The use of F-18 choline PET in the assessment of bone metastases in prostate cancer: correlation with morphological changes on CT

SPECT/CT, PET/CT, and PET/MRI for Response Assessment of Bone Metastases

Recent developments in hybrid SPECT/CT systems and the use of cadmium-zinc-telluride (CZT) detectors have improved the diagnostic accuracy of bone scintigraphy. These advancements have paved the way for novel quantitative approaches to accurate and reproducible treatment monitoring of bone metastases. PET/CT imaging using [18F]F-FDG and [18F]F-NaF have shown promising clinical utility in bone metastases assessment and monitoring response to therapy and prediction of treatment response in a broad range of malignancies. Additionally, specific tumor-targeting tracers like [99mTc]Tc-PSMA, [68Ga]Ga-PSMA, or [11C]C- or [18F]F-Choline revealed high diagnostic performance for early assessment and prognostication of bone metastases, particularly in prostate cancer. PET/MRI appears highly accurate imaging modality, but has associated limitations notably, limited availability, more complex logistics and high installation costs. Advances in artificial intelligence (Al) seem to improve the accuracy of imaging modalities and provide an assistant role in the evaluation of treatment response of bone metastases.

Review of imaging techniques for evaluating morphological and functional responses to the treatment of bone metastases in prostate and breast cancer

Bone metastases are very common complications associated with certain types of cancers that frequently negatively impact the quality of life and functional status of patients; thus, early detection is necessary for the implementation of immediate therapeutic measures to reduce the risk of skeletal complications and improve survival and quality of life. There is no consensus or universal standard approach for the detection of bone metastases in cancer patients based on imaging. Endorsed by the Spanish Society of Medical Oncology (SEOM), the Spanish Society of Medical Radiology (SERAM), and the Spanish Society of Nuclear Medicine and Molecular Imaging (SEMNIM) a group of experts met to discuss and provide an up-to-date review of our current understanding of the biological mechanisms through which tumors spread to the bone and describe the imaging methods available to diagnose bone metastasis and monitor their response to oncological treatment, focusing on patients with breast and prostate cancer. According to current available data, the use of next-generation imaging techniques, including whole-body diffusion-weighted MRI, PET/CT, and PET/MRI with novel radiopharmaceuticals, is recommended instead of the classical combination of CT and bone scan in detection, staging and response assessment of bone metastases from prostate and breast cancer.Clinical trial registration: Not applicable.

Multimodal Imaging-Based Potential Visualization of the Tumor Microenvironment in Bone Metastasis

Bone metastasis (BM) is the most common malignant bone tumor and a significant cause of morbidity and mortality for patients with cancer. Compared to other metastatic organs, bone has unique characteristics in terms of the tumor microenvironment (TME). Precise assessments of the TME in BM could be an important step for developing an optimized management plan for patient care. Imaging approaches for BM have several advantages, such as biopsy not being required, multiple site evaluation, and serial assessment in the same sites. Owing to the developments of new imaging tracers or imaging modalities, bone TME could be visualized using multimodal imaging techniques. In this review, we describe the BM pathophysiology, diagnostic principles of major imaging modalities, and clinically available imaging modalities to visualize the TME in BM. We also discuss how the interactions between various factors affecting the TME could be visualized using multimodal imaging techniques.

PET/CT-Based Salvage Radiotherapy for Recurrent Prostate Cancer After Radical Prostatectomy: Impact on Treatment Management and Future Directions

Biochemical recurrence is a clinical situation experienced by 20 to 40% of prostate cancer patients treated with radical prostatectomy (RP). Prostate bed (PB) radiation therapy (RT) remains the mainstay salvage treatment, although it remains non-curative for up to 30% of patients developing further recurrence. Positron emission tomography with computed tomography (PET/CT) using prostate cancer-targeting radiotracers has emerged in the last decade as a new-generation imaging technique characterized by a better restaging accuracy compared to conventional imaging. By adapting targeting of recurrence sites and modulating treatment management, implementation in clinical practice of restaging PET/CT is challenging the established therapeutic standards born from randomized controlled trials. This article reviews the potential impact of restaging PET/CT on changes in the management of recurrent prostate cancer after RP. Based on PET/CT findings, it addresses potential adaptation of RT target volumes and doses, as well as use of androgen-deprivation therapy (ADT). However, the impact of such management changes on the oncological outcomes of PET/CT-based salvage RT strategies is as yet unknown.

Current Overview of Treatment for Metastatic Bone Disease

The number of patients with bone metastasis increases as medical management and surgery improve the overall survival of patients with cancer. Bone metastasis can cause skeletal complications, including bone pain, pathological fractures, spinal cord or nerve root compression, and hypercalcemia. Before initiation of treatment for bone metastasis, it is important to exclude primary bone malignancy, which would require a completely different therapeutic approach. It is essential to select surgical methods considering the patient’s prognosis, quality of life, postoperative function, and risk of postoperative complications. Therefore, bone metastasis treatment requires a multidisciplinary team approach, including radiologists, oncologists, and orthopedic surgeons. Recently, many novel palliative treatment options have emerged for bone metastases, such as stereotactic body radiation therapy, radiopharmaceuticals, vertebroplasty, minimally invasive spine stabilization with percutaneous pedicle screws, acetabuloplasty, embolization, thermal ablation techniques, electrochemotherapy, and high-intensity focused ultrasound. These techniques are beneficial for patients who may not benefit from surgery or radiotherapy.

Assessment of the viability and treatment response of bone metastases in patients with metastatic castration-resistant prostate cancer using choline PET/CT

This study aimed to evaluate the clinical use of choline-PET/CT for discriminating viable progressive osteoblastic bone metastasis from benign osteoblastic change induced by the treatment effect and evaluating the response of bone metastasis to treatment in metastatic castration-resistant prostate cancer (mCRPC) patients. Thirty patients with mCRPC underwent a total of 56 11C-choline-PET/CT scans for restaging, because 4 patients received 1 scan and 26 had 2 scans. Using 2 (pre- and post-treatment) 11C-choline-PET/CT examinations per patient, treatment response was assessed according to European Organization for Research and Treatment of Cancer (EORTC) criteria in 20 situations, in which only bony metastases were observed on 11C-choline-PET/CT scans. Viable bone metastases and osteoblastic change induced by the treatment effect were identified in 53 (94.6%) and 29 (51.8%) of 56 11C-choline-PET/CT scans, respectively. In 27 cases (48.2%), 11C-choline-PET/CT scans could discriminate the 2 entities. The mean SUVmax of the metastatic bony lesions was 5.82 ± 3.21, 5.95 ± 3.96, 6.73 ± 5.04, and 7.91 ± 3.25 for the osteoblastic, osteolytic, mixed, and invisible types, respectively. Of the 20 situations analyzed, CMR, PMR, SMD, and PMD, as determined by the EORTC, were seen in 1, 2, 3, and 14 cases, respectively. Of the 13 patients with increasing PSA trend, all 13 showed PMD. Of the 2 patients with PSA response of <50%, both 2 showed SMD. Of the 5 patients with PSA response of ≥50%, 1 showed CMR, 2 showed PMR, 1 showed SMD, and 1 showed PMD. Choline-PET/CT is very useful to discriminate viable progressive osteoblastic bone metastasis from osteoblastic change, and assess treatment response of bone metastases in mCRPC.

Ring Sclerosis in Prostate Cancer: Circle of Malignancy or Benignity?

ABSTRACT

Prostate cancer osteoblastic metastases may have different morphologies, and some of these may overlap with certain benign bone lesions. In this series of 5 prostate cancer patients, we describe bone lesions with central lucency and surrounding peripheral sclerosis and their varying appearances on different imaging modalities. Although prostate cancer metastases are commonly associated with sclerotic lesions, they can also present as osteolytic or lucent lesions, and these lesions should be carefully evaluated. The findings emphasize the importance of correlation with prior imaging, comparing findings on different imaging techniques and follow-up to differentiate benign disease from metastatic disease in these situations.

Comparison of PET/CT and MRI in the Diagnosis of Bone Metastasis in Prostate Cancer Patients: A Network Analysis of Diagnostic Studies

BACKGROUND

Accurate diagnosis of bone metastasis status of prostate cancer (PCa) is becoming increasingly more important in guiding local and systemic treatment. Positron emission tomography/computed tomography (PET/CT) and magnetic resonance imaging (MRI) have increasingly been utilized globally to assess the bone metastases in PCa. Our meta-analysis was a high-volume series in which the utility of PET/CT with different radioligands was compared to MRI with different parameters in this setting.

MATERIALS AND METHODS

Three databases, including Medline, Embase, and Cochrane Library, were searched to retrieve original trials from their inception to August 31, 2019 according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement. The methodological quality of the included studies was assessed by two independent investigators utilizing Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). A Bayesian network meta-analysis was performed using an arm-based model. Absolute sensitivity and specificity, relative sensitivity and specificity, diagnostic odds ratio (DOR), and superiority index, and their associated 95% confidence intervals (CI) were used to assess the diagnostic value.

RESULTS

Forty-five studies with 2,843 patients and 4,263 lesions were identified. Network meta-analysis reveals that 68Ga-labeled prostate membrane antigen (68Ga-PSMA) PET/CT has the highest superiority index (7.30) with the sensitivity of 0.91 and specificity of 0.99, followed by 18F-NaF, 11C-choline, 18F-choline, 18F-fludeoxyglucose (FDG), and 18F-fluciclovine PET/CT. The use of high magnetic field strength, multisequence, diffusion-weighted imaging (DWI), and more imaging planes will increase the diagnostic value of MRI for the detection of bone metastasis in prostate cancer patients. Where available, 3.0-T high-quality MRI approaches 68Ga-PSMA PET/CT was performed in the detection of bone metastasis on patient-based level (sensitivity, 0.94 vs. 0.91; specificity, 0.94 vs. 0.96; superiority index, 4.43 vs. 4.56).

CONCLUSIONS

68Ga-PSMA PET/CT is recommended for the diagnosis of bone metastasis in prostate cancer patients. Where available, 3.0-T high-quality MRI approaches 68Ga-PSMA PET/CT should be performed in the detection of bone metastasis.

Reporting and handling of equivocal imaging findings in diagnostic studies of bone metastasis in prostate cancer

BACKGROUND

Equivocal scanning results occur. It remains unclear how these results are presented and their management influence diagnostic characteristics.

PURPOSE

To investigate the reporting and handling of equivocal imaging findings in diagnostic studies of bone metastases, and to assess the impact on diagnostic performance of the methods used to analyze equivocal findings. The conceptual issue was reified based on two actual observations.

MATERIAL AND METHODS

A recent meta-analysis of bone metastases in prostate cancer was conducted and data were obtained from a large clinical trial with a true reference of bone metastasis, where diagnostic characteristics were calculated with equivocal scans handled by: removal; considered malignant; considered benign; and intention-to-diagnose.

RESULTS

The meta-analysis included 18 trials where the median proportion of reported equivocal results was 27%. Eleven (61%) studies reported an equivocal option for the index test, 42% reported equivocal results and described how these were analyzed. The clinical trial included 583 prostate cancer patients with 20% equivocal results. The different methods of managing equivocal findings resulted in highly variable outcomes: sensitivity = 85%-100%; specificity = 78%-99%; and positive and negative predictive values = 44%-94% and 97%-100%, respectively. The diagnostic performances obtained using the four methods were differentially susceptible to the proportion of equivocal imaging findings and the prevalence of bone metastases.

CONCLUSION

Reporting of equivocal results was inadequate in bone imaging trials. The handling of equivocal findings strongly influenced diagnostic accuracy.

Molecular Imaging of Bone Metastases and Their Response to Therapy

Bone metastases are common, especially in more prevalent malignancies such as breast and prostate cancer. They cause significant morbidity and draw on health-care resources. Molecular and hybrid imaging techniques, including SPECT/CT, PET/CT, and whole-body MRI with diffusion-weighted imaging, have improved diagnostic accuracy in staging the skeleton compared with previous standard imaging methods, allowing earlier tailored treatment. With the introduction of several effective treatment options, it is now even more important to detect and monitor response in bone metastases accurately. Conventional imaging, including radiographs, CT, MRI, and bone scintigraphy, are recognized as being insensitive and nonspecific for response monitoring in a clinically relevant time frame. Early reports of molecular and hybrid imaging techniques, as well as whole-body MRI, promise an earlier and more accurate prediction of response versus nonresponse but have yet to be adopted routinely in clinical practice. We summarize the role of new molecular and hybrid imaging methods, including SPECT/CT, PET/CT, and whole-body MRI. These modalities are associated with improvements in diagnostic accuracy for the staging and response assessment of skeletal metastases over standard imaging methods, being able to quantify biologic processes related to the bone microenvironment as well as tumor cells. The described improvements in the imaging of bone metastases and their response to therapy have led to adoption of some of these methods into routine clinical practice in some centers. These methods also provide a better way to assess the treatment response of bone metastases in clinical trials.

18F-Fluoromethylcholine-positron emission tomography/computed tomography for diagnosing bone and lymph node metastases in patients with intermediate- or high-risk prostate cancer

Background

The use of molecular imaging in staging of prostate cancer (PC) is debated. In patients with newly diagnosed PC we investigated the diagnostic value of ¹⁸F-flouromethylcholine positron emission tomography/computed tomography (¹⁸F-FCH-PET/CT) for the detection of bone and lymph node metastases compared to whole-body bone scintigraphy (WBS) with technetium-99-methylene diphosphonate (^99mTc-MDP) and results of extended pelvic lymph node dissection, respectively.

Materials and methods

Between January 2013 and April 2016, 143 patients, aged 49-83, mean 69, years with newly diagnosed PC and disease characteristics necessitating WBS underwent both WBS and ¹⁸F-FCH-PET/CT using magnetic resonance imaging as standard. Eighty of these patients underwent pelvic lymph node dissection as part of radical prostatectomy or prior to external beam radiation and in these results of ¹⁸F-FCH-PET/CT were compared to histologic findings.

Results

Bone metastases were detected in 8/143 patients and sensitivity and specificity of WBS were 37.5% and 85.2% versus 100.0% and 96.3% with ¹⁸F-FCH-PET/CT, P=0.63 and 0.002, respectively. Histologically confirmed metastases to regional lymph nodes were found in 25/80 patients. Suspicious choline uptake on PET/CT in pelvic lymph nodes was found in 35 patients. Sensitivity, specificity, PPV, NPV and accuracy of ¹⁸F-FCH-PET/CT in detection of lymph node metastases were 62.5%, 69.6%, 46.9%, 81.3% and 67.5%, respectively.

Conclusions

Findings in this study suggested that ¹⁸F-FCH-PET/CT is a more sensitive and specific method for detection of bone metastases from PC than WBS and could potentially reduce the need for confirmatory imaging if used instead of WBS. However, ¹⁸F-FCH-PET/CT performs sub-optimally in pre-operative staging of lymph node metastases in patients undergoing extended pelvic lymph node dissection.

Molecular imaging of bone metastases using tumor-targeted tracers

Bone metastasis is a disastrous manifestation of most malignancies, especially in breast, prostate and lung cancers. Since asymptomatic bone metastases are not uncommon, early detection, precise assessment, and localization of them are very important. Various imaging modalities have been employed in the setting of diagnosis of bone metastasis, from plain radiography and bone scintigraphy to SPECT, SPECT/CT, PET/CT, MRI. However, each modality showed its own limitation providing accurate diagnostic performance. In this regard, various tumor-targeted radiotracers have been introduced for molecular imaging of bone metastases using modern hybrid modalities. In this article we review the strength of different cancer-specific radiopharmaceuticals in the detection of bone metastases. As shown in the literature, among various tumor-targeted tracers, 68Ga DOTA-conjugated-peptides, 68Ga PSMA, 18F DOPA, 18F galacto-RGD integrin, 18F FDG, 11C/18F acetate, 11C/18F choline, 111In octreotide, 123/131I MIBG, 99mTc MIBI, and 201Tl have acceptable capabilities in detecting bone metastases depending on the cancer type. However, different study designs and gold standards among reviewed articles should be taken into consideration.

Multimodal Treatment of Bone Metastasis-A Surgical Perspective

Over the past decades there has been an increase in the incidence of cancer worldwide. With the advancement in treatment, patient survival has improved in tandem with the increasing incidence. This, together with the availability of advanced modern diagnostic modalities, has resulted in more cases of metastatic bone disease being identified. Bone metastasis is an ongoing problem and has significant morbidity implications for patients affected. Multimodal treatment strategies are required in dealing with metastatic bone disease, which include both surgical and non-surgical treatment options. In the multidisciplinary team, orthopedic surgeons play an important role in improving the quality of life of cancer patients. Surgical intervention in this setting is aimed at pain relief, restoration of function and improvement in functional independence. In selected cases with resectable solitary metastasis, surgical treatment may be curative. With the advancement of surgical technique and improvement in implant design and manufacture, a vast array of surgical options are available in the modern orthopedic arena. In the majority of cases, limb salvage procedures have become the standard of care in the treatment of metastatic bone disease. Non-surgical adjuvant treatment also contributes significantly to the improvement of cancer patient care. A multidisciplinary approach in this setting is of paramount importance.

Diagnostic performance of choline PET/CT for the detection of bone metastasis in prostate cancer: A systematic review and meta-analysis

Purpose

The aim of this study was to evaluate the diagnostic performance of choline positron emission tomography/computed tomography (PET/CT) for the detection of bone metastasis in patients with prostate cancer.

Methods

MEDLINE, EMBASE and the Cochrane Library were searched up to 20 February 2018 for studies that used 11C-choline or 18F-choline PET/CT for the detection of bone metastasis in patients with prostate cancer and “histopathology and/or clinical follow-up” as the reference standard. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. Pooled diagnostic accuracy with the 95% confidence interval (CI) was calculated using a bivariate random effects model. We also constructed hierarchical summary receiver operating characteristic curves and performed meta-regression analyses.

Results

Fourteen studies with reasonable methodological quality were included in the analysis. On a per-patient basis, the pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were 0.89 (95% CI 0.80–0.94), 0.98 (95% CI 0.95–0.99), 40.4 (95% CI 19.7–82.6), 0.12 (95% CI 0.07–0.20), and 344 (95% CI 148–803), respectively. On a per-lesion basis, the pooled sensitivity, specificity, PLR, NLR, and DOR were 0.91 (95% CI 0.85–0.94), 0.97 (95% CI 0.95–0.98), 34.1 (95% CI 20.0–58.1), 0.10 (95% CI 0.06–0.16), and 358 (95% CI 165–778), respectively. In the meta-regression analysis, the clinical setting (staging vs. restaging) was the only source of study heterogeneity on a per-patient basis.

Conclusions

Choline PET/CT shows excellent diagnostic performance for the detection of bone metastasis. However, a negative choline PET/CT result cannot ensure the lack of bone metastasis.

Evaluation of Tumor Viability for Primary and Bone Metastases in Metastatic Castration-Resistant Prostate Cancer Using Whole-Body Magnetic Resonance Imaging

In contrast to bone scan and computed tomography (CT), which depend on osteoblastic response to detect bone metastasis, whole-body magnetic resonance imaging (WB-MRI) may be able to directly detect viable tumors. A 75-year-old male who had progressive metastatic prostate cancer during primary androgen deprivation therapy was referred to our hospital. Although bone scan and CT showed multiple bone metastases, WB-MRI suggested nonviable bone metastasis and viable tumor of the primary lesion. Prostate needle biopsy demonstrated viable prostate cancer cells from 10 of 12 cores. In contrast, CT-guided needle biopsy from bone metastasis of the lumbar vertebra revealed no malignant cells. Based on these findings, we reasoned that viable tumor cells inducing disease progression may primarily exist in the primary lesions and not in the metastatic lesions, and combined prostate radiotherapy and systemic hormonal therapy resulted in successful clinical response and disease control. The use of WB-MRI to detect viable disease lesions may enable us to design optimal treatment strategies for patients with metastatic castration-resistant prostate cancer.

Functional and Hybrid Imaging of Bone Metastases

Bone metastases are common, cause significant morbidity, and impact on healthcare resources. Although radiography, computed tomography (CT), magnetic resonance imaging (MRI), and bone scintigraphy have frequently been used for staging the skeleton, these methods are insensitive and nonspecific for monitoring treatment response in a clinically relevant time frame. We summarize several recent reports on new functional and hybrid imaging methods including single photon emission CT/CT, positron emission tomography/CT, and whole-body MRI with diffusion-weighted imaging. These modalities generally show improvements in diagnostic accuracy for staging and response assessment over standard imaging methods, with the ability to quantify biological processes related to the bone microenvironment as well as tumor cells. As some of these methods are now being adopted into routine clinical practice and clinical trials, further evaluation with comparative studies is required to guide optimal and cost-effective clinical management of patients with skeletal metastases. © 2018 American Society for Bone and Mineral Research.

Comparison of [68Ga]Ga-PSMA-11 PET/CT with [18F]NaF PET/CT in the evaluation of bone metastases in metastatic prostate cancer patients prior to radionuclide therapy

AIM

The purpose of this study was to investigate the diagnostic performance of ⁶⁸Ga-PSMA-11 PET/CT in the evaluation of bone metastases in metastatic prostate cancer (PC) patients scheduled for radionuclide therapy in comparison to [¹⁸F]sodium fluoride (¹⁸F-NaF) PET/CT.

METHODS

Sixteen metastatic PC patients with known skeletal metastases, who underwent both ⁶⁸Ga-PSMA-11 PET/CT and ¹⁸F-NaF PET/CT for assessment of metastatic burden prior to radionuclide therapy, were analysed retrospectively. The performance of both tracers was calculated on a lesion-based comparison. Intensity of tracer accumulation of pathologic bone lesions on ¹⁸F-NaF PET and ⁶⁸Ga-PSMA-11 PET was measured with maximum standardized uptake values (SUV_max) and compared to background activity of normal bone. In addition, SUV_max values of PET-positive bone lesions were analysed with respect to morphologic characteristics on CT. Bone metastases were either confirmed by CT or follow-up PET scan.

RESULTS

In contrast to 468 PET-positive lesions suggestive of bone metastases on ¹⁸F-NaF PET, only 351 of the lesions were also judged positive on ⁶⁸Ga-PSMA-11 PET (75.0%). Intensity of tracer accumulation of pathologic skeletal lesions was significantly higher on ¹⁸F-NaF PET compared to ⁶⁸Ga-PSMA-11 PET, showing a median SUV_max of 27.0 and 6.0, respectively (p < 0.001). Background activity of normal bone was lower on ⁶⁸Ga-PSMA-11 PET, with a median SUV_max of 1.0 in comparison to 2.7 on ¹⁸F-NaF PET; however, tumour to background ratio was significantly higher on ¹⁸F-NaF PET (9.8 versus 5.9 on ⁶⁸Ga-PSMA-11 PET; p = 0.042). Based on morphologic lesion characterisation on CT, ¹⁸F-NaF PET revealed median SUV_max values of 23.6 for osteosclerotic, 35.0 for osteolytic, and 19.0 for lesions not visible on CT, whereas on ⁶⁸Ga-PSMA-11 PET median SUV_max values of 5.0 in osteosclerotic, 29.5 in osteolytic, and 7.5 in lesions not seen on CT were measured. Intensity of tracer accumulation between¹⁸F-NaF PET and ⁶⁸Ga-PSMA-11 PET was significantly higher in osteosclerotic (p < 0.001) and lesions not visible on CT (p = 0.012).

CONCLUSION

In comparison to ⁶⁸Ga-PSMA-11 PET/CT, ¹⁸F-NaF PET/CT detects a higher number of pathologic bone lesions in advanced stage PC patients scheduled for radionuclide therapy. Our data suggest that ⁶⁸Ga-PSMA-11 PET should be combined with ¹⁸F-NaF PET in PC patients with skeletal metastases for restaging prior to initiation or modification of therapy.

Radium-223 in the treatment of bone metastasis in patients with castration-resistant prostate cancer. Review and procedure

Bone metastatic disease is the main cause of morbidity / mortality in patients with prostate cancer, presenting frequently as bone pain, pathological fractures or spinal cord compression, which requires early and timely therapy. Although, for the moment, the therapeutic window for its use has not been definitively established, radium-223 (²²³Ra), an alpha particle emitter, has proved to be an effective therapeutic tool, pre or post-chemotherapy, in patients with castration-resistant prostate cancer with symptomatic bone metastases and absence of visceral metastases, significantly modifying the prognosis of the disease. It is therefore imperative to define the ideal scenarios and the correct protocol for the use of this therapy and thus offer the greatest possible clinical benefit to the patient.

Single Skull Metastasis 15 Years after Primary Treatment of Prostate Cancer and with Undetectable PSA Levels: A Case Report and Review of the Literature

Prostate cancer is the first cause of skull metastases in men, accounting for 12–18% of all cases. This condition is generally a late event in the course of the disease, involving patients with disseminated lesions. Quite rarely is skull involvement the first and single site of distant recurrence. We report the case of a patient who developed a single skull lesion 15 years after primary treatment of prostate cancer, in the presence of undetectable PSA levels. Pathological assessment performed after resection of the lesion revealed a metastasis from prostate carcinoma. Basing on this experience the appearance of craniofacial pain or a nerve deficit in patients with a history of prostate cancer should alert the clinician to exclude distant recurrence of disease, even in the presence of undetectable PSA levels and even if many years have elapsed since the treatment of the primary tumor. Knowledge of these manifestations will reduce any diagnostic delay and lead to the effective delivery of appropriate treatment.

Osteoblastic bone metastases from neuroendocrine tumor (NET) of unknown origin detected by 18fluorocholine PET/CT and its comparison with 68gallium-DOTATOC PET/CT: Case report and review of the literature

RATIONALE

Choline (CH) positron emission tomography (PET)/computed tomography (CT) with fluorine 18 (F) CH is increasingly used not only to evaluate patients with biochemically recurrent prostate cancer but also to assess metastatic lesions that are difficult or impossible to identify using more conventional modalities. Our experience with CH PET/CT has shown that it can also be used for many other malignancies.

PRESENTING CONCERNS

A 71-year-old male with a neuroendocrine tumor (NET) of unknown origin showed osteoblastic bone metastases positive to F-CH PET.

INTERVENTIONS

Diffuse bone and liver metastases were gallium-DOTATOC PET-positive with only mild uptake on FDG PET/CT. An increased prostate specific antigen (8 μg/L) gave rise to a suspicion of concurrent prostate cancer and the patient underwent F-CH PET/CT which showed diffuse uptake in the bone. A CT-guided bone biopsy confirmed osteoblastic bone metastases from NET.

OUTCOMES

Given the aggressiveness of the tumor, the patient underwent treatment with temozolomide from July 2015 to December 2015, maintaining stable disease. However, progression was documented in January 2016 and the patient was enrolled onto a phase II peptide receptor radionuclide therapy retreatment trial, which is currently ongoing.

MAIN LESSON

Our study highlights that NETs should be taken into consideration in the differential diagnosis of osteoblastic bone metastases showing F-CH uptake. A prognostic role for this imaging technique can also be hypothesized.

11C- or 18F-Choline PET/CT for Imaging Evaluation of Biochemical Recurrence of Prostate Cancer

Recurrence of prostate cancer is suspected when an increase in the prostate-specific antigen level is detected after radical treatment; the recurrence could be local relapse, distant relapse, or both. Differentiation between the two patterns of relapse is critical for choosing the proper treatment strategy. Choline PET/CT could be of help in discriminating patients with local, lymph node, and bone recurrences, thus having an impact on patient management.

PET and PET/CT with radiolabeled choline in prostate cancer: a critical reappraisal of 20 years of clinical studies

We here aim to provide a comprehensive and critical review of the literature concerning the clinical applications of positron emission tomography/computed tomography (PET/CT) with radiolabeled choline in patients with prostate cancer (PCa). We will initially briefly summarize the historical context that brought to the synthesis of [¹¹C]choline, which occurred exactly 20 years ago. We have arbitrarily grouped the clinical studies in three different periods, according to the year in which they were published and according to their relation with their applications in urology, radiotherapy and oncology. Studies at initial staging and, more extensively, studies in patients with biochemical failure, as well as factors predicting positive PET/CT will be reviewed. The capability of PET/CT with radiolabeled choline to provide prognostic information on PCa-specific survival will also be examined. The last sections will be devoted to the use of radiolabeled choline for monitoring the response to androgen deprivation therapy, radiotherapy, and chemotherapy. The accuracy and the limits of the technique will be discussed according to the information available from standard validation processes, including biopsy or histology. The clinical impact of the technique will be discussed on the basis of changes induced in the management of patients and in the evaluation of the response to therapy. Current indications to PET/CT, as officially endorsed by guidelines, or as routinely performed in the clinical practice will be illustrated. Emphasis will be made on methodological factors that might have influenced the results of the studies or their interpretation. Finally, we will briefly highlight the potential role of positron emission tomography/magnetic resonance and of new radiotracers for PCa imaging.

Rationale for Modernising Imaging in Advanced Prostate Cancer

CONTEXT

To effectively manage patients with advanced prostate cancer (APC), it is essential to have accurate, reproducible, and validated methods for detecting and quantifying the burden of bone and soft tissue metastases and for assessing their response to therapy. Current standard of care imaging with bone and computed tomography (CT) scans have significant limitations for the assessment of bone metastases in particular.

OBJECTIVE

We aimed to undertake a critical comparative review of imaging methods used for diagnosis and disease monitoring of metastatic APC from the perspective of their availability and ability to assess disease presence, extent, and response of bone and soft tissue disease.

EVIDENCE ACQUISITION

An expert panel of radiologists, nuclear medicine physicians, and medical physicists with the greatest experience of imaging in advanced prostate cancer prepared a review of the practicalities, performance, merits, and limitations of currently available imaging methods.

EVIDENCE SYNTHESIS

Meta-analyses showed that positron emission tomography (PET)/CT with different radiotracers and whole-body magnetic resonance imaging (WB-MRI) are more accurate for bone lesion detection than CT and bone scans (BSs). At a patient level, the pooled sensitivities for bone disease by using choline (CH)-PET/CT, WB-MRI, and BS were 91% (95% confidence interval [CI], 83-96%), 97% (95% CI, 91-99%), and 79% (95% CI, 73-83%), respectively. The pooled specificities for bone metastases detection using CH-PET/CT, WB-MRI, and BS were 99% (95% CI, 93-100%), 95% (95% CI, 90-97%), and 82% (95% CI, 78-85%), respectively. The ability of PET/CT and WB-MRI to assess therapeutic benefits is promising but has not been comprehensively evaluated. There is variability in the cost, availability, and quality of PET/CT and WB-MRI.

CONCLUSIONS

Standardisation of acquisition, interpretation, and reporting of WB-MRI and PET/CT scans is required to assess the performance of these techniques in clinical trials of treatment approaches in APC.

PATIENT SUMMARY

PET/CT and whole-body MRI scans have the potential to improve detection and to assess response to treatment of all states of advanced prostate cancer. Consensus recommendations on quality standards, interpretation, and reporting are needed but will require validation in clinical trials of established and new treatment approaches.

Imaging of Prostate Cancer Using 18F-Choline PET/Computed Tomography

¹⁸F-fluorocholine (FCH) PET/computed tomography (CT) is a valuable imaging modality in prostate cancer disease. Probably, its main role is restaging of patients with biochemical recurrence after radical prostatectomy or external beam radiotherapy. ¹⁸F-FCH PET/CT is strengthening its position in the initial staging, biopsy target definition, radiotherapy planning, and therapy monitoring. Gleason score and prostate-specific antigen value, doubling time, and velocity can influence positivity of ¹⁸F-FCH PET/CT. The influence of androgen deprivation therapy on choline uptake is not precisely clarified. Collaboration between nuclear medicine physicians, radiologists, urologists, oncologists, and radiotherapists is crucial to help patients with prostate cancer disease.

How we read FCH-PET/CT for prostate cancer

Over the last decade, ¹⁸F-fluorocholine positron emission tomography/computed tomography (FCH-PET/CT) has gained in popularity for the staging and restaging of patients with prostate cancer (PCa). However, despite abundant literature on the topic, there is a lack of publications on how to actually interpret FCH-PET/CT in a clinical setting. Here we propose a practical, TNM-oriented approach to read FCH-PET/CT, with notes on procedure technique, image display, review sequence and report structure. The purpose of this article is to provide guidance to radiologists, nuclear medicine physicians and residents who are new to FCH-PET/CT, as well as to propose an alternate approach to more experienced physicians.

Skeletal Metastasis as Detected by 18F-FDG PET with Negative CT of the PET/CT: Frequency and Impact on Cancer Staging and/or Management

OBJECTIVES

The aim of our study is to assess the frequency of detection of PET-positive computed tomography (CT)-negative skeletal metastases (SM) and determine the impact of such detection on staging and/or management in patients who had FDG PET/CT as part of the cancer work-up.

METHODS

We retrospectively reviewed 2000 18F-FDG PET/CT scans of known cancer patients. A log was kept to record cases of suspected SM with or without bone changes from the low-dose non-contrast CT. The presence or absence of SM was evaluated based on available pathological and clinical data. The impact of detection of such lesions on cancer staging and/or management was evaluated by a board certified oncologist.

RESULTS

Of the 2000 cases, 18F-FDG PET/CT suggested SM in 146/2000 (7.3%). Of those 146 cases, 105 (72%) were positive on both PET and CT. The remaining 41 (28%) had PET-positive CT-negative bone lesions. SM was confirmed in 36/41 (88%) PET-positive/CT-negative cases. This was based on biopsy, imaging, or clinical follow-up. The detection of PET-positive CT-negative SM did not change staging or management in 7/36 (19.4%). However, staging and/or management was affected in 29/36 (80.6%).

CONCLUSION

SM is not uncommon in 18F-FDG PET/CT, as it accounts for 146/2000 (7.3%) of cases. PET demonstrated FDG-avid SM without a CT abnormality in at least 36/146 (25%). Patients staging and/or management changed in 29/36 (80.5%). We concluded that 18F-FDG PET is sensitive in the detection of SM with significant impact on staging and/or management.

[Focus on molecular imaging in prostate cancer]

INTRODUCTION

Prostate cancer is the most frequent cancer in men in France and it is a public health issue. This cancer is heterogenous. There is a clinical need of an accurate non-invasive imaging method to improve diagnosis, guide the choice of therapy and evaluate its efficacy. We undertook to critically review the different molecular imaging probes, currently used or in clinical trial.

METHOD

A systematic review of the literature was performed in Pubmed/Medline database by searching for articles in French or English published on PET tracer in prostate cancer in clinical application.

RESULTS

Several PET tracers are under investigation because of the low performance of the FDG in prostate cancer. In France, only two new PET tracers have the marketing authorization: the NaF and choline, but these tracers have several limitations. The NaF analyses only bone metastasis. The choline has changed the recurrence of prostate cancer but is not effective for recurrence with low PSA, furthermore its sensitivity is low for the detection of lymph nodes metastasis in initial disease. Several tracers in trial including the PSMA offer encouraging prospects in initial staging and for recurrences.

CONCLUSION

An accurate knowledge in molecular biology allowed to develop the metabolic imagery. Many new tracers are under evaluation in prostate cancer. The indication of each of them needs to be established.

Bone imaging in prostate cancer: the evolving roles of nuclear medicine and radiology

The bone scan continues to be recommended for both the staging and therapy response assessment of skeletal metastases from prostate cancer. However, it is widely recognised that bone scans have limited sensitivity for disease detection and is both insensitive and non-specific for determining treatment response, at an early enough time point to be clinically useful. We, therefore, review the evolving roles of nuclear medicine and radiology for this application. We have reviewed the published literature reporting recent developments in imaging bone metastases in prostate cancer, and provide a balanced synopsis of the state of the art. The development of single-photon emission computed tomography combined with computed tomography has improved detection sensitivity and specificity but has not yet been shown to lead to improvements in monitoring therapy. A number of bone-specific and tumour-specific tracers for positron emission tomography/computed tomography (PET/CT) are now available for advanced prostate cancer that show promise in both clinical settings. At the same time, the development of whole-body magnetic resonance imaging (WB-MRI) that incorporates diffusion-weighted imaging also offers significant improvements for detection and therapy response assessment. There are emerging data showing comparative SPECT/CT, PET/CT, and WB-MRI test performance for disease detection, but no compelling data on the usefulness of these technologies in response assessment have yet emerged.

The diagnostic imaging of bone metastases

BACKGROUND

Skeletal metastases are the most common malignant tumor in bone. Certain types of cancer (e.g., of the prostate or breast) are particularly likely to give rise to skeletal metastases, with prevalences of up to 70%. The diagnosis of skeletal metastases has a major impact on the overall treatment strategy and is an important determinant of the course of illness and the quality of life. The goal of diagnostic imaging is to detect skeletal metastases early, whenever they are suspected on the basis of clinical or laboratory findings or in patients who are at high risk. Other important issues include assessment of the risk of fracture and the response to treatment.

METHODS

This review is based on selected pertinent articles published up to December 2013.

RESULTS

Projectional radiography (plain films) is still useful for the immediate investigation of symptomatic bone pain and for the assessment of stability. Skeletal scintigraphy, the classic screening test for patients with cancer who do not have bone pain (specificity 81%, sensitivity 86%), has now been supplemented-in some cases, replaced-by other techniques. CT, including lowdose CT, is used to detect changes in bone structure due to metastases of some types of primary tumor (specificity 95%, sensitivity 73%); whole-body MRI, to detect metastases in the bone marrow and extraosseous soft tissues, e.g., metastases compressing the spinal cord (specificity 95%, sensitivity 91%); PET-CT, to detect metabolically active tumors (specificity 97%, sensitivity 90%).

CONCLUSION

Different imaging modalities are often used in combination to detect bone metastases optimally. Owing to advances in modern tomographic imaging, the current trend is toward whole-body imaging in a single session. The choice of method is based on the clinical situation and the type of primary tumor. Further research should address the impact of these costly and laborintensive imaging methods on treatment strategies and on the course of illness.

Comparisons between glucose analogue 2-deoxy-2-(18F)fluoro-D-glucose and 18F-sodium fluoride positron emission tomography/computed tomography in breast cancer patients with bone lesions

AIM: To compare 2-deoxy-2-(¹⁸F)fluoro-D-glucose(¹⁸F-FDG) and ¹⁸F-sodium (¹⁸F-NaF) positron emission tomography/computed tomography (PET/CT) accuracy in breast cancer patients with clinically/radiologically suspected or known bone metastases.

METHODS: A total of 45 consecutive patients with breast cancer and the presence or clinical/biochemical or radiological suspicion of bone metastatic disease underwent ¹⁸F-FDG and ¹⁸F-fluoride PET/CT. Imaging results were compared with histopathology when available, or clinical and radiological follow-up of at least 1 year. For each technique we calculated: Sensitivity (Se), specificity (Sp), overall accuracy, positive and negative predictive values, error rate, and Youden’s index. McNemar’s χ² test was used to test the difference in sensitivity and specificity between the two diagnostic methods. All analyses were computed on a patient basis, and then on a lesion basis, with consideration ofthe density of independent lesions on the co-registered CT (sclerotic, lytic, mixed, no-lesions) and the divergent site of disease (skull, spine, ribs, extremities, pelvis). The impact of adding ¹⁸F-NaF PET/CT to the work-up of patients was also measured in terms of change in their management due to ¹⁸F-NaF PET/CT findings.

RESULTS: The two imaging methods of ¹⁸F-FDG and ¹⁸F-fluoride PET/CT were significantly different at the patient-based analysis: Accuracy was 86.7% and 84.4%, respectively (McNemar’s χ² = 6.23, df = 1, P = 0.01). Overall, 244 bone lesions were detected in our analysis. The overall accuracy of the two methods was significantly different at lesion-based analysis (McNemar’s χ² = 93.4, df = 1, P < 0.0001). In the lesion density-based and site-based analysis, ¹⁸F-FDG PET/CT provided more accurate results in the detection of CT-negative metastasis (P < 0.002) and vertebral localizations (P < 0.002); ¹⁸F-NaF PET/CT was more accurate in detecting sclerotic (P < 0.005) and rib lesions (P < 0.04). ¹⁸F-NaF PET/CT led to a change of management in 3 of the 45 patients (6.6%) by revealing findings that were not detected at ¹⁸F-FDG PET/CT.

CONCLUSION: ¹⁸F-FDG PET/CT is a reliable imaging tool in the detection of bone metastasis in most cases, with a diagnostic accuracy that is slightly, but significantly, superior to that of ¹⁸F-NaF PET/CT in the general population of breast cancer patients. However, the extremely high sensitivity of ¹⁸F-fluoride PET/CT can exploit its diagnostic potential in specific clinical settings (i.e., small CT-evident sclerotic lesions, high clinical suspicious of relapse, and negative ¹⁸F-FDG PET and conventional imaging).

11C-choline PET/CT identifies osteoblastic and osteolytic lesions in patients with metastatic prostate cancer

AIM

The aim of this study was to compare C-choline PET/CT, prostate-specific antigen (PSA), PSA kinetics, and C-choline uptake in recurrent metastatic prostate cancer patients with osteoblastic and osteolytic bone metastases.

PATIENTS AND METHODS

We retrospectively analyzed 140 patients with the following criteria: (a) positive bone lesions identified with C-choline PET/CT and validated as true positive by histology (14.2%), correlative imaging (33.4%), or clinical follow-up (52.4%); (b) after radical prostatectomy (67.9%) or primary radiotherapy (22.1%); (c) proven biochemical relapse with rising PSA levels; (d) no chemotherapy, zoledronic acid, or palliative bone external beam radiation therapy previously administrated during biochemical relapse; and (f) asymptomatic for bone pain. Lesions were categorized as osteoblastic, osteolytic, or bone marrow lesions. Patients were divided into osteoblastic and osteolytic patient groups.

RESULTS

C-Choline PET/CT detected oligometastatic bone disease (1-3 lesions) in 98 (70%) of the 140 patients and multiple bone lesions in 42 (30%) of the 140 patients. By per-lesion analysis of 304 lesions, there were 184 osteoblastic, 99 osteolytic, and 21 bone marrow lesions.By per-patient analysis, 97 (69.3%) of the 140 patients were in the osteoblastic group, whereas 43 (30.7%) of the 140 patients were in the osteolytic group. Statistically significant differences in SUVmax (P < 0.001), fast PSA doubling time (P = 0.01), and PSA velocity (P = 0.01) were observed between osteoblastic (lower values) and osteolytic (higher values) groups. By multivariate analysis, fast PSA doubling time was a significant predictor for osteolytic lesions.

CONCLUSIONS

We demonstrated differences in PSA kinetics and SUVmax between osteolytic and osteoblastic lesions. C-Choline PET/CT may identify patients that could benefit from early targeted therapies, depending on the type of bone lesions expressed.

[Vertebral metastases of urogenital carcinomas: Diagnosis and conservative therapy]

The high incidence of bone metastases of urologic neoplasms and their morbidity, especially of vertebral metastases, requires exact diagnosis and consequent therapy. Conventional radiography plays an important role in the diagnosis of symptomatic bone lesions. Computed tomography can evaluate the stability of metastatic lesions and is indispensable for therapy planning. MRI and PET-CT have the highest diagnostic accuracy for the detection of bone metastases and MRI can evaluate their intra- and extraosseus components. PET-CT, PET-MRI, or SPECT-CT in combination with specific tracers - due to their high specificity and sensitivity - have the potential to replace conventional methods in the future. Conservative treatment basically consists of analgesic therapy, the administration of calcium and vitamin D3 and bisphosphonates or inhibitors of RANKL (denosumab). Moreover radium-223-dichloride can improve overall survival and the time to the first symptomatic skeletal event in castration-resistant prostate cancer patients with bone metastases.

Performance of 18F-fluoride PET or PET/CT for the detection of bone metastases: a meta-analysis

PURPOSE

This study aimed to evaluate the diagnostic accuracy of F-fluoride PET or PET/CT compared with Tc-MDP bone scintigraphy and F-FDG PET/CT in the detection of bone metastases.

PATIENTS AND METHODS

An electronic search was conducted using PubMed/MEDLINE and EMBASE. The methodological quality of the included studies was assessed with Quality Assessment of Diagnostic Accuracy Studies 2. All analyses were performed on Stata version 12.0 and Meta-DiSc version 1.4.

RESULTS

Twenty articles containing 1170 patients were identified. On a patient basis, the pooled sensitivity, specificity, and the area under the summary receiver operating characteristic curve of F-fluoride PET or PET/CT were 92% (95% confidence interval [CI], 89%-95%), 93% (95% CI, 91%-95%), and 0.985, respectively. On a lesion basis, the pooled sensitivity, specificity, and area under the summary receiver operating characteristic curve of F-fluoride PET or PET/CT were 87% (95% CI, 85%-88%), 95% (95% CI, 94%-96%), and 0.979, respectively. When compared with Tc-MDP bone scintigraphy, F-fluoride PET or PET/CT showed both higher sensitivity (96% vs. 88%, P = 0.002) and specificity (91% vs. 80%, P = 0.001). When compared with F-FDG PET/CT, F-fluoride PET/CT showed higher sensitivity (94% vs. 73%, P = 0.003), whereas no significant difference was observed in specificity (88% vs. 98%, P = 0.06).

CONCLUSIONS

F-fluoride PET or PET/CT has an excellent diagnostic capacity for the detection of bone metastases and shows advantages when compared with Tc-MDP bone scintigraphy and F-FDG PET/CT.

Dual-phase 11C-choline PET/computed tomography in the early evaluation of prostate cancer recurrence

PURPOSE

The aim of this study was to assess dual-phase 11C-choline PET/computed tomography (CT) for differentiating benign from malignant lesions in patients with biochemical recurrence of prostate cancer.

MATERIALS AND METHODS

We prospectively studied 56 patients with prostate cancer treated by surgery (n=22) or radiotherapy (n=34) who had hypermetabolic foci on 11C-choline PET/CT determined for biochemical recurrence (prostate-specific antigen 1.23-9.9 ng/ml). We used the dual-phase technique, calculating the standardized uptake value (SUV) for early (SUVearly) and late (SUVdelay) acquisitions and the difference between the two (SUVvariation) to determine whether tracer uptake remained stable or increased (accumulative pattern) or decreased (washout pattern). We used t-tests to compare mean and receiver operating characteristic curve analysis (SUVearly/SUVdelay/SUVvariation vs. benign/malignant).

RESULTS

We identified 106 hypermetabolic foci (34 local, 10 inguinal, 34 infradiaphragmatic, 14 supradiaphragmatic, and 14 in bone). We identified 34 local foci (eight after prostatectomy and 26 after radiotherapy). The eight postsurgical foci had an accumulative pattern and recurrence was confirmed (three histology, five follow-up). Of the 26 postradiotherapy foci, three had a washout pattern and follow-up ruled out recurrence; 23 had an accumulative pattern and recurrence was confirmed (14 histology, nine follow-up). The 10 inguinal foci had a washout pattern and were reactive (three histology, seven follow-up). The 34 infradiaphragmatic foci had an accumulative pattern and were malignant (34 follow-up). Of the 14 supradiaphragmatic foci, the three with a washout pattern were benign (three histology) and the 11 with an accumulative pattern were malignant (11 histology). Of the 14 foci in bone, two had a washout pattern and corresponded with signs of spondyloarthropathy. On the receiver operating characteristic curve analysis, SUVvariation best discriminated benign from malignant lesions [area under the curve (AUC)=0.993], followed by SUVdelay (AUC=0.933) and finally SUVearly (AUC=0.665).

CONCLUSION

Dual-phase PET/CT with 11C-choline is technically feasible despite this tracer's short physical half-life and is useful for discriminating benign from malignant lesions. SUVvariation accurately discriminated between benign and malignant lesions.

(18)F-Fluorocholine PET/CT for early response assessment in patients with metastatic castration-resistant prostate cancer treated with enzalutamide

PURPOSE

We investigated the role of (18)F-methylcholine (FCH) PET/CT in the early evaluation of patients with metastatic castration-resistant prostate cancer (mCRPC) treated with enzalutamide.

METHODS

The study group comprised 36 patients with a median age of 72 years (range 48-90 years) who were treated with enzalutamide 160 mg once daily after at least one chemotherapeutic regimen with docetaxel. Patients were evaluated monthly for serological prostate-specific antigen (PSA) response. FCH PET/CT was performed at baseline and repeated after 3-6 weeks. Univariate and multivariate Cox regression models addressed potential predictors of progression-free survival (PFS) and overall survival (OS).

RESULTS

At a median follow-up of 24.2 months (range 1.8-27.3 months), 34 patients were evaluable for early FCH PET/CT evaluation of response, and of these 17 showed progressive disease (PD) and 17 had stable disease or a partial response. A decrease in PSA level of more than 50% was observed in 21 patients. Early FCH PET/CT PD predicted radiological PD 3 months in advance of CT in 12 of 18 patients (66%) and was discordant with the decrease in PSA level in 13 patients. In 6 of these, biochemical PD was confirmed in 2 months. In multivariate analysis, only decrease in PSA level and FCH PET/CT were significant predictors of PFS (p = 0.0005 and p = 0.029, respectively), whereas decrease in PSA level alone was predictive of OS (p = 0.007).

CONCLUSION

This is one of the first studies to evaluate the role of FCH PET/CT as an early predictor of outcome in mCRPC patients treated with enzalutamide. Our preliminary results suggest that the combination of FCH PET/CT and decrease in PSA level could be a valid tool to predict PFS in mCRPC patients. PSA remains the single most important prognostic factor, while FCH PET/CT does not add more information on OS beyond that obtained from PSA. Further studies in larger populations are needed to confirm these data and to clarify the role of FCH PET/CT in predicting response to enzalutamide in mCRPC patients.

Salvage radical prostatectomy after external beam radiation therapy: a systematic review of current approaches

BACKGROUND

Radical external beam radiotherapy (EBRT) is a standard treatment for prostate cancer patients. Despite this, the rate of intraprostatic relapses after primary EBRT is still not negligible. There is no consensus on the most appropriate management of these patients after EBRT failure. For these patients, local salvage therapy such as radical prostatectomy, cryotherapy, and brachytherapy may be indicated.

OBJECTIVE

The objectives of this review were to analyze the eligibility criteria for careful selection of appropriate patients and to evaluate the oncological results and complications for each method.

METHODS

A review of the literature was performed to identify studies of local salvage therapy for patients who had failed primary EBRT for localized prostate cancer.

RESULTS

Most studies demonstrated that local salvage therapy after EBRT may provide long-term local control in appropriately selected patients, although toxicity is often significant.

CONCLUSIONS

Our results suggest that for localized prostate cancer recurrence after EBRT, the selection of a local treatment modality should be made on a patient-by-patient basis. An improvement in selection criteria and an integrated definition of biochemical failure for all salvage methods are required to determine which provides the best oncological outcome and least comorbidity.

[¹¹C]Choline PET/CT predicts survival in hormone-naive prostate cancer patients with biochemical failure after radical prostatectomy

PURPOSE

Over the last decade, PET/CT with radiolabelled choline has been shown to be useful for restaging patients with prostate cancer (PCa) who develop biochemical failure. The limitations of most clinical studies have been poor validation of [(11)C]choline PET/CT-positive findings and lack of survival analysis. The aim of this study was to assess whether [(11)C]choline PET/CT can predict survival in hormone-naive PCa patients with biochemical failure.

METHODS

This retrospective study included 302 hormone-naive PCa patients treated with radical prostatectomy who underwent [(11)C]choline PET/CT from 1 December 2004 to 31 July 2007 because of biochemical failure (prostate-specific antigen, PSA, >0.2 ng/mL). Median PSA was 1.02 ng/mL. PCa-specific survival was estimated using Kaplan-Meier curves. Cox regression analysis was used to evaluate the association between clinicopathological variables and PCa-specific survival. The coefficients of the covariates included in the Cox regression analysis were used to develop a novel nomogram.

RESULTS

Median follow-up was 7.2 years (1.4 - 18.9 years). [(11)C]Choline PET/CT was positive in 101 of 302 patients (33%). Median PCa-specific survival after prostatectomy was 14.9 years (95% CI 9.7 - 20.1 years) in patients with positive [(11)C]choline PET/CT. Median survival was not achieved in patients with negative [(11)C]choline PET/CT. The 15-year PCa-specific survival probability was 42.4% (95% CI 31.7 - 53.1%) in patients with positive [(11)C]choline PET/CT and 95.5% (95% CI 93.5 - 97.5 %) in patients with negative [(11)C]choline PET/CT. In multivariate analysis, [(11)C]choline PET/CT (hazard ratio 6.36, 95% CI 2.14 - 18.94, P < 0.001) and Gleason score >7 (hazard ratio 3.11, 95% CI 1.11 - 8.66, P = 0.030) predicted PCa-specific survival. An internally validated nomogram predicted 15-year PCa-specific survival probability with an accuracy of 80%.

CONCLUSION

Positive [(11)C]choline PET/CT after biochemical failure predicts PCa-specific survival in hormone-naive PCa patients. Prospective studies are warranted to confirm our results before more extensive use of [(11)C]choline PET/CT for prognostic stratification of PCa patients.

Intense 18F-choline uptake after minor head injury: misleading PET/CT result in a patient with biochemical relapse of prostate adenocarcinoma

We report the results of whole body 18F-fluorocholine (FCH) PET/CT in a single patient with biochemical suspicion of prostate adenocarcinoma relapse and recent history of minor head injury. PET showed an intense area of increased FCH uptake in the right parietal bone, without any morphological abnormality on either CT or skull radiographs. Understanding the radiotracer's physiological biodistribution as well as the nonmalignant etiologies of FCH uptake are essential requirements for a correct diagnostic interpretation of FCH PET/CT in patients with biological recurrence of prostate cancer.