Combination of Stereotactic Ablative Radiotherapy With Anti-PD-1 in Oligoprogressive Non-Small-Cell Lung Cancer And Melanoma: Results of a Prospective Multicenter Observational Study

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

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

Is Local Ablative Stereotactic Radiation Therapy a Valuable Rescue Strategy for Time on Drug in Patients Enrolled in Phase I Trials?

PURPOSE

Patients with advanced tumors enrolled in phase I trials display strong treatment expectations and few therapeutic alternatives. When oligoacquired resistance (OAR; ≤3 lesions of disease progression) occurs, local ablative stereotactic radiation therapy (SRT) could allow disease control and continuing the experimental systemic treatment.

METHODS AND MATERIALS

Data from patients enrolled in phase I trials evaluating systemic treatments, who experienced OAR while on the phase I systemic therapy and subsequently received SRT between January 2014 and April 2023, were retrospectively analyzed. Progression-free survival (PFS)1 (trial entry to OAR), PFS2 (SRT to first subsequent relapse), time to next systemic treatment (TTNT), and overall survival (OS) were assessed. First subsequent patterns of relapse after SRT were distinguished as OAR2, which could be locally rechallenged, or systemic acquired resistance (SAR; >3 lesions of disease progression). When available, correlations between molecular profile and pathway enrichments of OAR and SAR were explored.

RESULTS

Forty-two patients with 52 oligoprogressive lesions were analyzed. The median follow-up was 24 months. SRT allowed a median PFS2 of 7.1 months and a median TTNT of 12.8 months. PFS2 included 49% OAR2 and 51% SAR. Median time to first subsequent relapse (9.6 vs 3.5 months; P = .014) and TTNT (22.4 vs 7.6 months; P < .001) were longer for OAR2 compared with that for SAR. No severe toxicities were reported. A PFS1 of <6 months and de novo oligoprogressive lesions were associated with the presence of SAR. More diverse enriched gene pathways were observed for SAR compared with that for OAR2.

CONCLUSIONS

In patients enrolled in phase I trials, OAR managed with SRT may increase time on investigational systemic treatments. Predictive factors reflecting tumor aggressiveness and clonal heterogeneity could help deciphering OAR2 from SAR and maximize SRT output in the oligoprogressive setting.

Association between tumor cell in air space and treatment outcomes in early-stage lung cancer treated with stereotactic body radiation therapy

Background and purpose

Spread-through air space (STAS) is an unfavorable factor in patients with lung cancer treated with surgery. However, the relationship between the treatment outcomes of stereotactic body radiation therapy (SBRT) for lung cancer and STAS has not been adequately investigated. This study aimed to evaluate the impact of tumor cells in the air space (TCIAS), which show a STAS burden, on treatment outcomes in patients with early-stage lung cancer treated with SBRT.

Materials and methods

Data of patients who underwent SBRT for early-stage lung cancer treated with SBRT were retrospectively reviewed. The influence of the TCIAS status on local progression-free (LPF), regional failure-free (RFF), distant failure-free (DFF), progression-free survival (PFS), and overall survival (OS) rates was assessed using univariate and multivariate analyses.

Results

Overall, 68 patients were included. The median follow-up time was 24.3 months. For patients positive/negative for TCIAS, the 2-year LPF, RFF, DFF, PFS, and OS rates were 81.4 %/91.1 %, 73.7 %/96.2 %, 55.9 %/75.3 %, 55.0 %/84.6 %, and 67.8 %/92.2 %, respectively. In the multivariate analysis, TCIAS-positive was a significant unfavorable factor for RFF (hazard ratio [HR]: 4.10; 95 % confidence interval [CI]: 1.04-16.16, p = 0.04), DFF (HR: 2.61, 95 % CI: 1.03-6.57, p = 0.04), and PFS (HR: 2.36; 95 % CI: 1.05-5.30, p = 0.04). By contrast, TCIAS-positive was not a significant risk factor for LPF and OS.

Conclusion

TCIAS-positive is an unfavorable factor for regional and distant failure after SBRT. TCIAS status may be useful in predicting the treatment outcome of SBRT for early-stage lung cancer.

Beyond success: unveiling the hidden potential of radiotherapy and immunotherapy in solid tumors

Immunotherapy, particularly with immune checkpoint inhibitors, has significantly transformed cancer treatment. Despite its success, many patients struggle to respond adequately or sustain long-lasting clinical improvement. A growing consensus has emerged that radiotherapy (RT) enhances the response rate and overall efficacy of immunotherapy. Although combining RT and immunotherapy has been extensively investigated in preclinical models and has shown promising results, establishing itself as a dynamic and thriving area of research, clinical evidence for this combination strategy over the past five years has shown both positive and disappointing results, suggesting the need for a more nuanced understanding. This review provides a balanced and updated analysis of the combination of immunotherapy and RT. We summarized the preclinical mechanisms through which RT boosts antitumor immune responses and mainly focused on the outcomes of recently updated clinical trials, including those that may not have met expectations. We investigated the optimization of the therapeutic potential of this combined strategy, including key challenges, such as fractionation and scheduling, lymph node irradiation, and toxicity. Finally, we offered insights into the prospects and challenges associated with the clinical translation of this combination therapy, providing a realistic perspective on the current state of research and potential future directions.

Systematic review of the efficacy of stereotactic ablative radiotherapy for oligoprogressive disease in metastatic cancer

BACKGROUND

Stereotactic Ablative Radiotherapy (SABR) for the treatment of oligometastatic disease can improve survival and delay the requirement for systemic therapy. The benefits of SABR in oligoprogressive disease are less well-defined. Here, we evaluate the available evidence investigating the efficacy of SABR in the treatment of oligoprogressive disease.

METHODS

A systematic review was carried out following PRISMA guidelines. Medline and Embase databases were searched using the terms "stereotactic radiotherapy" OR "SABR" OR "Stereotactic Ablative Body Radiotherapy" OR "SBRT" OR "SRT" AND "oligoprogression" in May 2022, June 2023, and February 2024. Studies were excluded where: SABR was used as a radical treatment, a specific oligoprogressive cohort could not be identified, publication was as a conference abstract or where fewer than 10 patients were recruited. Studies treating only brain metastases were also excluded. The site of primary tumour, oligoprogressive sites, rates of overall survival (OS), progression free survival (PFS), local control (LC) and time to next systemic therapy were collected.

RESULTS

Thirty-three full text studies were included. These consisted of single centre and multi-institutional observational studies, case series and phase II trials. Twenty-two studies were related to a specific tumour type: 12 urological cancer (9 prostate, 3 renal cancer), 6 non-small cell lung cancer, 2 colorectal cancer, 2 breast cancer and 11 were studies covering multiple tumour sites (5 studies involving SABR to a single organ and 6 studies involving SABR to multi-organ). Median PFS was >6 months in patients with oligoprogressive prostate, non-small cell lung cancer and renal cancer patients.

CONCLUSIONS

SABR appears to have clinical benefit in oligoprogresssive prostate, lung, and renal patients. However, the optimal management of patients with oligoprogressive disease is still somewhat uncertain due to lack of prospective data. This will hopefully become clearer in the near future with the publication of further randomised trials.

Deciphering and overcoming Anti-PD-1 resistance in Melanoma: A comprehensive review of Mechanisms, biomarker Developments, and therapeutic strategies

Worldwide, tens of thousands of people die from melanoma each year, making it the most frequently fatal form of cutaneous cancer. Immunotherapeutic advancements, particularly with anti-PD-1 medications, have significantly enhanced treatment outcomes over recent decades. With the broad application of anti-PD-1 therapies, insights into the mechanisms of resistance have evolved. Despite the development of combination treatments and early predictive biomarkers, a comprehensive synthesis of these advancements is absent in the current literature. This review underscores the prevailing knowledge of anti-PD-1 resistance mechanisms and underscores the critical role of robust predictive biomarkers in stratifying patients for targeted combinations of anti-PD-1 and other conventional or innovative therapeutic approaches. Additionally, we offer insights that may shape future melanoma treatment strategies.

Novel Blood Biomarkers for Response Prediction and Monitoring of Stereotactic Ablative Radiotherapy and Immunotherapy in Metastatic Oligoprogressive Lung Cancer

Up to 80% of patients under immune checkpoint inhibitors (ICI) face resistance. In this context, stereotactic ablative radiotherapy (SABR) can induce an immune or abscopal response. However, its molecular determinants remain unknown. We present early results of a translational study assessing biomarkers of response to combined ICI and SABR (I-SABR) in liquid biopsy from oligoprogressive patients in a prospective observational multicenter study. Cohort A includes metastatic patients in oligoprogression to ICI maintaining the same ICI due to clinical benefit and who receive concomitant SABR. B is a comparative group of oligometastatic patients receiving only SABR. Blood samples are extracted at baseline (T1), after the first (T2) and last (T3) fraction, two months post-SABR (T4) and at further progression (TP). Response is evaluated by iRECIST and defined by the objective response rate (ORR)-complete and partial responses. We assess peripheral blood mononuclear cells (PBMCs), circulating cell-free DNA (cfDNA) and small RNA from extracellular vesicles. Twenty-seven patients could be analyzed (cohort A: n = 19; B: n = 8). Most were males with non-small cell lung cancer and one progressing lesion. With a median follow-up of 6 months, the last ORR was 63% (26% complete and 37% partial response). A decrease in cfDNA from T2 to T3 correlated with a good response. At T2, CD8+PD1+ and CD8+PDL1+ cells were increased in non-responders and responders, respectively. At T2, 27 microRNAs were differentially expressed. These are potential biomarkers of response to I-SABR in oligoprogressive disease.

Solid tumours showing oligoprogression to immune checkpoint inhibitors have the potential for abscopal effects

PURPOSE

Given the uncertainty surrounding the abscopal effect (AE), it is imperative to identify promising treatment targets. In this study, we aimed to explore the incidence of AE when administering radiotherapy to patients with oligoprogressive solid tumours while they are undergoing treatment with immune checkpoint inhibitors (ICIs).

MATERIALS AND METHODS

In this multicentre prospective observational study, oligoprogressive disease was defined as a < 20% increase in lesions compared to > 2 months before enrolment. We enrolled patients who requested radiotherapy during the ICI rest period between 2020 and 2023. AE was considered present if ≥ 1 non-irradiated lesion decreased by ≥ 30% before the next line of systemic therapy started.

RESULTS

Twelve patients were included in this study; the common primary lesions were in the lungs (four patients) and kidneys (three patients). AEs were observed in six (50%) patients, with a median time to onset of 4 (range 2-9) months after radiotherapy. No significant predictors of AEs were identified. Patients in the AE group had a significantly better 1-year progression-free survival (PFS) rate than those in the non-AE group (p = 0.008). Two patients from the AE group were untreated and progression-free at the last follow-up. Four (33%) patients experienced grade 2 toxicity, with two cases attributed to radiotherapy and the other two to ICI treatment. No grade 3 or higher toxicities were observed in any category.

CONCLUSION

Patients with oligoprogressive disease may be promising targets with potential for AEs. AEs can lead to improved PFS and, in rare cases, to a certain progression-free period without treatment. Irradiating solid tumours in patients with oligoprogressive disease during immune checkpoint inhibitor therapy may be a promising target with the potential for abscopal effects (AEs). AEs can lead to improved progression-free survival and, in rare cases, to a certain progression-free period without treatment.

The Next Chapter in Immunotherapy and Radiation Combination Therapy: Cancer-Specific Perspectives

Immunotherapeutic agents have revolutionized cancer treatment over the past decade. However, most patients fail to respond to immunotherapy alone. A growing body of preclinical studies highlights the potential for synergy between radiation therapy and immunotherapy, but the outcomes of clinical studies have been mixed. This review summarizes the current state of immunotherapy and radiation combination therapy across cancers, highlighting existing challenges and promising areas for future investigation.

Radiotherapy to reinvigorate immunotherapy activity after acquired resistance in metastatic non-small-cell lung cancer: A pooled analysis of two institutions prospective phase II single arm trials

AIM

The current work aimed to investigate the clinical benefit of radiotherapy in patients with metastatic non-small cell lung cancer (NSCLC) developing acquired resistance to immune checkpoint inhibitors.

METHOD

We report on a pooled, two-institution, phase II single-arm prospective cohort study. The study included patients with stage IV NSCLC who showed progression of one or more measurable lesions under anti-PD-(L)1 inhibition alone, after initially having achieved at least stable disease. Hypofractionated radiotherapy (hRT) of one to four metastases was performed, while one or more lesions were kept untreated. Following hRT, treatment with immune checkpoint inhibitors was continued unchanged until further evidence of tumor progression or unacceptable toxicity. Primary endpoint of the pooled analysis was progression-free survival (PFS), secondary endpoints included overall survival (OS) and toxicity.

RESULTS

A total of 48 patients were enrolled: mean age was 67.1 ± 9.3 years, 50 % were male and 72.9 % were PD-L1 positive. Immunotherapy was in 95.8 % of patients the first or second line therapy at time of enrollment. hRT was performed to one (93.8 % of cases) or more lesions (median total dose: 27.5 Gy, median 6.5 Gy/fraction). Forty-five patients (93.8 %) were able to continue immunotherapy for a median of 6.2 months following hRT. Median PFS was 4.4 months, with 62.5 % disease control at three months and 37.5 % at six months. Median OS was 14.9 months. Severe adverse events (grade ≥ 2) were reported in 12 cases (25 %), of which none were radiotherapy-related and four were immunotherapy-related. Salvage therapy consisted of chemotherapy (48.8 %) or repeated irradiation (21.9 %). No further tumor treatment was performed in 29.3 % of patients.

CONCLUSIONS

The current pooled analysis is a prospective evaluation of the role of radiation therapy for metastatic NSCLC in the setting of newly acquired immunotherapy resistance. Hypofractionated radiotherapy can support the outcome of immune checkpoint inhibitors and thus allow continuation of treatment for a relevant amount of time despite initial tumor progression.

Radiotherapy with or without immunotherapy in metastatic melanoma: efficacy and tolerability

INTRODUCTION

Radiotherapy (RT) is primarily considered as a palliative treatment in patients with metastatic melanoma. However, observations suggest that when RT is combined with immune checkpoint inhibitors (ICI), it can induce an immune response leading to an anti-tumoral effect also distant from the irradiated area - a phenomenon called 'abscopal effect'. The frequency and circumstances of abscopal effect among metastatic melanoma patients remains uncertain and further research is necessary.

MATERIAL AND METHOD

This retrospective study included all metastatic melanoma patients who received non-stereotactic RT in Stockholm, Sweden in 2015-2020. Patients were grouped depending on if RT was given at start of ICI (RT + ICI(start)), at ICI progression (RT + ICI(salvage)) or without ICI (RT(only)). Response rates in irradiated (RR(irradiated)) and overall response rates in non-irradiated (ORR(non-irradiated)) metastases were evaluated together with survival and toxicity in each cohort.

RESULTS

In the RT + ICI(start) (n = 47), RT + ICI(salvage) (n = 41) and RT(only) (n = 55) cohorts, RR(irradiated) was 70.7%, 67.5% and 43.1% (p = 0.018) while the ORR(non-irradiated) was 36.1%, 14.8% and 0.0% (p = 0.003), and the median overall survival was 18.2, 15.0 and 7.2 months, respectively (p = 0.014). Local response to RT was in all cohorts associated with longer survival (p < 0.001). The frequency of grade ≥3 immune-related adverse events was 17.0% and 19.5% in the RT + ICI(start) and RT + ICI(salvage) cohorts. No increased frequency of RT-related adverse events was seen in the RT + ICI cohorts, compared to the RT(only) cohort.

CONCLUSION

This retrospective study showed that melanoma patients receiving RT in combination with ICI had a superior antitumoral response in both irradiated and non-irradiated lesions as compared to patients receiving only RT. Additionally, a subgroup of patients receiving RT when progressing on ICI experienced tumor regression also in non-irradiated areas.

Local control strategies for management of NSCLC with oligoprogressive disease

Progresses of systemic treatments in advanced non-small cell lung cancer (NSCLC), such as immune checkpoint blockers (ICB) and targeted therapies, led to the increased incidence of oligoprogressive disease (OPD). The OPD is a subtype of oligometastatic disease (OMD) defined as a progression of a limited number of lesions during systemic treatment exposure. The hypothesis was formulated that local radical treatments (LRT) could eradicate progressive lesions resulting from resistant clones, ultimately leading to systemic treatment sensitivity restoration. Recently published international consensuses and guidelines aim to obtain a uniform definition of OMD NSCLC, to standardize the inclusion of these patients in future clinical trials, as well as their management in daily practice. Although there is no specific definition of OPD, LRT strategies in OPD are supported after reporting promising results. Both retrospective and preliminary prospective randomized data of LRT for patients with OPD NSCLC are encouraging. More clinical and translational data are needed for selecting best scenarios where LRT should be delivered. In this review, we analyze the current available literature on LRT for patients with OPD in advanced NSCLC and discuss about future trial design and challenges.

Combining stereotactic body radiotherapy with immunotherapy in stage IV non-small cell lung cancer

Immunotherapy has revolutionized the treatment of metastatic non-small cell lung cancer (NSCLC). Oligometastasis has been associated with better prognosis than widespread metastatic disease and may be curable by stereotactic body radiotherapy (SBRT). SBRT can stimulate immunogenic anti-tumor activity, which can be further augmented when combined with immunotherapy, such as immune checkpoint inhibitors (ICIs). Thus, its combination with immunotherapy was recognized as a promising treatment option, especially in the metastatic setting. However, the most optimal approach to combine SBRT with immunotherapy remains controversial with early clinical evidence emerging. Here, we review the current clinical evidence supporting the combination of SBRT with immunotherapy in the treatment of metastatic NSCLC. Also, we discuss the current controversies and areas for further exploration associated with this treatment strategy.

Oligorecurrent Non-Small-Cell Lung Cancer Treated by Chemo-Radiation Followed by Immunotherapy and Intracranial Radiosurgery: A Case Report and Mini Review of Literature

Locally advanced non-small-cell lung cancer still represents a "grey zone" in terms of the best treatment choice and optimal clinical outcomes. Indeed, most patients may be suitable to receive different treatments with similar outcomes such as chemo-radiotherapy (CHT-RT) followed by immunotherapy (IO) or surgery followed by adjuvant local/systemic therapies. We report a clinical case of a patient submitted to primary thoracic surgery who developed a mediastinal nodal recurrence successfully treated by CHT-RT-IO. Subsequently, a single brain lesion was found to have been successfully treated by single fraction stereotactic ablative radiotherapy. The patient is still on follow-up and she is free from disease having a good quality of life. In this report, we also perform a mini review about the role of CHT-RT followed by IO in treating loco-regional relapse after surgery. The role of SABR after IO is also evaluated, finding that it is safe and well tolerated. More robust and larger clinical data are needed in this particular setting to better define the role of the combination of systemic and local treatments in the management of intrathoracic and intracranial relapse for patients already submitted to CHT-RT followed by immunotherapy.

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.

Abscopal Effect after Stereotactic Body Radiotherapy with Nivolumab for Lung Metastasis of Head and Neck Cancer: A Case Report

Introduction

The abscopal effect (AE) is a phenomenon, in which radiotherapy exerts an antitumour effect on distant lesions outside the primary irradiated area. Although immune checkpoint inhibitors have been widely studied for their potential to enhance the AE and improve patient outcomes, findings in cases of head and neck cancers remain limited.

Case Presentation

We report the case of a 72-year-old man who experienced lung oligoprogression during nivolumab treatment for metastatic hypopharyngeal cancer. Stereotactic body radiotherapy (SBRT) was administered to one of the lung lesions, after which both irradiated and nonirradiated lesions regressed. Upon an 18-month follow-up period after SBRT, the patient showed no disease progression or toxicity, and continued receiving nivolumab therapy.

Conclusion

The intent behind presenting this case report was to contribute to the accumulation of evidence regarding the AE in cases of head and neck cancer.

Atypical Response in Metastatic Non-Small Cell Lung Cancer Treated with PD-1/PD-L1 Inhibitors: Radiographic Patterns and Clinical Value of Local Therapy

PURPOSE

To explore the clinical characteristics, management, and survival outcomes of advanced NSCLC patients treated with PD-1/PD-L1 inhibitors who presented with an atypical response (AR).

METHODS

A total of 926 PD-1/PD-L1-inhibitor-treated patients with metastatic NSCLC from three academic centers were retrospectively reviewed. All measurable lesions were evaluated by RECIST version 1.1.

RESULTS

Fifty-six (6.1%) patients developed AR. The median time to the occurrence of AR was 2.0 months. Patients with no fewer than 3 metastatic organs at baseline were more prone to develop AR in advanced NSCLC (p = 0.038). The common sites of progressive lesions were lymph nodes (33.8%) and lungs (29.7%). The majority (78.2%) of patients with AR had only 1-2 progressive tumor lesions, and most (89.1%) of the progressive lesions developed from originally existing tumor sites. There was no significance in terms of survival between patients with AR and those with typical response (TR). Local therapy was an independent predictor for PFS of patients with AR (p = 0.025).

CONCLUSIONS

AR was not an uncommon event in patients with metastatic NSCLC treated with PD-1/PD-L1 inhibitors, and it had a comparable prognosis to those with TR. Proper local therapy targeting progressive lesions without discontinuing original PD-1/PD-L1 inhibitors may improve patient survival.

The oligometastatic spectrum in the era of improved detection and modern systemic therapy

Metastases remain the leading cause of cancer-related mortality. The oligometastasis hypothesis postulates that a spectrum of metastatic spread exists and that some patients with a limited burden of metastases can be cured with ablative therapy. Over the past decade, substantial advances in systemic therapies have resulted in considerable improvements in the outcomes of patients with metastatic cancers, warranting re-examination of the oligometastatic paradigm and the role of local ablative therapies within the context of the improved therapeutic responses, shifting patterns of disease recurrence and possible synergy with systemic treatments. Herein, we reframe the oligometastatic phenotype as a dynamic state for which locally ablative, metastasis-directed therapy improves clinical outcomes, including by prolonging survival and increasing cure rates. Important risk factors defining the metastatic spectrum are highlighted that inform both staging and therapy. Finally, we synthesize the literature on combining local therapies with modern systemic treatments, identifying general themes to optimally integrate ablative therapies in this context.