Quantification of Bone Metastasis of Castration-resistant Prostate Cancer After Enzalutamide and Abiraterone Acetate Using Bone Scan Index on Bone Scintigraphy

Pluvicto-Induced 18 F-PSMA PET Bone Flare

ABSTRACT

A 79-year-old man with a history of metastatic prostate cancer was initially treated with Eligard and switched to relugolix in 2021. The 2022 bone scan presented superscan and extensive osseous metastatic lesions; some had intense PSMA uptake on the initial PSMA PET scan without nodal or visceral metastatic lesions. We treated him with Pluvicto and relugolix. The intermediate PSMA scan demonstrated prominent bone marrow PSMA uptake. However, PSA decreased 58.5%. We hypothesized that the patient might have a bone flare. The final PSMA scan confirmed our hypothesis. Based on our knowledge, this is the first case of Pluvicto-induced bone flare.

Radiographic Progression at Castration-Resistant Prostate Cancer Diagnosis: A Prognostic Indicator of Metastatic Hormone-Sensitive Prostate Cancer

BACKGROUND

The critical role of radiographic assessment at the time of castration-resistant prostate cancer (CRPC) diagnosis is underscored by this study. We performed a retrospective analysis of radiographic changes in metastasis from the time of diagnosis of metastatic hormone-sensitive prostate cancer (mHSPC) to CRPC diagnosis. We also explored its impact on prognosis post-CRPC.

MATERIALS AND METHODS

We retrospectively analyzed 98 men who underwent radiographic examinations (bone scans and computed tomography [CT]) at the time of CRPC diagnosis. When radiographic studies demonstrated progression at CRPC diagnosis, patients were assigned to the radiographic progressive disease (rPD) group. The remaining patients were placed in the "non-rPD" group. The overall survival (OS) post-CRPC was compared between the 2 groups.

RESULTS

The median OS post-CRPC was significantly shorter in the rPD group (n = 50) compared to the non-rPD group (n = 48) (32 months vs. not reached, P = .0124). Multivariate analysis showed that radiographic progression and shorter time to CRPC were associated with a shorter OS post-CRPC (hazard ratio [HR] = 3.14; 95% confidence interval [CI], 1.21-8.12, P = .019).

CONCLUSION

Radiographic progression at the point of CRPC diagnosis independently predicts a shorter OS post-CRPC in patients with mHSPC. Therefore, assessing radiographic changes at the time of CRPC diagnosis could be instrumental in managing CRPC in patients with mHSPC.

Emerging Applications of Deep Learning in Bone Tumors: Current Advances and Challenges

Deep learning is a subfield of state-of-the-art artificial intelligence (AI) technology, and multiple deep learning-based AI models have been applied to musculoskeletal diseases. Deep learning has shown the capability to assist clinical diagnosis and prognosis prediction in a spectrum of musculoskeletal disorders, including fracture detection, cartilage and spinal lesions identification, and osteoarthritis severity assessment. Meanwhile, deep learning has also been extensively explored in diverse tumors such as prostate, breast, and lung cancers. Recently, the application of deep learning emerges in bone tumors. A growing number of deep learning models have demonstrated good performance in detection, segmentation, classification, volume calculation, grading, and assessment of tumor necrosis rate in primary and metastatic bone tumors based on both radiological (such as X-ray, CT, MRI, SPECT) and pathological images, implicating a potential for diagnosis assistance and prognosis prediction of deep learning in bone tumors. In this review, we first summarized the workflows of deep learning methods in medical images and the current applications of deep learning-based AI for diagnosis and prognosis prediction in bone tumors. Moreover, the current challenges in the implementation of the deep learning method and future perspectives in this field were extensively discussed.

Sarcopenia and Visceral Metastasis at Cabazitaxel Initiation Predict Prognosis in Patients With Castration-resistant Prostate Cancer Receiving Cabazitaxel Chemotherapy

BACKGROUND/AIM

Cabazitaxel is recommended as first-line treatment after docetaxel for metastatic castration-resistant prostate cancer. However, the efficacy, adverse events and prognostic factors associated with cabazitaxel are unclear.

PATIENTS AND METHODS

This single-centre retrospective study including 30 patients with CRPC treated with cabazitaxel between 2014 and 2020 investigated efficacy, outcomes and prognostic factors.

RESULTS

Fourteen patients had visceral metastases. The median cabazitaxel dose was 20 mg/m² The prostate-specific antigen response rate, time to prostate-specific antigen response, and overall survival were 13.3%, 3.48 months, and 7.92 months, respectively. The rates of grade 3 or more neutropenia and febrile neutropenia were 20% and 6.7%, respectively. By multivariate analysis, sarcopenia and visceral metastasis at the time of cabazitaxel initiation were independent and significant factors conferring a poor prognosis.

CONCLUSION

The early introduction of cabazitaxel, prior to the development of sarcopenia and visceral metastasis, might contribute to improved prognosis in CRPC.

Flare phenomenon in prostate cancer: recent evidence on new drugs and next generation imaging

Over the years, an increasing proportion of metastatic prostate cancer patients has been found to experience an initial bone flare phenomenon under both standard therapies (androgen deprivation therapy, chemotherapy, radiotherapy, abiraterone, enzalutamide) and novel agents (immunotherapy, bone-targeting radioisotopes). The underlying biological mechanisms of the flare phenomenon are still elusive and need further clarification, particularly in relation to different types of treatment and their treatment response assessment. Flare phenomenon is often underestimated and, in some cases, can negatively affect clinical outcome. In cases with suspected bone flare, the treatment should be continued for a minimum of 12 more weeks before further decisions about efficacy can be taken. Physicians and patients should be aware of this effect to avoid unwarranted anxiety and inadequate early discontinuation of treatment. This review aims at highlighting new evidence on flare phenomenon arising after the introduction of new drugs extending across the biochemical, radiographic and clinical spectrum of the disease.

Assessment of a software for semi-automatically calculating the bone scan index on bone scintigraphy scans

AIMS

The incidence of bone metastases exceeds 85% in patients who die from prostate cancer. Bone scintigraphy is the most widely used method for the early detection of bone metastases in prostate cancer. We developed a software program that semi-automatically calculated the bone scan index (BSI) on technetium-99m hydroxymethylene diphosphonate bone scintigraphy scans with a computer-aided diagnosis system (CAD) and examined whether the BSI calculated using this software could replace the extent of disease (EOD) score.

METHODS

The subjects were 175 patients who were diagnosed with prostate cancer at our hospital and underwent bone scintigraphy. We analyzed receiver operating characteristic curves to determine the BSI cutoff value between EOD groups. The cutoff value was determined based on the maximum value of the sum of the sensitivity and specificity.

RESULTS

BSI cutoff values of 0.20, 1.56, and 4.56 were used to distinguish between EOD 0 and 1-4 (sensitivity [87.2%] and specificity [100.0%]), between EOD 0- and 2-4 (sensitivity [85.2%] and specificity [92.0%]), and between EOD 0-2 and 3-4 (sensitivity [88.4%] and specificity [99.2%]), respectively.

CONCLUSION

Our results suggest that this software can calculate BSI, and the software may play a role in predicting prognosis and selecting an appropriate treatment strategy. If a sufficient number of other nuclear medicine tests are performed, creating a similar CAD system is possible.

Eastern Cooperative Oncology Group Performance Score Is Associated With Survival After Radiotherapy of Bone Metastases from Prostate Cancer

BACKGROUND/AIM

Understanding prognostic factors of survival are important for treatment personalization in cancer patients. This study aimed to identify such factors for patients irradiated for bone metastases from prostate cancer.

PATIENTS AND METHODS

Data from 74 patients irradiated between 01/2009 and 04/2019 were retrospectively evaluated. Ten characteristics were investigated for survival.

RESULTS

Median survival in the entire cohort was 12 months. Survival rates at 3, 6, 9 and 12 months were 84%, 73%, 56% and 47%, respectively. On univariate analyses, the Eastern Cooperative Oncology Group (ECOG) performance score of 0-1 was associated with improved survival (p<0.001), absence of visceral metastases (p=0.099) and only one irradiated metastatic site (p=0.099) showed a trend. On Cox regression analysis, only ECOG performance score (risk ratio=3.58, p<0.001) was significant.

CONCLUSION

ECOG performance score is an independent prognostic factor of survival after irradiation of bone metastases from prostate cancer and may allow better personalization of care.

Prognostic value of the bone scan index in patients with metastatic castration-resistant prostate cancer: a systematic review and meta-analysis

Background

Many studies have reported the prognostic significance of the bone scan index (BSI) for metastatic castration-resistant prostate cancer (mCRPC); however, these reports are controversial. This study investigated the BSI in mCRPC and its relationship with prognosis.

Methods

The PubMed, Cochrane, and Embase databases were searched systematically for relevant articles published before September 1, 2019. Hazard ratios (HRs) were used to investigate the prognostic value.

Results

This study finally identified 9 eligible studies. The results suggested that high baseline BSI predicted poor OS (HR = 1.331, 95% CI: 1.081–1.640) and that elevated ΔBSI also predicted poor OS (HR = 1.220, 95% CI: 1.015–1.467). The subgroup analysis stratified by ethnicity showed that the baseline BSI and ΔBSI predicted poor OS in the Asian population but not in the Caucasian population. We also performed a subgroup analysis based on the different cut-off values of baseline BSI. The subgroup of ≤1 showed a significant association with OS in mCRPC patients.

Conclusion

Our study demonstrated that high baseline BSI and elevated ΔBSI predicted poor OS in patients with mCRPC. Hence, the BSI can serve as a prognostic indicator for mCRPC patients and may therefore guide clinical treatment in the future.