Stereotactic body radiotherapy for spinal oligometastases: a survey on patterns of practice on behalf of the Italian Association of Clinical Oncology and Radiotherapy (AIRO).

BACKGROUND: The Study Group for the Biology and Treatment of the OligoMetastatic Disease on behalf of the Italian Association of Radiotherapy and Clinical Oncology (AIRO) has conducted a national survey with the aim to depict the current patterns of practice of stereotactic body radiotherapy (SBRT) for spinal oligometastases. METHODS: The Surveymonkey platform was used to send a 28-items questionnaire focused on demographic, clinical and technical aspects related to SBRT for spinal oligometastases. All the AIRO members were invited to fill the questionnaire. Data were then centralized to a single center for analysis and interpretation. RESULTS: 53 radiation oncologists from 47 centers fulfilled the survey. A complete agreement was observed in proposing SBRT for spinal oligometastases, with the majority considering up to 3 concurrent spine oligometastases feasible for SBRT (73.5%), regardless of spine site (70%), vertebral segment (85%) and morphological features of the lesion (71.7%). Regarding dose prescription, fractionated regimens resulted as the preferred option, either in 3 (58.4%) or five sessions (34%), with a substantial agreement in applying a PTV-margin larger than 1 mm (almost 90% of participants), and ideally using both MRI and PET imaging to improve target volume and organs-at-risk delineation (67.9%). CONCLUSIONS: This national italian survey illustrates the patterns of practice and the main issues for the indication of SBRT for spinal oligometastases. A substantial agreement in the numerical cut-off and vertebral segment involved for SBRT indication was reported, with a slight heterogeneity in terms of dose prescription and fractionation schemes.

Trial Protocol of a Phase II Study of mFOLFOXIRI after Metastasectomy in Patients with Oligometastatic Colorectal Cancer (FANTASTIC Study).

Background: The survival benefit of adjuvant chemotherapy after surgical resection of oligometastases from colorectal cancer (CRC) remains unclear. The prognostic role of circulating-tumor DNA (ctDNA) was reported recently and a risk stratification strategy based on monitoring minimal/molecular residual disease (MRD) has been proposed, however, which drug regimen is most effective for ctDNA-positive patients is unknown. Methods/Design: Oligometastatic CRC patients planning to undergo surgery were registered in this study. After metastasectomy, the registered patients were enrolled in the treatment arm, in which 8 courses of modified-FOLFOXIRI (mFOLFOXIRI; irinotecan 150 mg/m2, oxaliplatin 85 mg/m2, l-leucovorin (l-LV) 200 mg/m2, and 46-h continuous infusion of 5-fluorouracil (5-FU) 2400 mg/m2 every 2 weeks) followed by 4 courses of 5-FU/l-LV are administered. The patients who did not meet the eligibility criteria for the treatment arm or did not consent to mFOLFOXIRI enrolled in the observation arm in which standard of care treatment is provided. Prospective blood collections for retrospective ctDNA analysis are scheduled pre-surgery, and at 28 days, 4 and 7 months after surgery. The primary endpoint is treatment compliance at 8 courses of mFOLFOXIRI and the key secondary endpoints are the ctDNA-positivity rate and survival outcomes in ctDNA-positive and -negative groups. A total of 85 patients will be enrolled from 11 institutions. First patient-in was on July 2020. Accrual completed in February 2024. Discussion: This study will potentially identify a better treatment strategy for patients with resectable oligometastatic CRC having postsurgical ctDNA positivity, compared to the current standard of care approaches.

Acute toxicity in patients with oligometastatic cancer following metastasis-directed stereotactic body radiotherapy: An interim analysis of the E2-RADIatE OligoCare cohort.

AIM: To evaluate acute toxicity at 6 months after stereotactic body radiotherapy (SBRT) in patients with oligometastatic cancer within the OligoCare cohort. MATERIAL AND METHODS: OligoCare is a prospective, registry-based, single-arm, observational study that aims to report prospective real-world data of patients with oligometastases from solid cancer treated with SBRT (NCT03818503). Primary tumor included non-small cell lung cancer (NSCLC), breast cancer (BC), colorectal cancer (CRC), and prostate cancer (PC). This analysis addresses a secondary endpoint of the trial, acute toxicity within 6 months after SBRT. RESULTS: Out of 1,597registered patients, 1'468 patients were evaluated for acute toxicity. Globally, 290 (20 %) had NSCLC primary disease, 227 (16 %) had BC, 293 (20 %) had CRC, and 658 (45 %) had PC. Concomitant systemic treatment was administered in 527 (35.9 %) patients. According to the EORTC/ESTRO oligometastatic disease (OMD) classification, 828 (56 %) patients had de novo OMD, 464 (32 %) repeat OMD, and 176 (12 %) induced OMD. Acute grade ≥ 3 SBRT related adverse events were reported in 8 (0.5 %) patients, including 2 (0.1 %) fatal AEs. In particular, 6 (0.4 %) grade 3 events were: 1 empyema, 1 pneumonia, 1 radiation pneumonitis, 1 radiation skin injury, 1 decreased appetite, and 1 bone pain. Among those 2 occurred in NSCLC patients, 2 in BC patients, and 1 in CRC and PC patients each. The two (0.1 %) grade 5 toxicity were represented by: pneumonitis and cerebral hemorrhage. CONCLUSION: OligoCare is the largest prospective registry cohort on oligometastatic disease. Acute toxicity within 6 months was low, confirming the safety of SBRT in the treatment of oligometastases.

A novel prognostic score (HAMP) for head and neck cancer patients with single and multiple SBRT-treated lung metastases derived from retrospective analyses of survival outcome.

BACKGROUND: We report on the characterization and introduction of a novel prognostic score for patients undergoing stereotactic body radiotherapy (SBRT) for the treatment of single and multiple pulmonary metastases (PMs) derived from head and neck cancer (HNC). METHODS: In this retrospective study, we examined selected factors associated with progression-free survival (PFS) and overall survival (OS) among 59 patients with HNC treated with SBRT for a total of 118 PMs, between 2009 and 2023. Factors related to survival were included in the prognostic scoring system. RESULTS: Prognostic factors including histology, age, number of metastases, and performance status at first SBRT were weighted differently depending on the strength of correlation to PFS and OS. Total prognostic scores (HAMP) ranged from 13 to 24 points, with a cut-off total score of ≤18 scoring points for patients in a high-risk (HR) subcohort, and of ≥19 scoring points for patients in a low-risk group (LR). Median PFS (23.8 vs. 5.5 months, p < 0.001) and OS (61.3 vs. 16.4 months, p < 0.001) were significantly longer in the low-risk group compared to the high-risk group. CONCLUSION: The HAMP score might be a convenient tool to facilitate individualized treatment decisions and appropriate follow-up. The accuracy and reliability of the score requires further evaluation in prospective studies.

The Landscape of Stereotactic Ablative Radiotherapy (SABR) for Renal Cell Cancer (RCC).

Renal cell cancer (RCC) has traditionally been considered radioresistant. Because of this, conventional radiotherapy (RT) has been predominantly relegated to the palliation of symptomatic metastatic disease. The implementation of stereotactic ablative radiotherapy (SABR) has made it possible to deliver higher ablative doses safely, shifting the renal radioresistance paradigm. SABR has increasingly been adopted into the multidisciplinary framework for the treatment of locally recurrent, oligoprogressive, and oligometastatic disease. Furthermore, there is growing evidence of SABR as a non-invasive definitive therapy in patients with primary RCC who are medically inoperable or who decline surgery, unsuited to invasive ablation (surgery or percutaneous techniques), or at high-risk of requiring post-operative dialysis. Encouraging outcomes have even been reported in cases of solitary kidney or pre-existing chronic disease (poor eGFR), with a high likelihood of preserving renal function. A review of clinical evidence supporting the use of ablative radiotherapy (SABR) in primary, recurrent, and metastatic RCC has been conducted. Given the potential immunogenic effect of the high RT doses, we also explore emerging opportunities to combine SABR with systemic treatments. In addition, we explore future directions and ongoing clinical trials in the evolving landscape of this disease.

SBRT in Lymph-Nodal Oligometastases from Prostate Cancer: Different Outcomes between Pelvic and Para-Aortic Disease.

Background: Lymph-nodal prostate cancer oligometastases are differently treated according to their site: pelvic are locoregional lymph nodes; instead, para-aortic lymph nodes are considered as distant metastases. The aim of the study was a comparison between para-aortic and pelvic oligometastases treated with stereotactic body radiation therapy (SBRT). Methods: This is a retrospective analysis. De novo metastatic or extra-nodal disease were excluded. Univariate and multivariate analyses were performed; the pattern of recurrence was also evaluated. A propensity score matching (PSM) was applied to create comparable cohorts. The primary end-point was the progression-free survival (PFS). The secondary end-points were biochemical relapse-free survival (BRFS), ADT-free survival (ADTFS), polymetastases-free survival (PMFS), local progression-free survival (LPFS), and pattern of relapse. Results: In total, 240 lymph-nodal oligometastases in 164 patients (127 pelvic and 37 para-aortic) were treated. The median PFS was 20 and 11 months in pelvic and para-aortic patients, respectively (p = 0.042). The difference was not confirmed in the multivariate analysis (p = 0.06). The median BRFS was 16 and 9 months, respectively, in the pelvic and para-aortic group (p = 0.07). No statistically significant differences for ADTFS or PMFS were detected. The cumulative 5-year LPFS was 90.5%. In PSM, no statistically significant differences for all the study end-points were detected. Conclusions: Patients affected by para-aortic disease might have a PFS comparable to pelvic disease; local control is high in both cohorts. Our results also support the use of SBRT for para-aortic metastases.

Evaluation of chest CT-scans following lung stereotactic ablative radiotherapy: Challenges and new insights.

Stereotactic ablative radiotherapy (SABR) is increasingly used for the treatment of early-stage non-small cell lung cancer (ES-NSCLC) and for pulmonary metastases. In patients with ES-NSCLC, SABR is highly successful with reported 5-year local control rates of approximately 90%. However, the assessment of local control following lung SABR can be challenging as radiological changes arising from radiation-induced lung injury (RILI) can be observed in up to 90% of patients. These so-called 'benign' radiological changes evolve with time and are often asymptomatic. Several radiological and metabolic features have been explored to help distinguish RILI from local recurrences (LR). These include the Response Evaluation Criteria for Solid Tumors (RECIST), high-risk features (HRF's) and maximum standardized uptake value (SUVmax) on FDG-PET-CT. However, use of some of these approaches have poor predictive values and low specificity for recurrence. A proposed new workflow for the evaluation of post-lung SABR radiological changes will be reviewed which uses the presence of so-called 'actionable radiological features' to trigger changes to imaging schedules and identifies the need for a multidisciplinary board review. Furthermore, this critical review of post-lung SABR imaging will highlight current challenges, new insights, and unknowns in this field.

Five-year outcomes of fractionated stereotactic body radiotherapy for oligometastatic prostate cancer from the TRANSFORM phase II trial.

Metastasis-directed therapy (MDT) for oligometastatic prostate cancer (PCa), including stereotactic body radiotherapy (SBRT), has shown promise but is still considered investigational. This is the 5-year analysis of the TRANSFORM trial, the largest prospective cohort of men with oligometastatic PCa treated with SBRT-based MDT. The primary endpoint was 5-year treatment escalation-free survival (TE-FS), defined as freedom from any new cancer therapy other than further SBRT. In total, 199 men received SBRT; 76.4% were hormone-naïve at baseline. The rate of 5-year TE-FS was 21.7% (95% confidence interval [CI]: 15.7%-28.7%) overall and 25.4% (95% CI: 18.1%-33.9%) in the hormone-naïve subgroup. The subgroups with International Society of Urological Pathology Grade Groups 4-5 disease (hazard ratio [HR] = 1.48, 95% CI: 1.05-2.01, p = .026), a higher baseline prostate-specific antigen (PSA) (HR = 1.06, 95% CI: 1.03-1.09, p < .001) and those who received prior androgen deprivation therapy (ADT) (HR = 2.13, 95% CI: 1.40-3.26, p < .001), were at greater risk of treatment escalation. Outcomes for participants with four or five initial lesions were comparable to those with one to three lesions. At last follow-up, 18.9% (95% CI: 13.2%-25.7%) of participants were free from treatment escalation (median follow-up of 67.9 months) and two participants had an undetectable PSA level. No treatment-related grade three or higher adverse events were reported. The findings of this study demonstrate that SBRT-based MDT is an effective option for delaying systemic treatment escalation in the context of oligometastatic PCa. Future randomised trials comparing SBRT-based MDT to standard-of-care ADT-based approaches are required to evaluate the impact of delaying ADT on survival.

Prognostic Factors of Oligometastasis After Stereotactic Body Radiotherapy: The Real-World Utility of the European Society for Radiotherapy and Oncology/European Organisation for Research and Treatment of Cancer Classification.

AIM: The efficacy of local therapy for oligometastatic disease (OMD) remains unclear. This study aimed to evaluate the prognostic utility of the classification system for OMD and explore which groups may benefit from stereotactic body radiation therapy (SBRT). METHODS: This single-center retrospective study included 45 patients (52 sites) with solid tumors and 1-3 extracranial oligometastases who underwent SBRT for all metastases at our institution between January 2018 and December 2021. OMD states were classified based on the European Society for Radiotherapy and Oncology (ESTRO) and the European Organisation for Research and Treatment of Cancer (EORTC) classification system. Local control (LC), overall survival (OS), and progression-free survival (PFS) for each group were analyzed using the Kaplan-Meier method. Acute and late adverse events (AEs) were evaluated according to the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. RESULTS: The median follow-up period was 14 months (range: 0-48 months). The numbers of patients in the de novo (first diagnosis of OMD), repeat (previous history of OMD), and induced (previous history of polymetastatic disease) OMD groups were 15, 17, and 13, respectively. The LC rates at one year for the entire, de novo, repeat, and induced cohorts were 87.2%, 87.5%, 90.2%, and 83.9%, respectively (p=0.80). The one-year PFS rates for each group were 35.0%, 56.7%, and 29.9%, respectively (p=0.58). The one-year OS rates for each group were 80.0%, 86.2%, and 80.8%, respectively (p=0.50). Grade 2 or 3 AEs occurred in five patients (10.4%). No grade 4 or 5 AEs were observed. CONCLUSIONS: SBRT is safe and highly effective for local control. Patients with repeat OMD demonstrated a trend of longer PFS, suggesting that this subgroup may benefit from local therapy at metastatic sites.

Prospective phase II trial on ablative stereotactic body radiation therapy (SBRT) for medically inoperable thoracic nodes metastases.

BACKGROUND: Oligometastases in mediastinal nodes are increasingly prevalent, posing challenges for treatment with stereotactic body radiotherapy (SBRT) due to proximity to organs at risk (OARs). We report the results of a single prospective observational phase II trial on ablative SBRT for medically inoperable thoracic nodes metastases (NCT02970955). MATERIAL AND METHODS: Since 2017, patients with < 3 nodal metastases were evaluated by the tumor board and included if deemed inoperable. SBRT was delivered using risk adaptive approach based on number, site and size of metastatic nodes (50 Gy/5fractions, 60 Gy/8fractions, 70 Gy/10 fractions). Planning target volume (PTV) partial underdosage was allowed. The primary end point was local control (LC) at 12 months. Secondary end points were: acute and late toxicities, overall survival (OS), progression free survival (PFS), and time to next systemic therapy (TTNS). RESULTS: Between 03/2017-11/2021, 32 patients (41 nodal metastases) were included. NSCLC (13pts), breast (5pts) and colorectal cancer (4pts) were the most represented primary tumour. In 66 % cases, partial PTV undercoverage was necessary. LC at 1 and 2 years was 93.5 % and 82.3 %, respectively. Treatment was well-tolerated with no acute or late toxicity ≥ G3. Median OS was 59.7 months. OS at 1 and 2 years was 96.9 % and 83.8 % respectively. Median PFS was 12.2 months. PFS at 1 and 2 years was 53.1 % and 31.3 %, respectively. CONCLUSION: This trial supported the feasibility and safety of ablative SBRT for thoracic nodes metastases thanks to risk adaptive approach allowing to delay of new systemic therapies. Larger studies are needed to confirm these observations.

Discussion of ABC7 Consensus and German Recommendations.

The rationale behind the "International Consensus Conference for Advanced Breast Cancer" (ABC) is to standardize the treatment of patients with advanced or metastatic breast cancer worldwide using an evidence-based approach. The aim is also to ensure that patients in all countries receive adequate treatment based on current treatment recommendations and standards. The 7th International Consensus Conference on Advanced Breast Cancer (ABC7) took place from November 9 to 12, 2023 in Lisbon/Portugal. ABC7 focused on metastatic disease as well as on locally advanced and inflammatory breast cancer. Special topics included the treatment of oligometastatic patients, leptomeningeal disease, treatment of brain metastases, and pregnant women with ABC. As in previous years, patient advocates from all over the world participated in the consensus conference and were involved in decision making.

Metastasectomy and Stereotactic Body Radiotherapy for Colorectal Cancer With Liver and Lung Oligometastases: A Case Report of Complete Remission in a 96-Year-Old Patient.

We report a rare case of an extremely old colorectal cancer (CRC) patient who had complete remission after liver metastasectomy and stereotactic body radiotherapy (SBRT) to lung oligometastases (OM), with good quality of life and no evidence of recurrence 12 years after the initial diagnosis. An 83-year-old male patient had a right hemicolectomy for stage pT3 pN0 adenocarcinoma of the colon. Soon he was found to have liver metastasis treated with radiofrequency ablation and then liver metastasectomy with clear margins, followed by chemotherapy in the form of FOLFIRI for six months. Six years later, positron emission tomography (PET) showed 1.6 cm OM in the left upper lobe lung. He was not considered a good candidate for surgery. We offered him SBRT 48 Gy in four fractions every other day. The lesion disappeared with no recurrence in the same location on PET and serial computed tomography (CT) scans. Three years later, PET-CT found a new OM in the left lingular lung measuring 1.2 cm. A CT-guided lung biopsy confirmed invasive adenocarcinoma favoring OM from the CRC. SBRT planning failed due to its proximity to the heart. He accepted the longer course of conventional volumetric modulated arc therapy at 60 Gy in 15 fractions with daily cone-beam CT guidance. Again, he tolerated treatment very well with no significant side effects, despite his age. He did not require any chemotherapy or other systemic treatment in the last 11 years, so he did not experience any toxicities related to such treatment. This case is important to show that old age alone should not be considered a contraindication for metastasectomy and SBRT for CRC with liver and lung OM.

The first real-world study on the role of carbon ion radiotherapy for oligo-metastatic, persistent, or recurrent (MPR) ovarian/fallopian tube cancer.

Introduction: In the multidisciplinary management of oligometastatic, persistent, or recurrent (MPR) ovarian cancer, radiotherapy (RT) is becoming a more and more worthwhile treatment to potentially improve the chronicity of the disease. Particle beam RT has proved to be effective in several gynecological malignancies, but so far no data are available for ovarian cancer. Material and Methods: This is a real-world, retrospective, bi-institutional, single-arm study aimed to assess the effectiveness and the safety of carbon ion RT (CIRT) in this setting. The co-first endpoints are 1-year and 2-year actuarial local control (LC) rates and the objective response rate (ORR) defined on a "per lesion" basis. The secondary endpoint was toxicity. Actuarial outcomes were evaluated using the Kaplan-Meier method while potential predictors were explored using the Log-rank test. Bi-variable logistic regression was employed in the analysis of factors predicting the complete response on a per-lesion basis. Results: 26 patients accounting for a total of 36 lesions underwent CIRT with a total median dose of 52.8 Gy[RBE] (range: 39-64 Gy[RBE]). Five patients received CIRT for re-irradiation. No concomitant systemic therapies were administered during CIRT. Within 12 months after the treatment, 17 lesions (47 %) achieved complete response while 18 (50 %) obtained a partial response with an ORR of 97 %. The achievement of a complete response is related to the dose per fraction (>4.2 Gy[RBE], p = 0.04) and total dose (>52,8 Gy[RBE], p = 0.05). The 1-year LC was 92 % and the 2-year LC was 83 %, according to the achievement of a CR (p = 0.007) and GTV ≤ 14 cm3 (p = 0.024). No grade > 3 toxicities were recorded both in naïve and re-irradiated patients. PARP-i and anti-VEGF seemed not to exacerbate the risk of severe toxicities. Conclusions: CIRT was effective and safe in MPR ovarian cancers, even in the case of re-irradiation. Largest cohort studies and longer follow-up are needed to confirm these data.

Long-term efficacy analysis of radiotherapy and local management of metastases in patients with newly diagnosed oligometastatic nasopharyngeal carcinoma: A prospective, single-arm, single-center clinical study.

PURPOSE: We conducted a single-center, single-arm study (NCT03129412) to prospectively analyze the long-term outcomes of newly diagnosed patients with oligometastatic nasopharyngeal carcinoma (NPC) who received radical radiotherapy and local treatment of metastases. PATIENTS AND METHODS: Patients who reached disease controll after platinum-based palliative chemotherapy continued to receive radical radiotherapy for the nasopharyngeal region and neck. Appropriate local treatments were selected to treat the metastatic lesions. The primary endpoint of this study was overall survival (OS) and the secondary endpoint was progression-free survival (PFS). RESULTS: Fifty-one patients were included in the final analysis. During a median follow-up of 60 months, the median OS and PFS were 53.87 and 24.23 months, respectively. The 1-year, 3-year, and 5-year PFS and OS rates were 76.5 %, 38.1 %, and 31.8 % and 98 %, 75.4 %, 45.6 %, respectively. Both single and multivariate analysis indicated that maintenance therapy after radiotherapy could significantly increase PFS (36.43 vs. 16.1 months, P = 0.005). The OS of patients with single organ metastasis was significantly better than that of patients with double organ metastasis (P = 0.001). In addition, the number of metastatic organs also significantly affected PFS in the multifactor analysis. CONCLUSION: Patients with newly diagnosed oligometastatic NPC can achieve long-term survival after receiving radical radiotherapy to the primary site and local treatment for metastases.

Metastases-directed radiotherapy in castration resistant oligo metastatic prostate cancer: A multicentric retrospective study from the French group COLib.

Oligometastases are defined as a number of detectable metastases less or equal to 5. In castrate-resistant oligo metastatic prostate Cancer (CR oligoM PC), Metastases-Directed Ablative radiotherapy (MDRT) is poorly investigated. Our study retrospectively reviewed the cases of CR oligoM PC treated with MDRT in 8 French high-volume radiotherapy centers. OS and PFS are defined as the delay between the first day of MDRT and death (OS) or progression according to PCWG criteria (PFS). OS and PFS are evaluated according to Kaplan Meyer, curves are compared with log rank test. Logistic regression was used to identify predictive factors for outcome: bone versus node metastasis, ISUP grade, PSA doubling Time (PSADT) at the time of MDRT, time to castration resistance. 107 patients were included in the study, among those 197 metastases received MDRT. For the overall population, the median follow-up was 25.2 months (1,4-145). OS was 93 % at 2 years and 81,4% at 3 years. At 2 years, 100 % of patients with node-only metastasis were alive versus 88,7% among those who have bone metastases (p = 0,72). The median PFS was 12,6 months (IC 95 % [9,6; 17]), with no difference among patients with node only disease versus the rest of the cohort. The PFS was 18,2 months (10,0; 32,4) in patients with PSADT >6 months versus 10,7 months (8,9; 14,3) when PSADT was inferior to 6 months. However, this difference did not reach significant. We did not find a correlation neither between ISUP grade (1-2 versus 3-4-5) and PFS, nor between hormone-sensitivity duration and PFS. Patients receiving MDRT for CR oligoM PC have a good prognosis with 81,6% OS at 3 years. PSA DT longer than 6 months could be related to better PFS. MDRT strategy could postpone the onset of new systemic treatment with median PFS >1 year.

Treatment Outcomes of Stereotactic Ablative Body Radiotherapy on Extra-cranial Oligometastatic and Oligoprogressive Breast Cancer: Mature Results from a Single Institution Experience.

AIMS: Evidence shows stereotactic ablative body radiotherapy (SABR) is used as a non-invasive ablative therapy in the treatment of multisite oligometastatic (OM) and oligoprogressive (OP) diseases originating from metastatic breast cancer. This study aims to report the treatment outcomes and to investigate what factors that are prognostic in terms of local control, progression-free survival (PFS) and overall survival (OS) in patients receiving SABR for extracranial OM and OP diseases originating from metastatic breast cancer. MATERIALS AND METHODS: A retrospective review on treatment records of patients with OM and OP from metastatic breast cancer who underwent SABR at a single was carried out. SABR was performed with daily image-guided radiotherapy (IGRT) using a dedicated robotic SABR machine. Local control, PFS and OS were calculated using Kaplan-Meier statistics and the post-treatment toxicity data was scored following the CTCAE v4.0 protocol. Univariate and multivariate Cox regression tests were used in the subgroup analysis of prognostic factors on PFS and OS including patients' age, types of follow-up imaging (staging CT only vs whole-body MR/PET), metastases status (OM vs OP), primary breast cancer tumour grade, hormone receptors (ER/PR/HER2) status, change of systemic treatments at SABR, number of metastases, SABR treatment sites and doses. RESULTS: 56 metastatic breast cancer patients (38 patients with OM and 18 patients with OP) were involved in this retrospective review. The median follow-up was 35.6 months (range 4.0-132.9 months). The estimated local control at 1 , 2 and 5 years were 90.9%, 88.7% and 88.7%, respectively. The estimated median PFS was 19.2 months (95%CI 10.3-28.1 months); the PFS at 1, 2 and 5 years were 63.3%, 44.4% and 33.2%. The estimated OS at 1, 2 and 5 years were 98.0%, 91.9% and 74.3%, respectively with the estimated median OS of 105.1 months (95%CI 51.5-158.7 months). The vast majority of patients tolerated the treatment well with the commonest acute side effects as grade 1 fatigue. There were no statistically significant factors found in OS regression analysis. The types of follow-up imaging, metastases status, oestrogen receptor status, and number of metastases for SABR were statistically significant factors (p < 0.05) in the multivariate Cox regression analysis on PFS. CONCLUSION: There are limited studies published on the efficacy and post-treatment toxicities of metastatic breast cancer OM and OP SABR with adequate length of follow-up. This study confirmed that SABR was a safe, non-invasive treatment option for patients with extracranial OM and OP diseases originated from primary breast cancer in terms of the acceptable post-treatment toxicities.

SBRT-SG-01: final results of a prospective multicenter study on stereotactic body radiotherapy for liver metastases.

OBJECTIVE: This study aimed to assess the efficacy and tolerability of stereotactic body radiation therapy (SBRT) for the treatment of liver metastases. METHODS: Patients with up to 5 liver metastases were enrolled in this prospective multicenter study and underwent SBRT. Efficacy outcomes included in-field local control (LC), progression-free survival (PFS), and overall survival (OS). Acute and late toxicities were evaluated using CTCAE v.4.0. RESULTS: A total of 52 patients with 105 liver metastases were treated between 2015 and 2018. The most common primary tumor was colorectal cancer (72% of cases). Liver metastases were synchronous with the primary tumor diagnosis in 24 patients (46.2%), and 21 patients (40.4%) presented with other extrahepatic oligometastases. All patients underwent intensity-modulated radiation therapy (IMRT)/volumetric-modulated arc therapy (VMAT) with image-guided radiation therapy (IGRT) and respiratory gating, and a minimum biologically effective dose (BED10Gy) of 100 Gy was delivered to all lesions. With a median follow-up of 23.1 months (range: 13.4-30.9 months) since liver SBRT, the median actuarial local progression-free survival (local-PFS) was not reached. The actuarial in-field LC rates were 84.9% and 78.4% at 24 and 48 months, respectively. The median actuarial liver-PFS and distant-PFS were 11 and 10.8 months, respectively. The actuarial median overall survival (OS) was 27.7 months from SBRT and 52.5 months from metastases diagnosis. Patients with lesion diameter ≤ 5 cm had significantly better median liver-PFS (p = 0.006) and OS (p = 0.018). No acute or late toxicities of grade ≥ 3 were observed. CONCLUSIONS: This prospective multicenter study confirms that liver SBRT is an effective alternative for the treatment of liver metastases, demonstrating high rates of local control and survival while maintaining a low toxicity profile.

Definitive results of a prospective non-randomized phase 2 study on stereotactic body radiation therapy (sbrt) for medically inoperable lung and liver oligometastases from breast cancer.

BACKGROUND AND PURPOSE: To report mature results for local control and survival in oligometastatic (OM) breast cancer patients treated with stereotactic body radiotherapy (SBRT) on lung and/or liver lesions in a phase II trial. METHODS: This is a prospective non-randomized phase II trial (NCT02581670) which enrolled patients from 2015 to 2021. Eligibility criteria included: age > 18 years, ECOG 0-2, diagnosis of breast cancer, maximum of 4 lung/liver lesions (with a maximum diameter < 5 cm), metastatic disease confined to the lungs and liver or extrapulmonary or extrahepatic disease stable or responding to systemic therapy. The primary end-points were local control (LC) and treatment-related toxicities. The secondary end-points included overall survival (OS), distant metastasis-free survival (DMFS), time to next systemic therapy (TTNS), poly-progression free survival (PPFS). RESULTS: The study included 64 patients with a total of 90 lesions treated with SBRT. LC at 1 and 2 years was 94.9 %, 91 % at 3 years. Median local control was not reached. Median OS was 16.5 months, OS at 1, 2 and 3 years was 87.5 %, 60.9 % and 51.9 %, respectively. Median DMFS was 8.3 months, DMFS at 1, 2 and 3 years was 38.1 %, 20.6 % and 16 % respectively. At univariate analysis, local response to SBRT was found to be statistically linked with better OS, DMFS and STFS. CONCLUSION: SBRT is a safe and valid option in oligometastatic breast cancer patients, with very high rates of local control. An optimal selection of patients is likely needed to improve survival outcomes and reduce the rate of distant progression.

Diagnostic challenge and survival analysis of pulmonary oligometastases and primary lung cancer in breast cancer patients.

BACKGROUND: The aim of this study was to compare breast cancer patients with pulmonary oligometastases (POM) and primary lung cancer (PLC) and to assess whether there were differences in clinical features, CT features, and survival outcomes between the two groups. METHODS: From January 2010 to December 2021, the clinical records of 437 with malignant pulmonary nodules who had breast cancer patients were reviewed. POM was identified in 45 patients and PLC in 43 patients after the initial detection of pulmonary nodules. The clinicopathological characteristics, CT appearance of pulmonary nodules, and survival of the two groups were compared. RESULTS: Stage II to IV breast tumors (p < 0.001), high pathological grade of breast cancer (p = 0.001), low proportion of luminal-type breast cancer (p = 0.003), and the higher serum CYFRA 21-1 level (p = 0.046) were the clinical characteristics of pulmonary nodules suggestive of POM rather than PLC. The CT features of lung nodules indicative of PLC rather than POM were the subsolid component (p < 0.001), lobulation (p = 0.010), air bronchogram (p < 0.001) and pleural indentation (p = 0.004). Ten-year survival rate for PLC was 93.2%, which was higher compared with 57.8% in those with POM (p = 0.001). CONCLUSIONS: Elevated serum CYFRA 21-1 levels and late-stage breast cancer may be beneficial for the diagnosis of POM. CT imaging appearances of the subsolid component, lobulation, air bronchogram, and pleural indentation increase the likelihood of PLC. Breast cancer patients with PLC presented better survival with attentive monitoring than those with POM.