Progression-free survival in patients with 68Ga-PSMA-PET-directed SBRT for lymph node oligometastases

Stereotactic body radiation therapy on abdominal-pelvic lymph node oligometastases: a systematic review on toxicity

BACKGROUND AND PURPOSE

To review available data on toxicity during and/or after treatment of abdominal-pelvic lymph node oligometastases (A-P LN) with stereotactic body radiation therapy (SBRT) and to provide an overview of adverse events and its relation to dose or fractionation.

MATERIAL AND METHODS

For this systematic review, we searched MEDLINE, Embase, Web of Science Core Collection, and CINAH for studies published between the database inception and October 3rd, 2023. Inclusion criteria were (1) patients with 1-5 A-P LN oligometastases, (2) treatment with SBRT to a median prescribed dose of ≥55 Gy BED10, and (3) description of acute and/or late toxicity. There were no language or date restrictions.

RESULTS

A total of 35 studies, including 1,512 patients, were selected. Late grade 3 and 4 adverse events occurred in 0.6% and 0.1% of the patients treated for A-P LN oligometastases. All late adverse events grade ≥ 3 occurred after treatment of the tumor with a minimum BED10 of 72 Gy. Of the 11 patients with severe late toxicity, five patients were re-irradiated. Late grade 2 and 1 toxicity was reported in 3.4% and 8.3% of the patients. Acute toxicity grades 4, 3, 2, and 1 occurred in 0.1%, 0.2%, 4.4%, and 19.8% of the patients, respectively.

INTERPRETATION

SBRT for A-P LN oligometastases show low toxicity rates. Nearly 50% of late adverse events ≥ grade 3 were associated with re-irradiation.

Prostate-specific membrane antigen-positron emission tomography (PSMA-PET) of prostate cancer: current and emerging applications

Prostate-specific membrane antigen-positron emission tomography (PSMA-PET) is transforming the management of patients with prostate cancer. In appropriately selected patients, PSMA-PET offers superior sensitivity and specificity compared to conventional imaging (e.g., computed tomography and bone scintigraphy) as well as choline and fluciclovine PET, with the added benefit of consolidating bone and soft tissue evaluation into a single study. Despite being a newly available imaging tool, PSMA-PET has established indications, interpretation guidelines, and reporting criteria, which will be reviewed. The prostate cancer care team, from imaging specialists to those delivering treatment, should have knowledge of physiologic PSMA radiotracer uptake, patterns of disease spread, and the strengths and limitations of PSMA-PET. In this review, current and emerging applications of PSMA-PET, including appropriateness use criteria as well as image interpretation and pitfalls, will be provided with an emphasis on clinical implications.

Age 70 +/- 5 Years and Cancer-Specific Outcomes After Treatment of Localized Prostate Cancer: A Systematic Review

A secondary analysis of 2 randomized Radiation Therapy Oncology Group trials demonstrated that age ≥70 years was a favorable prognostic factor among men treated with external beam radiation therapy (EBRT). In contrast, several series based on men undergoing radical prostatectomy (RP) suggested that older age was an unfavorable prognostic factor. Our study was initiated to determine whether these observations reflect a true but paradoxical underlying age-related treatment-dependent biological phenomenon. We conducted a systematic review (PubMed, January 1, 1999-January 30, 2023) evaluating the effect of age on cancer-specific outcomes after definitive local treatment with either RP or EBRT. Our main objective was to assess possible interactions between age (using a cutoff of 70 +/- 5 years) and treatment type, with regard to adverse cancer-specific outcomes (eg, pathology, biochemical failure, distant metastasis, or prostate cancer-specific survival). Forty-five studies were selected for inclusion in this systematic review, including 30 and 15 studies with patients treated with RP and EBRT, respectively. Among patients treated with RP, 10 (50%) of these studies suggested that older age was associated with worse outcome(s) after RP. None suggested that age was a favorable prognostic factor after RP. Among the EBRT-based studies, 8 (53%) suggested that older age was associated with better outcomes, with an additional 3 studies (21%) trending to support a better outcome. None of these studies involving EBRT suggested that older age was an adverse prognostic factor. This systematic review suggests that age using a categorical cutoff of 70 +/- 5 years may be an adverse prognostic factor for men undergoing RP but a favorable prognostic factor for men treated with EBRT. Further research is needed to validate these findings.

Stereotactic Body Radiotherapy for Lymph-Nodal Oligometastatic Prostate Cancer: A Multicenter Retrospective Experience

Background: The favorable role of SBRT for lymph-nodal oligometastases from prostate cancer has been reported by several retrospective and prospective experiences, suggesting a more indolent natural history of disease when compared to patients with bone oligometastases. This retrospective multicenter study evaluates the outcomes of a cohort of patients treated with stereotactic body radiotherapy for lymph-nodal oligometastases. Methods: Inclusion criteria were up to five lymph-nodal oligometastases detected either with Choline-PET or PSMA-PET in patients naïve for ADT or already ongoing with systemic therapy and at least 6 Gy per fraction for SBRT. Only patients with exclusive lymph-nodal disease were included. The primary endpoint of the study was LC; a toxicity assessment was retrospectively performed following CTCAE v4.0. Results: A total of 100 lymph-nodal oligometastases in 69 patients have been treated with SBRT between April 2015 and November 2022. The median age was 73 years (range, 60-85). Oligometastatic disease was mainly detected with Choline-PET in 47 cases, while the remaining were diagnosed using PSMA-PET, with most of the patients treated to a single lymph-nodal metastasis (48/69 cases), two in 14 cases, and three in the remaining cases. The median PSA prior to SBRT was 1.35 ng/mL (range, 0.3-23.7 ng/mL). Patients received SBRT with a median total dose of 35 Gy (range, 30-40 Gy) in a median number of 5 (range, 3-6) fractions. With a median follow-up of 16 months (range, 7-59 months), our LC rates were 95.8% and 86.3% at 1 and 2 years. DPFS rates were 90.4% and 53.4%, respectively, at 1 and 2 years, with nine patients developing a sequential oligometastatic disease treated with a second course of SBRT. Polymetastatic disease-free survival (PMFS) at 1 and 2 years was 98% and 96%. Six patients needed ADT after SBRT for a median time of ADT-free survival of 15 months (range, 6-22 months). The median OS was 16 months (range, 7-59) with 1- and 2-year rates of both 98%. In multivariate analysis, higher LC rates and the use of PSMA-PET were related to improved DPFS rates, and OS was significantly related to a lower incidence of distant progression. No G3 or higher adverse events were reported. Conclusions: In our experience, lymph-nodal SBRT for oligometastatic prostate cancer is a safe and effective option for ADT delay with no severe toxicity.

ASO Author Reflections: PSMA PET in the Prostate Cancer Primary Staging Scenario-A Reliable Method with a Remarkable Decision-Making Impact

Prostate cancer (PCa) is the second most common malignant tumor in men in Brazil and worldwide. Although positron emission tomography (PET) prostate-specific membrane antigen (PSMA) has been used for over 10 years and several studies have been published regarding its superior performance in PCa primary staging and other scenarios, the management decision is often still based on conventional imaging information. A retrospective analysis was performed in 35 patients with PCa in the primary staging scenario with conventional exams as well as with PET PSMA. The findings of our study showed changes on the staging classification and significant impact on the therapeutic choice. PET PSMA is a dependable imaging exam and has already proved its worth and superiority when compared with conventional methods to evaluate PCa patients in primary staging and biochemical relapse, in addition to other potential roles. Prospective studies are needed to assess the outcome of patients whose management was guided by PSMA.

Feasibility and first results of the 'Trials-within-Cohorts' (TwiCs) design in patients undergoing radiotherapy for lung cancer

Background: 'Trials-within-Cohorts' (TwiCs), previously known as 'cohort multiple randomized controlled trials' is a pragmatic trial design, supporting an efficient and representative recruitment of patients for (future) trials. To our knowledge, the 'COhort for Lung cancer Outcome Reporting and trial inclusion' (COLOR) is the first TwiCs in lung cancer patients. In this study we aimed to assess the feasibility and first year results of COLOR.Material and Methods: All patients diagnosed with lung cancer referred to the Radiotherapy department were eligible to participate in the ongoing prospective COLOR study. At inclusion, written informed consent was requested for use of patient data, participation in patient-reported outcomes (PROs), and willingness to participate in (future) trials. Feasibility was studied by assessing participation and comparing baseline PROs to EORTC reference values. First-year results of PROs at baseline and 3 months after inclusion were evaluated separately for stereotactic body radiotherapy (SBRT) and conventional radiotherapy patients.Results: Of the 338 eligible patients between July 2020 and July 2021, 169 (50%) participated. Among these, 127 (75%) gave informed consent to PROs participation and 110 (65%) were willing to participate in (future) trials. The inclusion percentage dropped from 77% to 33% when the information procedure was switched from in-person to by phone (due to COVID-19 pandemic measures). Baseline PROs for physical and cognitive functioning were comparable in COLOR patients compared to the EORTC reference values. No significant changes in PROs were observed 3 months after inclusion, except for a slight increase in pain scores in the SBRT group (n = 97).Conclusions: The TwiCs-design appears feasible in lung cancer patients with fair participation rates (although negatively impacted by the COVID-19 pandemic). With a planned expansion to other centers, the COLOR-study is expected to enable multiple (randomized) evaluations of experimental interventions with important advantages for recruitment, generalizability, and long-term outcome data collection.

Genomic Classifiers in Personalized Prostate Cancer Radiation Therapy Approaches: A Systematic Review and Future Perspectives Based on International Consensus

Current risk-stratification systems for prostate cancer (PCa) do not sufficiently reflect the disease heterogeneity. Genomic classifiers (GC) enable improved risk stratification after surgery, but less data exist for patients treated with definitive radiation therapy (RT) or RT in oligo-/metastatic disease stages. To guide future perspectives of GCs for RT, we conducted (1) a systematic review on the evidence of GCs for patients treated with RT and (2) a survey of experts using the Delphi method, addressing the role of GCs in personalized treatments to identify relevant fields of future clinical and translational research. We performed a systematic review and screened ongoing clinical trials on ClinicalTrials.gov. Based on these results, a multidisciplinary international team of experts received an adapted Delphi method survey. Thirty-one and 30 experts answered round 1 and round 2, respectively. Questions with ≥75% agreement were considered relevant and included in the qualitative synthesis. Evidence for GCs as predictive biomarkers is mainly available to the postoperative RT setting. Validation of GCs as prognostic markers in the definitive RT setting is emerging. Experts used GCs in patients with PCa with extensive metastases (30%), in postoperative settings (27%), and in newly diagnosed PCa (23%). Forty-seven percent of experts do not currently use GCs in clinical practice. Expert consensus demonstrates that GCs are promising tools to improve risk-stratification in primary and oligo-/metastatic patients in addition to existing classifications. Experts were convinced that GCs might guide treatment decisions in terms of RT-field definition and intensification/deintensification in various disease stages. This work confirms the value of GCs and the promising evidence of GC utility in the setting of RT. Additional studies of GCs as prognostic biomarkers are anticipated and form the basis for future studies addressing predictive capabilities of GCs to optimize RT and systemic therapy. The expert consensus points out future directions for GC research in the management of PCa.