Addition of Metastasis-Directed Therapy to Intermittent Hormone Therapy for Oligometastatic Prostate Cancer: The EXTEND Phase 2 Randomized Clinical Trial

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.

Overview of Radiation Therapy in the Management of Localized and Metastatic Prostate Cancer

PURPOSE OF REVIEW

The goal is to describe the evolution of radiation therapy (RT) utilization in the management of localized and metastatic prostate cancer.

RECENT FINDINGS

Long term data for a variety of hypofractionated definitive RT dose-fractionation schemes has matured, allowing patients and providers many standard-of-care options to choose from. Post-prostatectomy, adjuvant RT has largely been replaced by an early salvage approach. Multiparametric MRI and PSMA PET have enabled increasingly targeted RT delivery to the prostate and oligometastatic tumors. Areas of active investigation include determining the value of proton beam therapy and perirectal spacers, and optimally incorporate genomic tumor profiling and next generation hormonal therapies with RT in the curative setting. The use of radiation therapy to treat prostate cancer is rapidly evolving. In the coming years, there will be continued improvements in a variety of areas to enhance the value of RT in multidisciplinary prostate cancer management.

Genomic Determinants Associated with Modes of Progression and Patterns of Failure in Metachronous Oligometastatic Castration-sensitive Prostate Cancer

BACKGROUND AND OBJECTIVE

Oligometastatic castration-sensitive prostate cancer (omCSPC) represents an early state in the progression of metastatic disease for which patients experience better outcomes in comparison to those with higher disease burden. Despite the generally more indolent nature, there is still much heterogeneity, with some patients experiencing a more aggressive clinical course unexplained by clinical features alone. Our aim was to investigate correlation of tumor genomics with the mode of progression (MOP) and pattern of failure (POF) following first treatment (metastasis-directed and/or systemic therapy) for omCSPC.

METHODS

We performed an international multi-institutional retrospective study of men treated for metachronous omCSPC who underwent tumor next-generation sequencing with at least 1 yr of follow-up after their first treatment. Descriptive MOP and POF results are reported with respect to the presence of genomic alterations in pathways of interest. MOP was defined as class I, long-term control (LTC; no radiographic progression at last follow-up), class II, oligoprogression (1-3 lesions), or class III, polyprogression (≥4 lesions). POF included the location of lesions at first failure. Genomic pathways of interest included TP53, ATM, RB1, BRCA1/2, SPOP, and WNT (APC, CTNNB1, RNF43). Genomic associations with MOP/POF were compared using χ2 tests. Exploratory analyses revealed that the COSMIC mutational signature and differential gene expression were also correlated with MOP/POF. Overall survival (OS) was calculated via the Kaplan-Meier method from the time of first failure.

KEY FINDINGS AND CLINICAL IMPLICATIONS

We included 267 patients in our analysis; the majority had either one (47%) or two (30%) metastatic lesions at oligometastasis. The 3-yr OS rate was significantly associated with MOP (71% for polyprogression vs 91% for oligoprogression; p = 0.005). TP53 mutation was associated with a significantly lower LTC rate (27.6% vs 42.3%; p = 0.04) and RB1 mutation was associated with a high rate of polyprogression (50% vs 19.9%; p = 0.022). Regarding POF, bone failure was significantly more common with tumors harboring TP53 mutations (44.8% vs25.9%; p = 0.005) and less common with SPOP mutations (7.1% vs 31.4%; p = 0.007). Visceral failure was more common with tumors harboring either WNT pathway mutations (17.2% vs 6.8%, p = 0.05) or SPOP mutations (17.9% vs 6.3%; p = 0.04). Finally, visceral and bone failures were associated with distinct gene-expression profiles.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Tumor genomics provides novel insight into MOP and POF following treatment for metachronous omCSPC. Patients with TP53 and RB1 mutations have a higher likelihood of progression, and TP53, SPOP, and WNT pathway mutations may have a role in metastatic organotropism.

PATIENT SUMMARY

We evaluated cancer progression after a first treatment for metastatic prostate cancer with up to five metastases. We found that mutations in certain genes were associated with the location and extent of further metastasis in these patients.

Systemic and Tumor-directed Therapy for Oligorecurrent Metastatic Prostate Cancer (SATURN): Primary Endpoint Results from a Phase 2 Clinical Trial

Nearly all men with metastatic hormone-sensitive prostate cancer treated with intermittent androgen deprivation therapy (ADT) experience recurrence within 6 mo of testosterone recovery. We conducted a single-arm phase 2 trial to evaluate whether addition of dual androgen receptor pathway inhibitors (ARPIs) and metastasis-directed stereotactic body radiotherapy (SBRT) to intermittent ADT improves recurrence rates for men with between one and five nonvisceral, extrapelvic metastases on prostate-specific membrane antigen positron emission tomography/computed tomography after prior radical prostatectomy. Patients received 6 mo of androgen annihilation therapy (AAT; leuprolide, abiraterone acetate plus prednisone, and apalutamide) and metastasis-directed SBRT. The primary endpoint was the percentage of patients with prostate-specific antigen (PSA) <0.05 ng/ml 6 mo after testosterone recovery (≥150 ng/dl), with the study powered to detect an improvement from 1% to 12%. We enrolled 28 men between March 2021 and June 2022. Median follow-up was 20 mo (interquartile range 16-22). Twenty-six patients (93%) completed SBRT with 6 mo of hormone therapy, of whom six discontinued at least one ARPI; two patients withdrew prematurely. At 6 mo after testosterone recovery, PSA was maintained at <0.05 ng/ml in 13/26 patients (50%, 95% confidence interval 32-67%). Rates of grade 2 and 3 AAT toxicity were 21% and 21%. The results confirm that addition of metastasis-directed SBRT to highly potent systemic therapy can maintain low PSA after testosterone recovery, although further studies are needed to clarify the optimal systemic therapy regimen. PATIENT SUMMARY: We tested a combination of intensified hormone therapy (called androgen annihilation therapy) and radiotherapy targeted at metastases in men with recurrence of metastatic prostate cancer. We found that half of patients were recurrence-free 6 months after their testosterone level recovered, and that less than a quarter of patients experienced a severe drug-related side effect. Overall, this appears to be an effective therapy with acceptable side effects. This trial is registered on ClinicalTrials.gov as NCT03902951.

Balancing Hormone Therapy: Mitigating Adverse Effects of Androgen-Deprivation Therapy and Exploring Alternatives in Prostate Cancer Management

Androgen-deprivation therapy (ADT) is well established as the standard of care in metastatic prostate cancer (PCa) management; however, ADT has significant adverse effects (AEs) that must be addressed. This review aims to highlight opportunities to mitigate AEs of ADT and explore alternatives in PCa management. Specifically, we discuss behavioral and pharmacologic strategies for mitigating ADT AEs as well as ADT-sparing approaches for hormone-sensitive and castration-resistant PCa. Equipped with effective mitigation strategies and possible alternatives, clinicians and researchers can optimize health-related quality of life for patients currently receiving ADT for PCa and consider treatments that spare patients from AEs of ADT.

Cancer-specific dose and fractionation schedules in stereotactic body radiotherapy for oligometastatic disease: An interim analysis of the EORTC-ESTRO E2-RADIatE OligoCare study

BACKGROUND AND INTRODUCTION

Optimal dose and fractionation in stereotactic body radiotherapy (SBRT) for oligometastatic cancer patients remain unknown. In this interim analysis of OligoCare, we analyzed factors associated with SBRT dose and fractionation.

MATERIALS AND METHODS

Analysis was based on the first 1,099 registered patients. SBRT doses were converted to biological effective doses (BED) using α/β of 10 Gy for all primaries, and cancer-specific α/β of 10 Gy for non-small cell lung and colorectal cancer (NSCLC, CRC), 2.5 Gy for breast cancer (BC), or 1.5 Gy for prostate cancer (PC).

RESULTS

Of the interim analysis population of 1,099 patients, 999 (99.5 %) fulfilled inclusion criteria and received metastasis-directed SBRT for NSCLC (n = 195; 19.5 %), BC (n = 163; 16.3 %), CRC (n = 184; 18.4 %), or PC (n = 457; 47.5 %). Two thirds of patients were treated for single metastasis. Median number of fractions was 5 (IQR, 3-5) and median dose per fraction was 9.7 (IQR, 7.7-12.4) Gy. The most frequently treated sites were non-vertebral bone (22.8 %), lung (21.0 %), and distant lymph node metastases (19.0 %). On multivariate analysis, the dose varied significantly for primary cancer type (BC: 237.3 Gy BED, PC 300.6 Gy BED, and CRC 84.3 Gy BED), and metastatic sites, with higher doses for lung and liver lesions.

CONCLUSION

This real-world analysis suggests that SBRT doses are adjusted to the primary cancers and oligometastasis location. Future analysis will address safety and efficacy of this site- and disease-adapted SBRT fractionation approach (NCT03818503).

Challenges and Opportunities in Establishing Appropriate Intermediate Endpoints Reflecting Patient Benefit: A Roadmap for Research and Clinical Application in Nonmetastatic Prostate Cancer

Defining meaningful endpoints for research of early-stage high-risk prostate cancer is challenging, with established measures such as overall survival and metastasis-free survival facing limitations related to feasibility and adequate reflection of patient relevance. Developing endpoints must cater to diverse perspectives across scientific, clinical, regulatory, and patient viewpoints. Endpoints such as pathological complete response, no evidence of disease, and prevention of prostate-specific antigen relapse may reflect patient benefit by accounting for diagnostic and treatment burdens.

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

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

Optimal systemic therapy in men with low-volume prostate cancer

PURPOSE OF REVIEW

Low-volume prostate cancer is an established prognostic category of metastatic hormone-sensitive prostate cancer. However, the term is often loosely used to reflect the low burden of disease across different prostate cancer states. This review explores the definitions of low-volume prostate cancer, biology, and current evidence for treatment. We also explore future directions, including the impact of advanced imaging modalities, particularly prostate-specific membrane antigen (PSMA) positron emission tomography (PET) scans, on refining patient subgroups and treatment strategies for patients with low-volume prostate cancer.

RECENT FINDINGS

Recent investigations have attempted to redefine low-volume disease, incorporating factors beyond metastatic burden. Advanced imaging, especially PSMA PET, offers enhanced accuracy in detecting metastases, potentially challenging the conventional definition of low volume. The prognosis and treatment of low-volume prostate cancer may vary by the timing of metastatic presentation. Biomarker-directed consolidative therapy, metastases-directed therapy, and de-escalation of systemic therapies will be increasingly important, especially in patients with metachronous low-volume disease.

SUMMARY

In the absence of validated biomarkers, the management of low-volume prostate cancer as defined by CHAARTED criteria may be guided by the timing of metastatic presentation. For metachronous low-volume disease, we recommend novel hormonal therapy (NHT) doublets with or without consolidative metastasis-directed therapy (MDT), and for synchronous low-volume disease, NHT doublets with or without consolidative MDT and prostate-directed radiation. Docetaxel triplets may be a reasonable alternative in some patients with synchronous presentation. There is no clear role of docetaxel doublets in patients with low-volume disease. In the future, a small subset of low-volume diseases with oligometastases selected by genomics and advanced imaging like PSMA PET may achieve long-term remission with MDT with no systemic therapy.

Role of Metastasis-Directed Therapy in Genitourinary Cancers

OPINION STATEMENT

The treatment of oligometastatic genitourinary cancers is a rapidly advancing field with ablative radiotherapy as one of the critical treatment components. The oligometastatic disease state, which can be defined as 1-5 metastatic sites with a controlled primary, represents a distinct clinical state where comprehensive ablative local therapies may provide improved outcomes. Enhanced imaging has increased the number of patients identified with oligometastatic disease. Evidence for improved outcomes with metastasis-directed therapy (MDT) in oligometastatic genitourinary cancers is increasing, and previously published outcome data continues to mature with an increasing body of prospective data to inform the role of MDT in histology-specific settings or in the context of systemic therapy. In select patients, MDT can offer benefits beyond improved local control and allow for time off of systemic therapy, prolonged time until next therapy, or even the hope of cure. However, treatment decisions for locally ablative therapy must be balanced with consideration towards safety. There are exciting advances in technologies to target and adapt treatment in real-time which have expanded options for safer delivery and dose escalation to metastatic targets near critical organs at risk. The role of systemic therapies in conjunction with MDT and incorporation of tumor genetic information to further refine prognostication and treatment decision-making in the oligometastatic setting is actively being investigated. These developments highlight the evolving field of treatment of oligometastatic disease. Future prospective studies combining MDT with enhanced imaging and integrating MDT with evolving systemic therapies will enable the optimal selection of patients most likely to benefit from this "all-or-none" approach and reveal settings in which a combination of therapies could result in synergistic outcomes.

Stereotactic ablative radiation therapy in metastatic prostate cancer

PURPOSE OF REVIEW

The evolving role of stereotactic ablative radiation therapy (SABR) as metastasis-directed therapy (MDT) for oligometastatic prostate cancer (omPCa) will be discussed.

RECENT FINDINGS

Oligometastatic disease (OMD) is an intermediate state between localized and wide-spread malignant disease. OMD has recently been spotlighted given the increasing demonstration of clinical benefit from local therapies despite presence of metastatic disease and allure of the curative potential of MDT in select cases. Among the different forms of MDT, SABR has rapidly become a widely adopted treatment modality. Significant efforts in this space have focused on omPCa, owing to its relatively indolent biology, presence of a sensitive and specific serum biomarker and recent advances in molecular imaging. While most studies have evaluated the role of SABR MDT in hormone sensitive omPCa, new emerging clinical data also suggests benefits of SABR MDT for even castration-resistant disease.

SUMMARY

Treating omPCa with SABR MDT appears to generate an efficacy signal with minimal morbidity across both hormone-sensitive and castration-resistant disease. However, additional definitive omPCa trial data are needed. Future research efforts should investigate biomarkers for this heterogeneous disease space and the role of SABR MDT in combination with systemic agents to improve upon standard of care treatments.

Multi-institutional Analysis of Metastasis-directed Therapy with or Without Androgen Deprivation Therapy in Oligometastatic Castration-sensitive Prostate Cancer

BACKGROUND

Metastasis-directed therapy (MDT) is increasingly being used in oligometastatic castration-sensitive prostate cancer (omCSPC). However, it is currently unclear how to optimally integrate MDT with the standard of care of systemic hormonal therapy.

OBJECTIVE

To report long-term outcomes of MDT alone versus MDT and a defined course of androgen deprivation therapy (ADT) in omCSPC.

DESIGN, SETTING, AND PARTICIPANTS

Here, a multicenter, international retrospective cohort of omCSPC as defined by conventional imaging was reported.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Biochemical progression-free survival (bPFS), distant progression-free survival (dPFS), and combined biochemical or distant progression-free survival (cPFS) were evaluated with Kaplan-Meier and multivariable Cox proportional hazard regression models.

RESULTS AND LIMITATIONS

A total of 263 patients were included, 105 with MDT + ADT and 158 with MDT alone. The majority of patients had metachronous disease (90.5%). Five-year bPFS, dPFS, and cPFS were, respectively, 24%, 41%, and 19% in patients treated with MDT + ADT and 11% (hazard ratio [HR] 0.48, 95% confidence interval [CI] 0.36-0.64), 29% (HR 0.56, 95% CI 0.40-0.78), and 9% (HR 0.50, 95% CI 0.38-0.67) in patients treated with MDT alone. On a multivariable analysis adjusting for pretreatment variables, the use of ADT was associated with improved bPFS (HR 0.43, p < 0.001), dPFS (HR 0.45, p = 0.002), and cPFS (HR 0.44, p < 0.001).

CONCLUSIONS

In this large multi-institutional report, the addition of concurrent ADT to MDT appears to improve time to prostate-specific antigen progression and distant recurrence, noting that about 10% patients had durable control with MDT alone. Ongoing phase 3 studies will help further define treatment options for omCSPC.

PATIENT SUMMARY

Here, we report a large retrospective review evaluating the outcomes of metastasis-directed therapy with or without a limited course of androgen deprivation for patients with oligometastatic castration-sensitive prostate cancer. This international multi-institutional review demonstrates that the addition of androgen deprivation therapy to metastasis-directed therapy (MDT) improves progression-free survival. While a proportion of patients appear to have long-term disease control with MDT alone, further work in biomarker discovery is required to better identify which patients would be appropriate for de-escalated therapy.

Expert Perspectives on Controversies in Castration-Sensitive Prostate Cancer Management: Narrative Review and Report of the First US Prostate Cancer Conference Part 1

Purpose

Castration-sensitive prostate cancer (CSPC) is a complex and heterogeneous condition encompassing a range of clinical presentations. As new approaches have expanded management options, clinicians are left with myriad questions and controversies regarding the optimal individualized management of CSPC.

Materials and Methods

The US Prostate Cancer Conference (USPCC) multidisciplinary panel was assembled to address the challenges of prostate cancer management. The first annual USPCC meeting included experts in urology, medical oncology, radiation oncology, and nuclear medicine. USPCC co-chairs and session moderators identified key areas of controversy and uncertainty in prostate cancer management and organized the sessions with multidisciplinary presentations and discussion. Throughout the meeting, experts responded to questions prepared by chairs and moderators to identify areas of agreement and controversy.

Results

The USPCC panel discussion and question responses for CSPC-related topics are presented. Key advances in CSPC management endorsed by USPCC experts included the development and clinical utilization of gene expression classifiers and artificial intelligence (AI) models for risk stratification and treatment selection in specific patient populations, the use of advanced imaging modalities in patients with clinically localized unfavorable intermediate or high-risk disease and those with biochemical recurrence, recommendations of doublet or triplet therapy for metastatic CSPC (mCSPC), and consideration of prostate and/or metastasis-directed radiation therapy in select patients with mCSPC.

Conclusions

CSPC is a diverse disease with many therapeutic options and the potential for adverse outcomes associated with either undertreatment or overtreatment. Future studies are needed to validate and clinically integrate novel technologies, including genomics, AI, and advanced imaging, to optimize outcomes among patients with CSPC.

Global research landscape and trends of cancer radiotherapy plus immunotherapy: A bibliometric analysis

The aim of this study was to present current research trends on the synergistic use of radiotherapy and immunotherapy (IRT) for cancer treatment. On March 1, 2023, we conducted a literature search for IRT papers using the Web of Science database. We extracted information and constructed two databases - the Core Database (CD) with 864 papers and Generalized Database (GD) with 6344 papers. A bibliometric analysis was performed to provide insights into the research landscape, to identify emerging trends and highly cited papers and journals in the field of IRT. The CD contained 864 papers that were collectively cited 31,818 times. Prominent journals in this area included the New England Journal of Medicine, Lancet Oncology, and the Journal of Clinical Oncology. Corresponding authors from the USA contributed the most publications. In recent years, lung cancer, melanoma, stereotactic radiotherapy, immune checkpoint inhibitors, and the tumor microenvironment emerged as hot research areas. This bibliometric analysis presented quantitative insights into research concerning IRT and proposed potential avenues for further exploration. Moreover, researchers can use our findings to select appropriate journals for publication or identify prospective collaborators. In summary, this bibliometric analysis provides a comprehensive overview of the historical progression and recent advancements in IRT research that may serve as inspiration for future investigations.

[Metastasis-directed therapy in prostate cancer]

BACKGROUND

Metastasis-directed therapy (MDT) in oligometastatic prostate cancer (omHSPC) is playing an increasingly important role in therapy with the aim of delaying disease progression, the start of systemic treatment or switching systemic treatment to improve the patient's overall prognosis. Molecular imaging as prostate-specific membrane antigen positron emission tomography (PSMA-PET) imaging allows metastases to be detected with a higher sensitivity and specificity. This means that they can be detected early and made accessible for treatment.

RESULTS

The standard therapy for oligo-mHSPC is androgen deprivation (ADT), which is supplemented by novel hormonal therapeutics (NHT). A few small prospective trials have shown an extension of the ADT-free interval and progression-free survival (PFS), particularly in metachronous oligo-mHSPC, by MDT, usually radiotherapy. Additional ADT can further extend the PFS in particular. There are hardly any prospective data for synchronous oligo-mHSPC.

CONCLUSION

Despite the currently still poor evidence, MDT is playing an increasingly important role. The still unclear definition of oligometastasis and the large number of influencing factors make it difficult to compare current data. Large multicenter prospective data are still pending. It is also important to clarify the effect of limited ADT in combination with NHT in the treatment of synchronous and metachronous oligo-mHSPC with MDT. In synchronous oligo-mHSPC in particular, further benefit of additional local therapy of the primary in combination with MDT should also be investigated.

Prostate cancer presentation and management in the Middle East

BACKGROUND

Although prostate cancer is a prevalent malignancy worldwide, its clinical presentation and management in the Middle East are not well-documented. This study aims to provide insights into the initial clinical presentation and management of prostate cancer in this region.

METHODS

A retrospective review was conducted on seven institutional databases from six Middle Eastern countries, including Türkiye, Lebanon, Iraq, Syria, Bahrain, and Jordan, to identify patients diagnosed with prostate cancer in 2021. Descriptive analysis was performed on the collected data to provide an overview of the demographic, clinical, and treatment variables.

RESULTS

A total of 1,136 patients were identified with a median age of 70 (range, 50-84). Most patients (78%) received their prostate cancer diagnosis after presenting with symptoms, as opposed to routine PSA screening. At the time of diagnosis, 35% of men had clinical T3 or T4 disease, 54% with Stage IV disease and 50% with Gleason score ≥ 8. Regarding treatment, 20% of non-metastatic and 22% of metastatic patients received no treatment.

CONCLUSION

Most men in this study sought prostate cancer evaluation due to symptoms and were subsequently diagnosed with advanced-stage disease, providing a foundation for future research aimed at understanding the underlying factors behind the observed trends and enabling informed interventions.

Impact of PSMA PET on Prostate Cancer Management

OPINION STATEMENT

PSMA-PET has been a practice-changing imaging biomarker for the management of men with PCa. Research suggests improved accuracy over conventional imaging and other PET radiotracers in many contexts. With multiple approved PSMA-targeting radiotracers, PSMA PET will become even more available in clinical practice. Its increased use requires an understanding of the prospective data available and caution when extrapolating from prior trial data that utilized other imaging modalities. Future trials leveraging PSMA PET for treatment optimization and management decision-making will ultimately drive its clinical utility.

Applications of model simulation in pharmacological fields and the problems of theoretical reliability

The use of mathematical models has become increasingly prevalent in pharmacological fields, particularly in drug development processes. These models are instrumental in tasks such as designing clinical trials and assessing factors like efficacy, toxicity, and clinical practice. Various types of models have been developed and documented. Nevertheless, emphasizing the reliability of parameter values is crucial, as they play a pivotal role in shaping the behavior of the system. In some instances, parameter values reported previously are treated as fixed values, which can lead to convergence towards values that deviate substantially from those found in actual biological systems. This is especially true when parameter values are determined through fitting to limited observations. To mitigate this risk, the reuse of parameter values from previous reports should be approached with a critical evaluation of their validity. Currently, there is a proposal for a simultaneous search for plausible values for all parameters using comprehensive search algorithms in both pharmacokinetic and pharmacodynamic or systems pharmacological models. Implementing these methodologies can help address issues related to parameter determination. Furthermore, integrating these approaches with methods developed in the field of machine-learning field has the potential to enhance the reliability of parameter values and the resulting model outputs.

What is the predictive value of RECIST criteria following stereotactic lung radiation?

PURPOSE

Response EvaluationCriteriain Solid Tumors (RECIST) is commonly used to assess response to anti-cancer therapies. However, its application after lung stereotactic ablative radiotherapy (SABR) is complicated by radiation-induced lung changes. This study assesses the frequency of progressive disease (PD) by RECIST following lung SABR and correlates this with actual treatment outcomes as determined by longitudinal follow-up.

METHODS AND MATERIALS

We reviewed patients treated with lung SABR for primary lung tumors or oligometastases between 2010 and 2015. Patients were treated with SABR doses of 54-60 Gy in 3-8 fractions. All follow-up scans were assessed and the treated lesion was serially measured over time, with the maximum diameter on axial CT slices used for RECIST calculations. Lesions demonstrating PD by RECIST criteria were identified and subsequently followed for long-term outcomes. The final 'gold-standard' assessment of response was based on size changes after PD and, as available, positron emission tomography scan and/or biopsy.

RESULTS

Eighty-eight lesions met inclusion criteria. Seventy-five were lung primaries and thirteen were lung metastases. Median follow-up was 52 months (interquartile range: 33-68). Two-thirds (66 %, 58/88) of treated lesions met RECIST criteria for PD; however, local recurrence was only confirmed in 16 % (9/58) of cases. Most lesions that triggered PD by RECIST (47/58, 81 %) were ultimately found not to represent recurrence, while a minority (2/58, 3 %) had an uncertain response. The positive predictive value [PPV] of a RECIST defined PD event was 0.16. If PD was triggered within 12-months post-treatment, PPV was 0.08, compared to 0.21 for lesions triggering PD after 12-months.

CONCLUSION

Using RECIST criteria, two-thirds of patients treated with lung SABR met criteria for PD. However, only a minority had recurrence, leading to a poor PPV of RECIST. This highlights the limitations of RECIST in this setting and provides context for physicians when interpreting post-lung SABR imaging.

The diagnosis and treatment of castrate-sensitive oligometastatic prostate cancer: A review

BACKGROUND

Oligometastatic prostate cancer (OMPCa) is emerging as a transitional disease state between localized and polymetastatic disease. This review will assess the current knowledge of castrate-sensitive OMPCa.

METHODS

A review of the current literature was performed to summarize the definition and classification of OMPCa, assess the diagnostic methods and imaging modalities utilized, and to review the treatment options and outcomes. We further identify gaps in knowledge and areas for future research.

RESULTS

Currently there is no unified definition of OMPCa. National guidelines mostly recommend systemic therapies without distinguishing oligometastatic and polymetastatic disease. Next generation imaging is more sensitive than conventional imaging and has led to early detection of metastases at initial diagnosis or recurrence. While mostly retrospective in nature, recent studies suggest that treatment (surgical or radiation) of the primary tumor and/or metastatic sites might delay initiation of androgen deprivation therapy while increasing survival in selected patients.

CONCLUSIONS

Prospective data are required to better assess the incremental improvement in survival and quality of life achieved with various treatment strategies in patients with OMPCa.

Optimal combination therapy for metastatic hormone-sensitive prostate cancer: new evidence, challenges and unanswered questions

PURPOSE OF REVIEW

To evaluate the evidence supporting treatment intensification in mHSPC, with a focus on possible indications for treatment in each clinical setting.

RECENT FINDINGS

There is a growing armamentarium of treatment options for patients with metastatic hormone-sensitive prostate cancer (mHSPC). These include combinations of treatments such as androgen deprivation therapy (ADT), docetaxel, and new antiandrogenic therapies. Treatment intensification with chemotherapy or newer hormonal agents may improve patient's oncologic outcomes, but it can also come with additional toxicities and costs. Therefore, we need to take into account individual patient factors and preferences when deciding on the optimal combination therapy. Additionally, ongoing research is needed to identify biomarkers and new image techniques that can predict response to treatment and identify the best candidate for each treatment.

SUMMARY

Challenges and unanswered questions regarding treatment intensification and de-intensification are still present. Further studies are still needed to identify which patients would benefit most from this approach to improve quality of life without compromising overall survival outcomes.

Systemic therapy escalation after stereotactic body radiation therapy for oligometastatic hormone-sensitive prostate cancer

Purpose

To evaluate the oncological outcome after stereotactic body radiation therapy (SBRT) for oligometastatic hormone-sensitive prostate cancer (omHSPC) patients.

Materials-Methods

In this retrospective, observational, multi-institutional study, omHSPC patients (≤5 metastases) underwent SBRT. Primary endpoint was systemic therapy escalation-free survival (STE-FS) after SBRT. Local (LR), distant (DR), prostatic (PR) and isolated biochemical (iBR) relapses were reported with progression-free survival (PFS) and overall survival (OS). Prognostic factors for STE-FS were investigated. Toxicity was reported.

Results

From 01/07 to 09/19, 119 pts with omHSPC underwent SBRT. With a MFU of 34 months [12-97], median STE-FS was 33.4 months (95%CI 26.6---40.1). Median OS was not reached and PFS was 22.7 months (CI95% 18.6---32.3). Post-SBRT-PSA remained stable or decreased in 87 pts (73.1%). Progression events (LR, MR, PR, iBR) were observed in 72 pts (60.5%), among whom 6 relapsed in the irradiated area (local control rate: 95%). DR, BR, PR were observed in 44 pts (37%), 21pts (17.7%) and 2 pts (1.7%) respectively. In multivariate analysis, post-SBRT biochemical response was an independent prognostic factor for STE-FS. Grade ≥ 3 toxicity occurred in 1pt.

Conclusion

With excellent local control and tolerance, SBRT for omHSPC patients represents an attractive approach to defer systemic therapeutic escalation and prevent its side effects. Accurate patient selection for SBRT requires more data with longer follow-up and higher numbers of patients pending the results of upcoming randomized trials.

Advances and Challenges in Trials of Local Therapy for Patients With Oligometastatic or Oligoprogressive Disease

The paradigm of oligometastatic disease (OMD), characterized by a limited number of metastases potentially amenable to local therapies, presents unique opportunities and challenges in clinical trial design and implementation. Although local ablative therapies, such as stereotactic body radiation therapy, have shown promise in improving outcomes for patients with OMD, there is a lack of large-scale randomized phase III trials supporting their widespread use. This paper outlines the key challenges in trial design and implementation in the oligometastatic setting, including appropriate patient selection, the definition of the oligometastatic state, trial design considerations, endpoint selection, and logistical considerations related to enrollment and follow-up. We suggest potential strategies to address these challenges, emphasizing the importance of a comprehensive, patient-centric approach, and the integration of multidisciplinary teams in trial design and implementation. The aim is to encourage the design of well-structured clinical trials, ultimately refining best practices and enhancing patient outcomes in the management of OMD.

Node Oligorecurrence in Prostate Cancer: A Challenge

Within the oligometastatic state, oligorecurrent lymph node disease in prostate cancer represents an interesting clinical entity characterized by a relatively indolent biology that makes it unique: it can be treated radically, and its treatment is usually associated with a long period of control and excellent survival. Additionally, it is an emergent situation that we are facing more frequently mainly due to (a) the incorporation into clinical practice of the PSMA-PET that provides strikingly increased superior images in comparison to conventional imaging, with higher sensitivity and specificity; (b) the higher detection rates of bone and node disease with extremely low levels of PSA; and (c) the availability of high-precision technology in radiotherapy treatments with the incorporation of stereotaxic body radiotherapy (SBRT) or stereotaxic ablative radiotherapy (SABR) technology that allows the safe administration of high doses of radiation in a very limited number of fractions with low toxicity and excellent tolerance. This approach of new image-guided patient management is compelling for doctors and patients since it can potentially contribute to improving the clinical outcome. In this work, we discuss the available evidence, areas of debate, and potential future directions concerning the utilization of new imaging-guided SBRT for the treatment of nodal recurrence in prostate cancer.

Peering through the PSMA PET Lens: The Role of the European Association of Urology Biochemical Recurrence Risk Groups after Radical Prostatectomy

(1) Background: The European Association of Urology (EAU) biochemical recurrence (BCR) risk grouping relies on data from historical cohorts that used conventional imaging techniques. In the era of PSMA PET/CT, we compared the patterns of positivity in the two risk groups and provided insight into positivity predictive factors. (2) Methods: Data from 1185 patients who underwent ⁶⁸Ga-PSMA-11PET/CT for BCR was analyzed, out of which 435 patients treated initially treated by radical prostatectomy were included in the final analysis. (3) Results: A significantly higher rate of positivity in the BCR high-risk group was observed (59% vs. 36%, p < 0.001). BCR low-risk group demonstrated more local (26% vs. 6%, p < 0.001) and oligometastatic (100% vs. 81%, p < 0.001) recurrences. The BCR risk group and PSA level at the time of PSMA PET/CT were independent predictive factors of positivity. (4) Conclusions: This study confirms that the EAU BCR risk groups have different rates of PSMA PET/CT positivity. Even with a lower rate in the BCR low-risk group, oligometastatic disease was 100% in those with distant metastases. Given the presence of discordant positivity and risk classification, integrating PSMA PET/CT positivity predictors into risk calculators for BCR might improve patient classification for subsequent treatment options. Future prospective studies are still needed to validate the above findings and assumptions.