Metastasis-directed Radiotherapy Research Articles

Current and potential future role of PSMA-PET in patients with castration-resistant prostate cancer.

To review the current literature and discuss potential future roles of the novel positron emission tomography (PET) tracers targeting the prostate-specific membrane antigen (PSMA) in patients with castration-resistant prostate cancer (CRPC). A literature search on February 19th 2018 was conducted using the Medline database and www.clinicaltrials.gov . Additionally, illustrative cases of CRPC patients from our own institution who were restaged and treated based on PSMA-PET scan results are provided. 11 Studies met the inclusion criteria. PSMA-PET detected more metastatic lesions compared to conventional bone scan. Several patients were up-staged from non-metastatic CRPC (nmCRPC) to metastatic CRPC (mCRPC). Currently, no clear consensus exists regarding treatment response assessment in PSMA-PET scans for mCRPC patients undergoing treatment. Also, the role of PSMA-PET as a gatekeeper for systemic therapy or radioligands is currently undefined. PSMA-guided metastasis-directed radiotherapy may not only alleviate local symptoms but has the potential to defer systemic treatment in patients with oligoprogressive CRPC. Compared to bone scan, PSMA-PET is more sensitive and specific to detect metastases but the therapeutic consequences of PSMA-PET results in the setting of CRPC remain unclear. Until future studies define the role of PSMA-PET in patients with CRPC, the current standard for imaging remains bone scan and computerized tomography.

68Ga-PSMA 11 ligand PET imaging in patients with biochemical recurrence after radical prostatectomy \u2013 diagnostic performance and impact on therapeutic decision-making

ObjectiveTo evaluate the diagnostic performance of [68Ga]Ga-PSMAHBED-CC conjugate 11 positron emission tomography (PSMA-PET) in the early detection of metastases in patients with biochemical recurrence (BCR) after radical prostatectomy (RP) for clinically non-metastatic prostate cancer, to compare it to CT/MRI alone and to assess its impact on further therapeutic decisions.Material and methodsWe retrospectively assessed 117 consecutive hormone-naïve BCR patients who had 68Ga-PSMA 11 PET/CT (n = 46) or PET/MRI (n = 71) between May 2014 and January 2017. BCR was defined as two PSA rises above 0.2 ng/ml. Two dedicated uro-oncological imaging experts (radiology/nuclear medicine) reviewed separately all images. All results were presented in a blinded sequential fashion to a multidisciplinary tumorboard in order to assess the influence of PSMA-PET imaging on decision-making.ResultsThe median time from RP to BCR was 36 months (IQR 16–72). Overall, 69 (59%) patients received postoperative radiotherapy. Median PSA level at the time of imaging was 1.04 ng/ml (IQR 0.58–1.87). PSMA-positive lesions were detected in 100 (85.5%) patients. Detection rates were 65% for a PSA value of 0.2 to <0.5 ng/ml, 85.7% for 0.5 to <1, 85.7% for 1 to <2 and 100% for ≥2. PSMA-positive lesions could be confirmed by either histology (16%), PSA decrease in metastasis-directed radiotherapy (45%) or additional information in diffusion-weighted imaging when PET/MRI was performed (18%) in 79% of patients. PSMA-PET detected lesions in 67 patients (57.3%) who had no suspicious correlates according to the RECIST 1.1 criteria on MRI or CT. PSMA-PET changed therapeutic decisions in 74.6% of these 67 patients (p < 0.001), with 86% of them being considered for metastases-directed therapies.ConclusionsWe confirm the high performance of PSMA-PET imaging for the detection of disease recurrence sites in patients with BCR after RP, even at relatively low PSA levels. Moreover, it adds significant information to standard CT/MRI, changing treatment strategies in a significant number of patients.

Outcomes of Curative-Intent Treatment for Breast Cancer Patients Presenting with Sternal or Mediastinal Involvement

Purpose: Optimal treatment of patients diagnosed with de novo metastatic breast cancer limited to the mediastinum or sternum has never been delineated. Herein the authors sought to determine the efficacy of multimodality treatment, including metastasis-directed radiotherapy (RT), in curing patients with this presentation.

Oligometastatic prostate cancer: definitions, clinical outcomes, and treatment considerations.

The oligometastatic state has been proposed as an intermediate stage of cancer spread between localized disease and widespread metastases. With improvements in diagnostic modalities such as functional imaging, oligometastatic prostate cancer is being diagnosed with greater frequency than ever before. Furthermore, the paradigm for treatment of advanced prostate cancers is shifting toward a more aggressive approach. Many questions surround the understanding of the process and consequences of oligometastasis, meaning that the contemporary literature offers a wide variety of definitions of oligometastatic prostate cancer. Until genomic data exist to provide a biological component to the definition of oligometastatic disease, a clinical diagnosis made on the basis of up to five extrapelvic lesions is reasonable for use. Retrospective studies suggest that interventions such as radical prostatectomy and local or metastasis-directed radiotherapy can be performed in the metastatic setting with minimal risk of toxic effects. These therapies seem to decrease the need for subsequent palliative interventions, but insufficient data are available to draw reliable conclusions regarding their effect on survival. Thus, a protocol for clinicians to manage the patient presenting with oligometastatic prostate cancer would be a useful clinical tool.

Stereotactic body radiotherapy for multisite extracranial oligometastases

A subset of patients with metastatic cancer in limited organs may benefit from metastasis-directed therapy. The authors investigated whether patients with limited metastases could be safely treated with metastasis-directed radiotherapy. Patients with 1 to 5 metastatic cancer sites with a life expectancy of >3 months received escalating stereotactic body radiotherapy (SBRT) doses to all known cancer sites. Patients were followed radiographically with CT scans of the chest, abdomen, and pelvis and metabolically with fluorodeoxyglucose-positron emission tomography, 1 month after treatment, and then every 3 months. Acute toxicities were scored using the National Cancer Institute's Common Terminology Criteria for Adverse Events version 3.0, and late toxicities were scored using the Radiation Therapy Oncology Group late toxicity scoring system. Sixty-one patients with 113 metastases were enrolled from November 2004 to November 2009 on a prospective radiation dose escalation study. Median follow-up was 20.9 months. Patients tolerated treatment well; the maximal tolerated dose was not reached in any cohort. Eleven patients (18.3%) have not progressed. One and 2-year progression-free survival are 33.3% (95% confidence interval [CI], 22.8-46.1) and 22.0% (95% CI, 12.8-34.4); 1-year and 2-year overall survival are 81.5% (95% CI, 71.1-91.1) and 56.7% (95% CI, 43.9-68.9). Seventy-two percent of patients whose tumors progressed did so in limited (1-3) metastatic sites. Patients with 1 to 5 metastases can be safely treated to multiple body sites and may benefit from SBRT. Further investigation should focus on patient selection.