Radiopharmaceuticals in the elderly cancer patient: Practical considerations, with a focus on prostate cancer therapy

Prostate Cancer Diagnosis and Treatment in Elderly Patients: A Cross-Sectional Survey Exploring Practice Patterns and Preferences of Uro-Oncologists in Northeast Italy

Background: The optimal diagnostic and therapeutic strategies for prostate cancer (PCa) in patients aged ≥75 years (mild-old and oldest-old) are still contentious. Resource allocation and ideal treatment for older patients are challenges, mainly due to their comorbidities and reduced life expectancy. This survey aims to assess current clinical practices and the experiences of healthcare providers in the diagnosis and management of elderly patients with PCa. Materials and Methods: In Northeast Italy, members of the Gruppo Uro-Oncologico del Nord-Est (GUONE) conducted a survey involving 104 physicians of different specialties (Nuclear Medicine, Medical Oncology, Radiation Oncology, Radiology, Urology) between 1 November 2024 and 30 November 2024. The survey encompassed 51 questions, evaluating various diagnostic and therapeutic scenarios. Results: Digital rectal exam (DRE) was recommended by 35.9% of physicians for patients aged 75 or older at risk of PCa. PSA testing was continued in 76.3% of these patients. For 36.5% of the physicians, there should be no age limit for prostate biopsy. Moreover, 42.6% of physicians recommended a magnetic resonance imaging (MRI)-guided prostate biopsy regardless of age. A prostate biopsy was deemed mandatory before initiating any form of hormonal therapy by 57.7% of the participants. For 22.3% and 34.7% of physicians, there should be no age limit for prostate MRI and PET/CT for staging purposes. Interestingly, PET/CT was not recommended in 52% of cases as a staging tool for patients older than 85 years. For patients without comorbidities, the age limit to consider radical prostatectomy (RP) was 75, with 58.6% of physicians in favor. There were no definitive limits for radiotherapy (RT). Chemotherapy had an age limit for 81.6% of the respondents; for 18.4%, 22.5%, and 26.5% of physicians, age limits were 75, 80, and 85 years, respectively. The use of androgen receptor pathway inhibitors (ARPIs) had no definitive age limits for 46.5% of respondents. For patients with no comorbidities and low-volume metastatic PCa, the preferred option was androgen deprivation therapy + ARPIs + RT. The follow-up schedule after RP or RT exhibited heterogeneity with no consensus regarding the frequency of PSA testing or the age at which it should be discontinued. Conclusions: This survey highlights the need for consensus guidelines in diagnosing and managing mild-old and oldest-old elderly PCa patients. With the aging population, standardized protocols are essential to ensure optimal care.

Future Prospect of Low-Molecular-Weight Prostate-Specific Membrane Antigen Radioisotopes Labeled as Theranostic Agents for Metastatic Castration-Resistant Prostate Cancer

Prostate cancer ranks as the fourth most common cancer among men, with approximately 1.47 million new cases reported annually. The emergence of prostate-specific membrane antigen (PSMA) as a critical biomarker has revolutionized the diagnosis and treatment of prostate cancer. Recent advancements in low-molecular-weight PSMA inhibitors, with their diverse chemical structures and binding properties, have opened new avenues for research and therapeutic applications in prostate cancer management. These novel agents exhibit enhanced tumor targeting and specificity due to their small size, facilitating rapid uptake and localization at the target site while minimizing the retention in non-target tissues. The primary aim of this study is to evaluate the potential of low-molecular-weight PSMA inhibitors labeled with radioisotopes as theranostic agents for prostate cancer. This includes assessing their efficacy in targeted imaging and therapy and understanding their pharmacokinetic properties and mechanisms of action. This study is a literature review focusing on in vitro and clinical research data. The in vitro studies utilize PSMA-targeted radioligands labeled with radioisotopes to assess their binding affinity, specificity, and internalization in prostate cancer cell lines. Additionally, the clinical studies evaluate the safety, effectiveness, and biodistribution of radiolabeled PSMA ligands in patients with advanced prostate cancer. The findings indicate promising outcomes regarding the safety and efficacy of PSMA-targeted radiopharmaceuticals in clinical settings. The specific accumulation of these agents in prostate tumor lesions suggests their potential for various applications, including imaging and therapy. This research underscores the promise of radiopharmaceuticals targeting PSMA in advancing the diagnosis and treatment of prostate cancer. These agents improve diagnostic accuracy and patients' outcomes by enhancing imaging capabilities and enabling personalized treatment strategies.

A National Multicenter Study on overall survival in elderly metastatic castrate-resistant prostate cancer patients treated with Radium-223

BACKGROUND

Radium-223 prolongs overall survival (OS) and delays time to the first symptomatic skeletal events in patients with symptomatic metastatic castration-resistant prostate cancer (mCRPC). There is a lack of evidence on the safety and efficacy of Radium-223 treatment in the very elderly population.

AIMS

Aim of this multicentre study is to analyze mCRPC patients treated with Radium-223 in terms of OS and to assess whether there are differences between young and elderly, as well as to verify efficacy and safety in patients ≥ 75 years of age.

METHODS

430 mCRPC patients of six Italian Centres were analyzed in this multicenter retrospective study. At baseline and after each cycle were collected clinical and diagnostic patients' parameters. The whole cohort was divided into two groups based on the age of the patients (< 75 years old and ≥ 75 years old).

RESULTS

47% of the patients were < 75 years old and 53% were ≥ 75 years old. The primary outcome, OS, does not show significant differences between the two subgroups if other basal parameters are considered. Considering clinical covariates in univariate models (p < 0.05) several clinical aspects have an impact on OS, except for age (p = 0.072). Age continues to have no significant impact on the OS (p = 0.274) even in multivariate models in the two groups. The toxic effects are similar in the two groups.

CONCLUSIONS

Radium-223 prolongs survival in both younger and older patients at the same baseline condition and is a good option in the symptomatic mCRPC setting compared to other agents.

Radium-223 in mCPRC patients: a large real-life Italian multicenter study

BACKGROUND

Radium-223 is a targeted alpha-particles therapy approved for the treatment of mCRPC patients with symptomatic bone metastases. To our knowledge we account for the largest cohort of mCRPC patients subjected to Radium-223 treatment in our country. We aim to describe in a real-life setting the largest cohort of mCRPC patients treated with Radium-223 ever taken into consideration.

METHODS

Four hundred and thirty consecutive mCRPC patients were enrolled. Clinical data have been collected at baseline and at the end of the Radium-223 treatment. Furthermore, the overall survival(OS) of our population has been provided.

RESULTS

One hundred fifty-seven patients (36.5%) were still alive at the time of data analysis. A mean number of 4.95±1.6 cycles of Radium-223 was reached by our cohort. 265 patients (61.6%) completed the whole six cycles regimen. The mean follow-up period from the first cycle of Radium-223 to the date of the analysis was 12.7 months. The analysis of patients Annual Incidence Rate (AIR) in relation to the number of Radium-223 cycles received depicting a clear advantage for those patients who completed the whole six administrations planned, with an AIR (AIR=0.32) of much lesser value compared to those that have performed five cycles (AIR =0.98). 165 patients (38.4%) dropped out of treatment for death or disease progression.

CONCLUSIONS

This study offers a cross-section of the clinical performance of Radium-223 treatment in a real-world context, confirming on a large scale the effectiveness of Radium-223 in improving the OS and quality of life, along with the preservation of an excellent safety profile.

Radium-223 as an Approved Modality for Treatment of Bone Metastases

Radium-223 dichloride (²²³Ra) is an α-emitter radionuclide approved for treatment of osteoblastic metastases in castrate-resistant prostate cancer (mCRPC) patients. ²²³Ra increases overall survival, improves bone pain, increases the median time to the first skeletal-related event, reduces the use of external beam radiation therapy for bone pain palliation, reduces the rates of spinal cord compression, and hospitalization. ²²³Ra therapy has minimal side effects; the most common hematological side effects are anemia, thrombocytopenia and neutropenia while the nonhematological side effects that may occur are bone pain flare, nausea, fatigue, and diarrhea. Alongside ²²³Ra therapy there are currently a variety of first-line therapeutic options available to treat mCRPC patients and much debate regarding the appropriate treatment algorithm for these patients and the possible combination of therapies among the ones available. In this article, we review the rationale behind ²²³Ra therapy as well as ²²³Ra mechanisms of action, biodistribution and dosimetry, optimal timing possibilities to initiate ²²³Ra in contrast to other treatments available, the association of ²²³Ra with other therapies and the means of evaluating patients in order to properly deliver to ²²³Ra therapy. Furthermore, we will discuss ²²³Ra dose administration possibilities, patient and dose preparation and the challenges of treatment response evaluation during and after ²²³Ra.

Mechanisms for Radioprotection by Melatonin; Can it be Used as a Radiation Countermeasure?

BACKGROUND

Melatonin is a natural body product that has shown potent antioxidant property against various toxic agents. For more than two decades, the abilities of melatonin as a potent radioprotector against toxic effects of ionizing radiation (IR) have been proved. However, in the recent years, several studies have been conducted to illustrate how melatonin protects normal cells against IR. Studies proposed that melatonin is able to directly neutralize free radicals produced by IR, leading to the production of some low toxic products.

DISCUSSION

Moreover, melatonin affects several signaling pathways, such as inflammatory responses, antioxidant defense, DNA repair response enzymes, pro-oxidant enzymes etc. Animal studies have confirmed that melatonin is able to alleviate radiation-induced cell death via inhibiting pro-apoptosis and upregulation of anti-apoptosis genes. These properties are very interesting for clinical radiotherapy applications, as well as mitigation of radiation injury in a possible radiation disaster. An interesting property of melatonin is mitochondrial ROS targeting that has been proposed as a strategy for mitigating effects in radiosensitive organs, such as bone marrow, gastrointestinal system and lungs. However, there is a need to prove the mitigatory effects of melatonin in experimental studies.

CONCLUSION

In this review, we aim to clarify the molecular mechanisms of radioprotective effects of melatonin, as well as possible applications as a radiation countermeasure in accidental exposure or nuclear/radiological disasters.

Nuclear Medicine Imaging of Prostate Cancer in the Elderly

Due to the increasing life expectancy, the diagnosis of malignancy and treatment of elderly patients is becoming more common. Prostate cancer is particularly frequent in this setting. Many different approaches are now available, but some of them imply significant risks or collateral effects. In those patients an accurate evaluation of risk-to-benefit ratio is needed, and functional imaging such as PET/CT is important for the clinician to make the appropriate choice. PET/CT in prostate cancer is a well-tolerated procedure that can be used to accurately assess the tumor extent during the entire clinical history of the disease. Nowadays there are several available radiopharmaceuticals for prostate cancer PET/CT imaging, each one with specific advantages and disadvantages. The two most promising and more widely employed in the clinical setting are 18F-Flucyclovine and 68Ga-PSMA. This paper will provide an overview of these two tracers for imaging prostate cancer in elderly patients.