Case report: Efficacy of immunotherapy as conversion therapy in dMMR/MSI-H colorectal cancer: a case series and review of the literature

Immunotherapy has demonstrated a role in the therapeutic landscape of a small subset of patients with colorectal carcinoma (CRC) that harbor a microsatellite instability (MSI-H) status due to a deficient DNA mismatch repair (dMMR) system. The remarkable responses to immune checkpoint inhibitors (ICIs) are now being tested in the neoadjuvant setting in localized CRC, where the dMMR/MSI-H status can be found in up to 15% of patients, with remarkable results obtained in NICHE2 and 3 trials, among others. This case series aims to report our experience at a tertiary center and provide a comprehensive analysis of the possible questions and challenges to overcome if ICIs were established as standard of care in a neoadjuvant setting, as well as the potential role they may have as conversion therapy not only in locoregional advanced CRC but also in oligometastatic disease.

Patterns and kinetics of hepatocellular carcinoma relapse post-liver transplantation: oligorecurrence and role of local therapies

Background

Amongst patients with recurrent hepatocellular carcinoma (HCC) post-liver transplantation, systemic therapy options may be limited by immunosuppression or poor performance status. Thus, we aimed to assess the impact of metastasis-directed therapy to all sites of disease (MDT-All) in HCC patients with limited disease recurrence [i.e., oligorecurrence (oligoM1)] post-transplantation and characterize pre-transplant characteristics associated with oligoM1.

Methods

In this retrospective cohort study, patients at a single institution with recurrent HCC post-liver transplantation were identified. OligoM1 disease was defined as ≤3 lesions at recurrence, while polyrecurrent (polyM1) disease was defined as >3 lesions. Outcomes were compared in patients with oligoM1 disease by receipt of MDT-All. Regression analyses were used to identify predictors of polyM1 disease and characteristics associated with post-recurrence outcomes.

Results

Forty-three patients with recurrent HCC post-liver transplantation from 2005-2022 were identified. Twenty-seven (63%) patients had oligoM1. Microvascular invasion was independently associated with polyM1 [odds ratio (OR): 14.64; 95% confidence interval (CI): 1.48-144.77; P=0.022]. Elevated alpha-fetoprotein (AFP) ≥400 ng/mL [hazard ratio (HR): 2.44; 95% CI: 1.08, 5.52; P=0.033] at recurrence was independently associated with inferior overall survival (OS), while oligoM1 (HR: 0.42; 95% CI: 0.21, 0.87; P=0.018) was independently associated with favorable OS. Amongst patients with oligoM1 who received MDT-All (n=15) median OS was 38.4 vs. 16.1 months for those who did not receive MDT-All (log-rank P=0.021). There was a non-significant improvement in polyprogression-free survival (polyPFS) (median 14.0 vs. 10.7 months, P=0.1) amongst oligoM1 patients who received MDT-All compared to those who did not.

Conclusions

Receipt of MDT-All was associated with improved OS amongst patients with limited HCC disease recurrence following liver transplantation.

SBRT of Spinal Metastases Using a Simultaneous Integrated Boost Concept in Oligometastatic Cancer Patients Is Safe and Effective

(1) Purpose: To assess the safety and effectivity of stereotactic body radiotherapy (SBRT) on spinal metastases utilizing a simultaneous integrated boost (SIB) concept in oligometastatic cancer patients. (2) Methods: 62 consecutive patients with 71 spinal metastases received SIB-SBRT between 01/2013 and 09/2022 at our institution. We retrospectively analyzed toxicity, local tumor control (LC), and progression-free (PFS) and overall survival (OS) following SIB-SBRT and assessed possible influencing factors (Kaplan-Meier estimator, log-rank test and Cox proportional-hazards model). (3) Results: SIB-SBRT was delivered in five fractions, mostly with 25/40 Gy (n = 43; 60.56%) and 25/35 Gy (n = 19, 26.76%). Estimated rates of freedom from VCF were 96.1/90.4% at one/two years. VCF development was significantly associated with osteoporosis (p < 0.001). No ≥ grade III acute and one grade III late toxicity (VCF) were observed. Estimated LC rates at one/two years were 98.6/96.4%, and histology was significantly associated with local treatment failure (p = 0.039). Median PFS/OS was 10 months (95% CI 6.01-13.99)/not reached. Development of metastases ≥ one year after initial diagnosis and Karnofsky Performance Score ≥ 90% were predictors for superior PFS (p = 0.038) and OS (p = 0.012), respectively. (4) Conclusion: Spinal SIB-SBRT yields low toxicity and excellent LC. It may be utilized in selected oligometastatic patients to improve prognosis. To the best of our knowledge, we provide the first clinical data on the toxicity and effectivity of SIB-SBRT in spinal metastases in a larger patient cohort.

Survival benefit of local consolidative therapy for patients with single-organ metastatic pancreatic cancer: a propensity score-matched cross-sectional study based on 17 registries

Background

The continuous exploration of oligometastatic disease has led to the remarkable achievements of local consolidative therapy (LCT) and favorable outcomes for this disease. Thus, this study investigated the potential benefits of LCT in patients with single-organ metastatic pancreatic ductal adenocarcinoma (PDAC).

Methods

Patients with single-organ metastatic PDAC diagnosed between 2010 - 2019 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. Propensity score matching (PSM) was performed to minimize selection bias. Factors affecting survival were assessed by Cox regression analysis and Kaplan-Meier estimates.

Results

A total of 12900 patients were identified from the database, including 635 patients who received chemotherapy combined with LCT with a 1:1 PSM with patients who received only chemotherapy. Patients with single-organ metastatic PDAC who received chemotherapy in combination with LCT demonstrated extended median overall survival (OS) by approximately 57%, more than those who underwent chemotherapy alone (11 vs. 7 months, p < 0.001). Furthermore, the multivariate Cox regression analysis revealed that patients that received LCT, younger age (< 65 years), smaller tumor size (< 50 mm), and lung metastasis (reference: liver) were favorable prognostic factors for patients with single-organ metastatic PDAC.

Conclusion

The OS of patients with single-organ metastatic pancreatic cancer who received LCT may be prolonged compared to those who received only chemotherapy. Nevertheless, additional prospective randomized clinical trials are required to support these findings.

Real-world evidence of outcomes of oligometastatic hormone-sensitive prostate cancer patients treated with metastasis-directed therapy

OBJECTIVE

To investigate characteristics and outcomes of oligometastatic hormone-sensitive prostate cancer (mHSPC) patients undergoing metastases-directed therapy (MDT) with external beam radiation therapy (EBRT).

MATERIALS AND METHODS

We relied on an institutional tertiary-care database to identify mHSPC patients who underwent EBRT as MDT between 12/2019 and 12/2022. Main outcomes consisted of progression to metastatic castration-resistant prostate cancer (mCRPC) and overall mortality (OM). Oligometastatic was defined as ≤3 metastases and bone and/or lymph node deposits were treated with conventional doses up to 54 Gy or with hypofractionated stereotactic regimes of median 24 Gy (20-27 Gy).

RESULTS

Overall, 37 patients treated with EBRT as MDT were identified. The median follow-up was 13 months. Median age at MDT was 71 years and 84% exhibited ECOG performance status 0. The median baseline PSA at diagnosis was 10 ng/mL. Overall, primary local therapy consisted of radical prostatectomy (65%), followed by external beam radiation therapy to the prostate (11%), focal therapy (8%), and palliative transurethral resection of the prostate (5%). Overall, 32% exhibited de novo oligometastatic mHSPC. Bone metastases were present in 78% versus 19% lymph node metastases versus 3% both. The distribution of targeted oligo-metastases was 62% versus 38% for respectively one metastasis versus more than one metastasis. Androgen deprivation therapy (ADT) was combined with MDT in 84%. Moreover, 19% received combination therapy with apalutamide/enzalutamide and 12% with abiraterone or docetaxel. The median time to mCRPC was 50 months. In incidence analyses, 13% developed mCRPC after 24 months. OM after 24 months was 15% in mHSPC patients receiving MDT. Significant OM differences were observed after stratification into targeted metastatic burden (<0.05). No high-grade adverse events were recorded during MDT.

CONCLUSION

Our real-world data suggest that MDT represents a safe treatment option for well-selected oligometastatic mHSPC patients.

Hepatic Metastasectomy in Squamous Cell Carcinoma of the Anal Canal: A Case Series of a Curative Approach

BACKGROUND

Squamous cell carcinoma of the anal canal (SCCA) is rare. Most cases are diagnosed in a localized setting. Metastatic SCCA is rare, and investigation has been limited in the past for these patients. We believe that hepatic-only metastatic disease could have a unique treatment landscape compared to diseases with diffuse metastatic involvement. Here, we describe cases at our institution.

METHODS

We reviewed eight SCCA cases with hepatic-only metastatic disease (diagnosed February 2018-January 2022). The objectives were to determine the overall survival and disease-free survival with this approach.

RESULTS

The median age was 62 years old (yo). Patients had an ECOG of 0-1. All patients received definitive chemoradiation to their primary anal tumor. A median of three months of neoadjuvant systemic therapy was provided. All patients had a response on their first scan after systemic therapy. Sixty-two percent received carboplatin + paclitaxel. A complete pathologic response was seen in 62% of patients. At their last follow-up, all patients were alive. Three patients had recurrent disease. The estimated 1-year disease-free survival probability was 56.2%.

CONCLUSION

Our report shows the feasibility of a curative-intent approach for patients with hepatic-only metastatic SCCA following the neoadjuvant application of carboplatin + paclitaxel. This approach appears promising in these select patients and warrants further investigation.

Resection of Contralateral Scapular Oligometastasis in Non-small Cell Lung Cancer Post Right Salvage Pneumonectomy

A 74-year-old male was diagnosed with right hilar T4N1M0 squamous cell carcinoma of the lung. Radical oncological treatment was initiated with curative intent. Despite this, a post-operative computed tomography scan showed residual disease. Therefore, right thoracotomy and salvage pneumonectomy were performed. The patient recovered well post-operatively. Unfortunately, seven months later, he re-presented with a left scapula subcutaneous mass, with a biopsy confirming metastatic lung squamous cell carcinoma. Radiotherapy was not possible as it would have irradiated the remaining lung, and therefore, surgical resection and chest wall reconstruction were undertaken. The patient remains free of disease at 6 months follow-up. We present an interesting case of surgical management of oligometastatic lung cancer.

An International Multicenter Study Exploring Whether Surveillance After Esophageal Cancer Surgery Impacts Oncological and Quality of Life Outcomes (ENSURE)

OBJECTIVE

To determine the impact of surveillance on recurrence pattern, treatment, survival and health-related quality-of-life (HRQL) following curative-intent resection for esophageal cancer.

SUMMARY BACKGROUND DATA

Although therapies for recurrent esophageal cancer may impact survival and HRQL, surveillance protocols after primary curative treatment are varied and inconsistent, reflecting a lack of evidence.

METHODS

European iNvestigation of SUrveillance after Resection for Esophageal cancer was an international multicenter study of consecutive patients undergoing surgery for esophageal and esophagogastric junction cancers (2009-2015) across 20 centers (NCT03461341). Intensive surveillance (IS) was defined as annual computed tomography for 3 years postoperatively. The primary outcome measure was overall survival (OS), secondary outcomes included treatment, disease-specific survival, recurrence pattern, and HRQL. Multivariable linear, logistic, and Cox proportional hazards regression analyses were performed.

RESULTS

Four thousand six hundred eighty-two patients were studied (72.6% adenocarcinoma, 69.1% neoadjuvant therapy, 45.5% IS). At median followup 60 months, 47.5% developed recurrence, oligometastatic in 39%. IS was associated with reduced symptomatic recurrence (OR 0.17 [0.12-0.25]) and increased tumor-directed therapy (OR 2.09 [1.58-2.77]). After adjusting for confounders, no OS benefit was observed among all patients (HR 1.01 [0.89-1.13]), but OS was improved following IS for those who underwent surgery alone (HR 0.60 [0.47-0.78]) and those with lower pathological (y)pT stages (Tis-2, HR 0.72 [0.58-0.89]). IS was associated with greater anxiety ( P =0.016), but similar overall HRQL.

CONCLUSIONS

IS was associated with improved oncologic outcome in select cohorts, specifically patients with early-stage disease at presentation or favorable pathological stage post neoadjuvant therapy. This may inform guideline development, and enhance shared decision-making, at a time when therapeutic options for recurrence are expanding.

Definitive Chemoradiation Associated with Improved Survival Outcomes in Patients with Synchronous Oligometastatic Esophageal Cancer

BACKGROUND

The study of oligometastatic esophageal cancer (EC) is relatively new. Preliminary data suggests that more aggressive treatment regimens in select patients may improve survival rates in oligometastatic EC. However, the consensus recommends palliative treatment. We hypothesized that oligometastatic esophageal cancer patients treated with a definitive approach (chemoradiotherapy [CRT]) would have improved overall survival (OS) compared to those treated with a purely palliative intent and historical controls.

METHODS

Patients diagnosed with synchronous oligometastatic (any histology, ≤5 metastatic foci) esophageal cancer treated in a single academic hospital were retrospectively analyzed and divided into definitive and palliative treatment groups. Definitive CRT was defined as radiation therapy to the primary site with ≥40 Gy and ≥2 cycles of chemotherapy.

RESULTS

Of 78 Stage IVB (AJCC 8th ed.) patients, 36 met the pre-specified oligometastatic definition. Of these, 19 received definitive CRT, and 17 received palliative treatment. With a median follow-up of 16.5 months (Range: 2.3-95.0 months), median OS for definitive CRT and palliative groups were 90.2 and 8.1 months (p < 0.01), translating into 5-year OS of 50.5% (95%CI: 32.0-79.8%) vs. 7.5% (95%CI: 1.7-48.9%), respectively.

CONCLUSIONS

Oligometastatic EC patients treated with definitive CRT benefited from that approach with survival rates (50.5%) that vastly exceeded historical standards of 5% at 5 years for metastatic EC. Oligometastatic EC patients treated with definitive CRT had significantly improved OS compared to those treated with palliative-only intent within our cohort. Notably, definitively treated patients were generally younger and with better performance status versus those palliatively treated. Further prospective evaluation of definitive CRT for oligometastatic EC is warranted.

Difficulties in Defining Oligometastatic Prostate Cancer: Implications for Clinical Trial Accrual and Community Practice Adoption of Metastasis-Directed Therapy Approaches

BACKGROUND

Metastasis-directed therapy is widely utilized for oligometastatic prostate cancer patients, but standard imaging does not always identify metastases definitively and, even with PSMA PET, there may be equivocal findings. Not all clinicians have access to detailed imaging review, particularly outside of academic cancer centers, and PET scan access is also limited. We sought to understand how imaging interpretation impacted recruitment to a clinical trial for oligometastatic prostate cancer.

METHODS

IRB approval was obtained to review medical records from all patients screened for the institutional IRB-approved clinical trial for men with oligometastatic prostate cancer involving androgen deprivation plus stereotactic radiation to all metastatic sites, as well as radium223 (NCT03361735). Clinical trial inclusion required at least one bone metastatic lesion and no more than five total sites of metastasis, including soft tissue sites. Tumor board discussion records were reviewed, along with results from additional radiology studies ordered or confirmatory biopsies performed. Clinical characteristics such as PSA level and Gleason score were studied for association with likelihood of oligometastatic disease confirmation.

RESULTS

At the time of data analysis, 18 subjects were deemed eligible and 20 were not eligible. The most common reasons for ineligibility were no confirmed bone metastasis in 16 patients (59%) and too many metastatic sites in 3 (11%). The median PSA of eligible subjects was 3.28 (range 0.4-45.5), whereas the median PSA of those found to be ineligible was 10.45 (range 3.7-26.3) when there were too many metastases identified, and 2.7 (range 0.2-34.5) when metastases were unconfirmed. PET imaging (PSMA or fluciclovine PET) increased the number of metastases, while MRI resulted in downstaging to non-metastatic disease.

CONCLUSIONS

This research suggests that additional imaging (i.e., at least two independent imaging modalities of a possible metastatic lesion) or tumor board adjudication of imaging findings may be critical to correctly identify patients appropriate for enrollment in oligometastatic protocols. This should be considered as trials of metastasis-directed therapy for oligometastatic prostate cancer accrue and results are translated to broader oncology practice.

Prostate and metastasis-directed focal therapy in prostate cancer: hype or hope?

INTRODUCTION

The paradigm of focal therapy's role in metastatic patients is being challenged by evolving attitudes and emerging data. At the current time, specifically regarding prostate cancer, does the evidence indicate this is more hype or hope?

AREAS COVERED

We searched the literature via PubMed, MEDLINE, and Embase for studies from 2014 to the present addressing focal therapy with non-palliative intent in metastatic prostate cancer patients, emphasizing prospective trials when available. We sought to address all common clinical scenarios: de novo synchronous diagnosis, oligorecurrence, oligoprogression, and mCRPC disease.

EXPERT OPINION

Current evidence is strongest, and in our opinion practice-changing, for prostate-directed RT in de novo metastatic patients with low metastatic burden. Metastasis-directed therapy with SBRT is consistently shown to have low rates of toxicity, and promising rates of ADT-free survival and progression-free survival. These can be utilized on a patient-by-patient basis with these endpoints in mind, but do not yet show sufficient benefit to be standard of care. This is a rich area of ongoing research, and many trials should publish in the coming years to shed light on many unanswered questions, including the role of cytoreductive prostatectomy, systemic therapy combined with MDT, and the integration of modern PET imaging.

Stereotactic ablative radiotherapy for acquired resistance to EGFR therapy in metastatic non-small cell lung cancer

The advent of targeted therapy has transformed the treatment paradigm and survival of patients with metastatic non-small cell lung cancer (NSCLC) with driver mutations. The development of acquired resistances during treatment with tyrosine kinase inhibitors (TKIs) impedes a prolonged survival in many patients. This fact is leading to the use of locally ablative therapies such as stereotactic ablative radiotherapy (SABR) to counter these resistances. SABR is a non-invasive treatment that can be delivered in multiple locations and has already proven effective in oligometastatic disease. Clinical evidence suggests that the combination of SABR with TKIs prolongs progression-free survival (PFS) in metastatic NSCLC patients with mutations in epidermal growth factor receptor (EGFR), with international guidelines recommending their use in unfavorable scenarios such as oligoprogressive disease. In this publication, we have reviewed the available evidence on EGFR-TKIs resistance mechanisms and the combination of SABR with TKI in metastatic NSCLC with EGFR mutations. We also describe the utility and clinical recommendations of this combination in oligometastatic and oligoprogressive disease.

The oligometastatic paradigm and the role of radiotherapy

Most cancer-related deaths are due to metastatic disease. There is now an emerging evidence base suggesting that a subgroup of metastatic patients benefit significantly from local resection (surgery) or ablation (stereotactic ablative body radiation, SABR) of their metastatic sites. These patients are in what has been termed the 'oligometastatic state', a transitional window between local and disseminated disease where locally ablative, metastasis-directed therapy prolongs progression-free survival, improves overall survival and sometimes achieves cure. Appropriately selecting those who fit this oligometastatic phenotype, while integrating advances in ablative technologies such as SABR with modern systemic treatments, is an evolving challenge for oncologists.

Oligometastatic breast cancer to parotid gland with complete response

Breast cancer metastatic to parotid gland is a very rare condition which tend to confer poor prognosis and challenging approaches. Oligometastatic breast cancer is usually defined as advanced breast cancer with less or equal than 5 metastatic lesions. We report a case of oligometastatic HER-2 breast cancer to parotid gland and lymph nodes which presented with left hemifacial swelling with erythema and enlargement of cervical and axillary lymph nodes. After 6 cycles of Docetaxel plus Trastuzumab the patient had complete response that was complemented with posterior surgical removal of primary tumor followed by radiotherapy directed to plastron, left supraclavicular and cervical drainage. The patient is still on Trastuzumab therapy and is free of disease in the last two years. We discuss the presentation and approach of a patient with metastatic breast cancer to parotid gland in the oligometastatic scenario.

Oligometastatic breast cancer and metastasis-directed treatment: an aggressive multimodal approach to reach the cure

Metastatic breast cancer (BC) is considered an incurable disease and is usually treated with palliative intent. However, about 50% of metastatic BCs present with only a few metastatic lesions and are characterized by longer overall survival. These patients, defined as oligometastatic, could benefit from a multimodal approach, which combines systemic therapy with metastasis-directed treatment (stereotactic ablative therapy or surgery). The current definition of oligometastatic seems incomplete since it is based only on imaging findings and does not include biological features, and the majority of relevant data supporting this strategy comes from retrospective or non-randomized studies. However, the chance of reaching long-term complete remission or even a cure has led to the development of randomized trials investigating the impact of combined treatment in oligometastatic BC (OMBC). The SABR-COMET trial, the first randomized study to include BC patients, showed promising results from a combination of stereotactic ablative radiotherapy and systemic therapy. Considering the randomized trial's results, multidisciplinary teams should be set up to select OMBC patients who could achieve long-term survival with aggressive multimodal treatment.

Neoadjuvant radiohormonal therapy for oligo-metastatic prostate cancer: safety and efficacy outcomes from an open-label, dose-escalation, single-center, phase I/II clinical trial

To evaluate the safety and efficacy of neoadjuvant radiohormonal therapy for oligometastatic prostate cancer (OMPC), we conducted a 3 + 3 dose escalation, prospective, phase I/II, single-arm clinical trial (CHiCTR1900025743), in which long-term neoadjuvant androgen deprivation was adopted 1 month before radiotherapy, comprising intensity modulated radiotherapy to the pelvis, and stereotactic body radiation therapy to all extra-pelvic bone metastases for 4-7 weeks, at 39.6, 45, 50.4, and 54 Gy. Robotic-assisted radical prostatectomy was performed after 5-14 weeks. The primary outcome was treatment-related toxicities and adverse events; secondary outcomes were radiological treatment response, positive surgical margin (pSM), postoperative prostate-specific antigen (PSA), pathological down-grading and tumor regression grade, and survival parameters. Twelve patients were recruited from March 2019 to February 2020, aging 66.2 years in average (range, 52-80). Median baseline PSA was 62.0 ng/mL. All underwent RARP successfully without open conversions. Ten patients recorded pathological tumor down-staging (83.3%), and 5 (41.7%) with cN1 recorded negative regional lymph nodes on final pathology. 66.7% (8/12) recorded tumor regression grading (TRG) -I and 25% (3/12) recorded TRG-II. Median follow-up was 16.5 months. Mean radiological progression-free survival (RPFS) was 21.3 months, with 2-year RPFS of 83.3%. In all, neoadjuvant radiohormonal therapy is well tolerated for oligometastatic prostate cancer.

Evaluation of 5 Fraction Stereotactic Body Radiation Therapy (SBRT) for Osseous Renal Cell Carcinoma Metastases

OBJECTIVES

The best fractionation for stereotactic body radiotherapy (SBRT) in renal cell carcinoma (RCC) metastases has not been well defined. In addition, the literature on outcomes using 5-fraction SBRT in the setting of osseous metastases has not been well reported.

MATERIALS AND METHODS

Thirty-nine patients with 69 RCC osseous metastases were treated using 5-fraction SBRT at a single institution using 2 dose-fractionation schemes. Overall survival and local-control (LC) outcomes of the 2 fractionation schemes were studied using Kaplan-Meier curves.

RESULTS

Of the 69 lesions included in the study, 20 were treated with 30 grays (Gy) in 5 fractions and 49 were treated with 40 Gy in 5 fractions. The median age of patients at diagnosis was 58.4 years. The 1-year LC rate for all treated lesions was 85.5% (59/69) with an LC of 90% (18/20) for lesions receiving 30 Gy and 83.7% (41/49) in lesions receiving 40 Gy. There was no statistically significant difference in 1-year LC rate between the 2 fractionation schemes (P-value, 0.553).

CONCLUSIONS

Patients with osseous RCC metastases undergoing 5 fractions of SBRT had favorable LC outcomes. There was no difference in survival or LC between the 40 Gy and 30 Gy treatment arms.

Failure Patterns by PSMA PET for Recurrent Prostate Cancer after Prostatectomy and Salvage Radiation

OBJECTIVE

To characterize patterns of failure using prostate-specific membrane antigen positron emission tomography (PSMA PET) after radical prostatectomy (RP) and salvage radiotherapy (SRT).

METHODS

Patients with rising PSA post-RP+SRT underwent 68Ga-HBED-iPSMA PET/CT on a single-arm, prospective imaging trial (NCT03204123). Scans were centrally reviewed with pattern-of-failure analysis by involved site. Positive scans were classified using 3 failure categories: pelvic nodal, extra-pelvic nodal or distant non-nodal. Associations with failure categories were analyzed using cumulative incidence and generalized logits regression.

RESULTS

We included 133 men who received SRT a median of 20 months post-RP; 56% received SRT to the prostatic fossa alone, while 44% received pelvic SRT. PSMA PET/CT was performed a median of 48 months post-SRT. Overall, 31% of PSMA PET/CT scans were negative, 2% equivocal and 67% had at least 1 positive site. Scan detection was significantly associated with PSA level prior to PSMA PET/CT. Analysis of 89 positive scans demonstrated pelvic nodal (53%) was the most common relapse and fossa relapse was low (9%). Overall, positive scans were pelvic (n = 35, 26%), extra-pelvic nodal (n = 26, 20%) or distant non-nodal failure (n = 28, 21%), and 70% of positive scans were oligorecurrent. We observed similar cumulative incidence for all failure categories and relatively few clinicodemographic associations. Men treated with pelvic SRT had reduced odds of pelvic failure versus exclusive fossa treatment.

CONCLUSION

Pelvic, extra-pelvic nodal, and distant non-nodal failures occur with similar incidence post-SRT. Regional nodal relapse is relatively common, especially with fossa-only SRT. A high oligorecurrence rate suggests a potentially important role for PSMA-guided focal therapies.

The current role of precision surgery in oligometastatic prostate cancer

Oligometastatic prostate cancer (omPCa) is a novel intermediate disease state characterized by a limited volume of metastatic cells and specific locations. Accurate staging is paramount to unmask oligometastatic disease, as provided by prostate-specific membrane antigen-positron emission tomography. Driven by the results of prospective trials employing conventional and/or modern staging modalities, the treatment landscape of omPCa has rapidly evolved over the last years. Several treatment-related questions comprising the concept of precision strikes are under development. For example, beyond systemic therapy, cohort studies have found that cytoreductive radical prostatectomy (CRP) can confer a survival benefit in select patients with omPCa. More importantly, CRP has been consistently shown to improve long-term local symptoms when the tumor progresses across disease states due to resistance to systemic therapies. Metastasis-directed treatments have also emerged as a promising treatment option due to the visibility of oligometastatic disease and new technologies as well as treatment strategies to target the novel PCa colonies. Whether metastases are present at primary cancer diagnosis or detected upon biochemical recurrence after treatment with curative intent, targeted yet decisive elimination of disseminated tumor cell hotspots is thought to improve survival outcomes. One such strategy is salvage lymph node dissection in oligorecurrent PCa which can alter the natural history of progressive PCa. In this review, we will highlight how refinements in modern staging modalities change the classification and treatment of (oligo-)metastatic PCa. Further, we will also discuss the current role and future directions of precision surgery in omPCa.

Implementation of advanced radiotherapy techniques: stereotactic body radiotherapy (SBRT) for oligometastatic patients with lung metastasis - a single institution experience

Background and aims

The treatment of oligometastatic disease has become common practice as advanced radiotherapy techniques became more available. Lung is one of the main metastatic sites for a majority of cancers and many of these patients present with a limited metastatic disease burden. For these patients, SBRT (Stereotactic Body Radiation Therapy) represents a non-invasive treatment alternative. In this report we present our experience with our first series of patients with limited metastatic disease treated with lung SBRT. The purpose of this paper is to provide a qualitative and quantitative assessment of the lung SBRT treatment process and algorithm leading up to treatment delivery in a community-based radiotherapy department.

Methods

We have retrospectively reviewed our first series of 41 patients with lung oligometastases from various malignancies, treated using SBRT between March 2019 and December 2020. Demographic, technical and outcome data were analyzed.

Results

A number of 45 lung metastases (in 41 patients) were treated with SBRT during the specified time period. The median age was 65.7 years old (range 33-83). 16 patients (39%) were treated for multiple lesions and the mean number of treated lesions was 1 (range1-3). Median dose prescribed was 50 Gy /5 fractions (median BED₁₀ =77 Gy). The median intra-fraction displacements were: Vertical (0.23cm), Longitudinal (-0.27 cm), Lateral (-0.1 cm), Pitch [0.22°], Roll [0.15°], Rotation [0.32°]. The median session time was 40 minutes. All patients completed the prescribed course of treatment.Preliminary clinical data were recorded. With a median follow-up of 9 months, local control was recorded in all but one patient. At the last known follow-up, local control was recorded for 39 (85%) out of 45 treated lesions.

Conclusion

For lung SBRT, the required corrections at the time of treatment delivery are small, as long as strict protocols are implemented. Preliminary data for lung metastasis in oligometastatic patients support SBRT as a viable method of achieving high rates of early local control. These results need to be further confirmed in a larger cohort of patients with longer follow-up.

Outcome of lung oligometastatic patients treated with stereotactic body irradiation

Purpose

The oligometastatic stage is an intermediate stage of cancer between the localized stage and polymetastatic stage. The prognosis of patients in this stage also appears to be intermediate. Lung stereotactic body radiotherapy is a possible tool for treating oligometastatic lung sites. The objective of our study was to evaluate the clinical outcomes in terms of local control, progression-free survival, overall survival, and toxicity of SBRT in oligometastatic patients with lung metastases from any solid primary tumor.

Materials and methods

Clinical records of consecutive lung oligometastatic patients treated between January 2010 and December 2020 for lung SBRT at 60 Gy in 3- or 8-fraction schedules and a controlled primary tumor were retrospectively analyzed.

Results

After a median follow-up of 20.3 months, local failure occurred for 14 lesions, 57 patients experienced lung progression, and 64 patients experienced disease progression. Overall survival rates at 1 and 2 years were 85.6 and 69.7%, respectively. Fifty-two patients experienced radiation pneumonitis, but only 2 patients were symptomatic and presented grade 2 late pneumonitis. No grade 3-4 toxicity was observed. ECOG 0 was the only prognostic factor for overall survival (HR = 3.5; 95% CI 3.2-3.8; p < 0.01).

Conclusion

SBRT with a 60-Gy schedule in 8 fractions is an effective and well-tolerated treatment for patients with lung oligometastases from any solid primary tumor.

Loco-Regional Therapies in Oligometastatic Adrenocortical Carcinoma

Objective: The recommended first-line treatment for low-tumor-burden ACC (stage IVa ACC) not amenable to radical resection is mitotane in association with loco-regional treatments (LRs). The aim of this study was to determine the patient population that would benefit the most from LR. Materials and methods: This retrospective monocentric expert center chart review study was performed from 2008 to 2021 and included stage IVa patients (≤2 tumoral organs) treated with LR (either radiotherapy, surgery, or interventional radiology). The primary endpoint was disease control (DC). Correlations between DC, time to systemic chemotherapy (TTC), overall survival (OS), and tumor characteristics were analyzed using Kaplan−Meier survival analysis and Cox’s proportional hazards regression model for multivariate analysis. Results: Thirty-four women (57%) and 26 men with a median age of 48.1 years (IQR: 38.3−59.8) were included. One hundred and nine LRs were performed, with a median of 2 (IQR: 1−3) per patient. DC was achieved in 40 out of 60 patients (66.7%). Patients with DC had a significantly longer TTC (HR: 0.27, p < 0.001) and OS (HR: 0.22, p < 0.001). Patients with less than or equal to 5 metastases (HR: 6.15 (95% CI: 1.88−20.0), p = 0.002) or a maximum metastasis diameter below 3 cm had higher rates of DC (HR: 3.78 (95% CI: 1.09−13.14), p = 0.035). Conclusion: stage IVa ACC patients with ≤5 metastases or a maximum metastasis diameter below 3 cm had favorable responses to LR. We propose the name oligometastatic ACC for this subgroup of patients.

Radiating the prostate bed in relapsed oligometastatic prostate cancer: How comprehensive should we be?

PURPOSE

A subset of patients with high-risk pathological features at radical prostatectomy recur with oligometastatic disease. The aim of this study is to investigate the rate of prostate bed recurrence, with or without history of prostate bed irradiation (PBRT), in oligometastatic prostate cancer (OMPC) patients after metastasis-directed therapy (MDT).

METHODS

We performed a retrospective analysis of hormone-sensitive OMPC patients treated initially with curative-intent radical prostatectomy followed by disease recurrence and metastasis-directed stereotactic ablative radiotherapy (SABR) at our institution. Prostate bed recurrence rates were compared between patients who had PBRT at any point (i.e., before oligometastatic diagnosis or concurrently with MDT) versus those with no history of PBRT.

RESULTS

Seventy-seven patients were included, and 68.8% had received PBRT. There were no significant differences in baseline characteristics between those who had received and had not received PBRT. There were five prostate bed recurrences following MDT, specifically with a 24-month cumulative incidence of 30.4% in patients who did not have PBRT and 2.4% in those who did (p = 0.03). Three of the five recurrences were isolated to the prostate bed at time of recurrence.

CONCLUSIONS

Relapsed oligometastatic prostate cancer patients who have not received maximal local consolidative therapy to the prostate bed may have higher rates of local failure. Prospective studies are warranted investigating when prostate bed irradiation should be considered for patients after radical prostatectomy who ultimately have oligometastatic prostate cancer.

The Role of the CDK4/6 Inhibitor Ribociclib in Locally Advanced and Oligometastatic Hormone Receptor Positive, Her2 Negative, Advanced Breast Cancer: Case Series and Review of the Literature

The recent addition of cyclin-dependent kinase 4 (CDK4) and CDK6 inhibitors to endocrine therapy has remarkably improved the outcome of patients affected with hormone receptor positive (HR+), human epidermal grow factor receptor 2 negative (HER2 -) advanced breast cancer (ABC). Ribociclib showed to be effective across most subgroups, regardless of the number and the site of metastasis. Up to 10% of patients with ABC, reported an oligometastatic condition, recently defined as a slow-volume metastatic disease with limited number and size of metastatic lesions (up to 5 and not necessarily in the same organ), potentially amenable for local treatment, aimed at achieving a complete remission status. Despite the wide use of CDK4/6 inhibitors in HR+, HER2-, ABC treatment, data regarding both locally advanced, inoperable disease and oligometastatic conditions are still poor. We reported a review and case series of HR+, HER2-, ABC patients treated with ribociclib as first-line therapy, for a locally advanced and oligometastatic conditions, reporting an impressive response and good safety profile.

A multidisciplinary management algorithm for brain metastases

The incidence of brain metastases continues to present a management issue despite the advent of improved systemic control and overall survival. While the management of oligometastatic disease (ie, 1-4 brain metastases) with surgery and radiation has become fairly straightforward in the era of radiosurgery, the management of patients with multiple metastatic brain lesions can be challenging. Here we review the available evidence and provide a multidisciplinary management algorithm for brain metastases that incorporates the latest advances in surgery, radiation therapy, and systemic therapy while taking into account the latest in precision medicine-guided therapies. In particular, we argue that whole-brain radiation therapy can likely be omitted in most patients as up-front therapy.

Safety and Efficacy Study of Neoadjuvant Radiohormonal Therapy for Oligometastatic Prostate Cancer: Protocol of an Open-Label, Dose-Escalation, Single-Centre Phase I/II Clinical Trial

BACKGROUND

The optimal treatment for oligometastatic prostate cancer (OMPC) is still on its way. Accumulating evidence has proven the safety and feasibility of radical prostatectomy and local or metastasis-directed radiotherapy for oligometastatic patients. The aim of this trial is to demonstrate the safety and feasibility outcomes of metastasis-directed neoadjuvant radiotherapy (naRT) and neoadjuvant androgen deprivation therapy (naADT) followed by robotic-assisted radical prostatectomy (RARP) for treating OMPC.

METHODS

The present study will be conducted as a prospective, open-label, dose-escalation, phase I/II clinical trial. The patients with oligometastatic PCa will receive 1 month of naADT, followed by metastasis-directed radiation and abdominal or pelvic radiotherapy. Then, radical prostatectomy will be performed at intervals of 4-8 weeks after radiotherapy, and ADT will be continued for 2 years. The primary endpoints of the study are safety profiles, assessed by the Common Terminology Criteria for Adverse Events (CTCAE) 5.0 grading scale, and perioperativemorbidities, assessed by the Clavien-Dindo classification system. The secondary endpoints include positive surgical margin (pSM), biochemical recurrence-free survival (bPFS), radiological progression-free survival (RPFS), postoperative continence, and quality of life (QoL) parameters.

DISCUSSION

The optimal treatment for OMPC is still on its way, prompting investigation for novel multimodality treatment protocol for this patient population. Traditionally, radical prostatectomy has been recommended as one of the standard therapies for localized prostate cancer, but indications have expanded over the years as recommended by NCCN and EAU guidelines. RP has been carried out in some centres for OMPC patients, but its value has been inconclusive, showing elevated complication risks and limited survival benefit. Neoadjuvant radiotherapy has been proven safe and effective in colorectal cancer, breast cancer and other various types of malignant tumors, showing potential advantages in terms of reducing metastatic stem-cell activity, providing clinical downstaging, and reducing potential intraoperative risks. Existing trials have shown that naRT is well tolerated for high-risk and locally-advanced prostate cancer. In this study, we hope to further determine the optimal irradiation dose and patient tolerance for genitourinary, gastrointestinal and systemic toxicities with the design of 3+3 dose escalation; also, final pathology can be obtained following RP to further determine treatment response and follow-up treatment plans.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR1900025743. http://www.chictr.org.cn/showprojen.aspx?proj=43065.

Patient Selection for Local Aggressive Treatment in Oligometastatic Non-Small Cell Lung Cancer

Simple Summary

Since the first introduction of the oligometastatic state with a low burden of metastases in non-small cell lung cancer, accumulating evidence from retrospective and prospective studies has shown that a local aggressive, multimodality treatment may significantly improve the prognosis in these patients. Local aggressive treatment includes a systemic therapy of micrometastatic disease, as well as a radical resection of the primary tumor and surgical resection and/or radiation therapy of distant metastases. However, patient selection and treatment allocation remain a central challenge in oligometastatic disease. In this review, we aimed to address the current evidence on criteria for patient selection for local aggressive treatment in non-small cell lung cancer.

Abstract

One-fourth of all patients with metastatic non-small cell lung cancer presents with a limited number of metastases and relatively low systemic tumor burden. This oligometastatic state with limited systemic tumor burden may be associated with remarkably improved overall and progression-free survival if both primary tumor and metastases are treated radically combined with systemic therapy. This local aggressive therapy (LAT) requires a multidisciplinary approach including medical oncologists, radiation therapists, and thoracic surgeons. A surgical resection of the often advanced primary tumor should be part of the radical treatment whenever feasible. However, patient selection, timing, and a correct treatment allocation for LAT appear to be essential. In this review, we aimed to summarize and discuss the current evidence on patient selection criteria such as characteristics of the primary tumor and metastases, response to neoadjuvant or first-line treatment, molecular characteristics, mediastinal lymph node involvement, and other factors for LAT in oligometastatic NSCLC.

The concept of oligometastatic disease in gastric cancer: reality or fiction?

Positive results in the RENAISSANCE Trial will establish oligometastatic gastric cancer as a real independent entity where total surgical treatment will become the standard of care.

Highlighting the Place of Metastasis-Directed Therapy in Isolated Liver Metastases in Prostate Cancer: A Case Report

Metastatic prostate cancer remains a challenge for clinicians. Metastases involve mainly the bone compartment and can manifest as oligometastatic disease. In this setting, the role of metastasis-directed therapies (MDT) including surgery and/or stereotactic body radiotherapy is currently evaluated. Visceral metastases are less common and have very poor prognosis in mPC. Whether treating isolated visceral metastases such as liver metastases with MDT could increase the prognosis remains unknown. We report the management of a prostate cancer patient who progressed on androgen deprivation therapy with apparition of two liver metastases. We describe the feasibility of combining MDT with abiraterone acetate and prednisone in a patient with metastatic castration-resistant prostate cancer. MDT allowed the interruption of abiraterone acetate, preventing cumulative toxicity of this agent.

Gastrin-Releasing Peptide Receptor Antagonist [68Ga]RM2 PET/CT for Staging of Pre-Treated, Metastasized Breast Cancer

BACKGROUND

Positron emission tomography (PET)/computed tomography (CT) using the gastrin-releasing peptide receptor antagonist [⁶⁸Ga]RM2 has shown to be a promising imaging method for primary breast cancer (BC) with positive estrogen receptor (ER) status. This study assessed tumor visualization by [⁶⁸Ga]RM2 PET/CT in patients with pre-treated ER-positive BC and suspected metastases.

METHODS

This retrospective pilot study included eight female patients with initial ER-positive, pre-treated BC who underwent [⁶⁸Ga]RM2 PET/CT. Most of these patients (seven out of eight; 88%) were still being treated with or had received endocrine therapy. [⁶⁸Ga]RM2 PET/CTs were visually analyzed by two nuclear medicine specialists in consensus. Tumor manifestations were rated qualitatively (i.e., RM2-positive or RM2-negative) and quantitatively using the maximum standardized uptake value (SUVmax). SUVmax values were compared between the two subgroups (RM2-positive vs. RM2-negative).

RESULTS

Strong RM2 binding was found in all metastatic lesions of six patients (75%), whereas tracer uptake in all metastases of two patients (25%) was rated negative. Mean SUVmax of RM2-positive metastases with the highest SUVmax per patient (in lymph node and bone metastases; 15.8 ± 15.1 range: 3.7-47.8) was higher than mean SUVmax of the RM2-negative metastases with the highest SUVmax per patient (in bone metastases; 1.6 ± 0.1, range 1.5-1.7).

CONCLUSIONS

Our data suggest that RM2 binding is maintained in the majority of patients with advanced disease stage of pre-treated ER-positive BC. Thus, [⁶⁸Ga]RM2 PET/CT could support treatment decision in these patients, radiotherapy planning in oligometastatic patients or selection of patients for RM2 radioligand therapy. Further studies with larger patient cohorts are warranted to confirm these findings.

Results of Radiation Therapy as Local Ablative Therapy for Oligometastatic Non-Small Cell Lung Cancer

Oligometastatic cancer is characterized by a limited number of metastatic deposits. Compared with lung cancer patients who have more widespread disease, oligometastatic lung cancer patients have more favorable survival outcomes. Therefore, it has been hypothesized that local ablative therapy (LAT) directed at the metastatic deposits in addition to standard-of-care systemic therapy may further improve survival outcomes in oligometastatic lung cancer patients. One LAT modality that has been utilized in oligometastatic lung cancer is radiation therapy. In particular, ultra-hypofractionated radiotherapy, also known as stereotactic body radiotherapy (SBRT), has been shown to provide excellent local control with a favorable safety profile. Here, we reviewed the retrospective studies and prospective trials that have deployed radiation therapy as LAT in oligometastatic lung cancer, including randomized studies showing benefits for progression-free survival and overall survival with the addition of LAT. We also discuss the impact of targeted therapies and immunotherapy on radiation as LAT.

Metastasis-directed Therapy in Prostate Cancer: Prognostic Significance of the ESTRO/EORTC Classification in Oligometastatic Bone Disease

AIMS

Oligometastatic disease (OMD) represents a spectrum of clinical scenarios and various classification systems have been proposed. Bone-only OMD can occur in patients with advanced prostate cancer and validated decision-making tools are needed to assist patient selection for metastasis-directed therapy. The aim of the present study was to determine the prognostic utility of a classification system for OMD.

MATERIALS AND METHODS

A retrospective review was conducted of all patients with bone-only oligometastatic prostate cancer treated with stereotactic body radiotherapy (SBRT) since November 2011. SBRT was delivered using CyberKnife® and gantry-based linear accelerator platforms. All patients were classified into oligometastatic states based on the European Society for Radiotherapy and Oncology/European Organisation for Research and Treatment of Cancer (ESTRO/EORTC) classification system. Kaplan-Meier and Cox regression analyses were carried out to determine the prognostic utility of this classification system.

RESULTS

In total, 105 patients with 145 osseous metastases were treated over 119 sessions. The median follow-up after SBRT was 23 months (interquartile range 10-39.8). Twelve patients had died after a median time of 31 months. The 3-year metastatic progression-free survival was 23% (95% confidence interval 13-32) and the 3-year overall survival was 88% (95% confidence interval 80-96). Patients in a metachronous oligometastatic state were 4.50 (95% confidence interval 1.19-17.10, P = 0.03) times more likely to experience metastatic progression compared with those with synchronous oligometastases, and 6.69 (95% confidence interval 1.05-42.50, P = 0.04) times more likely to experience any failure. Hazard ratio magnitudes increased for patients in a repeat oligometastatic state. The multivariate model for both metastatic progression-free survival and failure-free survival found prostate-specific antigen doubling time <4 months (P = 0.002; P = 0.05) to independently predict for progression.

CONCLUSION

The ESTRO/EORTC classification of OMD predicts for progression in patients treated with SBRT for bone-only oligometastatic prostate cancer at our institution. Further validation in prospective series over multiple tumour sites is needed. These characterisation factors should be assessed in patients considered for metastasis-directed therapy together with established prognostic features.

Stereotactic Body Radiation Therapy for Oligometastatic Breast Cancer: A Retrospective Multicenter Study

INTRODUCTION

Stereotactic radiotherapy may improve the prognosis of oligometastatic patients. In the literature, there is very little data available that is specific to breast cancer.

MATERIALS AND METHODS

We conducted a multicenter retrospective study. The primary objective was to estimate progression-free survival after stereotactic body radiotherapy (SBRT) using Cyberknife of breast cancer oligometastases. The secondary objectives were to estimate overall survival, local control, and toxicity. The inclusion criteria were oligometastatic breast cancer with a maximum of five lesions distributed in one to three different organs, diagnosed on PET/CT and/or MRI, excluding brain metastases and oligoprogressions. This was combined with systemic medical treatment.

FINDINGS

Forty-four patients were enrolled from 2007 to 2017, at three high-volume cancer centers. The patients mostly had one to two lesion(s) whose most widely represented site was bone (24 lesions or 44.4%), particularly in the spine, followed by liver (22 lesions or 40.7%), then pulmonary lesions (six lesions or 11.1%). The primary tumor expressed estrogen receptors in 33 patients (84.6%); the status was HER2+++ in 7 patients (17.9%). The median dose was 40 Gy (min-max: 15-54) prescribed at 80% isodose, the median number of sessions was three (min-max: 3-10). The median D50% was 42 Gy (min max 17-59). After a median follow-up of 3.4 years, progression-free survival (PFS) at one year, two years, and three years was 81% (95% CI: 66-90%), 58% (95% CI: 41-72%), and 45% (95% CI: 28-60%), respectively. The median PFS was 2.6 years (95% CI: 1.3 - 4.9). Overall survival at three years was 81% (95% CI: 63-90%). The local control rate at two and three years was 100%. Three patients (7.3%) experienced G2 acute toxicity, no grade ≥3 toxicity was reported.

CONCLUSION

The PFS of oligometastatic breast cancer patients treated with SBRT appears long, with low toxicity. Local control is high. SBRT for oligometastases is rarely applied in breast cancer in light of the population in our study. Phase III studies are ongoing.

Oligometastatic Disease Detection with 68Ga-PSMA-11 PET/CT in Hormone-Sensitive Prostate Cancer Patients (HSPC) with Biochemical Recurrence after Radical Prostatectomy: Predictive Factors and Clinical Impact

Metastasis-directed therapy (MDT) in oligometastatic prostate cancer has the potential of delaying the start of androgen deprivation therapy (ADT) and disease progression. We aimed to analyze the efficacy of PSMA-PET/CT in detecting oligometastatic disease (OMD), to look for predictive factors of OMD, and to evaluate the impact of PSMA-PET/CT findings on clinical management. We retrospectively analyzed a homogeneous population of 196 hormone-sensitive prostate cancer patients (HSPC), considered potential candidates for MDT, with a PSMA-PET/CT performed at biochemical recurrence (BCR) after radical prostatectomy (RP). Multivariable logistic regression analysis was performed based on several clinico-pathological factors. Changes in clinical management before and after PSMA-PET/CT were analyzed. The OMD detection rate was 44% for a total positivity rate of 60%. PSMA-PET/CT positivity was independently related to PSA (OR (95% CI), p) (1.7 (1.3-2.3), p < 0.0001) and PSAdt (0.4 (0.2-0.8), p = 0.013), and OMD detection was independently related to PSA (1.6 (1.2-2.2), p = 0.001) and no previous salvage therapy (0.3 (0.1-0.9), p = 0.038). A treatment change was observed in 58% of patients, mostly to perform MDT after OMD detection (60% of changes). This study showed that PSMA-PET/CT is an excellent imaging technique to detect OMD early in HSPC patients with BCR after RP, changing therapeutic management mostly into MDT.

Treatments and Outcomes in Oligometastatic Soft Tissue Soft Sarcoma - A Single Centre Retrospective Analysis

BACKGROUND/AIM

Distinguishing true oligometastatic disease from early polymetastatic disease is vital in patients with soft tissue sarcoma as contemporary treatment strategies differ significantly. Clinical factors such as tumour biology, organ involved, number of lesions, and patient fitness influence clinical decisions.

PATIENTS AND METHODS

A retrospective search of a prospective database identified patients with new distant relapse, treated between 2009 and 2012.

RESULTS

A total of 223 patients were included, and oligometastases were diagnosed in 81 (36%) patients, which were pulmonary in just over half of cases. These were treated with local therapy in 66 of 89 cases, and 7 patients received subsequent treatment for additional oligometastases. Metastasectomy was the most common treatment modality. A total of 16/66 patients (24%) underwent active surveillance for >6 months prior to local therapy.

CONCLUSION

Patients with oligometastatic disease can experience durable disease control with timely multimodality treatment approaches for evolving metastatic disease, where disease biology allows.

PET/CT-Based Salvage Radiotherapy for Recurrent Prostate Cancer After Radical Prostatectomy: Impact on Treatment Management and Future Directions

Biochemical recurrence is a clinical situation experienced by 20 to 40% of prostate cancer patients treated with radical prostatectomy (RP). Prostate bed (PB) radiation therapy (RT) remains the mainstay salvage treatment, although it remains non-curative for up to 30% of patients developing further recurrence. Positron emission tomography with computed tomography (PET/CT) using prostate cancer-targeting radiotracers has emerged in the last decade as a new-generation imaging technique characterized by a better restaging accuracy compared to conventional imaging. By adapting targeting of recurrence sites and modulating treatment management, implementation in clinical practice of restaging PET/CT is challenging the established therapeutic standards born from randomized controlled trials. This article reviews the potential impact of restaging PET/CT on changes in the management of recurrent prostate cancer after RP. Based on PET/CT findings, it addresses potential adaptation of RT target volumes and doses, as well as use of androgen-deprivation therapy (ADT). However, the impact of such management changes on the oncological outcomes of PET/CT-based salvage RT strategies is as yet unknown.

Defining oligometastatic non-small cell lung cancer: concept versus biology, a literature review

Objective

In this review, the concept of (synchronous) oligometastatic disease in patients with non-oncogene-driven non-small cell lung cancer (NSCLC) will be placed in the context of tumor biology and metastatic growth patterns. We will also provide considerations for clinical practice and future perspectives, which will ultimately lead to better patient selection and oligometastatic disease outcome.

Background

The treatment landscape of metastasized NSCLC has moved from "one-size fits all" to a personalized approach. Prognosis has traditionally been poor but new treatment options, such as immunotherapy and targeted therapy, brighten future perspectives. Another emerging development is the recognition of patients with so-called "oligometastatic" state of disease. Oligometastatic disease has been recognized as a distinct clinical presentation in which the tumor is stated to be early in its evolution of metastatic potential. It is suggested that this stage of disease has an indolent course, comes with a better prognosis and therefore could be considered for radical multimodality treatment.

Methods

Narrative overview of the literature synthesizing the findings of literature retrieved from searches of computerized databases, hand searches, and authoritative texts.

Conclusions

Oligometastatic NSCLC is a broad spectrum disease, with a variable prognosis. Although the biology and behavior of "intermediate state" of metastatic disease are not fully understood, there is evidence that a subgroup of patients can benefit from local radical treatment when integrated into a multimodality regime. The consensus definition of oligometastatic NSCLC, including accurate staging, may help to uniform future trials. The preferable treatment strategy seems to sequential systemic treatment with subsequent local radical treatment in patients with a partial response or stable disease. Prognostic factors such as N-stage, number and site of distant metastases, tumor volume, performance status, age, and tumor type should be considered. The local radical treatment strategy has to be discussed in a multidisciplinary team meeting, taking into account patient characteristics and invasiveness of the procedure. However, many aspects remain to be explored and learned about the cancer biology and characteristics of intermediate state tumors.

Diagnostic and prognostic biomarkers in oligometastatic non-small cell lung cancer: a literature review

Objective

This review aims to summarize the possibilities of recently discovered molecular diagnostic techniques in lung cancer, by evaluating their impact on diagnosis, monitoring, and prognosis in oligometastatic disease.

Background

Oligometastatic non-small cell lung cancer (OM-NSCLC) is currently defined based on morphological rather than biological features. Major advances in the detection of molecular biomarkers in cell-free tumoral DNA and the models of oncogene addiction make as feasible an early diagnosis and guide the therapeutic decision-making progress to improve the prognosis.

Methods

This narrative review EXAMINES current approaches of diagnosis, monitoring, and prognosis of OM-NSCLC and describes the fast-evolving therapeutic scenario of this disease. We provide an overview of the powerful capability of liquid biopsy techniques applied to blood and fluid and we focus on the technological advancement of circulant biomolecular factors in OM NSCLC pathology, starting from apparently simpler models such as oncogene addicted tumors to evaluate themselves in the light of treatment with immune-checkpoint inhibitors.

Conclusions

A better understanding of spatial and temporal evolution of oligometastatic diseases would contribute to a more accurate diagnosis and tailored treatment. Data from prospective clinical trials in the early stage of disease, coupled with knowledge of genetic characteristics of lung tumors, are warranted. These efforts would lead to improving the possibility to eradicate the residual disease in these low burden tumoral settings, thus enhancing the definitive cure perspectives.

Stereotactic Body Radiotherapy for Patients with Lung Oligometastatic Disease: A Five-Year Systematic Review

For several years, oligometastatic disease has represented an intermediate state between localized disease accessible to local treatment and multimetastatic disease requiring systemic therapy. The lung represents one of the most common metastatic locations. Stereotactic body radiation therapy (SBRT) appears to be the treatment of choice for these patients. There are few data defining the place of radiotherapy and reporting outcome after SBRT in lung metastases. This 5-year review aimed to determine areas of SBRT usefulness and methods for the management of pulmonary metastasis in oligometastatic patients. A search for articles on PubMed allowed selection of the most relevant studies. Eighteen articles were selected according to pre-established criteria for this purpose. The analysis concludes that SBRT is an effective and safe treatment in selected patients when the disease remains localized from one to three organs.

Local ablative therapy in oncogenic-driven oligometastatic non-small cell lung cancer: present and ongoing strategies-a narrative review

Oligometastatic (OM) disease is defined by a low metastatic tumor spread. OM non-small cell lung cancer (NSCLC) treatment aims to improve the patient's prognosis and quality of life, in an attempt-to-cure objective. Oncogenic-driven metastatic NSCLC accounts for about 20-25% of NSCLCs, with an ever-increasing number of potentially druggable molecular alterations. Due to specific targeted therapy, the care and prognosis of mutated NSCLC is quite different from non-oncogenic-driven NSCLC. However, OM-NSCLC treatment guidelines do not specifically discuss oncogenic-driven OM-NSCLC patients. We conducted a narrative review regarding retrospective and prospective studies published from inception to May 2020 dealing with oncogenic-driven OM-NSCLC in order to: (I) describe the specific patterns of metastatic spread of oncogenic-driven NSCLC (i.e., bone and pleural tropism in EGFR mutated NSCLC and serous and brain metastases in ALK NSCLC); (II) review the low level of current evidence for local ablative therapy (LAT) strategies in patients with oncogenic-driven OM-NSCLC, focusing on the benefit/risk of tyrosine kinase inhibitors (TKI) and LATs combination and (III) present strategies to help to select the best candidate for an attempt-to-cure approach. Finally, the optimal strategy may be to introduce a targeted therapy, then treat all tumor sites with LAT, and finally continue TKI for unknown prolonged duration in an attempt to prolong progression free survival in most patients, improve overall survival for some patients, and potentially lead to a cancer cure for a few patients.

How to optimize the incorporation of immunotherapy in trials for oligometastatic non-small cell lung cancer: a narrative review

Patients with oligometastatic disease (OMD) non-small cell lung cancer (NSCLC) are considered as a subgroup of metastatic NSCLC that can obtain long-term survival or even cure. Oligometastatic refers to a state of a limited number of metastases in a limited number of organs. In clinical guidelines it is stated that patients with oligometastatic NSCLC can benefit from the addition of local radical therapy (LRT) to systemic therapy. With the introduction of minimally invasive surgery, advances in interventional radiology and stereotactic radiotherapy (SRT), LRT is becoming feasible for more and more patients. Furthermore, the introduction of immune checkpoint inhibitors (ICI) in the treatment landscape of advanced NSCLC has improved the survival of these patients. Importantly, the use of ICI in combination with LRT is also of interest in the subgroup of NSCLC patients with OMD. For example, it has been suggested that SRT may synergize with ICI as several preclinical studies reported an increased tumor antigen release, improved antigen presentation, and T-cell infiltration in irradiated tumors. In this narrative review, we describe the current evidence of immunotherapy treatment in OMD NSCLC, with a focus on future trial design and problems that need to be addressed.

Radiation for Oligometastatic Lung Cancer in the Era of Immunotherapy: What Do We (Need to) Know?

Simple Summary

The historical standard treatment of metastatic non-small cell lung cancer (NSCLC) consisted of palliative chemotherapy, with limited influence on survival. With the introduction of immuno- and targeted therapy, the prognosis improved largely. A subset of NSCLC patients with limited metastatic disease, called oligometastatic, might obtain long-term survival by adding a local ablative treatment on all visible disease sites, in addition to the standard systemic treatment. The evidence for this combined treatment is still scarce and comes mainly from the pre-immunotherapy era. As radiotherapy might stimulate the immune system making immunotherapy more efficient, here we review the evidence before and in the era of immunotherapy, and discuss the challenges and prospects of the combined treatment.

Abstract

Oligometastatic cancer is recognized as a separate entity within the spectrum of metastatic disease. It was suggested that patients with oligometastatic disease can obtain long-term survival by giving local ablative therapy (LAT) to all visible disease locations. However, the true extent from which metastatic cancer should be called “oligometastatic” is unknown, although a consensus definition for oligometastatic disease is proposed by research organizations, such as the EORTC (maximum of five metastases in three organs). Different states of the oligometastatic disease are defined, such as synchronous vs. metachronous, oligopersistent vs. oligoprogressive disease. All clinical trials including patients with non-small cell lung cancer (NSCLC) are small and most are not randomized. Two small randomized phase II trials on synchronous disease showed an improvement in progression free survival, with the addition of LAT, and one also demonstrated an overall survival benefit. Immune checkpoint inhibitors (ICI) were not part of the treatment in these trials, while ICI significantly improved long-term outcomes of patients with metastatic NSCLC. Radiotherapy might improve the prognosis of patients treated with ICI because of its immunostimulatory effects and the possibility to eradicate metastatic deposits. Here, we summarize the data for adding ablative radiotherapy to the treatment of oligometastatic NSCLC, especially in the ICI era, and discuss the challenges of combined treatment.

Rapid Development of Clinically Symptomatic Radiation Recall Pneumonitis Immediately Following COVID-19 Vaccination

In this report, we present the case of a 66-year-old man who received local consolidation radiotherapy to the right lung and mediastinum for oligometastatic non-small cell lung cancer (NSCLC) following partial response to upfront chemoimmunotherapy. He continued with maintenance immunotherapy and was asymptomatic for eight months after completing radiation therapy. He then developed symptoms consistent with pneumonitis within three to five days of his first administration of the coronavirus disease 2019 (COVID-19) vaccine injection. He reported that these symptoms significantly intensified within three to five days of receiving his second dose of the vaccine. The clinical time frame and radiographic evidence raised suspicion for radiation recall pneumonitis (RRP). Patients undergoing maintenance immunotherapy after prior irradiation may be at increased risk of this phenomenon that may be triggered by the administration of the COVID-19 vaccine.

Abscopal effect as part of treatment of oligometastatic head and neck cancer: A case report

A 66-year-old man with hypopharyngeal carcinoma with a single bone metastasis was treated with definitive chemo/radiotherapy omitting local treatment of the single bone lesion. He remained relapse-free for 6 years. We have concluded that radiotherapy-dependent abscopal effect might have allowed to avoid ablative treatment of metastatic site.

Survival Impact of Aggressive Treatment and PD-L1 Expression in Oligometastatic NSCLC

Background: Studies have shown that aggressive treatment of non-small cell lung cancer (NSCLC) with oligometastatic disease improves the overall survival (OS) compared to a palliative approach and some immunotherapy checkpoint inhibitors, such as anti-programmed cell death ligand 1 (PD-L1), anti-programmed cell death protein 1 (PD-1), and T-Lymphocyte-associated antigen 4 (CTLA-4) inhibitors are now part of the standard of care for advanced NSCLC. However, the prognostic impact of PD-L1 expression in the oligometastatic setting remains unknown. Methods: Patients with oligometastatic NSCLC were identified from the patient database of the Centre hospitalier de l’Université de Montréal (CHUM). “Oligometastatic disease” definition chosen is one synchronous metastasis based on the M1b staging of the eight IASLC (The International Association for the Study of Lung Cancer) Classification (within sixth months of diagnosis) or up to three cerebral metastasis based on the methodology of the previous major phase II randomized study of Gomez et al. We compared the OS between patients receiving aggressive treatment at both metastatic and primary sites (Group A) and patients receiving non-aggressive treatment (Group B). Subgroup analysis was performed using tumor PD-L1 expression. Results: Among 643 metastatic NSCLC patients, we identified 67 patients with oligometastasis (10%). Median follow-up was 13.3 months. Twenty-nine patients (43%) received radical treatment at metastatic and primary sites (Group A), and 38 patients (57%) received non-aggressive treatment (Group B). The median OS (mOS) of Group A was significantly longer than for Group B (26 months vs. 5 months, p = 0.0001). Median progression-free survival (mPFS) of Group A was superior than Group B (17.5 months vs. 3.4 months, p = 0.0001). This difference was still significant when controlled for primary tumor staging: stage I (p = 0.316), stage II (p = 0.024), and stage III (p = 0.001). In the cohort of patients who were not treated with PD-L1 inhibitors, PD-L1 expression negatively correlated with mOS. Conclusions: Aggressive treatments of oligometastatic NSCLC significantly improve mOS and mPFS compared to a more palliative approach. PD-L1 expression is a negative prognostic factor which suggests a possible role for immunotherapy in this setting.

The role of immunotherapy in combination with oligometastasis-directed therapy: a narrative review

Metastatic disease is a significant cause of morbidity and mortality among patients with cancer. Patients with oligometastatic cancer represent a subset of the metastatic population with a limited amount of disease that has metastasized distantly and progresses at a slow pace and thus has the potential to be cured with metastasis-directed local therapy. Recent studies examining the role of metastasis-directed therapy in patients with oligometastatic disease have primarily focused upon treatment with ablative doses of radiation, commonly referred to as stereotactic body radiation therapy (SBRT). While the use of SBRT to treat oligometastases has increased considerably in recent years, the benefit of this approach has yet to be confirmed in phase III randomized controlled trials; moreover, distant failure remains a significant problem in patients with oligometastatic disease treated with SBRT. Given the propensity for distant failure in patients with oligometastatic disease treated with SBRT, there is growing interest in the utility of combining SBRT with systemic agents such as immunotherapy. Immunotherapy, and specifically immune checkpoint blockade (ICB), represents a rapidly evolving systemic therapy option with a growing number of indications among patients with metastatic disease; however, despite its promise, only a minority of patients respond to ICB and among those who do, the majority eventually progress. SBRT and ICB are both dependent upon, and have the ability to shift, the balance between antitumor immune surveillance and immunosuppressive states in the tumor and tumor microenvironment. As a result, it has been speculated that SBRT and ICB have the potential to act synergistically when used in combination. SBRT has been demonstrated to be safe in combination with ICB in studies with short-term follow-up and although additional research is needed, preliminary prospective data support the potential efficacy of this approach. In addition to confirming the safety and efficacy of SBRT in combination with immunotherapy, further studies are needed to determine how to maximize the therapeutic ratio of this treatment paradigm for the full potential of immunotherapy in the oligometastatic population to be realized.

Oligometastatic Disease Management: Finding the Sweet Spot

Hematogenous dissemination represents a common manifestation of squamous cell carcinoma of the head and neck, and the recommended therapeutic options usually consist of systemically administered drugs with palliative intent. However, mounting evidence suggests that patients with few and slowly progressive distant lesions of small size may benefit from various local ablation techniques, which have already been established as standard-of-care modalities for example in colorectal and renal cell carcinomas and in sarcomas. In principle, serving as radical approaches to eradicate cancer, these interventions can be curative. Their impact on local control and overall survival has been shown in numerous retrospective and prospective studies. The term oligometastatic refers to the number of distant lesions which should generally not surpass five in total, ideally in one organ. Currently, surgical resection remains the method of choice supported by the majority of published data. More recently, stereotactic (ablative) body radiotherapy (SABR/SBRT) has emerged as a viable alternative. In cases technically amenable to such local interventions, several other clinical variables need to be taken into account also, including patient-related factors (general health status, patient preferences, socioeconomic background) and disease-related factors (primary tumor site, growth kinetics, synchronous or metachronous metastases). In head and neck cancer, patients presenting with late development of slowly progressive oligometastatic lesions in the lungs secondary to human papillomavirus (HPV)-positive oropharyngeal cancer are the ideal candidates for metastasectomy or other local therapies. However, literature data are still limited to say whether there are other subgroups benefiting from this approach. One of the plausible explanations is that radiological follow-up after primary curative therapy is usually not recommended because its impact on survival has not been unequivocal, which is also due to the rarity of oligometastatic manifestations in this disease. At the same time, aggressive treatment of synchronous metastases early in the disease course should be weighed against the risk of futile interventions in a disease with already multimetastatic microscopic dissemination. Therefore, attentive treatment sequencing, meticulous appraisal of cancer extension, refinement of post-treatment surveillance, and understanding of tumor biology and kinetics are crucial in the management of oligometastases.

Metastatic salivary gland carcinoma: A role for stereotactic body radiation therapy? A study of AIRO-Head and Neck working group

OBJECTIVES

The role of radiotherapy (RT) for oligometastases is currently established in different oncological settings but data on salivary gland cancer (SGC) are lacking. We evaluated the role of RT in oligometastatic SGC patients, focusing on stereotactic body radiation therapy (SBRT).

MATERIALS AND METHODS

We performed a retrospective, multicentric study of oligometastatic SGC treated with palliative RT or SBRT. Endpoints included response evaluation and local control (LC).

RESULTS

Between 2006 and 2016, 64 patients were collected from 9 Italian Cancer Centers, on behalf of the Italian Association of Radiotherapy and Clinical Oncology (AIRO) Head and Neck Working Group. 37 patients (57.8%) were suffering from adenoid cystic carcinoma (ACC) and 27 patients (42.2%) had non-ACC. Thirty-four patients underwent palliative RT (53,1%), and 30 received SBRT (46,9%). Most common metastatic sites were bone for palliative RT and lung for SBRT. Among patients treated with SBRT, an objective response or a stability was observed in all treated lesions. After a median follow-up of 29.2 months (range 2.3-117.1), LC at 12 months was 57.5% for patients treated with SBRT and was higher in ACC subgroup.

CONCLUSION

We confirmed the potential role of SBRT in the management of oligometastatic SGC patients to control limited burden of disease considering the absence of effective systemic therapies.