The oligometastatic state - separating truth from wishful thinking

Stereotactic radiotherapy for liver oligometastases: a pooled analysis following the estro/eortc consensus recommendations

A large pooled analysis of liver oligometastases, classified accordingly to the ESTRO/EORTC recommendations, treated by stereotactic radiotherapy (SBRT) and Radiosurgery (SRS) was carried out. The clinical and dosimetric data of patients who underwent SBRT/SRS for liver metastases were analysed in terms of efficacy and toxicity profile. In particular, the Local Control (LC), the Distant Metastases Free Survival (DMFS), the Disease-Free Survival (DFS), the Overall Survival (OS), and the Next Systemic Therapy Free Survival (NEST-FS) rates were analysed. 113 patients (M/F: 49/64), accounting for a total of 150 hepatic lesions (March 2006-February 2023) in two Italian radiotherapy Institutions were evaluated. Median age was 67 years old (36-92) and 48 (42.5%) patients had at least one comorbidity. The majority of the lesions were induced (30.7%) or repeated oligoprogressive (12.7%) metastases. 98 lesions were treated with more than one daily fraction (mainly 50 Gy in 5 fractions), while 52 were radiosurgery treatments (mainly 32 Gy). The treatment response at 3-4 months was evaluable in 147 lesions: complete response was 32.0%, partial response 17.0%, and stable disease 32.0%. Actuarial LC, DMFS, DFS, OS, and NEST-FS at 1 year were 75.8%, 37.7%, 34.9%, 78.7%, and 59.4% respectively; while actuarial LC, DMFS, DFS, OS, and NEST-FS at 2 years were 52.1%, 24.9%, 21.9%, 51.3%, and 36.8%, respectively. The achievement of complete response, synchronous oligometastases, and no treatment interruptions correlated with a more favorable outcomes. As per the toxicity profile, we registered only two acute and one late toxicity cases higher than grade 2. Stereotactic treatment for liver metastases seems to be a safe and promising option in terms of local control. The best results in term of outcomes have been obtained in patients with complete response, synchronous oligometastases, favorable histology, and no treatment interruptions.

Outcomes and prognostic factors in patients with synchronous and metachronous oligometastatic urothelial carcinoma with visceral metastases

OBJECTIVES

To evaluate the clinical characteristics of oligometastatic disease (OMD) in metastatic urothelial carcinoma (mUC) with visceral metastases when classified into synchronous and metachronous metastases.

METHODS

Of 957 cases of de novo mUC treated between 2008 and 2023, 374 with visceral metastases were analyzed. Cases were classified into OMD with up to three metastatic lesions and polymetastatic disease (PMD), and into synchronous and metachronous metastases. The clinical characteristics and overall survival (OS) for each group were analyzed.

RESULTS

Overall, 196 (52.4%) had synchronous metastasis and 178 (47.6%) had metachronous metastasis. Median OS for synchronous metastases was significantly shorter than for metachronous metastases (12.1 months vs. 15.3 months, p = 0.011). Among the synchronous metastases, 48 (24.5%) were OMD and 148 (75.6%) were PMD. There was no significant difference in OS between the OMDs and PMDs (median 14.9 months vs. 11.7 months, p = 0.32), and only decreased albumin level was identified as a significant predictor of poor OS. Among the metachronous metastases, 64 (36.0%) were OMD and 114 (64.0%) were PMD. There was no significant difference in OS between the OMD and PMD (median 21.2 months vs. 15.0 months, p = 0.35), and no significant predictors of poor OS were identified.

CONCLUSIONS

For mUC with visceral metastases, the timing of metastasis appearance was associated with prognosis, with synchronous metastases being a poorer prognostic factor compared to metachronous metastases. There was no prognostic difference between OMD and PMD with visceral metastases when classified into synchronous or metachronous metastases.

Radiation Oncologists' Perspectives on Oligometastatic Disease: A Korean Survey Study

PURPOSE

Perspectives of radiation oncologists on oligometastatic disease was investigated using multi-layered survey.

MATERIALS AND METHODS

Online survey on the oligometastatic disease was distributed to the board-certified regular members of the Korean Society for Radiation Oncology. The questionnaire consisted of four domains: five questions on demographics; five on the definition of oligometastatic disease; four on the role of local therapy; and three on the oligometastatic disease classification, respectively.

RESULTS

A total of 135 radiation oncologists participated in the survey. The median length of practice after board certification was 22.5 years (range, 1 to 44 years), and the vast majority (94.1%) answered affirmatively to the clinical experience in oligometastatic disease management. Nearly two-thirds of the respondents considered the number of involved organs as an independent factor in defining oligometastasis. Most frequently perceived upper limit on the numerical definition of oligometastasis was 5 (64.2%), followed by 3 (26.0%), respectively. Peritoneal and brain metastasis were nominated as the sites to be excluded from oligometastastic disease by 56.3% and 12.6% of the participants, respectively. Vast majority (82.1%) agreed on the role of local treatment in the management of oligometastatic disease. Majority (72%) of the participants acknowledged the European Society for Radiotherapy and Oncology (ESTRO)-European Organisation for Research and Treatment of Cancer (EORTC) classification of oligometastatic disease, however, only 43.3% answered that they applied this classification in their clinical practice. Underlying reasons against the clinical use were 'too complicated' (66.0%), followed by 'insufficient supporting evidence' (30.0%), respectively.

CONCLUSION

While most radiation oncologists supported the role of local therapy in oligometastatic disease, there were several inconsistencies in defining and categorizing oligometastatic disease. Continued education and training on oligometastatic disease would be also required to build consensus among participating caregivers.

Clinical experience of consolidative radiotherapy for localized metastatic non-small cell lung cancer who showed favorable tumor response after systemic treatment

BACKGROUND

Our study has aimed to assess the effects of consolidative high-dose radiotherapy on clinical outcomes in patients with localized metastatic non-small cell lung cancer (NSCLC) who showed favorable tumor response after systemic treatment.

METHODS

We retrospectively reviewed the medical records of 83 patients with localized metastatic NSCLC, who received systemic therapy followed by consolidative local radiotherapy at the Korea University Guro Hospital between March 2017 and June 2022. In the current study, we defined localized metastatic disease as the presence of one to three metastatic sites at the time of diagnosis. And patients who showed favorable tumor response after systemic treatment, including oligo-progressive disease at the thoracic site which was amenable to curative high-dose local radiotherapy, were included. The planned total dose and fraction size mainly depended on the location of lesions.

RESULTS

The median follow-up time after consolidative radiotherapy was 16 months (range: 5-52 months). The overall 2-year progression-free survival rates were 81.4%. Of 83 patients, only four (4.3%), treated with intensity-modulated radiation therapy, showed an in-field local recurrence. Interestingly, only one patient experienced a local failure among the 20 patients who showed an oligo-progressive disease at the thoracic site on the tumor response evaluation after systemic treatment. Regarding treatment-related pulmonary toxicity, three patients with grade-3 and one patient with grade-4 radiation pneumonitis were presented.

CONCLUSIONS

If the disease is sufficiently controlled and localized by systemic therapy, local consolidative radiotherapy is thought to improves local control rates with acceptable treatment-related toxicities in patients with localized metastatic NSCLC, especially those with oligo-progressive disease.

Progression-directed therapy in patients with oligoprogressive castration-resistant prostate cancer

PURPOSE

Oligoprogressive lesions are observed in a subset of patients who progress to castration-resistant prostate cancer (CRPC), while other lesions remain controlled by systemic therapy. This study evaluates the impact of progression-directed therapy (PDT) on these oligoprogressive lesions.

MATERIALS AND METHODS

This retrospective study included 40 patients diagnosed with oligoprogressive CRPC. PDT was performed for treating all progressive sites using radiotherapy. Fifteen patients received PDT using radiotherapy for all progressive sites (PDT group) while 25 had additional first-line systemic treatments (non-PDT group). In PDT group, 7 patients underwent PDT and unchanged systemic therapy (PDT-A group) and 8 patients underwent PDT with additional new line of systemic therapy on CRPC (PDT-B group). The Kaplan-Meier method was used to assess treatment outcomes.

RESULTS

The prostate specific antigen (PSA) nadir was significantly lower in PDT group compare to non-PDT group (p=0.007). A 50% PSA decline and complete PSA decline were observed in 13 patients (86.7%) and 10 patients (66.7%) of PDT group and in 18 patients (72.0%) and 11 patients (44.0%) of non-PDT group, respectively. The PSA-progression free survival of PDT-B group was significantly longer than non-PDT group. The median time to failure of first-line systemic therapy on CRPC was 30.2 months in patients in PDT group and 14.9 months in non-PDT group (p=0.014). PDT-B group showed a significantly longer time to progression than non-PDT group (p=0.025). Minimal PDT-related adverse events were observed.

CONCLUSIONS

PDT can delay progression of disease and enhance treatment efficacy with acceptable tolerability in oligoprogressive CRPC.

Sterotactic Ablative Radiotherapy in a Multicentric Series of Oligometastatic SCLC: The SAMOS Cohort

AIMS

SCLC is the most aggressive lung cancer histology with a 5-year OS <10%. At the diagnosis, almost two-thirds of the SCLC an Extended Disease presentation. Two randomized studies (CASPIAN and ImPower133) demonstrated an OS improvement, when immunotherapy was prescribed as maintenance therapy after standard chemotherapy. To date, SABR has had a limited indication in managing metastatic SCLC, although recent reports proposed it as a valid treatment option in selected patients. We propose a retrospective multicentric analysis of patients treated with SABR for oligometastatic SCLC.

METHOD

Data of patients affected by oligometastatic-SCLC treated with SABR between 2017 and 2022 in 11 Italian centers were collected. Clinical and therapeutic variables together with OS and time to next treatment were analyzed. Univariate analysis with Kaplan-Meier curve were calculated, and log-rank test were applied. Cox proportional hazard model was used for multivariate analysis.

RESULTS

Data from 93 patients and 132 metastatic lesions were analyzed. The median age was 64 years (36-86) and all but 1 had Performance Status 0 or 1. Fifty-two patients presented ED at diagnosis. The first line treatment was radiochemotherapy in 42%, CHT alone in 24% and CHT-IO in 28%, others treatment accounts for 4% and only 2% of patients underwent best supportive care. Of the 132 lesions treated with SBRT 55 were in brain, 27 in lung, 11 in liver, 10 in lymph nodes, 8 in bones and 20 in adrenal gland. Median OS was 14 months, 1 year-OS and 2 years OS were 53% and 27%, respectively. The median TtNT was 14 months for the entire population. Of all the analyzed variables only, the anatomical site of the metastases and their number showed statistical significance in the univariate analysist, confirmed in the subsequent multivariate.

CONCLUSION

SABR seems to play a role in delaying further systemic lines in oligometastatic disease and to extend the use of ongoing treatment in oligoprogressive state. Prospective studies are needed to confirm these findings.

Metastases-directed local therapies (MDT) beyond genuine oligometastatic disease (OMD): Indications, endpoints and the role of imaging

To further personalise treatment in metastatic cancer, the indications for metastases-directed local therapy (MDT) and the biology of oligometastatic disease (OMD) should be kept conceptually apart. Both need to be vigorously investigated. Tumour growth dynamics - growth rate combined with metastatic seeding efficiency - is the single most important biological feature determining the likelihood of success of MDT in an individual patient, which might even be beneficial in slowly developing polymetastatic disease. This can be reasonably well assessed using appropriate clinical imaging. In the context of considering appropriate indications for MDT, detecting metastases at the edge of image resolution should therefore suggest postponing MDT. While three to five lesions are typically used to define OMD, it could be argued that countability throughout the course of metastatic disease, rather than a specific maximum number of lesions, could serve as a better parameter for guiding MDT. Here we argue that the unit of MDT as a treatment option in metastatic cancer might best be defined not as a single procedure at a single point in time, but as a series of treatments that can be delivered in a single or multiple sessions to different lesions over time. Newly emerging lesions that remain amenable to MDT without triggering the start of a new systemic treatment, a change in systemic therapy, or initiation of best supportive care, would thus not constitute a failure of MDT. This would have implications for defining endpoints in clinical trials and registries: Rather than with any disease progression, failure of MDT would only be declared when there is progression to polymetastatic disease, which then precludes further options for MDT.

Multimodal Management of Colorectal Liver Metastases: State of the Art

Liver is the most common site of colorectal cancer (CRC) metastases. Treatment of CRC liver metastases (CRLM) includes different strategies, prevalently based on the clinical and oncological intent. Valid approaches in liver-limited or liver-prevalent disease include surgery, percutaneous ablative procedures (radiofrequency ablation, microwave ablation), intra-arterial perfusional techniques (chemo-embolization, radio-embolization) as well as stereotactic radiotherapy. Systemic treatments, including chemotherapy, immunotherapy and other biological agents, are the only options for patients with no chance of locoregional approaches. The use of chemotherapy in other settings, such as neoadjuvant, adjuvant or conversion therapy of CRLM, is commonly accepted in the clinical practice, although data from several clinical trials have been mostly inconclusive. The optimal integration of all these strategies, when applicable and clinically indicated, should be ever considered in patients affected by CRLM based on clinical evidence and multidisciplinary experience. Here we revised in detail all the possible therapeutic approaches of CRLM focusing on the current evidences, the studies still in progress and the often contradictory data.

Real-world effectiveness and safety of stereotactic body radiotherapy for liver metastases with different respiratory motion management techniques

PURPOSE

Stereotactic body radiotherapy (SBRT) has been firmly established as a treatment choice for patients with oligometastases, as it has demonstrated both safety and efficacy by consistently achieving high rates of local control. Moreover, it offers potential survival benefits for carefully selected patients in real-world clinical settings.

METHODS

Between January 2008 and May 2020, a total of 149 patients (with 414 liver metastases) received treatment. The Active Breathing Coordinator device was used for 68 patients, while respiratory gating was used for 65 and abdominal compression was used for 16 patients. The most common histological finding was colorectal adenocarcinoma, with 37.6% of patients having three or more metastases, and 18% having two metastases. The prescribed dose ranged from 36 to 60 Gy, delivered in 3-5 fractions.

RESULTS

Local control rates at 2 and 3 years were 76.1% and 61.2%, respectively, with no instances of local recurrence after 3 years. Factors negatively impacting local control included colorectal histology, lower prescribed dose, and the occurrence of new liver metastases. The median overall survival from SBRT was 32 months, with the presence of metastases outside the liver and the development of new liver metastases after SBRT affecting survival. The median disease-free survival was 10 months. No substantial differences in both local control and survival were observed between the respiratory motion control techniques employed. Treatment tolerance was excellent, with only one patient experiencing acute grade IV thrombocytopenia and two patients suffering from ≥ grade II chronic toxicity.

CONCLUSION

For radical management of single or multiple liver metastases, SBRT is an effective and well-tolerated treatment option. Regardless of the technology employed, experienced physicians can achieve similarly positive outcomes. However, additional studies are required to elucidate prognostic factors that can facilitate improved patient selection.

Treatment of Oligometastatic Non-Small Cell Lung Cancer: An ASTRO/ESTRO Clinical Practice Guideline

PURPOSE

This joint guideline by American Society for Radiation Oncology (ASTRO) and the European Society for Radiotherapy and Oncology (ESTRO) was initiated to review evidence and provide recommendations regarding the use of local therapy in the management of extracranial oligometastatic non-small cell lung cancer (NSCLC). Local therapy is defined as the comprehensive treatment of all known cancer-primary tumor, regional nodal metastases, and metastases-with definitive intent.

METHODS

ASTRO and ESTRO convened a task force to address 5 key questions focused on the use of local (radiation, surgery, other ablative methods) and systemic therapy in the management of oligometastatic NSCLC. The questions address clinical scenarios for using local therapy, sequencing and timing when integrating local with systemic therapies, radiation techniques critical for oligometastatic disease targeting and treatment delivery, and the role of local therapy for oligoprogression or recurrent disease. Recommendations were based on a systematic literature review and created using ASTRO guidelines methodology.

RESULTS

Based on the lack of significant randomized phase 3 trials, a patient-centered, multidisciplinary approach was strongly recommended for all decision-making regarding potential treatment. Integration of definitive local therapy was only relevant if technically feasible and clinically safe to all disease sites, defined as 5 or fewer distinct sites. Conditional recommendations were given for definitive local therapies in synchronous, metachronous, oligopersistent, and oligoprogressive conditions for extracranial disease. Radiation and surgery were the only primary definitive local therapy modalities recommended for use in the management of patients with oligometastatic disease, with indications provided for choosing one over the other. Sequencing recommendations were provided for systemic and local therapy integration. Finally, multiple recommendations were provided for the optimal technical use of hypofractionated radiation or stereotactic body radiation therapy as definitive local therapy, including dose and fractionation.

CONCLUSIONS

Presently, data regarding clinical benefits of local therapy on overall and other survival outcomes is still sparse for oligometastatic NSCLC. However, with rapidly evolving data being generated supporting local therapy in oligometastatic NSCLC, this guideline attempted to frame recommendations as a function of the quality of data available to make decisions in a multidisciplinary approach incorporating patient goals and tolerances.

Therapeutic approaches in patients with bone metastasis due to endometrial carcinoma - A systematic review

Background

Bone metastases (BM) are uncommon in endometrial carcinoma (EC), without information on the optimal oncologic management of patients with BM in EC. Here, we systematically review clinical characteristics, treatment approaches and prognosis in patients with BM in EC.

Methods

We conducted a systematic literature search until 27th March 2022 on PubMed, MEDLINE, Embase and clinicaltrials.gov. Outcomes included treatment frequency and survival after BM with comparators being treatment approaches (local cytoreductive bone surgery, systemic therapy, and local radiotherapy). Risk of bias was assessed using the NIH Quality Assessment Tool and Navigation Guide methodology.

Results

We retrieved 1096 records of which 112 retrospective studies (12 cohort studies, 12/12 fair quality; 100 case studies, 100/100 low quality) with a total of 1566 patients were included. The majority had a primary diagnosis of FIGO stage IV, grade 3 endometrioid EC. Singular BM were present in a median of 39.2%, multiple BM in 60.8% and synchronous additional distant metastases in 48.1% of patients respectively. In patients with secondary BM median time to bone recurrence was 14 months. Median survival after BM was 12 months. Local cytoreductive bone surgery was assessed in 7/13 cohorts and performed in a median of 15.8% (interquartile range [IQR] 10.3-43.0) of patients. Chemotherapy was assessed in 11/13 cohorts and administered in a median of 55.5% (IQR 41.0-63.9), hormonal therapy (7/13 cohorts) in 24.7% (IQR 16.3-36.0), and osteooncologic therapy (4/13 cohorts) in 2.7% (IQR 0.0-7.5) of patients respectively. Local radiotherapy was assessed in 9/13 cohorts and performed in a median of 66.7% (IQR 55.6-70.0) of patients. Survival benefits were seen in 2/3 cohorts after local cytoreductive bone surgery, and in 2/7 cohorts after chemotherapy without survival benefits in the remaining cohorts and investigated therapies. Limitations include the lack of controlled intervention studies, the heterogeneity and retrospective nature of the investigated populations.

Conclusions

This systematic review shows heterogenous therapeutic approaches in clinical practice without clear evidence for optimal oncologic management for patients with BM in EC.

A Bibliometric Analysis of the Oligometastatic State over the Last Two Decades: A Shifting Paradigm for Oncology? An AIRO Oligometastatic Study Group

The term "oligometastasis" represents a relatively novel idea, which denotes a condition characterized by cancer dissemination with a limited number of lesions (usually fewer than five). The aim of the present study is to report a bibliometric analysis of the oligometastatic disease/state, incorporating all relevant studies on the topic for more than 20 years. The research strategy included at least one the terms "Oligmetastases", "Oligometastasis", "Oligometastatic", "Oligoprogression, "Oligoprogressive", "Oligorecurrent", or "Oligorecurrency" in the title, abstract, and/or keywords. All English-language documents from 1 January 1995 (the year of the earliest available document in Scopus) to 31 December 2022 were considered for the analysis. R code (R version 4.2.0) with R Studio (version 2022.12.0-353) and the Bibliometrix package (version 4.0.1) were used for the analysis. A total of 3304 documents, mainly articles (n = 2083, 63.0%) and reviews (n = 813, 24.6%), were collected from 1995 to 2022. The average annual growth rate of literature on the topic was 26.7%. Overall 15,176 authors published on the topic, with an average of eight authors/publication. From 1995, 69 countries contributed to the literature, with the USA and Italy being the top contributors. Among all keywords used by authors, the top three were oligometastases (19%), SBRT (18%), and radiation therapy (8%). Themes regarding "locoregional treatment", "organ motion", and "immunotherapy" were the most recent trend topics, mainly developed from 2019 to 2022, while "high-dose chemotherapy", "whole-brain radiotherapy", and "metastatic breast cancer" saw their main development during 2009-2018. Our study shows the exceptionally flourishing scientific production on the oligometastatic state, summarizing the most influential studies and highlighting the future developments and interests. This analysis will serve as a benchmark to identify this area for the attention of researchers worldwide and contribute to the increasing scientific work.

Radiation and immune checkpoint inhibitors in the treatment of oligometastatic non-small-cell lung cancer: a practical review of rationale, recent data, and research questions

The combined use of stereotactic ablative radiotherapy (SABR) and immune checkpoint inhibitors (ICIs) is an emerging treatment paradigm for oligometastatic non-small-cell lung cancer (NSCLC). Recent phase I and II trial data suggest that SABR to multiple metastases in addition to ICI use is safe and effective with promising progression-free survival and overall survival signals. There is great interest in capitalizing on combined immunomodulation from these two modalities for the treatment of oligometastatic NSCLC. Ongoing trials seek to validate the safety, efficacy, and preferred sequencing of SABR and ICI. This narrative review of the role of SABR when combined with ICI in oligometastatic NSCLC discusses the rationale for this bimodality treatment, summarizes recent clinical trial evidence, and proposes key principles of management based on the available evidence.

Adrenal Metastasectomy in the Era of Immuno- and Targeted Therapy

Adrenal metastasectomy has an increasing role in multimodality oncologic care for diverse primary cancer types. In this review, we discuss the epidemiology, evaluation, and contemporary best practices in the management of adrenal metastases from various primaries. Initial evaluation of suspected adrenal metastases should include diagnostic imaging to assess the extent of tumor involvement and determine surgical resectability, as well as biochemical evaluation for hormone secretion. Biopsy has a minimal role and should only be performed in tumors that are established to be non-hormone secreting and when the biopsy results would change clinical management. Adrenal metastasectomy is associated with survival benefit in selected patients. We suggest that adrenal metastasectomy has the greatest benefit in four clinical scenarios: (1) disease limited to the adrenal gland in which adrenalectomy renders the patient disease-free; (2) isolated progression in the adrenal gland in the setting of otherwise controlled metastatic extra-adrenal disease; (3) need for palliation of symptoms related to adrenal metastases; or (4) in the context of tissue-based clinical trials. Both minimally invasive and open adrenalectomy techniques are safe and appear to have equivalent oncologic outcomes. Minimally invasive approaches are favored when technically feasible while maintaining oncologic principles. A multidisciplinary evaluation including clinicians with expertise in the primary cancer type is essential to the successful management of adrenal metastases.

The Management of Oligometastatic Disease in Colorectal Cancer: Present Strategies and Future Perspectives

Oligometastatic disease has been described as an intermediate clinical state between localized cancer and systemically metastasized disease. Recent clinical studies have shown prolonged survival when aggressive locoregional approaches are added to systemic therapies in patients with oligometastases. The aim of this review is to outline the newest options to treat oligometastatic colorectal cancer (CRC), also considering its molecular patterns. We present an overview of the available local treatment strategies, including surgical procedures, stereotactic body radiation therapy (SBRT), thermal ablation, as well as trans-arterial chemoembolization (TACE) and selective internal radiotherapy (SIRT). Moreover, since imaging methods provide crucial information for the early diagnosis and management of oligometastatic CRC, we discuss the role of modern radiologic techniques in selecting patients that are amenable to potentially curative locoregional treatments.

Clinical and pathological characterization of 158 consecutive and unselected oligometastatic breast cancers in a single institution

PURPOSE

Data about incidence, biological, and clinical characteristics of oligometastatic breast cancer (OMBC) are scarce. However, these data are essential in determining optimal treatment strategy. Gaining knowledge of these elements means observing and describing large, recent, and consecutive series of OMBC in their natural history.

METHODS

We collected data retrospectively at our institution from 998 consecutive patients diagnosed and treated with synchronous or metachronous metastatic breast cancer (MBC) between January 2014 and December 2018. The only criterion used to define OMBC was the presence of one to five metastases at diagnosis.

RESULTS

Of 998 MBC, 15.8% were classified OMBC. Among these, 88% had one to three metastases, and 86.7% had only one organ involved. Bone metastases were present in 52.5% of cases, 20.9% had progression to lymph nodes, 14.6% to the liver, 13.3% to the brain, 8.2% to the lungs, and 3.8% had other metastases. 55.7% had HR+/HER2- OMBC, 25.3% had HER2+OMBC, and 19% had HR-/HER2- OMBC. The HR+/HER2- subtype statistically correlated with bone metastases (p = 0.001), the HER2+subtype with brain lesions (p = 0.001), and the HR-/HER2- subtype with lymph node metastases (p = 0.008). Visceral metastases were not statistically associated with any OMBC subtypes (p = 0.186). OMBC-SBR grade III was proportionally higher than in the ESME series of 22,109 MBC (49.4% vs. 35.1%, p < 0.001).

CONCLUSION

OMBC is a heterogeneous entity whose incidence is higher than has commonly been published. Not an indolent disease, each subgroup, with its biological and anatomical characteristics, merits specific management.

Benchmarking Outcomes for Molecularly Characterized Synchronous Oligometastatic Non-Small-Cell Lung Cancer Reveals EGFR Mutations to Be Associated With Longer Overall Survival

PURPOSE

Local consolidative therapy (LCT) for patients with synchronous oligometastatic non-small-cell lung cancer is an evolving treatment strategy, but outcomes following LCT stratified by genetic mutations have not been reported. We sought to identify genomic associations with overall survival (OS) and progression-free survival (PFS) for these patients.

METHODS

We identified all patients presenting between 2000 and 2017 with stage IV non-small-cell lung cancer and ≤ 3 synchronous metastatic sites. Patients were grouped according to mutational statuses. Primary outcomes included OS and PFS following initial diagnosis.

RESULTS

Of 194 included patients, 121 received comprehensive LCT to all sites of disease with either surgery or radiation. TP53 mutations were identified in 40 of 78 (55%), KRAS in 32 of 95 (34%), EGFR in 24 of 109 (22%), and STK11 in nine of 77 (12%). At median follow-up of 96 months, median OS and PFS were 26 (95% CI, 23 to 31) months and 11 (95% CI, 9 to 13) months, respectively. On multivariable analysis, patients with EGFR mutations had lower mortality risk (hazard ratio [HR], 0.53; 95% CI, 0.29 to 0.98; P = .044) compared with wild-type patients, and patients with STK11 mutations had higher risk of progression or mortality (HR, 2.32; 95% CI, 1.12 to 4.79; P = .023) compared with wild-type patients. TP53 and KRAS mutations were not associated with OS or PFS. Among 71 patients with known EGFR mutational status who received comprehensive LCT, EGFR mutations were associated with lower mortality compared with wild-type (HR, 0.45; 95% CI, 0.22 to 0.94; P = .032).

CONCLUSION

When compared with wild-type patients, those with EGFR and STK11 mutations had longer OS and shorter PFS, respectively. EGFR mutations were associated with longer OS among oligometastatic patients treated with comprehensive LCT in addition to systemic therapy.

Oligometastases: Emerging Evidence

The hypothesis that ablative therapies (such as surgery or radiation) can be used to cure patients with a limited number of metastases was influential in changing practice. Early assertions of efficacy were based on observational studies, often without control groups, showing better-than-expected outcomes. However, in the past decade, new evidence from randomized trials has emerged, which in some cases have affirmed old hypotheses, but in other cases have raised new questions. In this review, we discuss the challenges in defining oligometastatic disease, summarize the randomized evidence evaluating metastasis-directed therapy in patients with oligometastatic disease, provide context for the difficulty in generating randomized evidence, and examine ongoing phase III studies.

Survival and prognostic factors in oligometastatic breast cancer

BACKGROUND

Guidelines for oligometastatic breast cancer (OMBC) propagate multimodality treatment including polychemotherapy and local ablative treatment (LAT) of all lesions. The aim of this approach is prolonged disease remission, or even cure. Long-term outcomes in OMBC and factors associated with prognosis are largely unknown, due to the rarity of this condition. We report overall survival (OS), event-free survival (EFS), and prognostic factors in a large real-world cohort of patients with OMBC.

METHODS

Patients with breast cancer and 1-3 distant metastatic lesions, treated in the Netherlands Cancer Institute between 1997 and 2020, were identified via text mining of medical files. We collected patient, tumor and treatment characteristics. The Kaplan-Meier method was used to calculate OS and EFS estimates, and Cox regression analyses to assess prognostic factors.

RESULTS

The cohort included 239 patients, of whom 54% had ERpos/HER2neg, 20% HER2pos and 20% triple negative disease. Median follow-up was 88.0 months (95% confidence interval (CI) 82.9-93.1) during which 107 patients died and 139 developed disease progression/recurrence; median OS was 93.0 months (95%CI 66.2-119.8). Factors associated with OS in multivariable analysis were subtype, disease-free interval and radiologic response to first-line systemic therapy; LAT was associated with EFS, but not OS.

CONCLUSIONS

In this large real-world cohort of patients with OMBC, OS and EFS compare favorably to survival in the general MBC population. Radiologic complete response to first-line systemic therapy was associated with favorable OS and EFS, indicating the importance of early optimal systemic therapy. The value of LAT in OMBC requires further study.

Dose-escalated radiotherapy with simultaneous integrated boost for bone metastases in selected patients with assumed favourable prognosis

BACKGROUND

Stereotactic body radiotherapy (SBRT) concepts for dose escalation are increasingly used for bone metastases in patients with oligometastatic or oligoprogressive disease. For metastases that are not suitable for SBRT-regimens, a treatment with 30/40 Gy with simultaneous integrated boost (SIB) in 10 fractions represents a possible regimen. The aim of this study was to investigate the feasibility of this concept and the acute and subacute toxicities.

PATIENTS AND METHODS

Clinical records for dose-escalated radiotherapy of all consecutive patients treated with this regimen were evaluated retrospectively (24 patients with 28 target volumes for oncologic outcomes and 25 patients with 29 target volumes for treatment feasibility and dose parameters analysis). Analysis of radiotherapy plans included size of target volumes and dosimetric parameter for target volumes and organs at risk (OAR). Acute and subacute toxicities were evaluated according to Common Terminology Criteria for Adverse Events (CTCAE) V4.0.

RESULTS

The most common localization was the spine (71.4%). The most common histology was prostate cancer (45.8%). Oligometastatic or oligoprogressive disease was the indication for dose-escalated radiotherapy in 19/24 patients (79.2%). Treatment was feasible with all patients completing radiotherapy. Acute toxicity grade 1 was documented in 36.0% of the patients. During follow up, one patient underwent surgery due to bone instability. The 1-year local control and patient-related progression-free survival (PFS) were 90.0 ± 6.7% and 33.3 ± 11.6%, respectively.

CONCLUSIONS

Dose-escalated hypofractionated radiotherapy with simultaneous integrated boost for bone metastases resulted in good local control with limited acute toxicities. Only one patient required surgical intervention. The regimen represents an alternative to SBRT in selected patients.

Systemic Therapy Combined with Locoregional Therapy Improved Survival in Oligometastatic Breast Cancer: A Single-Center Retrospective Cohort Study

The optimal therapeutic options, adding locoregional therapy (LRT) to systemic therapy (ST) or not, for patients with oligometastatic breast cancer (OMBC) have not been fully elucidated. Hence, we designed a retrospective observational study which enrolled patients with measurable extracranial OMBC having less than 5 metastatic lesions not necessarily in the same organ. We retrospectively reviewed a total of 199 patients diagnosed with extracranial OMBC, including 28 receiving ST followed by LRT (ST to LRT group), 44 receiving LRT followed by ST (LRT to ST group), and 127 receiving ST alone (ST alone group). After a median follow-up of 28.7 months, patients receiving both ST and LRT had a significantly better prognosis than those receiving ST alone: the median progression-free survival (PFS) was 16.3, 14.0, and 9.3 months (P < 0.001) and the median overall survival (OS) was 39.8, 70.5, and 26.7 months (P < 0.001) in the ST to LRT, LRT to ST, and ST alone groups, respectively. Sequence of ST and LRT had no significant impact on survival among patients receiving both. Further exploratory analysis identified ST plus LRT as an independent predictor for longer PFS. In conclusion, we demonstrated that adding LRT to ST was associated with survival benefits for patients with OMBC, and further prospective studies were warranted.

Clinical Outcomes of Stereotactic Ablative Radiotherapy for All Stages of Non-Small Cell Lung Cancer; Definitive versus Consolidative

Background and Objectives: Stereotactic ablative radiotherapy (SABR) is not confined to early stage non-small cell lung cancer (NSCLC) and has a potential role in stage IV disease. We aimed to evaluate the effect of SABR on local control rates and survival outcomes in patients with all stages of NSCLC according to the treatment aim. Materials and Methods: We retrospectively reviewed the medical records of 88 patients with NSCLC who received SABR at the Korea University Guro Hospital between January 2015 and March 2021. Among these, 64 patients with stage I–II NSCLC ineligible for surgery were treated with a definitive aim. Twenty-four patients with stage IV limited metastatic NSCLC showing a favorable response to prior systemic therapy were treated with a consolidative aim. Results: The median follow-up time was 34 (range: 5–88) months. Thirty-one patients developed recurrence (35.2%), with distant metastasis being the most common (25/31, 80.6%). In-field local recurrence occurred in four patients (4/88 patients, 4.5%). For patients treated with definitive SABR, the 3-year overall survival (OS) and disease-free survival (DFS) rates were 91.8% and 58.6%, respectively. In patients treated with consolidative SABR, the 3-year OS and DFS rates were 86.7% and 53.8%, respectively. With respect to treatment-related pulmonary toxicity, grade 3 radiation pneumonitis incidence requiring hospitalization was 2.3% (2/88). Conclusions: Definitive SABR is appropriate for medically inoperable or high surgical risk patients with early stage NSCLC with acceptable treatment-related toxicities. Consolidative SABR improves local control rates and helps achieve long-term survival in patients with limited metastatic NSCLC.

Local Consolidative Therapy for Oligometastatic Non-Small Cell Lung Cancer

Simple Summary

Metastatic non-small cell lung cancer (NSCLC) classically portends a poor prognosis and worse overall survival. However, recent advances in modern systemic therapy and the increasing recognition of a distant clinical entity known as “oligometastatic disease”—i.e., a controlled primary tumor and a limited number of distant lesions (≤5 metastases)—have led to paradigm shifts in management. Findings from Phase II randomized clinical trials suggest that aggressive local consolidative therapy (LAT) in the form of surgery or highly conformal radiation, known as stereotactic ablative body radiotherapy (SABR), may help to significantly mitigate disease progression and prolong survival. In this review, we summarize clinical evidence from published and ongoing trials that support the use of LAT/SABR in the treatment of oligometastatic NSCLC. We discuss key findings and caveats to these studies, and we highlight potential considerations and avenues for further investigation in the oligometastatic disease space.

Abstract

In the last 20 years, significant strides have been made in our understanding of the biological mechanisms driving disease pathogenesis in metastatic non-small cell lung cancer (NSCLC). Notably, the development and application of predictive biomarkers as well as refined treatment regimens in the form of chemoimmunotherapy and novel targeted agents have led to substantial improvements in survival. Parallel to these remarkable advancements in modern systemic therapy has been a growing recognition of “oligometastatic disease” as a distinct clinical entity—defined by the presence of a controlled primary tumor and ≤5 sites of metastatic disease amenable to local consolidative therapy (LAT), with surgery or stereotactic ablative body radiotherapy (SABR). To date, three randomized studies have provided clinical evidence supporting the use of LAT/SABR in the treatment of oligometastatic NSCLC. In this review, we summarize clinical evidence from these landmark studies and highlight ongoing trials evaluating the use of LAT/SABR in a variety of clinical contexts along the oligometastatic disease spectrum. We discuss important implications and caveats of the available data, including considerations surrounding patient selection and application in routine clinical practice. We conclude by offering potential avenues for further investigation in the oligometastatic disease space.

Assessing long-term locoregional control of spinal osseous metastases after microwave ablation

Osseous metastases to the spine result in significant pain and decreased quality of life. The purpose of this study was to evaluate the long-term efficacy of microwave ablation (MWA) for the treatment of spinal metastases regarding pain reduction and local control of disease progression. In this single center retrospective study, patients with osseous metastases to the spine undergoing MWA with vertebroplasty from 2013 to 2020 were included. Locoregional control of metabolic activity at the treated level was assessed using PET/CT scan both pre- and post-procedure. Pain reduction was measured using change in visual analog scale (VAS) pain score. Forty-eight spinal levels were treated with MWA in 28 patients (57 % male, mean age 68 ± 9 years). Median ablation time, energy, and temperature were 4 min and 13 s, 3.6 kJ, and 80 °C, respectively. Median pre-procedure maximum standard uptake value (SUVmax) was significantly reduced following ablation, from 4.55 (IQR 3.65-6.1) to 0 (IQR 0-1.8; p < 0.001), over an average of 29 ± 14.1 month follow up period. Pre-procedure VAS pain score was reduced from median (IQR) of 8 (6.5-9) to 1(1-2), 2(1-3) and 1(0.5-3) at 24 h, four weeks, and six months post-procedure, respectively (all p < 0.001 with respect to pre-procedure scores). In conclusion, this study supports microwave ablation as an effective technique for pain palliation and long-term locoregional tumor control of oligometastatic spinal disease as assessed by metabolic response.

Role of Consolidative Stereotactic Body Radiation Therapy in Oligoresistant/Oligoprogressive Pulmonary Parenchymal Metastases

Aim

To extend the survival of patients by providing local control of metastases in oligoresistance/oligoprogressive disease.

Methods

We retrospectively evaluated the efficacy of stereotactic body radiotherapy (SBRT) applied to 30 lesions in the lungs of 19 patients who were considered inoperable by the tumor board upon the development of oligoresistance/oligoprogressive lung metastasis while undergoing chemotherapy between January 2016 and December 2017. Each patient had one to five metastases in their lungs. The median SBRT biologic effective dose at α/β of 10 (BED₁₀) was 180.0 (IQR: 115.5–180.0) Gy.

Results

We obtained effective, low-toxicity results. The rates of local control were 89.4%, 84.2%, and 78.9% for the 1st, 2nd, and 3rd years, respectively. The median local control time was 4 (IQR: 3–6) months. The median overall survival (OS) was 36.3 (IQR: 29.7–42.9) months. The rates of OS for the 1st, 2nd, and 3rd years were 89.5%, 73.7%, and 61.4%, respectively. Despite the nonoccurrence of grade 4–5 toxicity in the lungs, six (31.6%) patients had grade 1–3 pulmonary pneumonia, one patient had a grade 4 skin ulceration, and two patients had increased chronic obstructive pulmonary disease in the follow-up period.

Discussion

In patients with oligometastatic lung tumors, SBRT is very effective in terms of progression-free survival and OS.

Imaging-based prevalence of oligometastatic disease: A single-center cross-sectional study

INTRODUCTION AND BACKGROUND

Oligometastatic disease refers to a distinct state in cancer patients characterized by a low metastatic burden, with diagnosis being defined by a limited number of distant metastases in radiological imaging. However, oligometastasis remains poorly understood in terms of its biology and prevalence in the metastatic cascade. In the absence of clinically viable molecular biomarkers, this study examined the prevalence of oligometastasis using oncological imaging.

MATERIALS AND METHODS

This study is based on all consecutive FDG- and PSMA-PET scans conducted at our cancer center between January and December 2020. We identified and analyzed all PET scans from patients with maximum five distant metastases from a solid malignancy and also reviewed concurrent cMRI imaging in all candidate patients. Data on number and site of metastases were extracted from the imaging reports and verified on imaging studies in case of uncertainties.

RESULTS

In total, 7,000 PET scans were analyzed, 1,155 of which were performed in unique metastatic patients, and 637 patients showed extra-cranial oligometastatic disease (55%). Concurrent cMRI scans were available for 20% (130/637) of extracranial oligometastatic patients, 36 of which proved to be polymetastatic after combined PET and cMRI analysis. Prevalence of oligometastatic disease was influenced by primary tumor histology and most frequent in pancreatic, liver and gallbladders cancers (59%), and least frequent in cancer of unknown primary (26%). In 72% of oligometastatic cases, only one or two metastases were detected. Bone/soft tissue metastases were the most common sites of distant metastasis (41%). About three quarters of patients had metachronous oligometastatic disease.

DISCUSSION AND CONCLUSION

Our analysis suggests that about half of metastatic cancer patients are characterized by a limited tumor burden detectable on PET and cMRI imaging. This finding warrants intensified research efforts to better understand the biology of oligometastatic disease and to optimize multidisciplinary treatment strategies.

Endoscopic nodal staging in oligometastatic non-small cell lung cancer (NSCLC) being treated with stereotactic ablative radiotherapy (ENDO-SABR)

Background

Research in treatment of non-small cell lung cancer (NSCLC) has shown promising results with stereotactic ablative radiotherapy (SABR) of oligometastatic disease, wherein distant disease may be limited to one or a few distant organs by host factors. Traditionally, PET/CT has been used in detecting metastatic disease and avoiding futile surgical intervention, however, sensitivity and specificity is limited to only 81 and 79%, respectively. Mediastinal staging still identifies occult nodal disease in up to 20% of NSCLC patients initially thought to be operative candidates. Endobronchial ultrasound and transbronchial needle aspiration (EBUS-TBNA) is a minimally invasive tool for the staging and diagnosis of thoracic malignancy. When EBUS is combined with endoscopic ultrasound using the same bronchoscope (EUS-B), the diagnostic sensitivity and negative predictive value increase to 84 and 97%, respectively. Endoscopic staging in patients with advanced disease has never been studied, but may inform treatment if a curative SABR approach is being taken.

Methods

This is a multi-centre, prospective, cohort study with two-stage design. In the first stage, 10 patients with oligometastatic NSCLC (lung tumour ± hilar/mediastinal lymphadenopathy) with up to 5 synchronous metastases will be enrolled An additional 19 patients will be enrolled in the second stage if rate of treatment change is greater than 10% in the first stage. Patients will be subject to EBUS or combined modality EBUS/EUS-B to assess bilateral lymph node stations using a N3 to N2 to N1 progression. Primary endpoint is defined as the rate of change to treatment plan including change from SABR to conventional dose radiation, change in mediastinal radiation field, and change from curative to palliative intent treatment.

Discussion

If a curative approach with SABR for oligometastatic disease is being explored, invasive mediastinal staging may guide treatment and prognosis. This study will provide insight into the use of endoscopic mediastinal staging in determining changes in treatment plan of NSCLC. Results will inform the design of future phase II trials.

Trial registration

Clinicaltrials.gov identifier NCT04852588. Date of registration: April 19, 2021. Protocol version: 1.1 on December 9, 2021.

Predictive preoperative clinical score for patients with liver-only oligometastatic colorectal cancer

Background

Resection of liver metastases from colorectal cancer (CRC) in the oligometastatic stage improves survival and is a potentially curative treatment. Thus, predictive scores that reliably identify those patients who especially benefit from surgery are essential.

Patients and methods

In this multicenter analysis, 512 patients had undergone surgery for liver metastases from CRC. We investigated distinct cancer-specific risk factors that are routinely available in clinical practice and developed a predictive preoperative score using a training cohort (TC), which was thereafter tested in a validation cohort (VC).

Results

Inflammatory response to the tumor, a right-sided primary tumor, multiple liver metastases, and node-positive primary tumor were significant adverse variables for overall survival (OS). Patients were stratified in five groups according to the cumulative score given by the presence of these risk factors. Median OS for patients without risk factors was 133.8 months [95% confidence interval (CI) 81.2-not reached (nr)] in the TC and was not reached in the VC. OS decreased significantly for each subsequent group with increasing number of risk factors. Median OS was significantly shorter (P < 0.0001) for patients presenting all four risk factors: 14.3 months (95% CI 10.5 months-nr) in the TC and 16.6 months (95% CI 14.6 months-nr) in the VC.

Conclusions

Including easily obtainable variables, this preoperative score identifies oligometastatic CRC patients with prolonged survival rates that may be cured, and harbors potential to be implemented in daily clinical practice.

•

We identified four variables of adverse outcome for patients treated with surgical resection of liver metastases from CRC.

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Adverse variables were inflammatory response to the tumor, multiple metastases, right-sided primary tumor, node-positive primary tumor.

•

We developed a preoperative clinical score according to the number of risk factors present.

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Using easily obtainable variables, this score identified patients with oligometastatic CRC with good prognosis.

•

Patients without risk factors should strongly be considered for surgical resection of their metastases.

The Road to Dissemination: The Concept of Oligometastases and the Barriers for Widespread Disease

Simple Summary

Oligometastatic disease is an intermediate state of metastatic dissemination with a limited number of metastatic sites and extent of disease. Tumor cells need multiple capabilities in order to migrate, survive and evolve to macroscopic metastases. These capabilities are acquired by evolutionary mechanisms and are associated with several clinical factors and biomarkers. Better understanding of these properties and biomarkers may help to select patients that can benefit from local ablative therapies, which have shown to be a promising approach in recent clinical evidence.

Abstract

Over the last years, the oligometastatic disease state has gained more and more interest, and randomized trials are now suggesting an added value of stereotactic radiotherapy on all macroscopic disease in oligometastatic patients; but what barriers could impede widespread disease in some patients? In this review, we first discuss the concept of oligometastatic disease and some examples of clinical evidence. We then explore the route to dissemination: the hurdles a tumoral clone has to overtake before it can produce efficient and widespread dissemination. The spectrum theory argues that the range of metastatic patterns encountered in the clinic is the consequence of gradually obtained metastatic abilities of the tumor cells. Tumor clones can obtain these capabilities by Darwinian evolution, hence early in their genetic progression tumors might produce only a limited number of metastases. We illustrate selective dissemination by discussing organ tropism, the preference of different cancer (sub)types to metastasize to certain organs. Finally we discuss biomarkers that may help to distinguish the oligometastatic state.

The Role of Ablative Radiotherapy in Older Adults With Limited Metastatic Disease

For patients with oligometastatic cancer, radiotherapy presents a promising avenue for achieving meaningful symptom relief and durable disease control. Data from recently published and ongoing randomized studies are helping to define the appropriate contexts for effective intervention with stereotactic ablative body radiotherapy (SABR) in the oligometastatic setting. Importantly, older adults represent a significant portion of patients with oligometastatic disease, yet often comprise a minority of patients in clinical trials. Moreover, older adults of the same chronologic age may have variable degrees of fitness and frailty. In this review, we highlight the specific challenges and considerations for the use of radiotherapy for older adults with oligometastatic disease-noting the importance of geriatric assessments in clinical decision-making about the appropriateness of SABR and other metastasis-directed therapies in this population. We then review data from existing trials, including a subset analysis of adverse events and survival estimates among older adults enrolled in the landmark SABR-COMET trial. Finally, we discuss future directions for research, including the need for focused clinical trials in older adult cohorts. Ultimately, a multidisciplinary approach is critical when carefully balancing the potential risks and benefits of this emerging treatment paradigm in the older adult population.

How to Improve SBRT Outcomes in NSCLC: From Pre-Clinical Modeling to Successful Clinical Translation

Simple Summary

Despite major research and clinical efforts, lung cancer remains the leading cause of cancer-related death. Stereotactic body radiotherapy (SBRT) has emerged as a major treatment modality for lung cancer in the last decade. Additional research is needed to elucidate underlying mechanisms of resistance and to develop improved therapeutic strategies. Clinical progress relies on accurate preclinical modelling of human disease in order to yield clinically meaningful results; however, successful translation of pre-clinical research is still lagging behind. In this review, we summarize the major clinical developments of radiation therapy for non-small-cell lung cancer (NSCLC), and we discuss the pre-clinical research models at our disposal, highlighting ongoing translational challenges and future perspectives.

Abstract

Despite major research and clinical efforts, lung cancer remains the leading cause of cancer-related death. While the delivery of conformal radiotherapy and image guidance of stereotactic body radiotherapy (SBRT) have revolutionized the treatment of early-stage non-small-cell lung cancer (NSCLC), additional research is needed to elucidate underlying mechanisms of resistance and identify novel therapeutic combinations. Clinical progress relies on the successful translation of pre-clinical work, which so far has not always yielded expected results. Improved clinical modelling involves characterizing the preclinical models and selecting appropriate experimental designs that faithfully mimic precise clinical scenarios. Here, we review the current role of SBRT and the scope of pre-clinical armamentarium at our disposal to improve successful clinical translation of pre-clinical research in the radiation oncology of NSCLC.

Heterogeneity of Synchronous Lung Metastasis Calls for Risk Stratification and Prognostic Classification: Evidence from a Population-Based Database

The epidemiology and associated potential heterogeneity of synchronous lung metastasis (sLM) have not been reported at a population-based level. Cancer patients with valid information about sLM status in the Surveillance, Epidemiology, and End Results database were enrolled. The prevalence of sLM, with a 95% confidential interval, and median survival of sLM, with interquartile range, were calculated and compared by Chi-square analyses and log-rank tests by primary cancer type and clinicopathological factors. Furthermore, the risk factors of sLM development were identified by multivariate logistic regression. Among 1,672,265 enrolled cases, 3.3% cases were identified with sLM, with a median survival of 7 months. Heterogeneity in prevalence and prognosis in sLM was observed among different primary cancers, with the highest prevalence in main bronchus cancer and best survival in testis cancer. Higher prevalence and poorer prognosis were observed in the older population, male population, African American, patients with lower socioeconomic status, and cases with advanced T stage, N stage, or more malignant pathological characteristics. Race, age, T stage, N stage, metastasis to other sites, insurance status and marital status were associated with sLM development (p < 0.001). The current study highlights the heterogeneity of the prevalence and prognosis in patients with sLM.

Efficacy and Safety of Radioactive 125I Seed Implantation for Patients with Oligo-Recurrence Soft Tissue Sarcomas

PURPOSE

To evaluate the efficacy and safety of computed tomography-guided radioactive iodine-125 (¹²⁵I) seed implantation for oligo-recurrence soft tissue sarcomas following surgical resection.

MATERIALS AND METHODS

Patients with oligo-recurrence soft tissue sarcomas after curative surgical resection between June 2013 and December 2020 were included. The primary outcome measure was objective response rate according to the Response Evaluation Criteria in Solid Tumors (RECIST 1.1). The secondary outcomes included progression-free survival, overall survival, and safety profiles.

RESULTS

Twenty-nine patients receiving computed tomography-guided ¹²⁵I seed implantation were included in the study. The objective response rates at 2-, 6- and 12-month follow-up were 48.3%, 65.5% and 40.9%, respectively. The median progression-free survival was 11.3 months. The median overall survival was 25.1 months, with a 1- and 2-year overall survival rate of 81.5% and 50.0%, respectively. No severe treatment-related adverse effects occured.

CONCLUSION

¹²⁵I seed implantation has the potential to be an effective and safe treatment for oligo-recurrence soft tissue sarcomas after surgical resection.

Repeated Multimodality Ablative Therapies for Oligorecurrent Pulmonary Metastatic Disease

Stereotactic body radiotherapy (SBRT) and percutaneous thermal ablation (TA) are alternatives to surgery for the management of pulmonary oligometastases. In this collaborative work, we retrospectively analyzed patients who had undergone iterative focal ablative treatments of pulmonary oligometastases. We hypothesized that repeated ablative therapies could benefit patients with consecutive oligometastatic relapses. Patients treated with SBRT and/or TA for pulmonary oligometastases in two French academic centers between October 2011 and November 2016 were included. A total of 102 patients with 198 lesions were included; 45 patients (44.1%) received repeated focal treatments at the pulmonary site for an oligorecurrent disease (the “multiple courses” group). Median follow-up was 22.5 months. The 3-year overall survival rates of patients who had a single treatment sequence (the “single course” group) versus the “multiple courses” were 73.9% and 78.8%, respectively, which was not a statistically significant difference (p = 0.860). The 3-year systemic therapy-free survival tended to be longer in the “multiple courses” group (50.4%) than in the “single course” group (44.7%) (p = 0.081). Tolerance of repeated treatments was excellent with only one grade 4 toxicity. Thereby, multimodality repeated ablative therapy is effective in patients with pulmonary oligorecurrent metastases. This strategy may delay the use of more toxic systemic therapy.

Outcomes and toxicities in oligometastatic patients treated with stereotactic body radiotherapy for adrenal gland metastases: A multi-institutional retrospective study

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SBRT to adrenal gland oligometastases achieves a satisfactory local control and OS.

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A minimum PTV dose BED₁₀ > 46 Gy was associated with an improved OS and LRFS.

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A prescribed BED₁₀ > 70 Gy was correlated with improved local control.

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High adrenal metastases volume should not preclude the delivery of SBRT.

Background

Studies reporting SBRT outcomes in oligometastatic patients with adrenal gland metastases (AGM) are limited. Herein, we present a multi-institutional analysis of oligometastatic patients treated with SBRT for AGM.

Material/methods

The Consortium for Oligometastases Research (CORE) is among the largest retrospective series of patients with oligometastases. Among CORE patients, those treated with SBRT for AGM were included. Clinical and dosimetric data were collected. Adrenal metastatic burden (AMB) was defined as the sum of all adrenal GTV if more than one oligometastases is present.

Competing risk analysis was used to estimate actuarial cumulative local recurrence (LR) and widespread progression (WP). Kaplan-Meier method was used to report overall survival (OS), local recurrence-free survival (LRFS), and progression-free survival (PFS). Treatment related toxicities were also reported.

Results

The analysis included 47 patients with 57 adrenal lesions. Median follow-up was 18.2 months. Median LRFS, PFS, and OS were 15.3, 5.3, and 19.1 months, respectively. A minimum PTV dose BED₁₀ > 46 Gy was associated with an improved OS and LRFS. A prescribed BED₁₀ > 70 Gy was an independent predictor of a lower LR probability. AMB>10 cc was an independent predictor of a lower risk for WP. Only one patient developed an acute Grade 3 toxicity consisting of abdominal pain.

Conclusion

SBRT to AGM achieved a satisfactory local control and OS in oligometastatic patients. High minimum PTV dose and BED₁₀ prescription doses were predictive of improved LR and OS, respectively. Prospective studies are needed to determine comprehensive criteria for patients SBRT eligibility and dosimetric planning.

Influence of Dexamethasone Premedication on Acute Lung Toxicity in Lung SBRT

Introduction

The cooperative group experience of thoracic sterotactic body radiation therapy (SBRT) in medically inoperable patients with early stage non-small cell lung cancer (NSCLC) historically utilized corticosteroid premedication. Patterns of care have been mixed as to whether premedication adds benefit in terms of improved lung toxicity and treatment tolerance.

Methods

Patients treated for NSCLC from 2014 to 2017 with definitive thoracic SBRT (BED₁₀≥100) at a single institution, in a prospectively collected database were evaluated. Pretreatment clinicopathologic characteristics, including Eastern Cooperative Oncology Group (ECOG) performance status, PFT parameters of FEV1, and diffusing capacity for carbon monoxide (DLCO) were collected. Treatment and dosimetric characteristics were collected, and patients were scored as to whether dexamethasone was prescribed and utilized with each fraction. Toxicity was graded on multiple domains including lung as during and 30 days after completion of treatment using Common Terminology Criteria for Adverse Events Version 4. Univariate analysis was performed with Fisher’s exact test for categorical variables and two-tailed Student’s t-test for continuous variables. Multivariate analysis was performed with Cox proportional hazards model to adjust for age, pretreatment DLCO, ECOG, tumor size, central versus peripheral location, and biological effective dose.

Results

A total of 86 patients treated with thoracic SBRT with 54–60 Gy in 3–8 fractions met inclusion criteria, with the majority (70%) receiving 5 fractions. Of these patients, 45 (52%) received 4 mg dexamethasone premedication prior to each fraction of SBRT and 41 (48%) were treated without dexamethasone premedication. Overall acute lung toxicity was low in both groups. Between the two groups of patients, 5/45 (11%) developed grade 2 or higher lung toxicity including hospital admission in the dexamethasone premedication arm vs. 2/41 (5%) without premedication (p = 0.4370, Fisher’s exact test). Freedom from acute SBRT lung toxicity was no different between dexamethasone premedication arm and no premedication (Log rank, p = 0.45). On multivariate Cox proportional hazard modeling adjusting for age, ECOG, tumor size, central vs. peripheral location, pretreatment DLCO, and BED, there was no difference in freedom from acute lung toxicity without dexamethasone premedication (HR: 0.305; 95% CI: 0.033, 2.792; p = 0.293).

Conclusions

In this retrospective analysis, pretreatment steroid prophylaxis with dexamethasone confers a similar acute toxicity profile and no added clinical benefit to treatment without pretreatment steroid prophylaxis.

Effect of 18F-DCFPyL PET/CT on the Management of Patients with Recurrent Prostate Cancer: Results of a Prospective Multicenter Registry Trial

Background The high positivity rate of prostate-specific membrane antigen (PSMA) PET in the setting of biochemical failure (BCF), even when conventional imaging is negative, is promising. Purpose To assess the disease detection rate of PSMA-based PET/CT with fluorine 18-DCFPyL as a radiotracer and the PET-directed management change in men with suspected limited recurrent prostate cancer. Materials and Methods This prospective multicenter registry (Ontario PSMA-PET Registry for Recurrent Prostate Cancer, or PREP) enrolled men with BCF after primary therapy (radical prostatectomy plus or minus salvage radiation therapy or primary radiation therapy) and zero to four disease sites at conventional imaging (CT and bone scintigraphy). The positivity rate of PSMA PET according to serum prostate-specific antigen (PSA) level; frequency of local-egional, oligometastatic, and extensive metastatic recurrence; and rate of change in management after PET findings were recorded. The nonparametric Mood median test was used to assess the association between serum PSA level and change in management. Results A total of 1289 men (median age, 71 years [interquartile range, 65-75 years]) were evaluated. PSMA PET helped detect disease in 841 of 1289 men (65%) and in 615 of 999 men (62%) with negative conventional imaging. The recurrence detection rates according to serum PSA level at enrollment were 38% (160 of 424 men), 63% (107 of 171 men), and 83% (573 of 692 men) for PSA under 0.5 ng/mL, 0.5-1.0 ng/mL, and above 1.0 ng/mL, respectively. At PSMA PET, 399 of 1289 men (31%) had local-regional recurrence, 314 (24%) had oligometastatic disease, and 128 (10%) had extensive metastases. Following PET examination, a change in planned management was recorded in 748 of 1289 men (58%), and in 371 of 1250 men (30%), there was a change in management intent, more commonly from palliative to potentially curative intent (255 of 1289 men [20%]). Conclusion Prostate-specific membrane antigen PET helped detect additional sites of disease compared with conventional imaging in approximately 60% of men with biochemical failure and suspected low-volume metastatic disease, resulting in frequent change in management, including a change from palliative to curative or radical intent therapy in 20% of men. Long-term follow-up is needed to determine whether this impacts disease control. Clinical trial registration no. NCT03718260 © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Civelek in this issue.

Efficacy and Safety of Local Radiotherapy to All Oligometastatic Sites in Elderly Patients with Metachronous Oligometastatic Cancers After Initial Treatment for the Primary Tumor

Background and Purpose

This study aimed to investigate the efficacy and safety of maintenance therapy combined with local radiotherapy at all oligometastatic sites (LRTOS) in elderly patients with metachronous oligometastatic cancers (MOC).

Patients and Methods

A total of 242 elderly patients with MOC (≤5 metastases) and primary tumor well controlled after definitive treatment was retrospectively analyzed between August 2014 and February 2020 at Beijing Geriatric Hospital and Air Force General Hospital. Patients were divided into maintenance therapy group (maintenance therapy alone) and local radiotherapy group (maintenance therapy combined with LRTOS).

Results

There were 86 patients in the local radiotherapy group and 156 patients in the maintenance therapy group. The median length of follow-up was 36 months (range, 8.0–62 months). Median overall survival (mOS) was 25 months (95% CI: 21.1–28.9) in the local radiotherapy group and 16 months (95% CI: 14.5–17.6) in the maintenance therapy group (p < 0.001). Multivariate analyses demonstrated that LRTOS (hazard ratio (HR) = 0.49, 95% confidence interval (CI): 0.35–0.67, p < 0.001), good Eastern Cooperative Oncology Group Performance Status (ECOG PS, HR = 0.69, 95% CI: 0.49–0.97, p = 0.032), longer duration between diagnosis of primary tumor and occurrence of progression (HR = 0.87, 95% CI: 0.78–0.97, p = 0.015), and subsequent systemic treatment (HR = 0.52, 95% CI: 0.38–0.72, p < 0.001) were independent predictors of good OS. In patients who did not receive subsequent systemic treatment, their mOS was 21 months (95% CI: 12.8–29.2) for those treated with LRTOS and 14 months (95% CI: 11.4–16.6) for those who did not receive local radiotherapy (p = 0.001). Further multivariate analysis showed that LRTOS was the only independent factor for predicting good OS (HR = 0.47, 95% CI: 0.26–0.83, p = 0.010). Patients with metachronous oligometastatic lung cancer, colorectal cancer, prostate cancer, and breast cancer had higher survival benefits following LRTOS. Most patients suffered from grade 1–2 toxicities, but no treatment-related death was recorded.

Conclusion

This retrospective study shows that elderly patients with MOC treated with LRTOS may have better survival outcomes.

[Imaging of oligometastatic disease in selected urologic cancers]

BACKGROUND

Local treatment of the primary or metastatic sites in urologic malignancies is promising when compared to systemic therapy alone, leading to the definition of a potentially curative oligometastatic state.

OBJECTIVES

Comparison of imaging modalities regarding local and metastatic tumor sites in urologic cancers.

METHODS

Review of comparative trials addressing quality criteria of imaging modalities.

RESULTS

Depending on primary tumor and metastatic site, conventional imaging modalities such as computer tomography (CT) and bone scintigraphy still represent the standard of care in Germany. Due to superior quality criteria, hybrid-imaging techniques were widely adopted for oncological staging and particular due to the new PSMA-ligand (PSMA-PET/CT) in prostate cancer imaging. The development of new radioisotopes as well as their clinical application remains a focus of current research.

CONCLUSIONS

High-quality diagnostic imaging modalities lay the groundwork for a precise definition of an oligometastatic state. By enabling treatment of the entire tumor burden, a delay of systemic therapy, longer progression-free survival, or even curative treatment may become achievable.

Modern Radiation Therapy for the Management of Brain Metastases From Non-Small Cell Lung Cancer: Current Approaches and Future Directions

Brain metastases (BMs) represent the most frequent event during the course of Non-Small Cell Lung Cancer (NSCLC) disease. Recent advancements in the diagnostic and therapeutic procedures result in increased incidence and earlier diagnosis of BMs, with an emerging need to optimize the prognosis of these patients through the adoption of tailored treatment solutions. Nowadays a personalized and multidisciplinary approach should rely on several clinical and molecular factors like patient’s performance status, extent and location of brain involvement, extracranial disease control and the presence of any “druggable” molecular target. Radiation therapy (RT), in all its focal (radiosurgery and fractionated stereotactic radiotherapy) or extended (whole brain radiotherapy) declinations, is a cornerstone of BMs management, either alone or combined with surgery and systemic therapies. Our review aims to provide an overview of the many modern RT solutions available for the treatment of BMs from NSCLC in the different clinical scenarios (single lesion, oligo and poly-metastasis, leptomeningeal carcinomatosis). This includes a detailed review of the current standard of care in each setting, with a presentation of the literature data and of the possible technical solutions to offer a “state-of-art” treatment to these patients. In addition to the validated treatment options, we will also discuss the future perspectives on emerging RT technical strategies (e.g., hippocampal avoidance whole brain RT, simultaneous integrated boost, radiosurgery for multiple lesions), and present the innovative and promising findings regarding the combination of novel targeted agents such as tyrosine kinase inhibitors and immune checkpoint inhibitors with brain irradiation.