significant risk factors of local recurrence (p = .02, p < .001 respectively). Estimated overall survival at 3 years for all patients in initial definitive treatment and salvage treatment groups were 71.5% (95% CI, 63.4-78.1%) and 66.1% (95% CI, 56.4-74.2%), respectively (p = .20). No treatment-related death caused by SBRT was observed.Conclusions: This analysis showed local control of salvage SBRT for recurrent/residual HCC was significantly worse than that of initial definitive SBRT for local treatment-naïve HCC. However, local control of salvage SBRT was relatively good, and salvage SBRT is one of the favorable treatment options for recurrent/residual HCC.

Clinical impact of radiofrequency ablation and stereotactic body radiation therapy for colorectal liver metastasis as local therapies for elderly, vulnerable patients

Background and Aim

Surgical resection is the standard local therapy for patients with colorectal liver metastases (CRLM). However, elderly and vulnerable patients sometimes have various organ dysfunctions. We have to conduct nonsurgical local therapies for those patients who might not tolerate surgery or systemic chemotherapy.

Methods

We retrospectively reviewed medical records of 254 patients who underwent local therapies, including surgery, radiofrequency ablation (RFA), and stereotactic body radiation therapy (SBRT), for CRLM from January 2010 to December 2016, at seven tertiary‐care institutions in Japan. This study was designed to include elderly, vulnerable patients who received local therapy for CRLM. For those undergoing liver resection, only those having one or more points of the Charlson comorbidity index (CCI) were enrolled.

Results

Of the total 169 enrolled patients, 122 patients underwent surgery, 42 RFA, and 5 SBRT as the first local therapy for CRLM. Median overall survival from the first local therapy was 5.9 years for the surgery group, 2.7 years for the RFA group, and 3.8 years for the SBRT group. The proportion of the patients with CCI ≧3 was significantly higher in the group of RFA/SBRT than surgery (P < 0.0001). In selected patients with CCI ≧3, there was no difference of the median survival time between the surgery group and the RFA group.

Conclusions

We could have other treatment options to provide nonsurgical local therapies (RFA/SBRT) for elderly, vulnerable CRLM patients who have risks for surgery.

The short-term outcomes of pulmonary metastasectomy or stereotactic body radiation therapy for pulmonary metastasis from epithelial tumors

Background

Stereotactic body radiation therapy (SBRT) has recently been widely performed for relatively small-volume tumors. We analyzed the short-term outcomes of pulmonary metastasectomy (PM) or SBRT for pulmonary metastases.

Methods

This study was a retrospective analysis of 82 patients with pulmonary metastasis from epithelial tumors who underwent PM or SBRT between 2013 and 2016.

Results

Fifty-nine patients underwent PM, 21 patients underwent SBRT, and 2 patients underwent combined PM and SBRT. The mean age of the PM group was significantly lower than that of the SBRT group (60.6 vs 67.4 years, p = 0.03). The most frequent types of primary tumor in the PM and SBRT groups were colorectal cancer (n = 27, 46%) and head and neck squamous cell carcinoma (n = 8, 38%), respectively. The rate of treatment-associated complications did not differ between the two groups to a statistically significant extent (20% vs 24%, p = 0.76). The 3-year local control rates of the two groups were similar (PM group, 88%; SBRT group, 92%; p = 0.48). The 3-year progression-free survival (PFS) rate of the PM group were better than that of SBRT groups (42% vs 11%, p = 0.01). The 3-year overall survival (OS) rates of the PM and SBRT groups were 77 and 52% respectively; although the rate of the PM group was higher, the difference was not statistically significant (p = 0.10).

Conclusions

SBRT provides a favorable 3-year local control rate. The 3-year OS rate of the SBRT group tended to be lower than that of the PM group, despite the difference was not statistically significant. PM and SBRT play complementary roles in patients with pulmonary metastases.

Structure guided deformable image registration for treatment planning CT and post stereotactic body radiation therapy (SBRT) Primovist® (Gd-EOB-DTPA) enhanced MRI

The purpose of this study was to assess the performance of structure‐guided deformable image registration (SG‐DIR) relative to rigid registration and DIR using TG‐132 recommendations. This assessment was performed for image registration of treatment planning computed tomography (CT) and magnetic resonance imaging (MRI) scans with Primovist^® contrast agent acquired post stereotactic body radiation therapy (SBRT). SBRT treatment planning CT scans and posttreatment Primovist^® MRI scans were obtained for 14 patients. The liver was delineated on both sets of images and matching anatomical landmarks were chosen by a radiation oncologist. Rigid registration, DIR, and two types of SG‐DIR (using liver contours only; and using liver structures along with anatomical landmarks) were performed for each set of scans. TG‐132 recommended metrics were estimated which included Dice Similarity Coefficient (DSC), Mean Distance to Agreement (MDA), Target Registration Error (TRE), and Jacobian determinant. Statistical analysis was performed using Wilcoxon Signed Rank test. The median (range) DSC for rigid registration was 0.88 (0.77–0.89), 0.89 (0.81–0.93) for DIR, and 0.90 (0.86–0.94) for both types of SG‐DIR tested in this study. The median MDA was 4.8 mm (3.7–6.8 mm) for rigid registration, 3.4 mm (2.4–8.7 mm) for DIR, 3.2 mm (2.0–5.2 mm) for SG‐DIR where liver structures were used to guide the registration, and 2.8 mm (2.1–4.2 mm) for the SG‐DIR where liver structures and anatomical landmarks were used to guide the registration. The median TRE for rigid registration was 7.2 mm (0.5–23 mm), 6.8 mm (0.7–30.7 mm) for DIR, 6.1 mm (1.1–20.5 mm) for the SG‐DIR guided by only the liver structures, and 4.1 mm (0.8–19.7 mm) for SG‐DIR guided by liver contours and anatomical landmarks. The SG‐DIR shows higher liver conformality as per TG‐132 metrics and lowest TRE compared to rigid registration and DIR in Velocity AI software for the purpose of registering treatment planning CT and post‐SBRT MRI for the liver region. It was found that TRE decreases when liver contours and corresponding anatomical landmarks guide SG‐DIR.

Prognostic factors for local control and survival for inoperable pulmonary colorectal oligometastases treated with stereotactic body radiotherapy

PURPOSE

The study aimed to evaluate overall survival and local control, and to identify factors independently associated with overall survival (OS) and local control (LC).

MATERIALS AND METHODS

This retrospective study examined 118 patients with primary colorectal cancer, in whom 202 inoperable pulmonary oligometastases were treated with stereotactic body radiotherapy between 2005 and 2015. Primary endpoint was to evaluate OS and identify prognostic factors associated with OS. Secondary aim was to evaluate LC and identify prognostic factors associated with LC.

RESULTS

Median follow-up was 31 months (range 3-88 months). Median OS was 39.2 months (95% CI 34.8-43.6 months). Two-, three-, and five-year OS was 69%, 55% and 36%, respectively. LC at 2-, 3-, and 5-year was 83%, 81% and 77% respectively. Factors independently associated with OS in the multivariable analysis included BED₁₀ ≥ 100 Gy (HR 0.52), male gender (HR 0.52), age < 70 years (HR 0.52) and presence of single metastasis (HR 0.37). BED₁₀ < 100 Gy (HR 3.67) and pre-SBRT chemotherapy (HR 2.66) were independently associated with poor LC in a multivariable analysis.

CONCLUSIONS

SBRT was associated with 2- year OS of 69% and 2-year LC of 83%. SBRT dose ≥ 100 Gy BED₁₀ was independently associated with both better overall survival and local control.

Prognostic Factors and Optimal Response Interval for Stereotactic Body Radiotherapy in Patients With Lung Oligometastases or Oligoprogression From Colorectal Cancer

Purpose: To analyze the prognostic factors and optimal response interval for stereotactic body radiotherapy (SBRT) in patients with lung oligometastases (OM) or oligoprogression (OP) from colorectal cancer (CRC).

Method: Patients with lung OM or OP from CRC treated by SBRT at our hospital were included in this retrospective review. The local control (LC), response to SBRT in different evaluation interval and regional metastases (RM) was analyzed. The risk factor for LC and RM was calculated using the Kaplan-Meier method and compared using the Log-rank test. Multivariate analysis with a Cox proportional hazards model was used to test independent significance.

Results: A total of 53 patients with 105 lung metastases lesions treated from 2012 to 2018 were involved in this retrospective study. The median biologically effective dose (BED) for these patients was 100 Gy (range: 75–131.2 Gy). Complete response (CR) increased from 27 (25.7%) to 46 (43.8%) lesions at 1.8 and 5.3 months following SBRT, and at the last follow-up, 52 (49.5%) lesions achieved CR. The median follow-up duration for all patients was 14 months (range: 5–63 months), and 1-year LC was 90.4%. During the follow-up, 10 lesions suffered local relapse after SBRT (9 of them occurred within 8 months after SBRT). The univariate analysis shows BED ≥ 100 Gy (P = 0.003) and gross tumor volume (GTV) < 1.6 cm³ (P = 0.011) were better predictors for 1-year LC. The patients with lung oligoprogression had higher 1-year RM when compared with patients with lung oligometastases (hazard ratio 2.78; 95% confidence interval [CI] 1.04–7.48, P = 0.042). Until the last follow up, 4 (7.5%) patients suffered grade 2 radiation pneumonitis, and no grade 3–4 toxicity was observed.

Conclusions: SBRT provides favorable LC in CRC patients with lung OM or OP, and the GTV and BED can affect the LC. Radiology examinations nearly 5–6 months following SBRT appear to represent the final local effect of SBRT, and the patients with oligoprogression has higher RM.

Local failure after stereotactic body radiation therapy or wedge resection for colorectal pulmonary metastases

OBJECTIVE

Several options are available for the local treatment of colorectal pulmonary metastases; however, the efficacy of each treatment has not been well characterized. We compared the risk of local recurrence after wedge resection or stereotactic body radiation therapy for pulmonary metastases of colorectal origin.

METHODS

We retrospectively reviewed records of patients treated for pulmonary colorectal metastases with stereotactic body radiation therapy or wedge resection from 2006 to 2016 at a single institution. Local recurrence was defined as an enlarging nodule either adjacent to the staple line or within the radiation field on computed tomography. Matching weights using the propensity score with death as a competing event was used to estimate the risk of local recurrence for each metastatic nodule.

RESULTS

A total of 381 patients underwent 762 wedge resections and 64 courses of stereotactic body radiation therapy for definitive treatment of 826 pulmonary nodules. The risk of local recurrence was increased with stereotactic body radiation therapy (hazard ratio, 3.28; 95% confidence interval, 1.53-7.04; P = .002) and larger tumor size (hazard ratio, 1.38 per additional centimeter; 95% confidence interval, 1.01-1.87; P = .042). After reweighting with matching weights, the marginal 2-year risk of local recurrence for each nodule was 14.1% (95% confidence interval, 9.8-18.5) after wedge resection and 29.4% (95% confidence interval, 13.8-45.0) after stereotactic body radiation therapy (P = .023).

CONCLUSIONS

Pulmonary colorectal metastases treated with stereotactic body radiation therapy have a higher risk of local recurrence than those treated with wedge resection. Stereotactic body radiation therapy should be reserved for patients with comorbidities precluding surgical resection.

Stereotactic Radiotherapy for Pulmonary Oligometastases From Colorectal Cancer: A Systematic Review and Meta-Analysis

PURPOSE

The purpose of this study was to determine whether pulmonary oligometastases from colorectal cancer have greater radioresistance than that of pulmonary oligometastases from other cancers and whether good local control can be achieved by dose escalation in stereotactic body radiotherapy.

MATERIALS AND METHODS

This systematic review and meta-analysis were conducted according to the preferred reporting items for systematic reviews and meta-analyses statement and methods. Studies were obtained from a database search of PubMed, Web of Science, and Google Scholar for publications using search terms designed to identify studies on "oligometastases," "lung," "stereotactic radiotherapy," and "colorectal cancer." For meta-analysis 1, studies that showed the number of local failures after stereotactic body radiotherapy for pulmonary metastases from colorectal carcinoma and other cancers were included. For meta-analysis2, studies in which a comparison was made of local control rates of pulmonary metastases from colorectal carcinoma by stereotactic body radiotherapy with a higher dose and that with a lower dose were included. A meta-analysis was performed using Mantel-Haenszel statics with the fixed or random-effect model by Review Manager 5.3.

RESULTS

Eighteen retrospective studies with 1920 patients with pulmonary oligometastases were used in meta-analysis 1. The local control rate in patients with pulmonary oligometastases from colorectal cancer was significantly lower than that in patients with pulmonary oligometastases from other cancers (odds ratio = 3.10, P < .00001). Next, 8 retrospective studies with 478 patients were included in meta-analysis 2 for dose escalation. Better local control was achieved by a higher prescription dose than by a lower prescription dose (odds ratio = 0.16, P < .00001).

CONCLUSION

Our meta-analysis indicated that local control of pulmonary oligometastases from colorectal cancer by stereotactic body radiotherapy was significantly worse than that of pulmonary metastases from other cancers; however, our results also indicated that good local control of pulmonary oligometastases from colorectal cancer can be achieved by dose escalation.

Chemo-Radiotherapy of Oligometastases of Colorectal Cancer With Pegylated Liposomal Mitomycin-C Prodrug (Promitil): Mechanistic Basis and Preliminary Clinical Experience

Hypo-fractionated radiotherapy and stereotactic body radiotherapy are viable options for treatment of oligometastases. A prodrug of mitomycin-C is under clinical testing as a pegylated liposomal formulation (Promitil) with an improved safety profile over mitomycin-C. Promitil was offered to two patients with oligometastases from colorectal cancer as radiosensitizer. Each derived durable clinical benefit from Promitil administered immediately prior to and following irradiation. Transient toxicity to normal tissues of moderate to severe degree was observed. Promitil appears to have potential clinical value in this setting.

HIGHLIGHTS

- Delivery of radio-sensitizing drugs with pegylated (long-circulating) liposomes is a pharmacologically rational approach which remains largely clinically untested.

- A mitomycin-c prodrug delivered by pegylated liposomes (Promitil) is activated by thiol groups, which are produced in excess by radiation-damaged cells, thus potentiating the radio-sensitizing effect of Promitil.

- Two durable clinical responses in patient with colorectal oligometastases to Promitil and radiotherapy suggest that this approach may be of value in cancer chemo-radiotherapy.

Integration of stereotactic radiotherapy in the treatment of metastatic colorectal cancer patients: a real practice study with long-term outcome and prognostic factors

Background

There are very few clinical or prognostic studies on the role of SRT (Stereotactic Radiation Therapy) in the continuum of care of metastatic colorectal cancer (mCRC) patients.

Patients and methods

Patients affected by oligo-mCRC were treated with SRT before or after front-line standard treatments. SRT was delivered according to a risk-adapted protocol. Total body CT (Computed Tomography) scan was done before therapy and every three months thereafter. The radiologic responses to therapy were evaluated by RECIST (Response Evaluation Criteria In Solid Tumors). FDG-PET (FluoroDeoxyGlucose - Positron Emission Tomography) was done before and after SRT; metabolic responses were evaluated by using the EORTC (European Organization for Research and Treatment of Cancer) criteria. The Kaplan-Meier product limit method was applied to graph Overall Survival (OS) and Progression-Free Survival (PFS).

Results

Forty-seven patients were included. Twenty-one patients had disease limited to lungs, 9 to lung and liver, 7 only to liver, 10 to multiple sites. The median prescription SRT dose was 60 Gy per organ in 3 fractions (median biological effective dose of 180 Gy). The reduction of delta SUVmax (maximum Standardized Uptake Value) correlated with the local control (p<0.001) and two-years survival (p=0.003). At univariate analysis, localization of primary tumor, site of metastases, KRAS (Kirsten RAt Sarcoma) oncogene mutational status, response to first-line chemotherapy, response to SRT and number of treated lesions predicted both PFS and OS.

Discussion

This real practice experience suggests that further studies are needed to analyze the promising role of SRT in the multidisciplinary management of mCRC.

Stereotactic body radiotherapy for colorectal cancer liver metastases: A systematic review

INTRODUCTION

While surgery is the preferred option for isolated, operable liver metastases from colorectal cancer (CRC), ablative techniques are endorsed for medically or technically inoperable lesions. Stereotactic body radiotherapy (SBRT) is an alternative ablative local therapy that delivers high RT doses in a few fractions to the cancer, sparing surrounding critical tissue. We have performed a systematic review of published trials to evaluate the efficacy of SBRT as a primary modality therapy for CRC liver oligometastases.

MATERIALS AND METHODS

We searched the Cochrane Central Register of Controlled Trials, Pubmed, and EMBASE for publications regarding SBRT for CRC liver metastases. Overall survival (OS: median, 1- and 2-year OS %) was the primary endpoint, and median PFS and one- and two-year local control (LC) were the secondary endpoints. A random-effect model pooled-analysis was performed to calculate the aggregated OS rates at 1 and 2 years as well as the one- and two-year LC.

RESULTS

A total of 18 studies, encompassing 656 patients, were included in the analysis. The pooled one- and two-year OS were 67.18% (95% CI, 42.1-92.2) and 56.5% (95% CI, 36.7-76.2), respectively. Median PFS and OS were 11.5 and 31.5 months. The pooled one-year LC was 67% (95% CI, 43.8-90.2), while the pooled two-year LC was 59.3% (95% CI, 37.2-81.5). Correlation analysis revealed a moderate/poor linear relationship between the SBRT (BED10) dose and LC (p = 0.001, R = 0.47)/OS (p = 0.001, R = 0.29) at 2 years. Mild-moderate and severe liver toxicity were 30.7% and 8.7%.

CONCLUSION

SBRT for liver oligometastases is an effective option for patients with advanced CRC, with encouraging local control and survival. However, a definitive validation in large randomised studies is required, due to the retrospective or non-randomised nature of the included studies and the limitations of series with different doses/schedules of treatment.

Stereotactic body radiotherapy for lung oligometastases: Literature review according to PICO criteria

Exhaustive criteria and definitive data to identify the ideal lung oligometastatic patient as a candidate for stereotactic body radiotherapy (SBRT) are lacking. Three distinct cohorts of oligometastatic patients could be distinguished: (1) patients with upfront diagnosis of oligometastases (synchronous or metachronous); (2) patients with oligorecurrent disease in terms of relapsed oligometastatic phase; (3) oligoprogressive patients after cytoreductive treatment. The aim of the present review is to analyze available data concerning the efficacy/safety of SBRT for oligometastatic/oligoprogressive/oligorecurrent lung metastases.

Early recurrence in patients undergoing curative resection of colorectal liver oligometastases: identification of its clinical characteristics, risk factors, and prognosis

PURPOSE

Oligometastatic disease can potentially be cured when an optimal approach is performed. Early recurrence after liver resection is an intractable problem, and the clinical implications remain unknown in colorectal liver oligometastases (CLOM) patients. This study aimed to investigate the clinical characteristics, risk factors, and prognosis related to early recurrence in these patients.

METHODS

A total of 307 consecutive patients with CLOM undergoing curative liver resection were retrospectively reviewed between September 1999 and June 2016. Early recurrence was defined as any recurrence or death from CLOM that occurred within 6 months of liver resection.

RESULTS

With a median follow-up time of 31.7 months, the 3-year overall survival (OS) and recurrence-free survival rates were 68.7 and 42.5%, respectively. Forty-nine (16.0%) patients developed early recurrence and showed a poorer 3-year OS than those with non-early recurrence (22.3 vs. 75.8%, P < 0.001) or later recurrence (22.3 vs. 52.8 vs. 63.2%, P < 0.001). Moreover, early recurrence was identified as an independent predictor of 3-year OS [hazard ratio (HR) 6.282; 95% confidence interval (CI) 3.980-9.915, P < 0.001]. In multivariate analysis, a node-positive primary tumor [odds ratio (OR) 2.316; 95% CI 1.097-4.892, P = 0.028) and metastatic diameter > 3 cm (OR 2.560; 95% CI 1.290-5.078; P = 0.007) were shown to be risk factors for early recurrence. The salvage liver resection rate for patients with early recurrence was significantly lower than that for patients with later recurrence (4.1 vs. 19.7%, P = 0.010).

CONCLUSIONS

Early recurrence should be investigated in routine clinical practice, even in patients with CLOM after curative liver resection. Detailed preoperative comprehensive measurements might help stratify high-risk patients, and a non-surgical treatment for early recurrence might represent an effective alternative.

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

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 BED10 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 (BED10 ≥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 (BED10 ≥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.

Stereotactic body radiation therapy for liver oligo-recurrence and oligo-progression from various tumors

Purpose

To evaluate the outcomes of stereotactic body radiation therapy (SBRT) for patients with liver oligo-recurrence and oligo-progression from various primary tumors.

Materials and Methods

Between 2002 and 2013, 72 patients with liver oligo-recurrence (oligo-metastasis with a controlled primary tumor) and oligo-progression (contradictory progression of a few sites of disease despite an overall tumor burden response to therapy) underwent SBRT. Of these, 9 and 8 patients with uncontrollable distant metastases and patients immediate loss to follow-up, respectively, were excluded. The total planning target volume was used to select the SBRT dose (median, 48 Gy; range, 30 to 60 Gy, 3–4 fractions). Toxicity was evaluated using the Common Toxicity Criteria for Adverse Events v4.0.

Results

We evaluated 55 patients (77 lesions) treated with SBRT for liver metastases. All patients had controlled primary lesions, and 28 patients had stable lesions at another site (oligo-progression). The most common primary site was the colon (36 patients), followed by the stomach (6 patients) and other sites (13 patients). The 2-year local control and progression-free survival rates were 68% and 22%, respectively. The 2- and 5-year overall survival rates were 56% and 20%, respectively. The most common adverse events were grade 1–2 fatigue, nausea, and vomiting; no grade ≥3 toxicities were observed. Univariate analysis revealed that oligo-progression associated with poor survival.

Conclusion

SBRT for liver oligo-recurrence and oligo-progression appears safe, with similar local control rates. For liver oligo-progression, criteria are needed to select patients in whom improved overall survival can be expected through SBRT.

Radiobiological parameters of liver and lung metastases derived from tumor control data of 3719 metastases

BACKGROUND AND PURPOSE

The radiobiological parameters for liver and lung metastases treated with stereotactic body radiation therapy (SBRT) are poorly defined. This project aimed at estimating these parameters from published tumor control probability (TCP) data, and separately for metastases with colorectal cancer (CRC) and non-CRC histology.

MATERIALS AND METHODS

A total of 62 studies with 89 different treatment prescriptions for a total of 3719 metastases were analyzed in a Bayesian framework using four different radiobiological models: The LQ, mLQ, LQ-L and the regrowth model which accounts for tumor regrowth after SBRT.

RESULTS

Depending on the particular model, α/β ratios in the range 13-23Gy for pulmonary metastases and 16-28Gy for hepatic metastases were estimated. For CRC metastases the estimated α/β ratio was 43.1±4.7Gy compared to 21.6±7.8Gy for non-CRC metastases. Typical isocenter dose prescriptions of 3×12Gy, 3×14.5Gy and 3×17Gy applied within 5days were predicted sufficient to control 90% of lung, liver and CRC metastases after 1yr, respectively.

CONCLUSIONS

α/β ratios for liver and lung metastases are higher than the usually assumed 10Gy. Differences between CRC and non-CRC histology were found. Future studies confirming these findings in individual patient data are needed.

Stereotactic Robotic Body Radiotherapy for Patients With Unresectable Hepatic Oligorecurrence

BACKGROUND

The purpose of this study was to analyze local control (LC), liver progression-free survival (PFS), and distant PFS (DFS), overall survival (OS), and toxicity in a cohort of patients treated with stereotactic body radiotherapy (SBRT) with fiducial tracking for oligorecurrent liver lesions; and to evaluate the potential influence of lesion size, systemic treatment, physical and biologically effective dose (BED), treatment calculation algorithms and other parameters on the obtained results.

PATIENTS AND METHODS

Unoperable patients with sufficient liver function had [18F]-fluorodeoxyglucose-positron emission tomography-computed tomography and liver magnetic resonance imaging to confirm the oligorecurrent nature of the disease and to further delineate the gross tumor volume (GTV). An intended dose of 45 Gy in 3 fractions was prescribed on the 80% isodose and adapted if risk-related. Treatment was executed with the CyberKnife system (Accuray Inc) platform using fiducials tracking. Initial plans were recalculated using the Monte Carlo algorithm. Patient and treatment data were processed using the Kaplan-Meier method and log rank test for survival analysis.

RESULTS

Between 2010 and 2015, 42 patients (55 lesions) were irradiated. The mean GTV and planning target volume (PTV) were 30.5 cc and 96.8 cc, respectively. Treatments were delivered 3 times per week in a median of 3 fractions to a PTV median dose of 54.6 Gy. The mean GTV and PTV D98% were 51.6 Gy and 51.2 Gy, respectively. Heterogeneity corrections did not influence dose parameters. After a median follow-up of 18.9 months, the 1- and 2-year LC/liver PFS/DFS/OS were 81.3%/55%/62.4%/86.9%, and 76.3%/42.3%/52%/78.3%, respectively. Performance status and histology had a significant effect on LC, whereas age (older than 65 years) marginally influenced liver PFS. Clinical target volume physical dose V45 Gy > 95%, generalized equivalent uniform dose (a = -30) > 45 Gy and a BED (α/β = 10) V105 Gy > 96% showed statistically significant effect on the LC. Acute Grade 3 gastrointestinal (GI) and late Grade 2 GI and fatigue toxicity were found in 5% and 11% patients, respectively.

CONCLUSION

Favorable survival and toxicity results support the potential paradigm shift in which the use of SBRT in oligorecurrent liver disease could benefit patients with unresectable or resectable liver metastases.

Patients with colorectal lung oligometastases (L-OMD) treated by dose adapted SABR at diagnosis of oligometastatic disease have better outcomes than patients previously treated for their metastatic disease

AIM

To evaluate the clinical outcomes of patients with OMD from a CRC primary, who underwent SABR either as first treatment at diagnosis of metachronous oligometastatic disease to lung or at progression in lung after prior treatments for metastatic disease.

METHODS

This is a retrospective review of 60 patients with 85 lung oligometastases treated by SABR at two institutions, between May 2009 and September 2014. Local control (LC), overall survival (OS), progression - free survival (PFS), and toxicity were evaluated.

RESULTS

Median follow-up was 22.9±15.5 months (range: 2.6-68.6). For the entire cohort, LC was observed for 76.6% of the target lesions; the 2- year OS and PFS were 77% and 28 % respectively. After a median of 7.9 months from SABR, 39 patients presented a first progression. In univariate analysis, patients with multiple recurrences prior to SABR (p=0.001) and those who received chemotherapy for metastatic progression (p=0.014) had poorer PFS from time of SABR. Median PFS for patients with no prior treatment for L-OMD vs. prior chemotherapy +/- local treatment vs. local treatment only was: not reached vs. 8.83 (± 2) vs. 32.5 (±2.75) months. The main pattern of first progression was out of field progression: in-field progression alone occurred in 7 patients (12%) and with synchronous regional/distant progression in 10 patients (17%. In all patients, chemotherapy was withheld until progression post-SABR. Treatment was well tolerated; only one patient experienced grade 3 bronchial toxicity, three months after completion of SABR.

CONCLUSIONS

SABR achieves high rates of local control with limited toxicities in patients with lung oligometastatic disease from a colorectal primary. This retrospective data indicates that patients with newly diagnosed lung oligometastatic disease may be safely treated with SABR as first treatment, with chemotherapy held in reserve. In heavily pretreated patients, SABR may allow patients a treatment break from systemic therapy, which may be beneficial both psychologically and physically. Future randomized SABR studies should evaluate sequencing of chemotherapy, the role of immunotherapies, and the quality of life of patients undergoing SABR.

Stereotactic body radiation therapy for oligoprogression of metastatic disease from gastrointestinal cancers: A novel approach to extend chemotherapy efficacy

Chemotherapy and targeted therapies are effective palliative options for numerous unresectable or metastatic cancers. However, treatment resistance inevitably develops leading to mortality. In a subset of patients, systemic therapy appears to control the majority of tumors leaving 5 or less to progress, a phenomenon described as oligoprogression. Reasoning that the majority of lesions remain responsive to ongoing systemic chemotherapy, we hypothesized that local treatment of the progressing lesions would confer a benefit. The present study describes the cases of 5 patients whose metastatic disease was largely controlled by chemotherapy. The oligoprogressive lesions (≤5) were treated with stereotactic body radiotherapy (SBRT), justifying continued use of an effective systemic regimen. A total of 5 patients with metastatic disease on chemotherapy, with ≤5 progressing lesions amenable to SBRT, were treated with ablative intent. Primary tumor site and histology were as follows: 2 with metastatic colon adenocarcinoma, 2 with metastatic rectal adenocarcinoma and 1 with metastatic pancreatic adenocarcinoma. Imaging was performed prior to SBRT and every 3 months after SBRT. In total, 4 out of the 5 patients achieved disease control for >7 months with SBRT, without changing chemotherapy regimen. The median time to chemotherapy change was 9 months, with a median follow-up time of 9 months. The patient who failed to respond developed progressive disease outside of the SBRT field at 3 months. In conclusion, the addition of SBRT to chemotherapy is an option for the overall systemic control of oligoprogressive disease.