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

AIMS

Evidence shows stereotactic ablative body radiotherapy (SABR) is used as a non-invasive ablative therapy in the treatment of multisite oligometastatic (OM) and oligoprogressive (OP) diseases originating from metastatic breast cancer. This study aims to report the treatment outcomes and to investigate what factors that are prognostic in terms of local control, progression-free survival (PFS) and overall survival (OS) in patients receiving SABR for extracranial OM and OP diseases originating from metastatic breast cancer.

MATERIALS AND METHODS

A retrospective review on treatment records of patients with OM and OP from metastatic breast cancer who underwent SABR at a single was carried out. SABR was performed with daily image-guided radiotherapy (IGRT) using a dedicated robotic SABR machine. Local control, PFS and OS were calculated using Kaplan-Meier statistics and the post-treatment toxicity data was scored following the CTCAE v4.0 protocol. Univariate and multivariate Cox regression tests were used in the subgroup analysis of prognostic factors on PFS and OS including patients' age, types of follow-up imaging (staging CT only vs whole-body MR/PET), metastases status (OM vs OP), primary breast cancer tumour grade, hormone receptors (ER/PR/HER2) status, change of systemic treatments at SABR, number of metastases, SABR treatment sites and doses.

RESULTS

56 metastatic breast cancer patients (38 patients with OM and 18 patients with OP) were involved in this retrospective review. The median follow-up was 35.6 months (range 4.0-132.9 months). The estimated local control at 1 , 2 and 5 years were 90.9%, 88.7% and 88.7%, respectively. The estimated median PFS was 19.2 months (95%CI 10.3-28.1 months); the PFS at 1, 2 and 5 years were 63.3%, 44.4% and 33.2%. The estimated OS at 1, 2 and 5 years were 98.0%, 91.9% and 74.3%, respectively with the estimated median OS of 105.1 months (95%CI 51.5-158.7 months). The vast majority of patients tolerated the treatment well with the commonest acute side effects as grade 1 fatigue. There were no statistically significant factors found in OS regression analysis. The types of follow-up imaging, metastases status, oestrogen receptor status, and number of metastases for SABR were statistically significant factors (p < 0.05) in the multivariate Cox regression analysis on PFS.

CONCLUSION

There are limited studies published on the efficacy and post-treatment toxicities of metastatic breast cancer OM and OP SABR with adequate length of follow-up. This study confirmed that SABR was a safe, non-invasive treatment option for patients with extracranial OM and OP diseases originated from primary breast cancer in terms of the acceptable post-treatment toxicities.

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.

Stereotactic Body Radiotherapy for Extracranial Oligometastatic Disease from Head and Neck Primary Cancers: A Systematic Review and Meta-Analysis

INTRODUCTION

Stereotactic body radiotherapy (SBRT) is increasingly used to treat disease in the oligometastatic (OM) setting due to mounting evidence demonstrating its efficacy and safety. Given the low population representation in prospective studies, we performed a systematic review and meta-analysis of outcomes of HNC patients with extracranial OM disease treated with SBRT.

METHODS

A systematic review was conducted with Cochrane, Medline, and Embase databases queried from inception to August 2022 for studies with extracranial OM HNC treated with stereotactic radiotherapy. Polymetastatic patients (>five lesions), mixed-primary cohorts failing to report HNC separately, lack of treatment to all lesions, nonquantitative endpoints, and other definitive treatments (surgery, conventional radiotherapy, and radioablation) were excluded. The meta-analysis examined the pooled effects of 12- and 24-month local control (LC) per lesion, progression-free survival (PFS), and overall survival (OS). Weighted random-effects were assessed using the DerSimonian and Laird method, with heterogeneity evaluated using the I2 statistic and Cochran Qtest. Forest plots were generated for each endpoint.

RESULTS

Fifteen studies met the inclusion criteria (639 patients, 831 lesions), with twelve eligible for quantitative synthesis with common endpoints and sufficient reporting. Fourteen studies were retrospective, with a single prospective trial. Studies were small, with a median of 32 patients (range: 6-81) and 63 lesions (range: 6-126). The OM definition varied, with a maximum of two to five metastases, mixed synchronous and metachronous lesions, and a few studies including oligoprogressive lesions. The most common site of metastasis was the lung. Radiation was delivered in 1-10 fractions (20-70 Gy). The one-year LC (LC1), reported in 12 studies, was 86.9% (95% confidence interval [CI]: 79.3-91.9%). LC2 was 77.9% (95% CI: 66.4-86.3%), with heterogeneity across studies. PFS was reported in five studies, with a PFS1 of 43.0% (95% CI: 35.0-51.4%) and PFS2 of 23.9% (95% CI: 17.8-31.2%), with homogeneity across studies. OS was analyzed in nine studies, demonstrating an OS1 of 80.1% (95% CI: 74.2-85.0%) and OS2 of 60.7% (95% CI: 51.3-69.4%). Treatment was well tolerated with no reported grade 4 or 5 toxicities. Grade 3 toxicity rates were uniformly below 5% when reported.

CONCLUSIONS

SBRT offers excellent LC and promising OS, with acceptable toxicities in OM HNC. Durable PFS remains rare, highlighting the need for effective local or systemic therapies in this population. Further investigations on concurrent and adjuvant therapies are warranted.

Is oligoprogression a potentially curable disease in epidermal growth factor receptor mutant lung adenocarcinoma?

Third-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) have shown impressive results in EGFR mutant lung cancer (LC) patients in terms of disease control rate with a positive impact on overall survival. Nevertheless, after months of treatment with targeted therapy, progression inevitably occurs. Some patients develop oligoprogression and local treatment is required for optimal disease control while maintaining EGFR-TKIs. This work features a clinical case of a patient harboring an EGFR mutant LC undergoing oligoprogression to EGFR-TKIs, first into the brain and afterward to the primary tumor, requiring local ablative strategies, including primary tumor resection three years after the start of osimertinib. Currently, the patient is still alive and continues with a complete response upon EGFR-TKIs maintenance. Hence, oligoprogression, even in driven oncogenic tumors, represents a distinct biological entity and potential curative disease that deserves particular consideration in multidisciplinary tumor boards. In this case, tumor primary resection after three years of the initial diagnosis represents a paradigm shift in the treatment of EGFR mutant patients.

Incorporating Stereotactic Ablative Radiotherapy into the Multidisciplinary Management of Renal Cell Carcinoma

Stereotactic ablative radiotherapy (SABR) has challenged the conventional wisdom surrounding the radioresistance of renal cell carcinoma (RCC). In the past decade, there has been a significant accumulation of clinical data to support the safety and efficacy of SABR in RCC. Herein, we review the use of SABR across the spectrum of RCC. We performed an online search of the Pubmed database from January 1990 through April 2023. Studies of SABR/stereotactic radiosurgery targeting primary, extracranial, and intracranial metastatic RCC were included. For SABR in non-metastatic RCC, this includes its use in small renal masses, larger renal masses, and inferior vena cava tumor thrombi. In the metastatic setting, SABR can be used at diagnosis, for oligometastatic and oligoprogressive disease, and for symptomatic reasons. Notably, SABR can be used for both the primary renal tumor and metastasis-directed therapy. Management of RCC is evolving rapidly, and the role that SABR will have in this landscape is being assessed in a number of ongoing prospective clinical trials. The objective of this narrative review is to summarize the evidence corroborating the use of SABR in RCC.

[Electrochemotherapy in metastatic melanoma]

INTRODUCTION

In metastatic melanoma, despite the increased survival rates with new innovative therapies, therapeutic response is still quite heterogenous, not always durable. In the case of oligoprogression, several additional therapeutic modalities are available such as electrochemotherapy in the local treatment of cutaneous or subcutaneous metastases.

OBJECTIVE

Analysis of our experiences with electrochemotherapy in patients with metastatic melanoma.

METHOD AND RESULTS

23 patients with metastatic melanoma (10 male and 13 female) were treated with electrochemotherapy, between 2016 and 2021 in our Institute. Median age was 74.5 years. The location of metastases varied. 13 of our patients (57%) had metastases on the lower limbs, in 5 cases (22%) metastases were located in the head and neck region, in 4 cases (17%) on the upper limbs, and one (4%) patient received electrochemotherapy for metastases located on the chest. Prior to electrochemotherapy, 7 patients (30%) received chemotherapy, 6 patients (26%) were treated with immunotherapy and 2 patients (9%) received targeted therapy, while electrochemotherapy was first-line treatment for 8 patients (35%). Complete remission was achieved in 12 cases (52%), and partial remission in 6 cases (26%). In 1 case (4%) stable disease was observed, and in 4 patients (35%) progression was detected. We continued the previous systemic therapy which was effective in other localizations after the electrochemotherapy in 8 patients (35%) and in the case of 4 patients (17%) no further systemic therapy was needed. Side effects were observed in 8 patients (35%), 1 had severity of G3.

CONCLUSION

Electrochemotherapy in melanoma results in effective local tumor control, improved quality of life, and survival advantage in most of the patients, with tolerable side effects. Orv Hetil. 2023; 164(35): 1381-1386.

Image-guided thermal ablation for patients with epidermal growth factor receptor-mutant nonsmall cell lung cancer

Nonsmall cell lung cancer (NSCLC) is treated by various therapies such as surgical intervention, radiotherapy, chemotherapy, molecular targeted therapy, and immunotherapy. Currently, molecular targeted therapy, including epidermal growth factor receptor (EGFR) inhibitors and Anaplastic Lymphoma Kinase (ALK) and Kirsten Rat Sarcoma viral Oncogene (KRAS) inhibitors, has received much attention and improved the prognosis of NSCLC. Nevertheless, the terminal point of molecular targeted drugs is resistance. Drug resistance has been classified into oligoprogression and extensive progression based on the tumor lesion progression after drug resistance. There is extensive research demonstrating that local therapy (surgical resection, radiotherapy, and thermal ablation) can prolong the survival of patients with drug resistance. This review is intended to determine the efficacy of image-guided thermal ablation in patients with NSCLC with EGFR mutation.

The Effectiveness and Safety of Stereotactic Body Radiation Therapy (SBRT) in the Treatment of Oligoprogressive Breast Cancer: A Systematic Review

Stereotactic body radiotherapy (SBRT) has emerged as a technique to treat oligoprogressive sites among patients with breast cancer who are otherwise doing well on systemic therapy. This study systematically reviewed the efficacy and safety of SBRT in the setting of oligoprogressive breast cancer. A literature search was conducted in the MEDLINE database. Studies regarding SBRT and oligoprogressive breast cancer were included. Key outcomes of interest were toxicity, local control, progression, and overall survival. From 863 references, five retrospective single-center cohort studies were identified. All studies included patients with both oligometastatic and oligoprogressive disease; 112 patients with oligoprogressive breast cancer were identified across these studies. Patient age ranged from 22 to 84, with a median of 55 years of age. Most patients had hormone-receptor-positive and HER2-negative disease. SBRT doses varied from 24 to 60 Gy in 1-10 fractions based on the location/size of the lesion. Forty toxicity events were reported, of which the majority (n = 25, 62.5%) were grade 1-2 events. Among 15 patients who received SBRT concurrently with a CDK4/6 inhibitor, 37.5% of patients experienced grade 3-5 toxicities. Progression-free and overall survival ranged from 17 to 57% and 62 to 91%, respectively. There are limited data on the role of SBRT in oligoprogressive breast cancer, and prospective evaluation of this strategy is awaited to inform its safety and efficacy.

Role of radiation in oligometastases and oligoprogression in metastatic non-small cell lung cancer: consensus and controversy

INTRODUCTION

The oligometastatic state in non-small cell lung cancer (NSCLC) has recently become well-established. However, the specific definition of oligometastases remains unclear. Several smaller randomized studies have investigated the safety and efficacy of radiation as metastasis-directed therapy (MDT) in oligometastatic NSCLC, which have led the way to larger studies currently accruing patients globally.

AREAS COVERED

This review covers the definitions of 'oligometastases' and explains why the oligometastatic state is becoming increasingly relevant in metastatic NSCLC. This includes the rationale for MDT in oligometastatic NSCLC, specifically reviewing stereotactic body radiation therapy (SBRT) as a treatment strategy. This review details many randomized trials that support radiation as MDT and introduces trials that are currently accruing patients. Finally, it explores some of the controversies that warrant further investigation.

EXPERT OPINION

Radiation treatment, specifically SBRT, has been shown to be safe, convenient, and cost-effective as MDT. As systemic therapy, including targeted agents and immunotherapy, continues to improve, the precise role(s) and timing of radiation therapy may evolve. However, radiation therapy as MDT will continue to be an integral part of treatment in patients with oligometastatic NSCLC.

Effectiveness of Stereotactic Ablative Radiotherapy for Systemic Therapy Respondents with Inoperable Pulmonary Oligometastases and Oligoprogression

Stereotactic ablative radiotherapy (SABR) may improve survival in patients with inoperable pulmonary oligometastases. However, the impact of pulmonary oligometastatic status after systemic therapy on SABR outcomes remains unclear. Hence, we investigated the outcomes of SABR in 45 patients with 77 lung tumors and the prognostic value of pulmonary oligoprogression. Eligibility criteria were pulmonary oligometastases (defined as ≤5 metastatic lung tumors), controlled extrapulmonary disease (EPD) after front-line systemic therapy, SABR as primary local treatment for inoperable pulmonary metastases, and consecutive imaging follow-up. Oligometastatic lung tumor was classified into controlled or oligoprogressive status. Overall survival (OS), in-field progression-free survival (IFPFS), out-field progression-free survival (OFPFS), and prognostic variables were evaluated. With 21.8 months median follow-up, the median OS, IFPFS, and OFPFS were 28.3, not reached, and 6.5 months, respectively. Two-year OS, IFPFS, and OFPFS rates were 56.0%, 74.2%, and 17.3%, respectively. Oligoprogressive status (p = 0.003), disease-free interval < 24 months (p = 0.041), and biologically effective dose (BED₁₀) < 100 Gy (p = 0.006) were independently associated with inferior OS. BED₁₀ ≥ 100 Gy (p = 0.029) was independently correlated with longer IFPFS. Oligoprogressive status (p = 0.017) and EPD (p = 0.019) were significantly associated with inferior OFPFS. Grade ≥ 2 radiation pneumonitis occurred in four (8.9%) patients. Conclusively, SABR with BED₁₀ ≥ 100 Gy could provide substantial in-field tumor control and longer OS for systemic therapy respondents with inoperable pulmonary oligometastases. Oligoprogressive lung tumors exhibited a higher risk of out-field treatment failure and shorter OS. Hence, systemic therapy should be tailored for patients with oligoprogression to reduce the risk of out-field treatment failure. However, in the absence of effective systemic therapy, SABR is a reasonable alternative to reduce resistant tumor burden.

Stereotactic Radiation for Oligometastatic and Oligoprogressive Stage IV Breast Cancer: A Case-Based Review

For decades, the distant progression of breast cancer has been the purview of systemic therapy alone or with low to moderate-dose radiation therapy intended for the palliation of symptomatic metastases. However, for decades there have been anecdotes of long-term disease-free survival with more aggressive local treatment of one or more metastases. The hypothesis of oligometastases is that the treatment of a clinically limited number of distant metastases can change the natural history of stage IV breast cancer. The advance in the technology of stereotactic body radiation (SBRT) has made it more possible to offer a non-invasive, yet potentially disease-modifying, metastases-directed ablative treatment in place of surgery or a palliative radiation regimen. Although there are promising local control and survival outcomes in phase I/II trials, there is still a lack of phase III evidence of ablative SBRT results showing any change in the natural history of metastatic breast cancer. Limited oligometastases may call for an ablative approach with SBRT when definitive long-term local control is needed for the best palliation against symptomatic progression in challenging locations. Some oligometastases that have progression on a certain systemic regimen, while others remain stable or in remission, may also be treated with SBRT in the hopes of prolonging the use of that regimen. Whether SBRT should represent the standard management for stage IV breast cancer of a limited number or of limited progression requires confirmation by phase III data. This review will discuss the data from key clinical trials as it applies to decision making in typical clinical cases considered for potentially ablative SBRT for oligometastases or oligoprogression.

Treatment strategies based on different oligoprogressive patterns after immunotherapy failure in metastatic NSCLC

Background

Oligoprogressive disease is recognized as the overall umbrella term; however, a small number of progressions on imaging can represent different clinical scenarios. This study aims to explore the optimal treatment strategy after immunotherapy (IO) resistance in advanced non-small-cell lung cancer (NSCLC), especially in personalized therapies for patients with different oligoprogressive patterns.

Methods

Based on European Society for Radiotherapy and Oncology/European Organization for Research and Treatment of Cancer consensus, metastatic NSCLC patients with cancer progression after IO resistance were divided into four patterns, repeat oligoprogression (REO, oligoprogression with a history of oligometastatic disease), induced oligoprogression (INO, oligoprogression with a history of polymetastatic disease), de-novo polyprogression (DNP, polyprogression with a history of oligometastatic disease), and repeat polyprogression (REP, polyprogression with a history of polymetastatic disease). Patients with advanced NSCLC who received programmed cell death-1/programmed cell death ligand-1 inhibitors between January 2016 and July 2021 at Shanghai Chest Hospital were identified. The progression patterns and next-line progression-free survival (nPFS), overall survival (OS) were investigated stratified by treatment strategies. nPFS and OS were calculated using the Kaplan-Meier method.

Results

A total of 500 metastatic NSCLC patients were included. Among 401 patients developed progression, 36.2% (145/401) developed oligoprogression and 63.8% (256/401) developed polyprogression. Specifically, 26.9% (108/401) patients had REO, 9.2% (37/401) patients had INO, 27.4% (110/401) patients had DNP, and 36.4% (146/401) patients had REP, respectively. The patients with REO who received local ablative therapy (LAT) had significant longer median nPFS and OS compared with no LAT group (6.8 versus 3.3 months; p = 0.0135; OS, not reached versus 24.5 months; p = 0.0337). By contrast, there were no nPFS and OS differences in INO patients who received LAT compared with no LAT group (nPFS, 3.6 versus 5.3 months; p = 0.3540; OS, 36.6 versus 45.4 months; p = 0.8659). But in INO patients, there were significant longer median nPFS and OS using IO maintenance by contrast with IO halt treatment (nPFS, 6.1 versus 4.1 months; p = 0.0264; OS, 45.4 versus 32.3 months; p = 0.0348).

Conclusions

LAT (radiation or surgery) is more important for patients with REO while IO maintenance plays a more dominant role in patients with INO.

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.

Palliative surgery for malignant superior vena cava obstruction resistant to immunotherapy: a case report

BACKGROUND

A disease progression pattern in a limited number of sites, called oligoprogression, is relatively common in patients with lung cancer during immunotherapy. It is controversial how to manage clinically problematic oligoprogressive lesions, such as superior vena cava (SVC) obstruction resistant to immunotherapy.

CASE DESCRIPTION

We present a case of a 43-year-old man who presented with facial swelling and pain in the right shoulder. Contrast-enhanced computed tomography (CT) revealed a tumor at the apex of the right lung, pulmonary and pleural nodules, and swollen mediastinal lymph nodes. A swollen mediastinal lymph node directly invaded into the SVC. Pathological diagnosis of the lymph node revealed adenocarcinoma. On the basis of these findings, the patient was diagnosed with lung adenocarcinoma with SVC obstruction (cT3N2M1c; stage IVB). First-line chemotherapy with carboplatin, pemetrexed, and pembrolizumab reduced the size of the primary tumor, pulmonary and pleural metastases, and most mediastinal lymph node metastases after four cycles of treatment, but one lesion invading the SVC increased. Therefore, surgical resection of the lesion and vascular replacement were performed. At present, 22 months have passed since the surgery, and maintenance therapy with pemetrexed and pembrolizumab is ongoing, without disease progression nor any adverse events.

CONCLUSIONS

The clinical course of the case presented here suggests that palliative surgery may be an effective management option for a clinically problematic lesion, such as SVC obstruction, which increases during immunotherapy.

The Management of Oligometastases in Non-small Cell Lung Cancer - is Stereotactic Ablative Radiotherapy now Standard of Care?

Oligometastatic non-small cell lung cancer encompasses a number of distinct clinical scenarios with a pattern of limited tumour burden on imaging. Delivering local ablative therapy to individual metastatic lesions may assist in disease modification and contribute to improved outcomes. We review the published randomised clinical trials that support the implementation of stereotactic ablative radiotherapy as a standard of care in certain oligometastatic non-small cell lung cancer clinical scenarios, and highlight the current knowledge gaps and areas of ongoing research.

Oligoprogression of Solid Tumors on Immune Checkpoint Inhibitors: The Impact of Local Ablative Radiation Therapy

The breakthrough of a limited number of clones while on immune checkpoint inhibitors (ICIs), known as oligoprogression, has been previously described. The benefit of ablative radiation therapy (RT) directed at these clones, as opposed to changing systemic therapy, is unclear. We analyzed 30 patients with advanced solid tumors, the majority of whom (23/30, 86.7%) had either hepatocellular or urothelial carcinoma, who experienced oligoprogression on ICIs and were referred for RT. In this study, oligoprogression was defined as having experienced progression at three or fewer metastatic sites outside of the brain after achieving at least stable disease on ICIs for a minimum of three months. The median time to oligoprogression was 11.1 months from the initiation of immunotherapy. 24 patients had one oligoprogressive lesion and six had two. The median radiation dose delivered was 4650 cGy in a median of five fractions. The median progression-free survival (PFS) after RT was 7.1 months, and the time to oligoprogression was not a significant predictor of PFS2. 26 patients continued on ICIs after RT. While 17 patients subsequently progressed, 15 did so at three or fewer metastatic sites and could have theoretically stood to benefit from an additional course of salvage RT to further extend the lifespan of their ICIs. Overall survival at 6, 12, and 24 months was 100.0%, 96.3%, and 82.8%, respectively. These results suggest that RT may provide a PFS benefit and extend the lifespan of ICIs in patients who experience oligoprogression. Regardless of PFS, however, overall survival in this population appears to be excellent.

Radiotherapy with continued EGFR-TKIs for oligoprogressive disease in EGFR-mutated non-small cell lung cancer: A real-world study

BACKGROUND

Epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC) develops resistance to tyrosine kinase inhibitors (TKIs). Here, we evaluated the efficacy of radiotherapy and continuation of TKIs in patients with advanced NSCLC with oligoprogression after EGFR-TKIs.

METHODS

From January 2011 to January 2019, 33 patients with EGFR-mutated NSCLC on TKIs were treated by radiotherapy and continuation of TKIs for oligoprogressive disease. The primary endpoints were median progression-free survival 1 (mPFS1), mPFS2, and median overall survival (mOS). PFS1 was measured from the start of EGFR-TKIs therapy to the oligoprogression of the disease. PFS2 was measured from the date of oligoprogression to the further progression of the disease, while OS was calculated from oligoprogression to death from any cause or was censored at the last follow-up date.

RESULT

The mPFS1, mPFS2, and mOS were 11.0 (95% CI, 4.4-17.6), 6.5 (95% CI, 1.4-11.6) and 21.8 (95% CI, 14.8-28.8) months, respectively. Univariate analysis showed that EGFR mutation type (p = 0.024), radiotherapy method (p = 0.001), and performance status (p = 0.017) were significantly correlated with PFS2. Univariate analysis showed that sex (p = 0.038), smoking history (p = 0.031), EGFR mutation type (p = 0.012), and radiotherapy method (p = 0.009) were significantly correlated with OS. Multivariate analysis suggested that radiotherapy method (p = 0.001) and performance status (p = 0.048) were prognostic factors for PFS2, and radiotherapy method (p = 0.040) was a prognostic factor for OS.

CONCLUSION

Radiotherapy with continued TKIs is effective for EGFR-mutated NSCLC with oligoprogression, and it should be conducted as soon as possible. T790M+ patients have higher sensitivity to radiotherapy, and patients with good performance status and stereotactic body radiation therapy have better PFS2 and OS.

Systemic Therapy for Oligoprogression in Patients with Metastatic NSCLC Harboring Activating EGFR Mutations

After a variable period of activity of the epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) treatment, patients with advanced non-small cell lung cancer (NSCLC) harboring EGFR mutations develop resistance to these TKIs. In some cases, an oligoprogression is diagnosed, and its management is still controversial. The oligoprogression represents an intermediate stage of metastatic NSCLC between localized and widely disseminated disease, and is characterized by a limited number and/or sites of metastases in which a disease progression appears, together with a more indolent tumor biology. Currently, the management of oligoprogressed NSCLC involves local treatment, including radiotherapy and/or surgery, to control the progressive lesions. Systemic therapy should also be a potential approach to boost the activity of EGFR-TKIs. However, considering the lack of large trials addressing this topic, the optimal therapeutic strategies remain undefined and should be evaluated on an individualized basis. In this paper, we review the most relevant scientific evidence of continuing the systemic therapy with the same EGFR-TKI for the management of patients with NSCLC harboring EGFR mutations and oligoprogressed to first-line EGFR-TKIs, also discussing the controversies and potential future directions.

Management of Oligoprogression in Patients with Metastatic NSCLC Harboring ALK Rearrangements

Simple Summary

The growing efficacy and availability of new targeted systemic therapies have markedly improved the prognosis of metastatic lung cancer patients harboring ALK rearrangements. The use of effective targeted therapies capable of maintaining a prolonged control of disease, for as long as possible, is paramount to ensure the best survival outcomes. In this regard, in cases of oligoprogression, “beyond progression” systemic treatment added to local ablative therapies is considered a feasible option in an attempt to improve the quality and quantity of patients’ lives, even if based on retrospective data. Certainly, treatment of ALK rearranged lung cancer patients with oligoprogressive disease must be individualized and based on multidisciplinary decisions. Above all, when further molecular targeted therapies are available, options must always be evaluated, especially in case of cerebral progression. In this review, we provide an updated and comprehensive overview of the main treatment strategies in cases of ALK rearranged oligoprogression.

Abstract

Personalized treatment based on driver molecular alterations, such as ALK rearrangement, has revolutionized the therapeutic management of advanced oncogene-addicted NSCLC patients. Multiple effective ALK tyrosine kinase inhibitors (TKIs), with the amelioration of the activity at central nervous system level, are now available, leading to substantial prognosis improvement. The exposure to TKIs triggers resistance mechanisms and the sequential administration of other TKIs and chemotherapy is, for the most part, not targeted. In this context, extending the benefit deriving from precision medicine is paramount, above all, when disease progression occurs in a limited number of sites. Retrospective data indicate that, in oligoprogressive disease, targeted therapy beyond progression combined with definitive local treatment of the progressing site(s) is an effective alternative. In these cases, a multidisciplinary approach becomes essential for an integrated treatment strategy, depending on the site of disease progression, in order to improve not only survival, but also quality of life. In this review we provide an updated and comprehensive overview of the main treatment strategies in cases of ALK rearranged oligoprogression, including systemic treatment as well as local therapy, and report a real-world clinical story, with the final aim of identifying the most promising management for this subset of patients.

Oligoprogression in Metastatic, Castrate-Resistant Prostate Cancer-Prevalence and Current Clinical Practice

Aims

Oligoprogression is poorly defined in current literature. Little is known about the natural history and significance of oligoprogression in patients with hormone-resistant prostate cancer on abiraterone or enzalutamide treatment [termed androgen receptor-targeted therapy (ARTT)]. The aim of this study was to determine the prevalence of oligoprogression, describe the characteristics of oligoprogression in a cohort of patients from a single center, and identify the number of patients potentially treatable with stereotactic body radiotherapy (SBRT).

Methods

Castration-resistant prostate cancer (CRPC) patients who radiologically progressed while on ARTT were included. Patients with oligoprogressive disease (OPD) (≤3 lesions) on any imaging were identified in a retrospective analysis of electronic patient records. Kaplan-Meier method and log-rank test were used to calculate progression-free and overall survival.

Results

A total of 102 patients with metastatic CRPC on ARTT were included. Thirty (29%) patients presented with oligoprogression (46 lesions in total); 21 (21% of total) patients had lesions suitable for SBRT. The majority of lesions were in the bone (21, 46%) or lymph nodes (15, 33%). Patients with oligoprogression while on ARTT had a significantly better prostate-specific antigen (PSA) response on commencing ARTT as compared to patients who later developed polyprogression. However, PSA doubling time immediately prior to progression did not predict OPD. Median progression-free survival to oligoprogression versus polyprogression was 16.8 vs. 11.7 months. Time to further progression after oligoprogression was 13.6 months in those treated with radiotherapy (RT) for oligoprogression vs. 5.7 months in those treated with the continuation of ARTT alone.

Conclusions

In this study, nearly a third of patients on ARTT for CRPC were found to have OPD. OPD patients had a better PSA response on ART and a longer duration on ARTT before developing OPD as compared to those developing polyprogressive disease (Poly-PD). The majority of patients (70%) with OPD had lesions suitable for SBRT treatment. Prospective randomized control trials are needed to establish if there is a survival benefit of SBRT in oligoprogressive prostate cancer and to determine predictive indicators.

A narrative review on tumor microenvironment in oligometastatic and oligoprogressive non-small cell lung cancer: a lot remains to be done

Objective

In this review, we aim to collect and discuss available data about the role and composition of tumor microenvironment (TME) in oligometastatic (OMD) and oligoprogressive (OPD) non-small cell lung cancer (NSCLC). Furthermore, we aim to summarize the ongoing clinical trials evaluating as exploratory objective the TME composition, through tissue and/or blood samples, in order to clarify whether TME and its components could explain, at least partially, the oligometastatic/oligoprogressive process and could unravel the existence of predictive and/or prognostic factors for local ablative therapy (LAT).

Background

OMD/OPD NSCLC represent a heterogeneous group of diseases. Several data have shown that TME plays an important role in tumor progression and therefore in treatment response. The crucial role of several types of cells and molecules such as immune cells, cytokines, integrins, protease and adhesion molecules, tumor-associated macrophages (TAMs) and mesenchymal stem cells (MSCs) has been widely established. Due to the peculiar activation of specific pathways and expression of adhesion molecules, metastatic cells seem to show a tropism for specific anatomic sites (the so-called “seed and soil” hypothesis). Based on this theory, metastases appear as a biologically driven process rather than a random release of cancer cells. Although the role and the function of TME at the time of progression in patients with NSCLC treated with tyrosine-kinase inhibitors and immune checkpoint inhibitors (ICIs) have been investigated, limited data about the role and the biological meaning of TME are available in the specific OMD/OPD setting.

Methods

Through a comprehensive PubMed and ClinicalTrials.gov search, we identified available and ongoing studies exploring the role of TME in oligometastatic/oligoprogressive NSCLC.

Conclusions

Deepening the knowledge on TME composition and function in OMD/OPD may provide innovative implications in terms of both prognosis and prediction of outcome in particular from local treatments, paving the way for future investigations of personalized approaches in both advanced and early disease settings.

Definitive radiotherapy for extracranial oligoprogressive metastatic renal cell carcinoma as a strategy to defer systemic therapy escalation

OBJECTIVE

To study whether delivering definitive radiotherapy (RT) to sites of oligoprogression in metastatic renal cell carcinoma (mRCC) enabled deferral of systemic therapy (ST) changes without compromising disease control or survival.

PATIENTS AND METHODS

We identified patients with mRCC who received RT to three or fewer sites of extracranial progressive disease between 2014 and 2019 at a large tertiary cancer centre. Inclusion criteria were: (1) controlled disease for ≥3 months before oligoprogression, (2) all oligoprogression sites treated with a biologically effective dose of ≥100 Gy, and (3) availability of follow-up imaging. Time-to-event end-points were calculated from the start of RT.

RESULTS

A total of 72 patients were identified (median follow-up 22 months, 95% confidence interval [CI] 19-32 months), with oligoprogressive lesions in lung/mediastinum (n = 35), spine (n = 30), and non-spine bone (n = 5). The most common systemic therapies before oligoprogression were none (n = 33), tyrosine kinase inhibitor (n = 23), and immunotherapy (n = 13). At 1 year, the local control rate was 96% (95% CI 87-99%); progression-free survival (PFS), 52% (95% CI 40-63%); and overall survival, 91% (95% CI 82-96%). At oligoprogression, ST was escalated (n = 16), maintained (n = 49), or discontinued (n = 7), with corresponding median (95% CI) PFS intervals of 19.7 (8.2-27.2) months, 10.1 (6.9-13.2) months, and 9.8 (2.4-28.9) months, respectively. Of the 49 patients maintained on the same ST at oligoprogression, 21 did not subsequently have ST escalation.

CONCLUSION

Patients with oligoprogressive mRCC treated with RT had comparable PFS regardless of ST strategy, suggesting that RT may be a viable approach for delaying ST escalation. Randomised controlled trials comparing treatment of oligoprogression with RT vs ST alone are needed.

A pilot study of everolimus and radiation for neuroendocrine liver metastases

Liver metastases are common in patients with neuroendocrine tumours. For patients, management must balance disease control with consideration of toxicity, given limited treatment options. Everolimus has demonstrated effectiveness in neuroendocrine neoplasms. Given emerging data of a synergistic effect with radiation therapy, we evaluated combined everolimus and radiation for neuroendocrine liver metastases. This single-arm, single-centre prospective pilot study evaluated the safety and efficacy of combined everolimus and radiotherapy for well-differentiated neuroendocrine liver metastases. Patients with unresectable liver metastases received everolimus for 30 days, followed by concurrent everolimus and liver radiotherapy, then a further 14 days of everolimus. Tolerability was evaluated using the CTCAE v.4.03. Individual metastasis response rate and local control were measured by RECIST v1.1. Overall survival, progression-free survival and freedom from a change in systemic therapy were estimated by the Kaplan-Meier method. Forty metastases were treated in 14 patients. No grade 3 or higher toxicities were identified in the concurrent treatment phase; one patient developed grade 3 toxicity in the post-radiation phase. Overall response rate was 38%. One- and 2-year local control were 97% and 71%. Median progression-free survival was 12 months. One- and 2-year overall survival were 100% and 92%. In conclusion, combined everolimus and radiation are well-tolerated for neuroendocrine liver metastases and are associated with excellent local control. The approach of selective local ablation of oligometastatic or oligoprogressive disease warrants further evaluation in this patient population.

Beyond First-Line Immunotherapy: Potential Therapeutic Strategies Based on Different Pattern Progressions: Oligo and Systemic Progression

First-line immune-checkpoint inhibitor (ICI)-based therapy has deeply changed the treatment landscape and prognosis in advanced non-small cell lung cancer (aNSCLC) patients with no targetable alterations. Nonetheless, a percentage of patients progressed on ICI as monotherapy or combinations. Open questions remain on patients' selection, the identification of biomarkers of primary resistance to immunotherapy and the treatment strategies to overcome secondary resistance to first-line immunotherapy. Local ablative approaches are the main therapeutic strategies in oligoprogressive disease, and their role is emerging in patients treated with immunotherapy. Many therapeutic strategies can be adapted in aNSCLC patients with systemic progression to personalize the treatment approach according to re-characterization of the tumors, previous ICI response, and type of progression. This review's aim is to highlight and discuss the current and potential therapeutic approaches beyond first-line ICI-based therapy in aNSCLC patients based on the pattern of disease progression (oligoprogression versus systemic progression).

Progression Patterns, Treatment, and Prognosis Beyond Resistance of Responders to Immunotherapy in Advanced Non-Small Cell Lung Cancer

Introduction

Immune checkpoint inhibitors (ICIs) have changed the management of non-small cell lung cancer (NSCLC). However, resistance is inevitable. The disease progression patterns, sequential treatment, and prognosis beyond ICI resistance are not completely understood.

Methods

We retrospectively analyzed stage IV NSCLC patients who underwent ICI treatment at Zhejiang Cancer Hospital between January 2016 and January 2020 and who suffered disease progression after at least stable disease on immunotherapy for more than 3 months (at least two cycles). Oligoprogression and systematic progression were defined as previous reports. The main outcome measures were progression-free survival (PFS), second PFS (PFS2), and overall survival (OS). Survival curves were plotted using the Kaplan-Meier method. The Cox proportional hazards model was used for multivariate analysis.

Results

Totally 1,014 NSCLC patients were administered immunotherapy. Of them, 208 NSCLC patients were included in this retrospective study. The estimated PFS, PFS2 and OS were 6.3 months (95% CI 5.6–7.0 months), 10.7 months (95% CI 10.1–12.7 months), and 21.4 months (95% CI 20.6–26.4 months), respectively. After resistance, 55.3% (N = 115) patients developed oligoprogression, and 44.7% (N = 93) systemic progression. For patients with systemic progression, chemotherapy (N = 35, 37.6%), best supportive care (N = 30, 32.3%), and antiangiogenic therapy alone (N = 11, 11.8%) were the major strategies. A combination of local radiotherapy (N = 38, 33.0%) with continued ICIs was the most common treatment used in oligoprogression group, followed by continued immunotherapy with antiangiogenic therapy (N = 19, 16.5%) and local radiotherapy only (N = 17, 14.9%). For patients with oligoprogression, continued immunotherapy plus local radiotherapy can lead to a significantly longer PFS2 (12.9 vs. 10.0 months; p = 0.006) and OS (26.3 vs. 18.5 months, p = 0.001). The PFS2 and OS of patients with oligoprogression were superior to those of patients with systemic progression (PFS2: 13.1 vs. 10.0 months, p = 0.001; OS: 25.8 vs. 19.1 months, p = 0.003).

Conclusions

The major progression pattern after acquired resistance from immunotherapy is oligoprogression. Local radiotherapy with continued immunotherapy beyond oligoprogression in responders was feasible and led to prolonged PFS2 and OS in advanced NSCLC patients.

Outcomes of Stereotactic Body Radiotherapy for Metastatic Colorectal Cancer With Oligometastases, Oligoprogression, or Local Control of Dominant Tumors

AIM

To evaluate the clinical outcomes of metastatic colorectal cancer (mCRC) patients with oligometastases, oligoprogression, or local control of dominant tumors after stereotactic body radiotherapy (SBRT) and establish a nomogram model to predict the prognosis for these patients.

METHODS AND MATERIALS

A cohort of 94 patients with 162 mCRC metastases was treated with SBRT at a single institution. Treatment indications were oligometastases, oligoprogression, and local control of dominant tumors. End points of this study were the outcome in terms of progression-free survival (PFS), overall survival (OS), local progression (LP), and cumulative incidence of starting or changing systemic therapy (SCST). In addition, univariate and multivariable analyses to assess variable associations were performed. The predictive accuracy and discriminative ability of the nomogram were determined by concordance index (C-index) and calibration curve.

RESULTS

Median PFS were 12.6 months, 6.8 months, and 3.7 months for oligometastases, oligoprogression, and local control of dominant tumors, respectively. 0-1 performance status, < 10 ug/L pre-SBRT CEA, and ≤ 2 metastases were significant predictors of higher PFS on multivariate analysis. Median OS were 40.0 months, 26.1 months, and 6.5 months for oligometastases, oligoprogression, and local control of dominant tumors, respectively. In the multivariate analysis of the cohort, the independent factors for survival were indication, performance status, pre-SBRT CEA, and PTV, all of which were selected into the nomogram. The calibration curve for probability of survival showed the good agreement between prediction by nomogram and actual observation. The C-index of the nomogram for predicting survival was 0.848.

CONCLUSIONS

SBRT for metastases derived from colorectal cancer offered favorable survival and symptom palliation without significant complications. The proposed nomogram could provide individual prediction of OS for patients with mCRC after SBRT.

Efficacy of local therapy for oligoprogressive disease after programmed cell death 1 blockade in advanced non-small cell lung cancer

Immune checkpoint inhibitors (ICIs) have dramatically changed the strategy used to treat patients with non-small-cell lung cancer (NSCLC); however, the vast majority of patients eventually develop progressive disease (PD) and acquire resistance to ICIs. Some patients experience oligoprogressive disease. Few retrospective studies have evaluated clinical efficacy in patients with oligometastatic progression who received local therapy after ICI treatment. We conducted a retrospective analysis of advanced NSCLC patients who received PD-1 inhibitor monotherapy with nivolumab or pembrolizumab to evaluate the effects of ICIs on the patterns of progression and the efficacy of local therapy for oligoprogressive disease. Of the 307 patients treated with ICIs, 148 were evaluated in our study; 42 were treated with pembrolizumab, and 106 were treated with nivolumab. Thirty-eight patients showed oligoprogression. Male sex, a lack of driver mutations, and smoking history were significantly correlated with the risk of oligoprogression. Primary lesions were most frequently detected at oligoprogression sites (15 patients), and 6 patients experienced abdominal lymph node (LN) oligoprogression. Four patients showed evidence of new abdominal LN oligometastases. There was no significant difference in overall survival (OS) between the local therapy group and the switch therapy group (reached vs. not reached, P = .456). We summarized clinical data on the response of oligoprogressive NSCLC to ICI therapy. The results may help to elucidate the causes of ICI resistance and indicate that the use of local therapy as the initial treatment in this setting is feasible treatment option.

Lung cancer management: monitoring and treating resistance development in third-generation EGFR TKIs

INTRODUCTION

Patients treated with third-generation EGFR TKIs will develop resistance to treatment at a certain point. Early detection of resistance occurrence could allow more options for treatment.

AREAS COVERED

We discuss the development of third-generation EGFR TKIs, focusing on osimertinib and discuss the most common resistance mechanisms under evaluation. We also debate how this resistance can be detected; particularly we review the possible application of liquid biopsy in this scenario. Lastly we discuss available treatment options when resistance occurs, with an eye on ongoing trials and possible future developments.

EXPERT OPINION

As resistance will ultimately develop, a strict instrumental follow-up as per international guidelines is required with the aim of detecting this resistance in an early phase. Detecting an oligoprogression could allow the integration of local ablative therapies while further delaying the need for a systemic therapy change. By exploiting the increasing potentiality of liquid biopsy, in the near future, physicians could be able to understand why a patient develops resistance and therefore can choose the best possible individualized treatment option.

Extracranial Stereotactic Body Radiotherapy in Oligometastatic or Oligoprogressive Breast Cancer

Purpose/Objective: Oligometastatic disease (OMD) and oligoprogressive disease (OPD) describe tumor states with a limited metastasization. In contrast to other disease states, treatment of OMD or OPD has not yet become common for breast cancer. We sought to understand the outcomes and toxicities of this treatment paradigm.

Material/Methods: We retrospectively analyzed female breast cancer patients with OMD (≤3 metastases) or OPD (1 progressive lesion) who received stereotactic body radiotherapy (SBRT) for their respective extracranial metastatic lesions between 01/2002 and 07/2019. Survival analysis was performed using the Kaplan-Meier method with log-rank test being used for evaluation of significance. Cox regression was used to detect prognostic outcome factors. Toxicity was evaluated using the Common Terminology Criteria for Adverse Events (CTCAE v. 5.0).

Results: Forty-six patients (70% OMD; 30% OPD) with 58 lesions met criteria for inclusion. The majority of treatments (34 out of 58; 58.6%) were delivered from 2017 to 2018. Treatment sites were bone, liver, lung [n = 19 (33%) for each site], and adrenal gland [n = 1 (1%)]. Median biologically effective dose (BED at α/β = 10) was 81.6 Gy (range: 45–112.5 Gy) and median planning target volume was 36.60 mL (range: 3.76–311.00 mL). At 2 years, local control (LC) was 89%, distant control (DC) was 44%, progression free survival (PFS) was 17% and overall survival (OS) was 62%. Multivariate analysis identified the diagnosis of a solitary metastasis as an independent prognostic factor for superior DC (HR = 0.186, CI [0.055; 0.626], p = 0.007) and PFS (HR = 0.363, CI [0.152; 0.863], p = 0.022). OS was independently inferior for patients treated at a higher age (HR = 5.788, CI [1.077; 31.119] p = 0.041). Nine (15.5%) grade I° and one (1.7%) grade II° toxicities were recorded, with no grade III° or higher toxicities.

Conclusion: Extracranial SBRT in breast cancer patients with OMD or OPD was well-tolerated with excellent LC. SBRT should especially be offered to younger OMD and OPD breast cancer patients with only one metastasis. The increase in utilization since 2017 points toward a growing acceptance of SBRT for OMD and OPD in breast cancer.

Management of oligometastatic and oligoprogressive renal cell carcinoma: state of the art and future directions

INTRODUCTION

The aim of this paper was to perform a narrative review of the literature on the available approaches in the treatment of two emerging subpopulations of metastatic renal cell carcinoma (mRCC) patients: the oligometastatic disease (less than 5 metastasis) and the oligoprogressive disease, defined as worsening in maximum 3-5 sites while all other tumor sites are controlled by systemic therapy.

AREAS COVERED

We explore all possible approaches in these settings of patients: the role of local therapies, considering both surgical metastasectomy and/or ablative techniques, the efficacy of systemic therapies and the rationale behind active surveillance. We also discuss ongoing clinical trials in these settings.

EXPERT OPINION

Two different strategies are emerging as the most promising for the approach to the oligometastatic/oligoprogressive mRCC patient: (1) the use of immunocheckpoint inhibitors following metastasectomy; (2) the use of stereotactic radiotherapy alone or combined with immunotherapy for oligometastatic disease. The lack of validated biomarkers of response in these mRCC patient subpopulations is opening the way to the employment of novel technologies. Among them, the use of artificial intelligence seems to be the candidate to contribute to precision oncology in patients with mRCC.

Oligoprogressive Non-Small-Cell Lung Cancer under Treatment with PD-(L)1 Inhibitors

Oligoprogression (OPD) of non-small-cell lung cancer (NSCLC) occurs in approximately half of patients under targeted compounds (TKI) and facilitates use of regional therapies that can prolong survival. In order to characterize OPD in immunotherapy (IO)-treated NSCLC, we analyzed the failure pattern under PD-1/PD-L1 inhibitors (n = 297) or chemoimmunotherapy (n = 75). Under IO monotherapy, OPD was more frequent (20% vs. 10%, p < 0.05), occurred later (median 11 vs. 5 months, p < 0.01), affected fewer sites (mean 1.1 vs. 1.5, p < 0.05), and involved fewer lesions (1.4 vs. 2.3, p < 0.05) in the first compared to later lines. Lymph nodes (42%, mainly mediastinal) and the brain (39%) were mostly affected, followed by the lung (24%) and other organs. Compared to multifocal progression, OPD occurred later (11 vs. 4 months, p < 0.001) and was associated with longer survival (26 vs. 13 months, p < 0.001) and higher tumor PD-L1 expression (p < 0.001). Chemoimmunotherapy showed a similar incidence of OPD as IO monotherapy (13% vs. 11% at 2 years). Local treatments were applied regularly for brain but only in 50% for extracranial lesions. Thus, NSCLC oligoprogression is less common under IO than under TKI, but also favorable. Since its frequency drops later in the disease, regular restaging and multidisciplinary evaluation are essential in order to exploit the full therapeutic potential.

Survival outcome of tyrosine kinase inhibitors beyond progression in association to radiotherapy in oligoprogressive EGFR-mutant non-small-cell lung cancer

Aim: The association of tyrosine kinase inhibitors (TKIs) and local radiotherapy in EGFR-mutated non-small-cell lung cancer patients experiencing disease progression under TKIs could be a valid an option. Patients & methods: We included 131 patients experiencing disease progression during first-line TKI. In group A, patients received TKI beyond progression and site(s) of progression were irradiated; in group B, patients remained on TKI alone beyond progression; and group C stopped TKI at first disease progression. Results: Median overall survival resulted longer in group A versus B and C (p < 0.0001). Group A had a trend toward a longer second progression-free survival (measured from the time of first progression until second progression) versus group B (p = 0.06). Conclusion: TKI beyond progression in association with local ablative treatment is a valid treatment option in oligoprogressive patients.

Prognostic Factors and Optimal Response Interval for Stereotactic Body Radiotherapy in Patients With Lung Oligometastases or Oligoprogression From Colorectal Cancer

Purpose: To analyze the prognostic factors and optimal response interval for stereotactic body radiotherapy (SBRT) in patients with lung oligometastases (OM) or oligoprogression (OP) from colorectal cancer (CRC).

Method: Patients with lung OM or OP from CRC treated by SBRT at our hospital were included in this retrospective review. The local control (LC), response to SBRT in different evaluation interval and regional metastases (RM) was analyzed. The risk factor for LC and RM was calculated using the Kaplan-Meier method and compared using the Log-rank test. Multivariate analysis with a Cox proportional hazards model was used to test independent significance.

Results: A total of 53 patients with 105 lung metastases lesions treated from 2012 to 2018 were involved in this retrospective study. The median biologically effective dose (BED) for these patients was 100 Gy (range: 75–131.2 Gy). Complete response (CR) increased from 27 (25.7%) to 46 (43.8%) lesions at 1.8 and 5.3 months following SBRT, and at the last follow-up, 52 (49.5%) lesions achieved CR. The median follow-up duration for all patients was 14 months (range: 5–63 months), and 1-year LC was 90.4%. During the follow-up, 10 lesions suffered local relapse after SBRT (9 of them occurred within 8 months after SBRT). The univariate analysis shows BED ≥ 100 Gy (P = 0.003) and gross tumor volume (GTV) < 1.6 cm³ (P = 0.011) were better predictors for 1-year LC. The patients with lung oligoprogression had higher 1-year RM when compared with patients with lung oligometastases (hazard ratio 2.78; 95% confidence interval [CI] 1.04–7.48, P = 0.042). Until the last follow up, 4 (7.5%) patients suffered grade 2 radiation pneumonitis, and no grade 3–4 toxicity was observed.

Conclusions: SBRT provides favorable LC in CRC patients with lung OM or OP, and the GTV and BED can affect the LC. Radiology examinations nearly 5–6 months following SBRT appear to represent the final local effect of SBRT, and the patients with oligoprogression has higher RM.

The Management of Oligoprogression in the Landscape of New Therapies for Metastatic Melanoma

Background: A limited degree of progression after a response to treatment is labelled as oligoprogression and is a hot topic of metastatic melanoma (MM) management. Rogue progressive metastases could benefit from local treatment, which could allow the continuation of ongoing systemic therapy, also known as treatment beyond progression (TBP). Methods: We retrospectively reviewed 214 selected MM patients who developed oligoprogression during treatment with v-Raf murine sarcoma viral oncogene homolog B (BRAF)/mitogen-activated-extracellular signal-regulated kinase (MEK) or programmed cell death protein 1 (PD-1) inhibitors and received a local treatment continuing TBP. We performed univariate and multivariable analyses to assess the association between therapy outcomes and a series of clinical and biological features. Results: We identified 27 (10%) oligoprogressed patients treated locally with surgery (14), radiosurgery (11), and electrochemotherapy (2). TBP included PD-1 inhibitors (13) and BRAF/MEK inhibitors (14). The median progression-free survival post oligoprogression (PFSPO) was 14 months (5-19 95% confidence interval (C.I.)). In the univariate analysis, a significantly longer PFSPO was associated with complete response (CR), Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0, neutrophils/lymphocytes ratio (N/L) <2, and progression-free survival (PFS) at oligoprogression >11 months. Nevertheless, in the multivariable analysis, only CR and N/L <2 were found to be associated with longer PFSPO. Conclusions: In selected patients, local treatments contribute to controlling oligoprogression for a long time, allowing the continuation of systemic treatment and prolongation of overall survival (OS). Increasing biological and clinical knowledge is improving the accuracy in identifying patients to apply for local ablative therapies.

Stereotactic Body Radiation Therapy (SBRT) as Salvage Therapy for Oligorecurrent Pleural Mesothelioma After Multi-Modality Therapy

Introduction: Therapy options for patients with oligoprogressive malignant pleural mesothelioma (MPM) are limited. Stereotactic Body Radiotherapy (SBRT) may be a promising therapeutic option, as it delivers a localized ablative dose of radiation and therefore balances efficacy and treatment related toxicities. The intent of this retrospective analysis was to evaluate the feasibility of SBRT for limited pleural recurrences.

Methods and Materials: This retrospective single-institution study is based on the 21 consecutive patients treated with hypofractionated radiotherapy for oligoprogressive MPM. Clinical and radiological data was collected at regular follow-up visits including toxicity, local control and survival.

Results: At primary diagnosis, 57% of the patients presented with stage III disease. Initial treatment of MPM consisted of induction chemotherapy (n = 12) prior to a macroscopic complete resection (n = 18). Three patients received additional intracavitary chemotherapy and another three patients were treated with chemotherapy alone without another treatment at the time of first diagnosis. A total of 50 lesions in recurrent MPM were treated with SBRT. The median number of radiotherapy fractions was 5 (range 3–20) with a median dose per fraction of 5 Gy (range 2.5–12.5 Gy). The median total treatment dose was 30 Gy (20–50 Gy) with a median prescription isodose line (IDL) of 65% (65–100%). Median follow-up of all patients from diagnosis was 28 months (range 7–152 months). Analyzing all lesions separately, the 12-months-local control from SBRT was 73.5%. The median progression free survival (PFS) after SBRT was 6 months (range 0–21 months) and the median OS from first first SBRT was 29 months (range 0–61 months). Only one patients experienced above Grade 3 toxicities.

Conclusion: This analysis demonstrates the feasibility of a SBRT approach for oligorecurrent MPM. SBRT was well-tolerated even after multiple repetitions and local control was high with a promising median OS.

Management of one patient with oligoprogressive thyroid cancer during treatment with lenvatinib

Recent thyroid cancer guidelines found it reasonable to use local therapies during treatment with tyrosine kinase inhibitors (TKIs) in selected patients with oligoprogressive disease, namely, in the presence of a single progressing lesion in an otherwise TKI-responsive metastatic cancer. However, there is a lack of experience in the management of oligoprogressive thyroid cancers. This report illustrates the case of one patient with oligoprogressive thyroid cancer during therapy with lenvatinib. We found that the application of local ablative therapy in oligoprogressive disease prolonged the progression-free survival and thus extended the time to therapy interruption. However, the optimal care for TKI-treated oligoprogressive cancers remains unclear and needs to be investigated in prospective trials.

Hypofractionated Image-Guided Radiation Therapy With Simultaneous-Integrated Boost Technique for Limited Metastases: A Multi-Institutional Analysis

Purpose: To perform a multi-institutional analysis following treatment of limited osseous and/or nodal metastases in patients using a novel hypofractionated image-guided radiotherapy with simultaneous-integrated boost (HIGRT-SIB) technique.

Methods: Consecutive patients treated with HIGRT-SIB for ≤5 active metastases at Duke University Medical Center or Durham Veterans' Affairs Medical Center between 2013 and 2018 were analyzed to determine toxicities and recurrence patterns following treatment. Most patients received 50 Gy to the PTV_boost and 30 Gy to the PTV_elect simultaneously in 10 fractions. High-dose treatment volume recurrence (HDTVR) and low-dose treatment volume recurrence (LDTVR) were defined as recurrences within PTV_boost and PTV_elect, respectively. Marginal recurrence (MR) was defined as recurrence outside PTV_elect, but within the adjacent bone or nodal chain. Distant recurrence (DR) was defined as recurrences not meeting HDTVR, LDTVR, or MR criteria. Freedom from pain recurrence (FFPR) was calculated in patients with painful osseous metastases prior to HIGRT-SIB. Outcome rates were estimated at 12 months using the Kaplan-Meier method.

Results: Forty-two patients met inclusion criteria with 59 sites treated with HIGRT-SIB (53% nodal and 47% osseous). Median time from diagnosis to first metastasis was 31 months and the median age at HIGRT-SIB was 69 years. The most common primary tumors were prostate (36%), gastrointestinal (24%), and lung (24%). Median follow-up was 11 months. One acute grade ≥3 toxicity (febrile neutropenia) occurred after docetaxel administration immediately following HIGRT-SIB. Four patients developed late grade ≥3 toxicities: two ipsilateral vocal cord paralyzes and two vertebral compression fractures. The overall pain response rate was 94% and the estimated FFPR at 12 months was 72%. The estimated 12 month rate of HDTVR, LDTVR, MR, and DR was 3.6, 6.2, 7.6, and 55.8%, respectively. DR preceded MR, HDTVR, or LDTVR in each instance. The estimated 12 month probability of in-field and marginal control was 90.0%.

Conclusion: Targeting areas at high-risk for occult disease with a lower radiation dose, while simultaneously boosting gross disease with HIGRT in patients with limited osseous and/or nodal metastases, has a high rate of treated metastasis control, a low rate of MR, acceptable toxicity, and high rate of pain palliation. Further investigation with prospective trials is warranted.

The Dandelion Dilemma Revisited for Oligoprogression: Treat the Whole Lawn or Weed Selectively?

Oligoprogressive disease is a relatively new clinical concept describing progression at only a few sites of metastasis in patients with otherwise controlled widespread disease. In the era of well-tolerated targeted treatments, resistance inevitably occurs and overcoming this is a challenge. Local ablative therapy for oligoprogressive disease may allow the continuation of systemic treatments by overcoming the few sub-clones that have developed resistance. Stereotactic body radiotherapy is now frequently used in treating oligometastatic disease using ablative doses with minimally invasive techniques and acceptable toxicity. We discuss the current retrospective clinical evidence base supporting the use of local ablative therapy for oligoprogression in metastatic patients on targeted treatments within multiple tumour sites. As there is currently a lack of published prospective data available, the best management for these patients remains unclear. We discuss current trials in recruitment and the potential advancements in treating this group of patients with stereotactic radiotherapy.

Utilization of stereotactic ablative radiotherapy in oligometastatic & oligoprogressive skeletal metastases: Results and pattern of failure

AIM

To evaluate the outcome and toxicities of stereotactic ablative radiotherapy (SABR) for skeletal metastasis in a tertiary cancer center.

METHODS

This is a retrospective review of 22 patients treated with SABR for skeletal metastases for oligometastases (OM) or oligoprogression (OP) since October 2012. There are a total of 27 treatments with 20 spinal and seven non-spinal metastases. Treatment outcome including local control (LC), progression-free survival (PFS), overall survival (OS), pain control, treatment-related toxicity and failure pattern are described. Patients are assessed by interval computed tomography (CT), positron emission tomography-CT, magnetic resonance imaging or bone scintigraphy by physicians' discretion. Toxicities are graded by common toxicities criteria version 4.03.

RESULT

The median age of the patients is 64 years. Primary sites include lung (50%), breast (32%), nasopharynx (9%), prostate (4.5%) and colon (4.5%). Twelve patients with OM and 10 with OP are included. Dose to most spinal and non-spinal metastases is 35 and 50 Gy, respectively, in five fractions. With a median follow up of 15.6 months, there are three local failures (1-year LC 91.2%). The median PFS and OS are 10.1 and 37.3 months, while PFS of OP and OM group is 6.6 and 10.6 months, respectively. Two-third of symptomatic patients have at least 1-year complete pain control. There are two vertebral fractures and one grade 3 esophagitis.

CONCLUSION

Our series shows excellent LC of SABR to skeletal metastases with limited toxicities in OM and OP diseases. However, its benefit of survival warrants further studies.

Canadian consensus: oligoprogressive, pseudoprogressive, and oligometastatic non-small-cell lung cancer

Background

Little evidence has been generated for how best to manage patients with non-small-cell lung cancer (nsclc) presenting with rarer clinical scenarios, including oligometastases, oligoprogression, and pseudoprogression. In each of those scenarios, oncologists have to consider how best to balance efficacy with quality of life, while maximizing the duration of each line of therapy and ensuring that patients are still eligible for later options, including clinical trial enrolment.

Methods

An expert panel was convened to define the clinical questions. Using case-based presentations, consensus practice recommendations for each clinical scenario were generated through focused, evidence-based discussions.

Results

Treatment strategies and best-practice or consensus recommendations are presented, with areas of consensus and areas of uncertainty identified.

Conclusions

In each situation, treatment has to be tailored to suit the individual patient, but with the intent of extending and maximizing the use of each line of treatment, while keeping treatment options in reserve for later lines of therapy. Patient participation in clinical trials examining these issues should be encouraged.

Treatment of Adrenal Metastases with Conventional or Hypofractionated Image-guided Radiation Therapy - Patterns and Outcomes

BACKGROUND/AIM

Metastases involving the adrenal glands can be treated surgically or with radiation therapy. Retrospective studies indicate that radiotherapy for this indication is safe, well-tolerated and associated with symptom palliation and good local control. We conducted this analysis to report on patterns and outcomes of patients with adrenal metastases treated with hypo- or conventionally fractionated image-guided radiotherapy.

PATIENTS AND METHODS

Patients with adrenal metastases from solid tumors treated at our department between 01/2010-12/2017 were reviewed. A total of 22 lesions were treated in 18 patients with a median dose of 35 Gy (20-60 Gy) in a median number of 7 (4-25) fractions.

RESULTS

No grade ≥3 toxicity occurred. Median overall survival was 11.9 months. Five local failures occurred (22.7%). Lesion sizes or radiation dose were not correlated with local control. Patients treated for oligometastatic and oligoprogressive disease had a median overall survival of 33 and 6.5 months, respectively (palliative/polymetastatic: 1.6 months). Symptoms improved in all patients treated for clinically apparent lesions.

CONCLUSION

Stereotactic radiotherapy of adrenal metastases was safe and effective in patients with oligometastases or oligoprogression. In palliative patients, short-course radiotherapy complemented with supportive care should be preferred.

Crizotinib plus radiotherapy in brain oligoprogressive NSCLC ROS1 rearranged and PD-L1 strong

ROS1+ patients represent a unique molecular subset of non-small cell lung cancer (NSCLC). Early phase clinical trials have shown a high response rate to crizotinib in these patients. We describe a case of an 18 years old woman, never smoker, with NSCLC ROS1+ and miliary brain metastases treated with crizotinib and radiotherapy. From October 2014 to June 2015 the Patient was treated with crizotinib. The first intracranial time to progression (IT-TTP) occurred after 7 months; the patient underwent stereotactic radiosurgery (SRS) and continued TKI treatment. The second IT-TTP appeared after 16 months. A continued response in the chest was observed for all the 23 months of crizotinib treatment. At the progression, we assessed programmed death ligand 1 (PD-L1) expression by immunohistochemistry, that resulted highly expressed. Our report indicates that the integration of crizotinib with local treatments should be considered in ROS1 NSCLC patients experiencing oligometastatic progression. Moreover, this case is an example of PD-L1 strong in oncogene addicted patients.

Outcome of oligoprogressing metastatic renal cell carcinoma patients treated with locoregional therapy: a multicenter retrospective analysis

Locoregional treatment with radical intent should be considered during therapy with targeted agents in patients with metastatic renal cell carcinoma (mRCC) in order to achieve a complete response, especially in the setting of an oligo-progression in one or more metastatic sites.

We retrospectively enrolled 55 patients who experienced a disease oligo-progression after at least 6 months from the beginning of first-line therapy in one or more metastatic sites radically treated with locoregional treatments. Post-first-oligo-progression overall survival (PFOPOS) and post-first-oligo-progression free survival (PFOPFS) were evaluated.

The global median PFOPOS and PFOPFS were 37 months and 14 months respectively. Patients who continued the same therapy after a locoregional treatment on a site of progression had a significantly longer mPFOPOS compared to patients who changed therapy (39 vs 11 months, p=0.014). An advantage in mPFOPOS was also observed in patients with a Memorial Sloan-Kettering Cancer Center (MSKCC) good risk score compared to patients of the intermediate risk group (39 vs 29 months, p=0.036); patients with bone metastases had a longer mPFOPOS compared to those with visceral metastases (not reached vs 31 months, p=0.045). The only independent predictor of poor prognosis, in terms of PFOPOS at multivariate analysis (p=0.007), proved out to be change of treatment after first progression.

In this paper we aim to illustrate that continuing the same systemic therapy, after a radical locoregional treatment on a site of progression, seems to be associated with a prolongation of mPFOPOS.

The Role of Radiotherapy in Epidermal Growth Factor Receptor Mutation-positive Patients with Oligoprogression: A Matched-cohort Analysis

AIMS

Almost all patients with epidermal growth factor receptor (EGFR) mutations will develop resistance to first-line EGFR tyrosine kinase inhibitors (TKIs). The management of oligoprogression on EGFR TKI is controversial. Irradiating progressing tumours may potentially eradicate the resistant clone and allow continuation of EGFR TKI, but the clinical data remain sparse. We aimed to assess the effect of radiotherapy on survival outcomes in patients with oligoprogression in a matched-cohort study.

MATERIALS AND METHODS

This was a retrospective matched-cohort study comparing patients with EGFR mutation-positive stage IV non-small cell lung cancer receiving radiotherapy versus chemotherapy for progression. Patients in the radiotherapy group received radiotherapy (mainly stereotactic ablative radiotherapy) for oligoprogression, whereas the chemotherapy group received only systemic chemotherapy upon progression. Key prognostic factors including gender, age, performance status, time to first progression and mutation subtypes were matched.

RESULTS

Twenty-five patients with oligoprogression (radiotherapy group) were identified, and a matched chemotherapy group with the same number of patients was generated. The median duration of follow-up was 24.3 and 34 months for the radiotherapy and chemotherapy groups, respectively. The median overall survival of the radiotherapy group was significantly longer than the chemotherapy group, 28.2 versus 14.7 months (P = 0.026). The median progression-free survival (PFS) was 7.0 and 4.1 months after radiotherapy and chemotherapy, respectively (P = 0.0017). The use of radiotherapy was an independent predictive factor of overall survival and PFS in multivariate analysis. Only one patient had ≥grade 3 toxicity after radiotherapy. The frequency of secondary T790M mutation and subsequent Osimertinib exposure were similar in both groups.

CONCLUSION

Radiotherapy may effectively extend EGFR TKI therapy for patients with oligoprogression on TKI. Improved PFS and overall survival were observed, although potential biases should not be overlooked. Further randomised studies are warranted.

Stereotactic body radiation therapy for oligoprogression of metastatic disease from gastrointestinal cancers: A novel approach to extend chemotherapy efficacy

Chemotherapy and targeted therapies are effective palliative options for numerous unresectable or metastatic cancers. However, treatment resistance inevitably develops leading to mortality. In a subset of patients, systemic therapy appears to control the majority of tumors leaving 5 or less to progress, a phenomenon described as oligoprogression. Reasoning that the majority of lesions remain responsive to ongoing systemic chemotherapy, we hypothesized that local treatment of the progressing lesions would confer a benefit. The present study describes the cases of 5 patients whose metastatic disease was largely controlled by chemotherapy. The oligoprogressive lesions (≤5) were treated with stereotactic body radiotherapy (SBRT), justifying continued use of an effective systemic regimen. A total of 5 patients with metastatic disease on chemotherapy, with ≤5 progressing lesions amenable to SBRT, were treated with ablative intent. Primary tumor site and histology were as follows: 2 with metastatic colon adenocarcinoma, 2 with metastatic rectal adenocarcinoma and 1 with metastatic pancreatic adenocarcinoma. Imaging was performed prior to SBRT and every 3 months after SBRT. In total, 4 out of the 5 patients achieved disease control for >7 months with SBRT, without changing chemotherapy regimen. The median time to chemotherapy change was 9 months, with a median follow-up time of 9 months. The patient who failed to respond developed progressive disease outside of the SBRT field at 3 months. In conclusion, the addition of SBRT to chemotherapy is an option for the overall systemic control of oligoprogressive disease.

The role of local ablative therapy in oligometastatic non-small-cell lung cancer: hype or hope

In recent years, the emergence of the oligometastatic state has called into question whether patients found to have a limited or low metastatic tumor burden may benefit from locally ablative therapy (LAT). In the past two decades, stereotactic body radiation therapy has been increasingly used to safely deliver LAT and provide high local control in nonoperable non-small-cell lung cancer patients. Mostly retrospective analyses suggest that using LAT for oligometastatic disease in non-small-cell lung cancer offers excellent local control and may provide an improvement in progression-free survival. Any meaningful improvement in cancer-specific survival remains debatable. We examine the role of integrating LAT in this patient population and the rationale behind its use in combination with targeted therapy and immunotherapy.