Stereotactic Ablative Radiotherapy for the Comprehensive Treatment of Oligometastatic Cancers: Long-Term Results of the SABR-COMET Phase II Randomized Trial

Role of stereotactic radiotherapy in the management of small-cell lung cancer

Small-cell lung cancer is the most aggressive form of lung neoplasia, treated in recent decades with chemoradiotherapy in case of limited stage and chemotherapy alone at the metastatic stage. In the last few years, the advent of immunotherapy has changed the landscape in the treatment of non-small-cell lung cancer, and to a lesser degree in small-cell lung cancer. Despite the recent advances in research, small-cell lung cancer is still considered an aggressive and lethal disease characterized by high recurrence or metastatic potential. As stereotactic radiotherapy has established itself as the standard of care in the early stage of inoperable non-small-cell lung cancer and in metastatic disease to treat brain and extracranial metastases, these same issues now arise in the management of small-cell lung cancer. This article aims to review the current knowledge and the potential of stereotactic radiotherapy in small-cell lung cancer.

Multi-institutional analysis of extracranial oligometastatic colorectal cancer patients treated with stereotactic body radiation therapy: TROD 02-008 study

PURPOSE

To investigate the treatment outcomes of extracranial oligometastatic colorectal cancer (CRC) patients treated with stereotactic body radiotherapy (SBRT).

MATERIALS AND METHODS

The clinical data of 388 extra-cranial oligometastatic CRC (≤ 5 lesions) patients and 463 lesions treated with SBRT at 19 cancer institutions were retrospectively analyzed. The prognostic factors predicting overall survival (OS), progression-free survival (PFS), and local control (LC) were assessed in uni- and multivariable analyses.

RESULTS

The median age was 62 years (range, 29-92 years). The majority of the patients (90.5%) received surgery and systemic treatment for their primary tumor, had ≤ 2 metastasis (83.3%), had single organ involvement (90.3%), and staged using flouro-deoxyglucose positron emission tomography (FDG-PET/CT) (76%). The median fraction and total radiation doses were 10 Gy (range: 6-34 Gy) and 50 Gy (range: 8-64 Gy), respectively, delivered in a median of 4 fractions (range: 1-8). The median follow-up time for the entire cohort was 30.7 months (interquartile range: 27.0-34.3 months). The 3‑year OS, PFS, and LC rates were 64.0%, 42.3%, and 72.7%, respectively. The 3‑year LC rate was significantly higher in patients receiving BED10 ≥ 100 Gy than those receiving BED10 < 100 Gy (76.0% vs. 67.3%; p = 0.04). The 3‑year PFS and OS rates were higher in patients receiving BED10 ≥ 100 Gy than those receiving BED10 < 100 Gy (33.2% vs. 25.2%; p = 0.03; 53.7% vs.  44.8%; p = 0.02). Single metastasis and complete response after SBRT were independent prognostic factors for survival in multivariable analysis.

CONCLUSIONS

In this multi-center study, we demonstrated that SBRT is an effective treatment option of metastatic lesions in oligometastatic CRC patients by providing promising LC rates. Higher SBRT doses beyond BED10 ≥ 100 Gy were associated with improved LC and survival. LC of treated lesion and lower tumor burden after SBRT were associated with better outcomes.

Recommendations on the treatment of metastatic hormone-sensitive prostate cancer: Patient selection

The standard treatment for metastatic hormone-sensitive prostate cancer (mHSPC) is now a combination of androgen deprivation therapy plus an androgen receptor-targeted therapy (abiraterone, apalutamide, enzalutamide or darolutamide), with or without chemotherapy (docetaxel). The selection of suitable patients for each therapeutic approach has become a determining factor to ensure efficacy and minimize side effects. This article combines recent clinical evidence with the accumulated experience of experts in medical oncology, radiation oncology and urology, to provide a comprehensive view and therapeutic recommendations for mHSPC.

Management of oligometastatic head and neck squamous cell carcinoma: A systematic review

Head and neck squamous cell carcinoma (HNSCC) is the seventh most common type of cancer worldwide. It is mainly discovered in a locally advanced stage, but it is estimated that 40% of recurrences after the treatment of the primary disease will be in a metastatic form, with one third being oligometastatic. There is no clear consensus regarding the treatment of oligometastatic HNSCC, whether it being local treatment, systemic treatment or a combination of both. We put together a systematic review using the Preferred Reporting Item for Systematic review and Meta-Analysis (PRISMA) method to gather all pertinent articles approaching the therapeutic management of oligometastatic HNSCC, especially in the metachronous setting. Out of 344 articles, 21 articles fit our inclusion criteria and were deemed pertinent to help answer the question of our review. Eight studies included only head and neck cancers (HNC) and the other 13 tackled multiple histologies including HNC. Stereotactic body radiotherapy (SBRT) was the treatment of choice for oligometastatic HNSCC with good local control rates and manageable toxicity. Most included studies were retrospective and not randomized. The association of local treatment and systemic treatment was difficult to assess as treatment protocols were not always standardized. There is crucial need for more prospective randomized trials that compare all treatments and sequences as some patients with a high risk of developing polymetastatic disease could derive benefit form a more intensified approach.

Stereotactic body radiation therapy on abdominal-pelvic lymph node oligometastases: a systematic review on toxicity

BACKGROUND AND PURPOSE

To review available data on toxicity during and/or after treatment of abdominal-pelvic lymph node oligometastases (A-P LN) with stereotactic body radiation therapy (SBRT) and to provide an overview of adverse events and its relation to dose or fractionation.

MATERIAL AND METHODS

For this systematic review, we searched MEDLINE, Embase, Web of Science Core Collection, and CINAH for studies published between the database inception and October 3rd, 2023. Inclusion criteria were (1) patients with 1-5 A-P LN oligometastases, (2) treatment with SBRT to a median prescribed dose of ≥55 Gy BED10, and (3) description of acute and/or late toxicity. There were no language or date restrictions.

RESULTS

A total of 35 studies, including 1,512 patients, were selected. Late grade 3 and 4 adverse events occurred in 0.6% and 0.1% of the patients treated for A-P LN oligometastases. All late adverse events grade ≥ 3 occurred after treatment of the tumor with a minimum BED10 of 72 Gy. Of the 11 patients with severe late toxicity, five patients were re-irradiated. Late grade 2 and 1 toxicity was reported in 3.4% and 8.3% of the patients. Acute toxicity grades 4, 3, 2, and 1 occurred in 0.1%, 0.2%, 4.4%, and 19.8% of the patients, respectively.

INTERPRETATION

SBRT for A-P LN oligometastases show low toxicity rates. Nearly 50% of late adverse events ≥ grade 3 were associated with re-irradiation.

Stereotactic Body Radiation therapy for Liver Metastases: Systematic Review and Meta-Analysis With International Stereotactic Radiosurgery Society (ISRS) Practice Guidelines

PURPOSE

Liver metastases are a significant clinical challenge in cancer management, often representing a stage of disease in which curative treatment is still possible. Stereotactic body radiation therapy (SBRT) has emerged as a promising modality for treating these metastases, offering a noninvasive approach with potential for high efficacy. This systematic review and meta-analysis provides a comprehensive analysis of the efficacy and safety of SBRT in treating liver metastases, and practice recommendations are provided.

METHODS AND MATERIALS

We performed a thorough literature review, adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses approach, and included 33 studies with a total of 3101 patients and 4437 liver metastases.

RESULTS

The review revealed pooled local control rates at 1, 2, and 3 years of 85%, 75%, and 68% respectively, while overall survival rates were 79%, 54%, and 37%. Grade 3 and 4 side effects occurred in only 3% of patients. The review of the studies highlighted the importance of factors such as primary tumor histology, lesion characteristics, and radiation dose in predicting treatment outcomes.

CONCLUSIONS

This review supports the growing body of evidence that SBRT is an efficacious and safe treatment option for liver metastases. It underscores the need for careful patient selection and personalized treatment planning to optimize outcomes.

Stereotactic Body Radiation Therapy for Primary Lung Cancer and Metastases: A Case Based Discussion on Challenging Cases

PURPOSE

Data informing the safety, efficacy, treatment logistics, and dosimetry of stereotactic body radiation therapy (SBRT) for lung tumors has primarily been derived from patients with favorably located solitary tumors. SBRT is now considered a standard-of-care treatment for inoperable early-stage non-small cell lung cancer and lung metastases, and therefore extrapolation beyond this limited foundational patient population remains an active source of interest.

MATERIALS AND METHODS

This case-based discussion provides a practical framework for delivering SBRT to challenging, yet frequently encountered, cases in radiation oncology. The cases highlighted herein include the use of SBRT for ultracentral tumors, multiple tumors, and re-irradiation. Patient characteristics, fractionation, prescription dose, treatment technique, and dose constraints were discussed. Relevant literature to these cases was summarized to provide a framework for the treatment of similar patients.

RESULTS

Treatment of challenging cases with lung SBRT requires many considerations, including treatment intent, fractionation selection, tumor localization, and plan optimization. In such scenarios, patient selection is critical to understanding the risk-benefit profile of an SBRT approach despite significant advances in delivery techniques and safety.

CONCLUSIONS

A case-based discussion was developed by the Radiosurgery Society to provide a practical guide to the common challenging scenarios noted above affecting patients with lung tumors. A multidisciplinary approach should guide the treatment of such cases to maximize the therapeutic window.

Thoracic Radiotherapy Improves the Survival in Patients With EGFR-Mutated Oligo-Organ Metastatic Non-Small Cell Lung Cancer Treated With Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitors: A Multicenter, Randomized, Controlled, Phase III Trial

PURPOSE

This multicenter, randomized, phase III clinical trial (Northern Radiation Oncology Group of China-002) focused on patients with oligo-organ metastatic non-small cell lung cancer (NSCLC) who have epidermal growth factor receptor (EGFR) mutations. We aimed to investigate whether first-line concurrent thoracic radiotherapy (TRT) and EGFR-tyrosine kinase inhibitors (TKIs), compared with TKIs alone, could achieve better survival.

MATERIALS AND METHODS

The patients in the TKI plus TRT group received 60 Gy to primary lung tumor and positive regional lymph nodes. Radiotherapy for metastases to other sites was determined by clinicians. The primary end point was the progression-free survival (PFS). Secondary end points included overall survival (OS) and treatment-related adverse events (TRAEs). The first and second interim analyses were performed in March 2021 and March 2022.

RESULTS

Between April 14, 2016, and February 25, 2022, a total of 118 patients were enrolled. Compared with the TKI alone group, the TKI plus TRT group achieved significantly better PFS (hazard ratio [HR], 0.57; P = .004) and OS (HR, 0.62; P = .029). The median PFS was 10.6 months in the TKI alone group and 17.1 months in the TKI plus TRT group. The median OS was 26.2 months and 34.4 months in the TKI alone group and TKI plus TRT group, respectively. The TKI plus TRT group showed better local control but was associated with a higher incidence of severe TRAEs (11.9% v 5.1%).

CONCLUSION

For patients with EGFR-mutated oligo-organ metastatic NSCLC treated with first-line EGFR-TKIs, concurrent TRT improves the PFS and OS, and TRAEs are acceptable and tolerable.

Follow-up of early breast cancer in a public health system: A 2024 AIGOM consensus project

Breast cancer stands as the most frequently diagnosed cancer and the primary cause of cancer-related mortality among women worldwide, including Italy. With the increasing number of survivors, many are enrolled in regular follow-up programs. However, adherence to recommendations from scientific societies (such as ASCO, ESMO, AIOM) for breast cancer follow-up management varies in daily clinical practice across different cancer centers, potentially resulting in unequal management and escalating costs. To address these concerns, the Italian Association of Multidisciplinary Oncology Groups (AIGOM) orchestrated a Consensus on early Breast Cancer follow-up utilizing the Estimate-Talk-Estimate methodology. Following the identification of 18 Items and 38 statements by a select Board, 46 out of 54 (85.1%) experts comprising a multidisciplinary and multiprofessional panel expressed their degree of consensus (Expert Panel). The Expert Panel underscores the potential for the multidisciplinary team to tailor follow-up intensity based on the individual risk of recurrence. In selected cases, the general practitioner may be recommended as the clinical lead for breast cancer follow-up, both after completion of adjuvant treatment and at early initiation of endocrine therapy in low-risk patients. Throughout follow-up, and alongside oncologic surveillance, the expert panel advises osteometabolic, cardiologic, and gynecologic surveillance for the early detection and management of early and late treatment toxicities. Moreover, preserving quality of life is emphasized, with provisions for psycho-oncologic support and encouragement to adopt protective lifestyle behaviors.

Predictors of brain metastases in patients with oligometastatic solid tumours treated with stereotactic body radiation therapy

PURPOSE

In patients with oligometastatic disease (OMD) treated with stereotactic body radiation therapy (SBRT), those who develop brain metastases (BrM) may have poor outcomes. We aimed to investigate variables associated with BrM development in this population.

METHODS

Patients with ≤ 5 extracranial metastases from solid tumors treated with SBRT from 2008 to 2016 at Sunnybrook Odette Cancer Centre were included. We investigated the association between covariates and CIBrM (cumulative incidence of BrM) using Fine-Gray analysis, and progression-free survival (PFS) and overall survival (OS) using Cox regression. We investigated the association between extracranial progression and CIBrM using time-based conditional analysis.

RESULTS

Among 404 patients, the most common primary sites were lung, colorectal, prostate, breast and kidney. Median follow-up was 49 months. Median PFS was 25 months. Median OS was 70 months. 58 patients developed BrM, and 5-year CIBrM was 16%. On multivariable analysis, number of extracranial metastases, location of metastases, total planning target volume (PTV), and time from primary diagnosis to OMD were not associated with CIBrM, although several of these variables were associated with extracranial PFS and OS. Primary site was associated with CIBrM, with colorectal and prostate cancer associated with lower CIBrM compared to lung cancer. Widespread extracranial progression (≥ 5 sites) within 24, 36, 48 and 60 months of OMD diagnosis was independently associated with higher CIBrM.

CONCLUSION

In patients with OMD treated with SBRT, baseline variables related to extracranial disease burden and distribution were not associated with BrM development, while primary site and widespread extracranial progression were associated with BrM development.

Radiotherapy Improves Survival in NSCLC After Oligoprogression on Immunotherapy: A Cohort Study

Introduction

The patterns of oligoprogression after first-line immune checkpoint inhibitors (ICIs) for metastatic NSCLC are yet to be well established. An increasing volume of data suggests that directed radiotherapy improves survival outcomes in patients with progression after ICIs.

Methods

A retrospective cohort study was performed on patients with metastatic NSCLC who had completed first-line programmed death-(ligand) 1 inhibitor therapy with or without chemotherapy at two high-volume cancer centers. We sought to characterize the frequency and location of oligoprogression and determine the overall survival (OS) after radiotherapy in this population.

Results

A total of 159 patients were included in the study. At first progression, 62 (39.0%) were classified as undergoing oligoprogression. Multivariate analysis confirmed the presence of brain metastases was associated with an increased likelihood of oligoprogression (OR = 2.44, p = 0.04) with most (63.2%) of these patients experiencing progression intracranially. The presence of liver metastases was associated with a decreased likelihood of oligoprogression (OR = 0.17, p < 0.01). For patients with oligoprogression, those who received radiotherapy had a longer median progression-free survival-2 (PFS2) (17 versus 11.5 mo, HR = 0.51, p = 0.02) and a longer median OS (23 versus 13 mo, HR = 0.40, p < 0.001) compared with those who did not receive radiotherapy. No difference in PFS2 or OS outcomes was observed between patients who received radiotherapy versus those who did not for systemic progression.

Conclusions

In patients with oligoprogressive metastatic NSCLC after treatment with first-line ICIs, radiotherapy significantly improves OS and PFS2 outcomes. Patients with baseline brain metastases are more likely to experience oligoprogression. Further prospective studies in directed, less heterogeneous populations of patients with metastatic NSCLC will be fundamental to optimize management.

CT-Guided Adaptive Radiotherapy for the Treatment of Technically Challenging Oligometastatic Disease: A Case Report

There is a growing interest in the application of stereotactic body radiotherapy (SBRT) for the treatment of oligometastatic cancers. This increasing appeal of SBRT has highlighted the need for more sophisticated radiotherapy techniques that allow high doses of radiation to be delivered to multiple sites while limiting the exposure of neighboring healthy tissue. A major obstacle to achieving this aim has been the occurrence of interfraction target variability: the tendency of both the tumor and the surrounding tissue to undergo day-to-day non-synchronous shifts in position. Such changes in the conformation of the tumor field often compromise the effectiveness of conventional SBRT prescribed for a fixed target. We report a case of oligometastatic pelvic disease where the challenge of an unusually mobile tumor was overcome with the use of a novel technique employing cone beam CT (CBCT)-based online adaptive radiotherapy (OART). The Phase I "Adaptive Radiation for Abdominopelvic Metastases (ARAM)" clinical trial was designed to determine if OART can achieve dosing targets superior to those attained using conventional radiotherapy techniques. In this case, CT adaptive planning enabled the treatment of a pelvic target prescribed per protocol to 45Gy that would otherwise have not been amenable to treatment with conventional SBRT planning. Adaptive plans showed significant improvements in target coverage while respecting critical organ constraints, resulting in a total treatment V35Gy of 89.3% and V45Gy of 52.8%, whereas the scheduled plan would have achieved V35Gy of 67.4% and V45Gy of 13.6%. Treatment times were variable (38.1-96.7 mins), and correlated with the magnitude of daily translation which ranged from 4 to 7 cm of total linear translation. The patient tolerated treatment without any adverse events. These results demonstrate a novel application of CBCT-guided OART that allowed for the administration of ablative treatment to an unexpectedly mobile target unamenable to conventional SBRT. CBCT-guided OART currently requires increased treatment time, a need which might be reduced by optimization of daily contouring. The phase 1 clinical trial NCT05880667 is ongoing and may provide further evidence that CBCT-guided OART can meet the technical challenges posed by radiotherapy for oligometastatic abdominal and pelvic disease.

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.

Targeting the Dendritic Cell-Secreted Immunoregulatory Cytokine CCL22 Alleviates Radioresistance

PURPOSE

Radiation-mediated immune suppression limits efficacy and is a barrier in cancer therapy. Radiation induces negative regulators of tumor immunity including regulatory T cells (Treg). Mechanisms underlying Treg infiltration after radiotherapy (RT) are poorly defined. Given that conventional dendritic cells (cDC) maintain Treg, we sought to identify and target cDC signaling to block Treg infiltration after radiation.

EXPERIMENTAL DESIGN

Transcriptomics and high dimensional flow cytometry revealed changes in murine tumor cDC that not only mediate Treg infiltration after RT but also associate with worse survival in human cancer datasets. Antibodies perturbing a cDC-CCL22-Treg axis were tested in syngeneic murine tumors. A prototype interferon-anti-epidermal growth factor receptor fusion protein (αEGFR-IFNα) was examined to block Treg infiltration and promote a CD8+ T cell response after RT.

RESULTS

Radiation expands a population of mature cDC1 enriched in immunoregulatory markers that mediates Treg infiltration via the Treg-recruiting chemokine CCL22. Blocking CCL22 or Treg depletion both enhanced RT efficacy. αEGFR-IFNα blocked cDC1 CCL22 production while simultaneously inducing an antitumor CD8+ T cell response to enhance RT efficacy in multiple EGFR-expressing murine tumor models, including following systemic administration.

CONCLUSIONS

We identify a previously unappreciated cDC mechanism mediating Treg tumor infiltration after RT. Our findings suggest blocking the cDC1-CCL22-Treg axis augments RT efficacy. αEGFR-IFNα added to RT provided robust antitumor responses better than systemic free interferon administration and may overcome clinical limitations to interferon therapy. Our findings highlight the complex behavior of cDC after RT and provide novel therapeutic strategies for overcoming RT-driven immunosuppression to improve RT efficacy. See related commentary by Kalinski et al., p. 4260.

Organ-Specific Tumor Response to Enfortumab Vedotin for Metastatic Urothelial Carcinoma: A Multicenter Retrospective Study

INTRODUCTION

To evaluate the organ-specific therapeutic effect of enfortumab vedotin (EV) after chemotherapy and immunotherapy failed for advanced urothelial carcinoma.

MATERIALS METHODS

At 6 institutions between December 2021 and July 2023, we retrospectively analyzed patients with metastatic upper and lower urinary tract cancer who received EV monotherapy after platinum-based chemotherapy and immune checkpoint blockade therapy. Objective response rate (ORR) and organ-specific response rate (OSRR) were evaluated according to the Response Evaluation Criteria in Solid Tumors, version 1.1.

RESULTS

This study analyzed 58 patients with 210 tumor lesions, of which 24% were females and 48% had upper urinary tract cancer. The ORR and disease control rate were 53.5% and 74.1%. Moreover, we found 15 target lesions in the primary site, 7 in local recurrence, 93 in the lymph nodes, 46 in the lung, 29 in the liver, and 20 in the bone, with OSRRs of 40%, 71.4%, 61.1%, 70.6%, 90.9%, and 18.2%, respectively. Over time from baseline, the reduction rate (median) in tumor burden was 50% or more in the lymph node, lung, and liver metastases.

CONCLUSION

The organ-specific tumor response to EV in patients with metastatic urothelial carcinoma was almost favorable. The antitumor activity of EV monotherapy may be less in bone metastasis than in other organ sites. Conversely, EV showed remarkably high efficacy against liver metastasis.

Cyclin-dependent kinase 4/6 inhibitors combined with stereotactic ablative radiotherapy in oligometastatic HR-positive/HER2-negative breast cancer patients

OBJECTIVES

Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) have significantly improved the survival of patients with hormone receptor-positive HER2-negative advanced breast cancer (ABC). Although stereotactic ablative radiotherapy (SABR) is used more often in routine clinical practice, data on the safety and efficacy of combining SABR with CDK4/6i are lacking. Herein, we present the results of SABR combined with CDK4/6i in ABC.

METHODS

Patients with ABC who received CDK4/6i and SABR between 2018 and 2023 were analysed.

RESULTS

Among 384 patients treated with CDK4/6i, 34 patients received 44 courses of SABR. Two-year progression-free survival (PFS) was 63.6% (95% CI, 45.8-88.3), and the median PFS was 32 months. Three-year overall survival (OS) was 88.9% (95% CI, 77.7-100). Two-year local control (LC) was 92.7% (95% CI, 83.4-100). Median OS and LC were not reached. The subgroup analysis showed the difference in survival between oligometastatic patients (OMD) and non-OMD subgroup. Two-year PFS was 69.2% (95% CI, 44.5-100) in OMD compared with 57.4% (95% CI, 36-91.7) in the non-OMD (P = .042). Three-year OS was 90% (95% CI, 73.2-100) in OMD compared with 86.2% (95% CI, 70-100) in the non-OMD (P = .67). Median PFS and OS in the non-OMD were 26 and 56 months, respectively, and were not reached in OMD. Fifteen patients required CDK4/6i dose reduction, and 2 discontinued treatment due to toxicity. No difference in high-grade toxicity was observed between the sequential and concurrent SABR.

CONCLUSION

The addition of SABR to CDK4/6i seems to be safe and effective, especially in patients with oligometastatic disease.

ADVANCES IN KNOWLEDGE

In advanced breast cancer patients treated with CDK4/6i, SABR provides a high local control and may provide additional benefit in an oligometastatic setting.

Is primary breast melanoma a true pathological entity? The argument against it

Background

Previous studies have reported cases of primary melanoma of the breast parenchyma (PMBP), but the pathogenesis of this disease remains poorly understood. We review the presentation and outcomes of reported cases and provide detailed pathological analysis of four additional cases. Furthermore, we discuss potential theories regarding the pathogenesis of this clinical presentation.

Results

We identified 29 published studies (n = 95 patients) and report four new cases (n = 99). Ninety-one (92 %) patients were female, with a median age of 50 years. Previous skin melanomas were reported by 56 % of patients, with the trunk being the most common location (32.7 %) followed by the upper extremities (20 %). The most common tumor location reported (n = 73) was the right (49 %) upper outer quadrant (56 %). The median time from skin melanoma diagnosis to the presence of a breast mass was 65 months (1-192). Nodal status at presentation was reported in n = 67 (68 %) patients. Of these, positive nodal metastases were seen in 40.3 %, while distant metastatic disease at presentation was reported in 30 % of patients. Surgery was performed in 66 %, being partial mastectomy (PM) the most common procedure in 82 %. Adjuvant therapy was described in 38 patients. The reported (n = 12) median survival was 11.5 (1-70) months.

Conclusion

Melanomas identified in the breast parenchyma are likely the result of nodal or hematogenous spread from previously known or unknown melanomas, and should not be considered as PMBP. Management should be multidisciplinary, including surgical excision aimed at obtaining negative margins with lymphadenectomy of clinically positive nodes and neoadjuvant/adjuvant immunotherapy.

The Role of Stereotactic Body Radiotherapy (SBRT) in Oligoprogressive Renal Cell Carcinoma (RCC) Treated with ICIs-TKIs: A Retrospective Multicentric Study

BACKGROUND

This multicentric, retrospective study investigated the use of stereotactic body radiotherapy (SBRT) in patients (pts) with metastatic renal cell carcinoma (mRCC) who experienced oligoprogression during a combination therapy with an immune checkpoint inhibitor (ICI) and a tyrosine-kinase inhibitor (TKI).

METHODS

We retrospectively evaluated 34 pts affected by oligoprogressive RCC treated with an ICI-TKI combination between January 2020 and December 2023. SBRT was delivered to each site of oligoprogressive metastatic disease. After SBRT, pts were given follow-up clinical evaluations. 6-12-18-month local control (LC) rates and median next-line treatment-free survival (NEST-FS) were the primary endpoints. The secondary endpoints were overall response rate (ORR), clinical benefits and safety.

RESULTS

After a median follow-up of 24 months, 6-12-18-month LC rates were 100%, 71% and 43%, respectively, and the median NEST-FS was 20 months. ORR was 90%, while clinical benefit was 100%. No > G2 adverse events related to SBRT were recorded.

CONCLUSIONS

In our study, SBRT for oligoprogressive mRCC turned out to be a safe and useful treatment which was able to preserve current treatment. Further prospective studies are necessary to explore the effects of the ICIs-TKIs combination and SBRT upon oligoprogressive sites in mRCC.

Oligometastatic non-small cell lung cancer: Impact of local and contemporary systemic treatment approaches on clinical outcome

Oligometastatic (OMD) non-small cell lung cancer (NSCLC) is a distinct but heterogeneous entity. Current guidelines recommend systemic therapy and consolidation with local ablative therapy (LAT). However, evidence regarding the optimal choice of multimodal treatment approaches is lacking, in particular with respect to the integration of immunotherapy. This real-world study identified 218 patients with OMD NSCLC (2004-2023, prespecified criteria: ≤5 metastases in ≤2 organ systems) from three major German comprehensive cancer centers. Most patients had one (72.5%) or two (17.4%) metastatic lesions in a single (89.9%) organ system. Overall survival (OS) was significantly longer with a single metastatic lesion (HR 0.54, p = .003), and female gender (HR 0.4, p < .001). Median OS of the full cohort was 27.8 months, with 29% survival at 5 years. Patients who had completed LAT to all NSCLC sites, typically excluding patients with early progression, had a median OS of 34.4 months (37.7% 5-year OS rate) with a median recurrence-free survival (RFS) of 10.9 months (13.3% at 5 years). In those patients, systemic treatment as part of first-line therapy was associated with doubling of RFS (12.3 vs. 6.4 months, p < .001). Despite limited follow-up of patients receiving chemo-immunotherapy (EU approval 2018/2019), RFS was greatly improved by adding checkpoint inhibitors to chemotherapy (HR 0.44, p = .008, 2-year RFS 51.4% vs. 15.1%). In conclusion, patients with OMD NSCLC benefitted from multimodality approaches integrating systemic therapy and local ablation of all cancer sites. A substantial proportion of patients achieved extended OS, suggesting a potential for cure that can be further augmented with the addition of immunotherapy.

Stereotactic Ablative Radiation Therapy for Oligometastatic Ovarian Cancer Lymph Node Disease: The MITO-RT3/RAD Phase II Trial

PURPOSE

MITO-RT3/RAD (NCT04593381) is a prospective multicenter phase 2 trial designed to assess the effectiveness and safety of stereotactic body radiation therapy (SBRT) in patients who received diagnoses of oligometastatic ovarian cancer. In this report, we provide the results of the trial in the setting of lymph node disease.

METHODS AND MATERIALS

The primary endpoint was the complete response (CR) rate, secondary endpoints included local control (LC), progression-free survival (PFS), overall survival, treatment-free interval, and toxicity rates. The sample size was based on a previous study reporting an average 70.0% CR with SBRT. The study was powered to detect an improvement in the CR rate from 70.0% to 85.0%, with an α error of 0.05 (one-side) and a β error of 0.1.

RESULTS

The study met its primary endpoint of a statistically significant improvement in CR. One hundred thirty-five patients with 249 lesions were enrolled across 15 institutions from May 2019 to November 2023. CRs were observed in 194 lesions (77.9%), partial responses in 40 (16.1%), stable disease in 14 (5.6%), and progressive disease in 1 lesion (0.4%). The objective response rate was 94%, with an overall clinical benefit rate of 99.6%. CR lesions exhibited a significantly higher LC rate than partial or not responding lesions (12-month LC: 92.7% vs 63.1%, P < .001). The 12-month actuarial rates for PFS and for overall survival were 36.6% (CR, 38.3% vs not-CR, 18.8%; P, .022) and 97.2% (CR, 97.8% vs not-CR, 93.8%; P, .067), respectively. The 12-month actuarial rate for treatment-free interval was 52.7% (CR, 58.4% vs not-CR, 24.4%; P, .004). CR was substantially associated with higher PFS (P, .036) and treatment-free interval (P, .006) rates in the univariate analysis. Twenty-three patients (17.0%) experienced mild acute toxicity. Late toxicity was reported in 9 patients (6.7%), mostly grade 1.

CONCLUSIONS

This trial confirms the efficacy of ablative SBRT, with minimal toxicity observed. SBRT offered a high CR rate, promising long-term outcomes, and a significant systemic therapy-free survival period for complete responders.

Local treatment for oligoprogressive metastatic sites of breast cancer: efficacy, toxicities and future perspectives

Metastatic breast cancer (MBC) is still an incurable disease, which eventually develops resistance mechanisms against systemic therapies. While most patients experience widespread disease progression during systemic treatment (ST), in some cases, progression may occur at a limited number of metastatic sites. Evidence from other malignancies suggests that local treatment with stereotactic ablative radiotherapy (SABR) of oligoprogressive disease (OPD) may allow effective disease control without the need to modify ST. Available evidence regarding local treatment of oligoprogressive breast cancer is limited, mostly consisting of retrospective studies. The only randomized data come from the randomized CURB trial, which enrolled patients with oligoprogressive disease, including both small cell lung cancer and breast cancer patients, and did not show a survival benefit from local treatment in the latter group. However, local treatment of oligoprogressive MBC is still considered in clinical practice, especially to delay the switch to more toxic STs. This review aims to identify patients who may benefit from this approach based on the current available knowledge, focusing also on the potential risks associated with the combination of radiotherapy (RT) and ST, as well as on possible future scenarios.

Overview of cardiac toxicity from radiation therapy

Radiotherapy is an essential part of treatment for many patients with thoracic cancers. However, proximity of the heart to tumour targets can lead to cardiac side effects, with studies demonstrating link between cardiac radiation dose and adverse outcomes. Although reducing cardiac dose can reduce associated risks, most cardiac constraint recommendations in clinical use are generally based on dose to the whole heart, as dose assessment at cardiac substructure levels on individual patients has been limited historically. Furthermore, estimation of an individual's cardiac risk is complex and multifactorial, which includes radiation dose alongside baseline risk factors, and the impact of systemic therapies. This review gives an overview of the epidemiological impact of cancer and cardiac disease, risk factors contributing to radiation-related cardiotoxicity, the evidence for cardiac side effects and future directions in cardiotoxicity research. A better understanding of the interactions between risk factors, balancing treatment benefit versus toxicity and the ongoing management of cardiac risk is essential for optimal clinical care. The emerging field of cardio-oncology is thus a multidisciplinary collaborative effort to enable better understanding of cardiac risks and outcomes for better-informed patient management decisions.

Radiation Therapy for Primary and Metastatic Spine Tumors

Radiation therapy plays an important role in the management of patients with primary and metastatic spine tumors. Technological innovations in the past decade have allowed for improved targeting, dose escalation, and precision of radiation therapy while concomitant improvements in surgical techniques have resulted in improved outcomes with reduced morbidity. Patients with cancer have increasingly complex oncologic needs, and multidisciplinary management is more essential than ever. This review will provide an overview of radiation principles, modern radiation techniques, management algorithms, and expected toxicities of common radiation treatments in the management of spine tumors.

Focal therapy for oligometastatic and oligoprogressive renal cell carcinoma: a narrative review

Metastatic renal cell carcinoma (RCC) can present with oligometastatic disease and/or develop oligoprogression following systemic therapy. Cytoreductive and focal metastasis-directed therapy options include resection, stereotactic ablative radiation and thermal ablation. Aggressive focal therapy may allow delay in initiation of or modification to systemic therapy and improve clinical outcomes. In this narrative review we synthesize current practice guidelines and prospective data on focal therapy management options and highlight future research. Patient selection and the choice of focal treatment techniques are controversial due to limited and heterogeneous data and patients may benefit from multidisciplinary evaluation. Prospective comparative trials with clearly defined inclusion criteria and relevant end points are needed to clarify the risks and benefits of different approaches.

The Role of Stereotactic Body Radiotherapy in Oligoprogressive Malignant Disease (RADIANT): Oncologic Outcomes From a Phase 2 Nonrandomized Controlled Trial

PURPOSE

In oligoprogressive (OP) cancer, there are a limited number of metastatic areas progressing on a background of stable or responding to widespread cancer. Although the standard of care for OP is changing systemic therapy (ST), stereotactic body radiation therapy (SBRT) is being explored as an alternative local therapy targeting the sites of progression.

METHODS AND MATERIALS

RADIANT (NCT04122469) was a single-center phase 2 study of patients with metastatic genitourinary (GU), breast, and gastrointestinal (GI) cancers, receiving ST for ≥3 months, with radiographic OP disease in ≤5 sites. Patients received SBRT for all OP disease in 1 to 5 fractions and were maintained on ST. The primary endpoint was the cumulative incidence of change in ST, which was estimated using the Aalen-Johansen method. Secondary endpoints included progression-free survival (PFS) and overall survival estimated using the Kaplan-Meier method, as well as toxicity and health-related quality of life. Comparisons between diagnosis groups were done using the log-rank test. A 2-sided p value <.05 was considered statistically significant.

RESULTS

Seventy patients were analyzed, with a median age of 69 years; 32 patients (46%) were women; the median number of lines of prior ST was 3. Primary sites were GU (n = 32; 46%), breast (n = 23; 33%), and GI (n = 15; 21%). The median follow-up was 12.3 months (IQR, 8.2-21.6 months). At 1 year, change in ST occurred in 47% (95% CI, 36%-61%) (GU 45%, breast 41%, and GI 60%; p = .23). PFS at 1 year was 32% (95% CI, 23%-45%), and median PFS was 4.7 months (95% CI, 3.8-8.1) (GU 4.8, breast 6.5, and GI 3.2), which significantly differed by disease type (p = .006). Overall survival was 75% at 1 year (95% CI, 65%-87%), which significantly differed between cancer types (GU 86%, breast 96%, and GI 22%; p < .001). The cumulative incidence of late grade ≥2 toxicity was 1.2%, with 1 patient experiencing late grade 3 toxicity and no grade 4 to 5 acute or late toxicities. Health-related quality of life declined from the mean (SD) of 66.9 (20.2) at baseline to 60.5 (22.2) at 6 months, which did not meet the threshold for a minimal clinically important difference.

CONCLUSIONS

SBRT for OP metastases delayed change in ST in approximately half of patients, warranting investigation in randomized trials.

Stereotactic Body Radiation Therapy for Oligoprogressive Ovarian Cancer Patients Treated During Poly(ADP-Ribose)-Polymerase Inhibitor Maintenance: Efficacy and Adverse Events From the Epimetheo Retrospective Study

PURPOSE

The aim of this observational, retrospective, multicenter study (Epimetheo) was to analyze the activity and the safety of stereotactic body radiation therapy (SBRT) during poly(ADP-ribose)-polymerase inhibitor (PARPi) maintenance in a series of oligometastatic ovarian cancer (OC) patients.

METHODS AND MATERIALS

Patients treated with PARPi in maintenance setting received SBRT if oligometastatic progression occurred. Maintenance treatment was continued until the extensive progression of the disease. The primary endpoints of the study were as follows: next systemic treatment change-free survival (NEST-FS) and acute and late toxicity; the secondary endpoints were as follows: the rate of clinical complete response (CR), the 2-year actuarial local control (LC, progression of disease inside SBRT field) rate on "per lesion" basis, the 2-year actuarial progression-free survival, and 2-year overall survival (OS).

RESULTS

From April 2018 to September 2023, SBRT was used to treat 74 OC patients with a total of 158 lesions (98 lymph nodes and 60 parenchymal lesions) under PARPi maintenance. Olaparib, niraparib, and rucaparib were administered to 41.9%, 48.6%, and 9.5% of patients, respectively. CR, partial response, stable disease, and progressive disease were observed in 115 (72.8%), 32 (20.3%), 9 (5.7%), and 2 lesions (1.3%), respectively. Severe toxicities were reported in less than 3% of patients. The actuarial median NEST-FS was 10 months, with a range of 6.7-13.3 months. The 12- and 24-month actuarial NEST-FS rates were 44.9% and 31.4%, respectively. The 2-year actuarial LC, progression-free survival, and OS were 68.1%, 22.5%, and 77%, respectively with differences in figures between complete and incomplete responders. The achievement of CR was found to be correlated with an improvement in LC and OS.

CONCLUSIONS

This study reports the activity and the low toxicity profile of SBRT in association with PARPi in oligometastatic OC patients. A rapid, minimally invasive, and cost-effective treatment such as SBRT may be proposed as a means of prolonging NEST-FS and maintaining an effective treatment regimen involving PARPi.

A randomized phase III trial of stereotactic ablative radiotherapy for patients with up to 10 oligometastases and a synchronous primary tumor (SABR-SYNC): study protocol

BACKGROUND

Emerging randomized data, mostly from phase II trials, have suggested that patients with oligometastatic cancers may benefit from ablative treatments such as stereotactic ablative radiotherapy (SABR). However, phase III data testing this paradigm are lacking, and many studies have examined SABR in the setting of metachronous oligometastatic disease. The goal of the SABR-SYNC trial is to assess the effect of SABR in patients with oligometastatic cancers and a synchronous primary tumor.

METHODS

One hundred and eighty patients will be randomized in a 1:2 ratio between standard of care (SOC) palliative-intent treatments vs. SOC + ablative therapy (SABR preferred) to all sites of known disease. Randomization will be stratified based on histology and number of metastases at enrollment. SABR may be delivered in 1-, 3- and 5-fraction regimens, with recommended doses of 20 Gy, 30 Gy, and 35 Gy, respectively. Non-SABR local modalities (e.g. surgery, thermal ablation, conventional radiation) may be used for treatment of the primary or metastases at the discretion of the treating physicians, if those modalities are clinically preferred. The primary endpoint is overall survival, and secondary endpoints include progression-free survival, time to development of new metastatic lesions, time to initiation of next systemic therapy, quality of life, and toxicity. Translational endpoints include assessment of circulating tumor DNA and immunological predictors of outcomes.

DISCUSSION

SABR-SYNC will provide phase III data to assess the impact of SABR on overall survival in a population of patients with synchronous oligometastases. The translational component will attempt to identify novel prognostic and predictive biomarkers to aid in clinical decision making.

TRIAL REGISTRATION

Clinicaltrials.gov NCT05717166 (registration date: Feb. 8, 2023).

Radiosurgery Society Case-Based Guide to Stereotactic Body Radiation Therapy for Challenging Cases of Spinal Metastases

PURPOSE

Spinal stereotactic body radiation therapy (SBRT) has become the standard of care in management of patients with limited sites of metastatic disease, radioresistant histologies, painful vertebral metastases with long life expectancy and cases of reirradiation. Our case-based guidelines aim to assist radiation oncologists in the appropriate utilization of SBRT for common, yet challenging, cases of spinal metastases.

METHODS AND MATERIALS

Cases were selected to include scenarios of large volume sacral disease with nerve entrapment, medically inoperable disease abutting the thecal sac, and local failure after prior SBRT. Relevant literature was reviewed, and areas requiring further investigation were discussed to offer a framework for evidence-based clinical practice.

RESULTS

Spinal SBRT can be effectively delivered in challenging cases following multidisciplinary discussion by using a methodical approach to patient selection, appropriate dose selection, and adherence to evidence-based dose constraints.

CONCLUSIONS

The Radiosurgery Society's case-based practice review offers guidance to practicing physicians treating technically challenging SBRT candidate patients with spinal metastases.

Current issues and management consensus of advanced prostate cancer: Report of the Advanced Prostate Cancer Consensus Conference-JAPAN 2023

OBJECTIVE

To evaluate and compare the voting results of Japanese urologists with the global panel at the Advanced Prostate Cancer Consensus Conference (APCCC) 2022.

METHODS

Among the 198 questions discussed at the APCCC 2022, the APCCC-JAPAN 2023 focused on 14 key questions related to the management of advanced prostate cancer with insufficient high-level evidence based on their relevance to the Japanese cohort. A panel of six prostate cancer experts addressed these 14 questions and presented the latest evidence to Japanese urologists who voted on-site using a web-based system. The results were compared with those of APCCC 2022.

RESULTS

This study found significant differences in the voting results between Japanese urologists and the global panel regarding several crucial issues related to advanced prostate cancer management. These differences were those observed in treatment preferences, monitoring strategies, and treatment choices in specific clinical scenarios. These findings highlight the need for a nuanced approach tailored to the unique challenges with considerations of the Japanese healthcare environment.

CONCLUSIONS

APCCC-JAPAN 2023 provides valuable insights into the current clinical issues surrounding the management of advanced prostate cancer in Japan. The partial divergence in the consensus between Japanese urologists and the global panel underscores the importance of a context-specific approach. The results of this study provide practical guidance for physicians facing complex challenges and should be used to inform decision-making in the management of advanced prostate cancer.

Dosimetric impact of the respiratory motion of the liver dome in stereotactic body radiotherapy for spine metastasis: A planning study

PURPOSE

This study aimed to clarify the dosimetric impact of the respiratory motion of the liver on stereotactic body radiation therapy (SBRT) for spine metastasis and examine the utility of introducing beam avoidance (beam-off at specific gantry angles).

METHODS

A total of 112 consecutive patients who underwent SBRT for spine metastasis between 2018 and 2024 were examined. Overall, 15 patients who had lesions near the liver dome were included in this study. Retrospective treatment plans were generated using computed tomography (CT) images acquired during inhalation and exhalation to evaluate the dosimetric impact of respiratory motion of the liver. The dose difference (DD) and relative value (DD%) were evaluated using the dose-volume histogram (DVH) metrics, planning target volume Dmax, D95%, spinal cord D0.035 cc, and esophagus D2.5 cc. The magnitude of the liver movements was evaluated based on differences of liver size Lave at the isocentric axial plane between the inspiratory and expiratory CT images.

RESULTS

The DD in almost all DVH metrics tended to increase when the liver moved away from the target during inhalation: For example, Mean ± $ \pm $ a standard deviation (SD) DD in PTV D95% for the treatment plan incorporating beam avoidance and those without beam avoidance was 0.5 ± $\pm$ 0.3 and 0.9 ± $ \pm $ 0.6 Gy, respectively. The spinal cord D0.035 cc for those shows 0.4 ± $ \pm $ 0.2 and 0.7 ± $ \pm $ 0.7 Gy, respectively. The treatment plans without beam avoidance also showed moderate or strong correlations between Lave and DD for almost all DVH metrics. No correlation was seen in the beam avoidance plan. The spinal cord D0.035 cc revealed approximately 1 Gy or +4% in DD when Lave was < -4 cm.

CONCLUSIONS

Respiratory motion of the liver dome can cause substantial dosimetric discrepancies in the dose delivered to the spinal cord, although the extent depends on patient variables. Dose assessment should be performed for determining the appropriate means of respiratory management, such as breath-hold. Alternatively, beam avoidance effectively mitigates the impact.

Clinical management of oligometastatic cancer: Applying multidisciplinary tumor board recommendations in practice

Aims

Multidisciplinary tumor boards (MDTs) are an integral part of ensuring high-quality, evidence-based and personalized cancer care. In this study, we aimed to evaluate the adherence to and implementation of MDT recommendations in patients with oligometastatic disease (OMD).

Methods

We screened all oncologic positron emission tomography (PET) scans conducted at a single comprehensive cancer center in 2020. Patients were included if they had evidence of imaging-based OMD from a solid organ malignancy on the index scans, had their OMD case discussed at an MDT, and were treated and followed up at the same center. A switch away from the MDT-recommended treatment modalities was classified as a major deviation; non-MDT-mandated adjustments to a recommended treatment modality were coded as minor deviation. Clinical data was obtained via chart review; statistical calculations were computed using the R software.

Results

After review of PET and/or concurrent brain scans, 787 cases of OMD were identified. Thereof, 347 (44.1 %) cases were discussed at MDT, of which 331 (42.1 %) were therapeutically managed and subsequently followed. The three most commonly recommended therapies were systemic therapy (35.6 %), multimodality treatment including definitive local therapy (17.8 %), and radiotherapy (13.9 %). A major deviation was recorded in 16.3 % of cases (most commonly: none of the MDT-recommended treatment modalities were performed: 19 (35.2 %); not all MDT-planned treatment modalities were performed: 12 (22.2 %); and additional treatment modality was performed: 11 (20.3 %). A minor deviation was found in 1.5 % of cases. On multivariable regression, number of distant metastases (n > 1) was associated with a major deviation (OR: 1.85; 95 % CI, 1.0-3.52). Major deviations were associated with a significantly worse OS (p = 0.0034).

Conclusions

Adherence to and implementation of MDT recommendations in OMD patients was generally high (83.7%). Major deviations might be further reduced by more careful and elaborate discussions of OMD patient characteristics s and patient preferences.

HDR brachytherapy versus robotic-based and linac-based stereotactic ablative body radiotherapy in the treatment of liver metastases - A dosimetric comparison study of three radioablative techniques

Purpose

The aim of our study was to compare dosimetric aspects of three radioablation modalities - direct high-dose-rate brachytherapy (HDR-BT) and virtually planned stereotactic body radiation therapy performed on CyberKnife (SBRTck) and Elekta Versa HD LINAC (SBRTe) applied in patients with liver metastases.

Material and methods

We selected 30 patients with liver metastases, who received liver interstitial HDR-BT and virtually prepared plans for SBRTck and SBRTe. In all the cases, the prescribed dose was a single fraction of 25 Gy. Treatment delivery time, doses delivered to PTV and organs at risk, as well as conformity indices, were calculated and compared.

Results

The longest median treatment delivery time was observed in SBRTck in contrast to HDR-BT and SBRTe which were significantly shorter and comparable. HDR-BT plans achieved better coverage of PTV (except for D98%) in contrast to SBRT modalities. Between both SBRT modalities, SBRTck plans resulted in better dose coverage in Dmean, D50%, and D90% values compared to SBRTe without difference in D98%. The SBRTe was the most advantageous considering the PCI and R100%. SBRTck plans achieved the best HI, while R50% value was comparable between SBRTe and SBRTck. The lowest median doses delivered to uninvolved liver volume (V5Gy, V9.1Gy) were achieved with HDR-BT, while the difference between SBRT modalities was insignificant. SBRT plans were better regarding more favourable dose distribution in the duodenum and right kidney, while HDR-BT achieved lower doses in the stomach, heart, great vessels, ribs, skin and spinal cord. There were no significant differences in bowel and biliary tract dose distribution between all selected modalities.

Conclusions

HDR-BT resulted in more favourable dose distribution within PTVs and lower doses in organs at risk, which suggests that this treatment modality could be regarded as an alternative to other local ablative therapies in carefully selected patients' with liver malignancies. Future studies should further address the issue of comparing treatment modalities in different liver locations and clinical scenarios.

Predictive Value of the Prostate-specific Antigen Doubling Time for the Effectiveness of Metastasis-directed Radiotherapy in Patients With Oligometastases After Radical Treatment for Non-metastatic Prostate Cancer

Background/Aim

Data on metastasis-directed radiotherapy (MDRT) are limited, particularly regarding its association with the prostate-specific antigen (PSA) doubling time (PSADT). The present study evaluated the oncological outcomes of MDRT on the basis of the PSADT in oligo-recurrent prostate cancer patients.

Patients and Methods

We retrospectively reviewed clinical data of 35 MDRTs for 29 patients at the Kitasato University Hospital, targeting oligometastatic prostate cancer developed after radical treatment for non-metastatic prostate cancer. Thirty-five MDRTs were classified into the PSADT >3 months (n=25) or PSADT ≤3 months group (n=10). Statistical analyses were performed to compare associations between the two PSADT groups and oncological outcomes such as progression-free survival (PFS) and PSA response after MDRT.

Results

There were no significant differences between the two groups in terms of the clinicopathological features. Kaplan-Meier analysis showed that PFS was significantly better in the PSADT >3 months group than in the PSADT ≤3 months group [median: 13.3 versus (vs.) 2.6 months, p=0.046]. Regarding castration sensitivity, the predictive role of PSADT >3 months was maintained in 21 patients who received MDRT without prior salvage hormone therapy (median PFS: 12.7 vs. 2.6 months, p=0.024). In the castration-resistant setting (n=14), the frequency of a decrease in serum PSA levels after MDRT by 90% was 54.5% (median PFS: 23.1 months).

Conclusion

MDRT can provide benefit especially for patients with PSADT ≥3 months who had oligo-recurrence after the radical treatment for non-metastatic prostate cancer.

Adaptive Stereotactic Body Radiation Therapy in the Management of Oligometastatic Uterine Leiomyosarcoma: A Clinical Case Report

Safe delivery of stereotactic body radiation therapy (SBRT) to large (>5 cm) oligometastatic abdominopelvic tumors can often be challenging, especially in tumors that require a higher biologically effective dose (BED) for tumor control. Adaptive stereotactic body radiation therapy (A-SBRT) involves inter-fraction and real-time replanning while the patient is on the treatment table, potentially allowing for improved dose coverage and greater sparing of critical structures. Our case report illustrates the benefit of CT-based A-SBRT in the treatment and management of an oligometastatic uterine leiomyosarcoma patient with a rapidly enlarging pelvic recurrence. A 60-year-old female presented to the radiation oncology clinic for treatment of an enlarging, right pelvic oligometastatic leiomyosarcoma. She was prescribed 35 Gy in five fractions. Planning prioritized the sparing of nearby small bowels while maximizing coverage of the planning target volume (PTV). On treatment day, two plans were calculated, the initial plan recalculated on the current CBCT (scheduled plan) and a plan reoptimized using current contours (adapted plan), and the more appropriate one was chosen for delivery. The adapted plan was chosen for all five fractions, with the adapted plan offering better small bowel sparing in five fractions and better target coverage in four fractions, delivering a total of 34 Gy to 95% of the PTV while limiting the small bowel to a maximum point dose of 37 Gy. At approximately six months out from treatment, the patient showed continued radiographic response and resolved acute Grade 1 gastrointestinal toxicity. This case study therefore demonstrates the successful treatment of a large oligometastatic abdominopelvic tumor using CT-based A-SBRT and builds on previous experience treating abdominal cases adaptively.

Stereotactic body radiation therapy for colorectal cancer liver metastases

The management of colorectal cancer liver metastases requires a multidisciplinary approach, which may incorporate systemic therapy, surgery, or local ablative therapies. Stereotactic body radiation therapy (SBRT) is a non-invasive highly conformal radiation technique that enables the delivery of large doses of radiation in a few fractions to well-defined targets using image-guidance and motion management. For selected patients with colorectal cancer liver metastases, stereotactic body radiation therapy can be delivered safely, with excellent long-term local control and overall survival. The purpose of this clinical practice review is to review the background, indications, and treatment details of stereotactic body radiation therapy for the treatment of colorectal liver metastases. SBRT for colorectal cancer liver metastases may be considered for patients with oligometastatic colorectal cancer in combination with surgery or other locally ablative therapies; for patients who are not candidates for surgical resection; or after failure of resection or other ablative therapies. When planning SBRT both a computed tomography and magnetic resonance imaging simulation may be obtained, where feasible, for target delineation. One or 3 fraction SBRT can be considered for lesions away from the central liver and luminal organs at risk, whereas 5 fraction SBRT is preferred otherwise. Image-guidance and motion management strategies are essential components of liver SBRT and will guide the creation of relevant internal and planning target volume margins. For lesions in close proximity to or overlapping with organs-at-risk, the balance between adequate local control and potential for cure with potential acute and late toxicity must be carefully considered.

Stereotactic body radiation therapy in non-liver colorectal metastases: a scoping review

Background

In oligometastatic colorectal cancer (CRC), stereotactic body radiation therapy (SBRT) represents a valid non-invasive local ablative treatment with high rates of local control (LC) and a low toxicity profile. This literature review was performed to evaluate the clinical benefit and toxicity of SBRT on non-liver metastases in CRC oligometastatic patients.

Methods

After searching PubMed, Medscape and Embase databases, 18 retrospective studies focused on body oligometastases excluding bone metastases were included in the analysis.

Results

A total of 1,450 patients with 3,227 lung metastases and 53 patients with 66 nodes lesions were analyzed. BED10 ranged from 76 to 180 Gy. In the lung group, the LC rate was 62-91%, 54-81% and 56-77% after 1, 3 and 5 years, respectively. In the nodes group, the 3-year LC rate was 65-75%. The 1-, 3- and 5-year OS rates were 73-100%, 51-64% and 34-43%, respectively for the lung group, and 63-81% at 3 years for the nodes group.

Conclusions

In CRC patients with non-liver oligometastases, the use of SBRT is effective and safe reaching high LC and survival, with few severe side effects. However, prospective randomized studies are needed to validate the results. These studies will also be useful for identifying any predictive factors that allow us to select the subgroup of patients who benefit from SBRT.

Palliative Thoracic Radiotherapy in the Era of Modern Cancer Care for NSCLC

Palliative thoracic radiotherapy provides rapid and effective symptom relief in approximately two-thirds of NSCLC patients treated. In patients with poor performance status, the degree of palliation appears unrelated to the radiation dose or fractionation schedule. Conversely, in patients with good performance status, higher radiation doses administered over longer periods have shown modest survival benefits. These findings stem from studies conducted before the advent of immunotherapy and targeted therapy in clinical practice. Currently, there are no large prospective studies specifically dedicated to palliative radiotherapy conducted in this new treatment era. Modern radiotherapy technologies are now widely available and are increasingly used for palliative purposes in selected patients, reflecting the expanded array of therapeutic options for disseminated NSCLC and improved prognosis. Some traditional tenets of palliative thoracic radiotherapy, such as the improvement of overall survival with a protracted radiation schedule and the use of simple, cost-effective radiation techniques for palliative purposes, may no longer hold true for patients receiving immunotherapy or targeted therapy. The application of IMRT or SBRT in the context of palliative radiotherapy for NSCLC is not yet sufficiently explored, and this is addressed in this review. Moreover, new risks associated with combining palliative radiotherapy with these systemic treatments are being explored and are discussed within the context of palliative care. The optimal timing, doses, fractionation schedules, and treatment volumes for radiotherapy combined with immunotherapy or targeted therapy are currently subjects of investigation. In emergencies, radiotherapy should be used as a life-saving measure without delay. However, for other indications of palliative thoracic radiotherapy, decisions regarding doses, timing relative to systemic treatments, and treatment volumes should be made in a multidisciplinary context, considering the patient's prognosis, anticipated outcomes, and access to potentially effective treatments. We still lack robust data from prospective studies on this matter. This review examines and discusses available evidence on the use of palliative thoracic radiotherapy within the framework of modern treatment strategies for NSCLC.

Radiotherapy plus pembrolizumab for advanced urothelial carcinoma: results from the ARON-2 real-world study

The addition of metastasis-directed radiotherapy (MDRT) to immunotherapy in patients with advanced urothelial carcinoma (aUC) has shown promising results. We report the real-world data from the ARON-2 study (NCT05290038) on the impact of conventional (CRT) or stereotactic body radiotherapy (SBRT) on the outcome of aUC patients receiving pembrolizumab after platinum-based-chemotherapy. Medical records of 837 patients were reviewed from 60 institutions in 20 countries. Two hundred and sixty-two patients (31%) received radiotherapy (cohort A), of whom 193 (23%) received CRT and 69 (8%) received SBRT. Patients were assessed for overall survival (OS), progression-free survival (PFS), and overall response rate (ORR). Univariate and multivariate analyses were used to explore the association of variables of interest with OS and PFS. With a median follow-up of 22.7 months, the median OS was 10.2 months, 6.8 months and 16.0 months in no RT, CRT and SBRT subgroups (p = 0.005), with an 1y-OS rates of 47%, 34% and 61%, respectively (p < 0.001). The 1y-OS rate in the SBRT subgroup were significantly higher for both lower (63%) and upper tract UC (68%), for pure urothelial histology (63%) and variant histologies (58%), and for patients with bone (40%) and lymph-node metastases (61%). Median PFS was 4.8 months, 9.6 months and 5.8 months in the CRT, SBRT and no RT subgroups, respectively (p = 0.060). The 1y-PFS rate was significantly higher (48%) in the SBRT population and was confirmed in all patient subsets. The difference in terms of ORR was in favour of SBRT. Our real-world analysis showed that the use of SBRT/pembrolizumab combination may play a role in a subset of aUC patients to increase disease control and possibly overall survival.

Predictive Factors for Long-Term Disease Control in Systemic Treatment-Naïve Oligorecurrent Renal Cell Carcinoma Treated with Up-Front Stereotactic Ablative Radiotherapy (SABR)

BACKGROUND

Stereotactic ablative radiotherapy (SABR) is emerging as a potential local treatment option for oligometastatic RCC. This study aims to evaluate the efficacy of SABR in patients with oligorecurrent RCC.

METHODS

A total of 50 patients with histologically confirmed RCC underwent SABR for oligorecurrence between 2006 and 2022. Eligible patients had up to five extracranial metastases and were systemic treatment-naïve at the time of irradiation. The primary endpoints of the analysis were overall survival (OS), local control (LC), distant metastasis-free survival (DMFS), and time to systemic therapy initiation.

RESULTS

The median OS was not reached, with 1- and 3-year OS rates of 93.8% and 77.5%, respectively. LC rates at one and three years were 95.8% and 86.5%, respectively. The median time to systemic therapy initiation was 63.8 months, and the median DMFS was 17.9 months, with one- and three-year rates of 63.4% and 36.6%, respectively. Multiple metastases were a negative predictive factor for DMFS (HR 2.39, p = 0.023), whereas lung metastases were associated with a more favorable outcome (HR 0.38, p = 0.011).

CONCLUSIONS

SABR offers a valuable treatment option for oligometastatic RCC, demonstrating significant potential for achieving long-term disease control and delaying the need for systemic therapy.

Overcoming Resistance to Checkpoint Inhibitors with Combination Strategies in the Treatment of Non-Small Cell Lung Cancer

Lung cancer continues to contribute to the highest percentage of cancer-related deaths worldwide. Advancements in the treatment of non-small cell lung cancer like immune checkpoint inhibitors have dramatically improved survival and long-term disease response, even in curative and perioperative settings. Unfortunately, resistance develops either as an initial response to treatment or more commonly as a progression after the initial response. Several modalities have been utilized to combat this. This review will focus on the various combination treatments with immune checkpoint inhibitors including the addition of chemotherapy, various immunotherapies, radiation, antibody-drug conjugates, bispecific antibodies, neoantigen vaccines, and tumor-infiltrating lymphocytes. We discuss the status of these agents when used in combination with immune checkpoint inhibitors with an emphasis on lung cancer. The early toxicity signals, tolerability, and feasibility of implementation are also reviewed. We conclude with a discussion of the next steps in treatment.

Stereotactic body radiation therapy for the primary tumor and oligometastases versus the primary tumor alone in patients with metastatic pancreatic cancer

BACKGROUND

Local therapies may benefit patients with oligometastatic cancer. However, there were limited data about pancreatic cancer. Here, we compared the efficacy and safety of stereotactic body radiation therapy (SBRT) to the primary tumor and all oligometastases with SBRT to the primary tumor alone in patients with metastatic pancreatic cancer.

METHODS

A retrospective review of patients with synchronous oligometastatic pancreatic cancer (up to 5 lesions) receiving SBRT to all lesions (including all oligometastases and the primary tumor) were performed. Another comparable group of patients with similar baseline characteristics, including metastatic burden, SBRT doses, and chemotherapy regimens, receiving SBRT to the primary tumor alone were identified. The primary endpoint was overall survival (OS). The secondary endpoints were progression frees survival (PFS), polyprogression free survival (PPFS) and adverse events.

RESULTS

There were 59 and 158 patients receiving SBRT to all lesions and to the primary tumor alone. The median OS of patients with SBRT to all lesions and the primary tumor alone was 10.9 months (95% CI 10.2-11.6 months) and 9.3 months (95% CI 8.8-9.8 months) (P < 0.001). The median PFS of two groups was 6.5 months (95% CI 5.6-7.4 months) and 4.1 months (95% CI 3.8-4.4 months) (P < 0.001). The median PPFS of two groups was 9.8 months (95% CI 8.9-10.7 months) and 7.8 months (95% CI 7.2-8.4 months) (P < 0.001). Additionally, 14 (23.7%) and 32 (20.2%) patients in two groups had grade 3 or 4 treatment-related toxicity.

CONCLUSIONS

SBRT to all oligometastases and the primary tumor in patients with pancreatic cancer may improve survival, which needs prospective verification.

Stereotactic Ablative Radiation for Oligoprogressive Cancers: Results of the Randomized Phase 2 STOP Trial

PURPOSE

This trial examined if patients with ≤5 sites of oligoprogression benefit from the addition of SABR to standard of care (SOC) systemic therapy.

METHODS AND MATERIALS

We enrolled patients with 1 to 5 metastases progressing on systemic therapy, and after stratifying by type of systemic therapy (cytotoxic vs noncytotoxic), randomized 1:2 between continued SOC treatment versus SABR to all progressing lesions plus SOC. The trial was initially limited to non-small cell lung cancer but was expanded to include all nonhematologic malignancies to meet accrual goals. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), lesional control, quality of life, adverse events, and duration of systemic therapy postrandomization.

RESULTS

Ninety patients with 127 oligoprogressive metastases were enrolled across 8 Canadian institutions, with 59 randomized to SABR and 31 to SOC. The median age was 67 years, and 39 (43%) were women. The most common primary sites were lung (44%), genitourinary (23%), and breast (13%). Protocol adherence in the SOC arm was suboptimal, with 11 patients (35%) either receiving high-dose/ablative therapies (conflicting with trial protocol) or withdrawing from the study. The median follow-up was 31 months. There was no difference in PFS between arms (median PFS 8.4 months in the SABR arm vs 4.3 months in the SOC arm, but curves cross and 2-year PFS was 9% vs 24%, respectively; P = .91). The median OS was 31.2 months versus 27.4 months, respectively (P = .22). Lesional control was superior with SABR (70% vs 38%, respectively; P = .0015). There were 2 (3.4%) grade 3 and no grade 4/5 adverse events attributable to SABR.

CONCLUSIONS

SABR was well-tolerated with superior lesional control but did not improve PFS or OS. Accrual to this study was difficult, and the results may have been impacted by an unwillingness to forgo ablative treatments on the SOC arm. (NCT02756793).

PSMA-PET/CT response after metastasis-directed radiotherapy of bone oligometastases in prostate cancer

OBJECTIVE

Bone metastases are very common in advanced prostate cancer and can sensitively be detected utilizing PSMA-PET/CT. Therefore, our goal was to evaluate the suitability of PSMA-PET/CT-guided metastasis-directed external beam radiotherapy (MDT) as treatment option for patients with biochemical recurrence and oligometastatic bone lesions.

MATERIALS & METHODS

We retrospectively examined 32 prostate cancer patients with biochemical recurrence and PSMA-positive oligometastatic disease limited to the bone (n = 1-3). A total of 49 bone lesions were treated with MDT. All patients received a post-radiotherapy PSMA-PET/CT-Scan. Changes in SUVmax, PSMA-positive tumor volume per lesion and PSA, as well as the correlation between the PET/CT-interval and SUVmax response were calculated.

RESULTS

MDT lead to a SUVmax decrease in 46/49 (94%) of the lesions. The median relative decline of SUVmax was 60.4%, respectively. Based on PSMA-positive lesion volume with a SUV cut-off of 4, 46/49 (94%) of lesions showed complete response, two (4%) partial response and one lesion (2%) was stable on PSMA-PET/CT after MDT. Most of the treated patients (56.3%) showed an initial PSA decline at three months and a PSA nadir of median 0.14 ng/ml after a median time of 3.6 months after MDT. The median relative PSA change at three months after MDT was 3.9%.

CONCLUSION

MDT is a very effective treatment modality for prostate cancer bone oligometastases and lesion response to MDT can be assessed using the (semi-)quantitative parameters SUVmax and PSMA-positive lesion volume with established SUV cut-offs.

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.

Safety and efficacy of thermal ablation of adrenal metastases secondary to lung cancer

OBJECTIVES

Assess safety and efficacy of thermal ablation for adrenal metastases (AM) secondary to non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

This retrospective study included patients with NSCLC AM treated with thermal ablation between 2/2010-11/2021. Local tumor progression free survival (LTPFS) and overall survival (OS) were calculated using Kaplan-Meier method. Adverse events were graded using Common Terminology Criteria for Adverse Events v5.

RESULTS

Seven patients (mean age ± SD, 63.9 ± 12.5 years; 6 males) with seven AM were treated in eight sessions. Retreatment was performed in one patient with residual disease. Five sessions were with microwave ablation and 3 with radiofrequency ablation. Mean tumor size was 20.1 ± 7.0 mm. Median number of ablation probes used was 1 (range, 1-5), with a median of 3 activations (range, 1-3), and average ablation time of 14.4 ± 15.0 minutes. Response based on RECIST v 1.1 or PERCIST criteria revealed stable disease in 1 tumor, progression of disease in 3 tumors (one was re-ablated), and partial response in 3 tumors. Median LTPFS was not reached (NR) [95 % CI: 1- NR]. Median OS was 47.97 months (95 % CI: 18.63- NR). Intraprocedural hypertension (blood pressure ≥180 mmHg) occurred during 5/8 (62.5 %) sessions and intraoperative tachycardia occurred during 2/8 (25 %) sessions. Complications within one month of ablation occurred in 3/8 (37.5 %) sessions: grade 2 pneumothorax, grade 1 hematuria, and grade 2 adrenal insufficiency.

CONCLUSIONS

In this small series, thermal ablation for NSCLC AM resulted in prolonged local control and OS with no major complications.

Associations amongst genes, molecules, cells, and organs in breast cancer metastasis

This paper is a cross fertilization of ideas about the importance of molecular aspects of breast cancer metastasis by basic scientists, a pathologist, and clinical oncologists at the Henry Ford Health symposium. We address four major topics: (i) the complex roles of lymphatic endothelial cells and the molecules that stimulate them to enhance lymph node and systemic metastasis and influence the anti-tumor immunity that might inhibit metastasis; (ii) the interaction of molecules and cells when breast cancer spreads to bone, and how bone metastases may themselves spread to internal viscera; (iii) how molecular expression and morphologic subtypes of breast cancer assist clinicians in determining which patients to treat with more or less aggressive therapies; (iv) how the outcomes of patients with oligometastases in breast cancer are different from those with multiple metastases and how that could justify the aggressive treatment of these patients with the hope of cure.

Longitudinal cell-free DNA characterization by low-coverage whole-genome sequencing in patients undergoing high-dose radiotherapy

BACKGROUND AND PURPOSE

Current radiotherapy guidelines rely heavily on imaging-based monitoring. Liquid biopsy monitoring promises to complement imaging by providing frequent systemic information about the tumor. In particular, cell-free DNA (cfDNA) sequencing offers a tumor-agnostic approach, which lends itself to monitoring heterogeneous cohorts of cancer patients.

METHODS

We collected plasma cfDNA from oligometastatic patients (OMD) and head-and-neck cancer patients (SCCHN) at six time points before, during, and after radiotherapy, and compared them to the plasma samples of healthy and polymetastatic volunteers. We performed low-pass (on average 7x) whole-genome sequencing on 93 plasma cfDNA samples and correlated copy number alterations and fragment length distributions to clinical and imaging findings.

RESULTS

We observed copy number alterations in 4/7 polymetastatic cancer patients, 1/7 OMD and 1/7 SCCHN patients, these patients' imaging showed progression following radiotherapy. Using unsupervised learning, we identified cancer-specific fragment length features that showed a strong correlation with copy number-based tumor fraction estimates. In 4/4 HPV-positive SCCHN patient samples, we detected viral DNA that enabled the monitoring of very low tumor fraction samples.

CONCLUSIONS

Our results indicate that an elevated tumor fraction is associated with tumor aggressiveness and systemic tumor spread. This information may be used to adapt treatment strategies. Further, we show that by detecting specific sequences such as viral DNA, the sensitivity of detecting cancer from cell-free DNA sequencing data can be greatly increased.

6th and 7th International consensus guidelines for the management of advanced breast cancer (ABC guidelines 6 and 7)

This manuscript describes the Advanced Breast Cancer (ABC) international consensus guidelines updated at the last two ABC international consensus conferences (ABC 6 in 2021, virtual, and ABC 7 in 2023, in Lisbon, Portugal), organized by the ABC Global Alliance. It provides the main recommendations on how to best manage patients with advanced breast cancer (inoperable locally advanced or metastatic), of all breast cancer subtypes, as well as palliative and supportive care. These guidelines are based on available evidence or on expert opinion when a higher level of evidence is lacking. Each guideline is accompanied by the level of evidence (LoE), grade of recommendation (GoR) and percentage of consensus reached at the consensus conferences. Updated diagnostic and treatment algorithms are also provided. The guidelines represent the best management options for patients living with ABC globally, assuming accessibility to all available therapies. Their adaptation (i.e. resource-stratified guidelines) is often needed in settings where access to care is limited.