Indium-111-capromab pendetide radioimmunoscintigraphy and prognosis for durable biochemical response to salvage radiation therapy in men after failed prostatectomy

Fluorine-18-Labeled Fluciclovine PET/CT in Primary and Biochemical Recurrent Prostate Cancer Management

OBJECTIVE. The purpose of this article is to review the utility of ¹⁸F-fluciclovine PET/CT in the evaluation of recurrent prostate cancer. CONCLUSION. Fluorine-18-labeled fluciclovine PET/CT has shown promise in the evaluation of recurrent prostate cancer. Its performance has been superior to that of other imaging modalities. It has had good diagnostic accuracy, especially in the detection of extra-prostatic disease recurrence, and the findings have an impact on treatment planning. Gallium-68-labeled prostate-specific membrane antigen PET/CT has also had excellent performance in the detection of biochemically recurrent prostate cancer with detection rates superior to those of fluciclovine PET/CT.

Post-prostatectomy radiation therapy for locally recurrent prostate cancer

INTRODUCTION

Approximately 15-30% of men with localized prostate cancer will experience biochemical recurrence (BCR) after radical prostatectomy. Postoperative radiation therapy is used in men with adverse pathological features to reduce the risk of BCR or with curative intent in men with known BCR. In this study, we review the evidence for the adjuvant and salvage radiation therapy after radical prostatectomy. Areas covered: A literature review of the Medline and Embase databases was performed. The search strategy included the following terms: prostate cancer, adjuvant radiotherapy, salvage radiotherapy, radical prostatectomy, biochemical recurrence, and prostate cancer recurrence. Prospective randomized trials for the adjuvant radiotherapy and observational studies supporting salvage radiotherapy were included for discussion. Expert commentary: As postoperative radiotherapy is associated with non-trivial risks of acute and long-term toxicity and given the absence of compelling data supporting adjuvant over early salvage radiotherapy, the authors advocate, with rare exceptions, close observation and timely (early) salvage radiotherapy for patients with BCR and long life expectancy. Adjuvant radiotherapy may be considered in patients at high-risk for recurrence. Observation is appropriate in patients with limited life expectancy and/or absence of adverse features.

Improving postoperative radiotherapy following radical prostatectomy

INTRODUCTION

Prostate cancer has one of the highest incidences in the world, with good curative treatment options like radiotherapy and radical prostatectomy. Unfortunately, about 30% of the patients initially treated with curative intent will develop a recurrence and need adjuvant treatment. Five randomized trials covered the role of postoperative radiotherapy after radical prostatectomy, but there is still a lot of debate about which patients should receive postoperative radiotherapy. Areas covered: This review will give an overview on the available literature concerning post-operative radiotherapy following radical prostatectomy with an emphasis on the five randomized trials. Also, new imaging techniques like prostate-specific membrane antigen positron emission tomography (PSMA-PET) and multiparametric magnetic resonance imaging (mp-MRI) and the development of biomarkers like genomic classifiers will be discussed in the search for an improved selection of patients who will benefit from postoperative radiotherapy following radical prostatectomy. With new treatment techniques like Intensity Modulated Radiotherapy, toxicity profiles will be kept low. Expert commentary: Patients with biochemical recurrence following radical prostatectomy with an early rise in prostate-specific antigen (PSA) will benefit most from postoperative radiotherapy. In this way, patients with only high risk pathological features can avoid unnecessary treatment and toxicity, and early intervention in progressing patients would not compromise the outcome.

Methodology of patient care for elevated PSA after prostate cancer treatment: A primary care perspective

Prostate cancer (PCa) remains one of the most common cancers in men. Each year there are 230,000 new cases and it causes nearly 30,000 deaths. Elevations in prostate-specific antigen (PSA) after treatment with radiation or surgery can indicate the presence of PCa recurrence. About 15-18% of men treated for PCa will have an elevation of their PSA, which is a source of great concern and will lead to a management discussion with the patient. Approximately 25-33% of men with PCa will experience a recurrence of their cancer after surgery or radiation. This article will discuss the different options for men with a rising PSA after definitive therapy or an attempt at curative treatment for PCa. The purpose of this article is to help the primary care doctor, internist and geriatrician to become knowledgeable about the treatment options of recurrent PCa so that they can participate in the discussion with the patient and help the patient reach a decision regarding treatment and management of the elevated PSA levels, which signal recurrent disease.

Meeting the challenges of PET-based molecular imaging in cancer

As personalized medicine becomes a reality, there is a need for specific imaging agents that reflect molecular characteristics of a cancer. Fluorodeoxyglucose is an important advance because of its sensitivity. Newer molecular imaging probes offer higher specificity and are categorized as: radiolabeled biomimetics; antibody-antibody fragments and drug-drug-like compounds. Biomimetics have high sensitivity but tend to be less specific as they often engage natural transporters and metabolic pathways. Antibodies and their fragments are specific but may be limited by slow clearance. Labeled drugs and drug-like compounds offer good specificity but may be limited in sensitivity. There are numerous challenges facing molecular imaging related to their complexity. Additionally, fear of ionizing radiation and regulatory constraints have somewhat inhibited clinical translation. However, there is reason for optimism due to economies of scale and a changing health care system, which places a premium on diagnostic accuracy. Although molecular imaging is not likely to become mainstream in the near future, its long-term prospects for doing so are excellent.

Molecular imaging of urogenital diseases

There is an expanding and exciting repertoire of PET imaging radiotracers for urogenital diseases, particularly in prostate cancer, renal cell cancer, and renal function. Prostate cancer is the most commonly diagnosed cancer in men. With growing therapeutic options for the treatment of metastatic and advanced prostate cancer, improved functional imaging of prostate cancer beyond the limitations of conventional CT and bone scan is becoming increasingly important for both clinical management and drug development. PET radiotracers, apart from ¹⁸F-FDG, for prostate cancer are ¹⁸F-sodium fluoride, ¹¹C-choline, and ¹⁸F-fluorocholine, and (¹¹C-acetate. Other emerging and promising PET radiotracers include a synthetic l-leucine amino acid analogue (anti-¹⁸F-fluorocyclobutane-1-carboxylic acid), dihydrotestosterone analogue (¹⁸F-fluoro-5α-dihydrotestosterone), and prostate-specific membrane antigen-based PET radiotracers (eg, N-[N-[(S)-1,3-dicarboxypropyl]carbamoyl]-4-¹⁸F-fluorobenzyl-l-cysteine, ⁸⁹Zr-DFO-J591, and ⁶⁸Ga [HBED-CC]). Larger prospective and comparison trials of these PET radiotracers are needed to establish the role of PET/CT in prostate cancer. Although renal cell cancer imaging with FDG-PET/CT is available, it can be limited, especially for detection of the primary tumor. Improved renal cell cancer detection with carbonic anhydrase IX (CAIX)-based antibody (¹²⁴I-girentuximab) and radioimmunotherapy targeting with ¹⁷⁷Lu-cG250 appear promising. Evaluation of renal injury by imaging renal perfusion and function with novel PET radiotracers include p-¹⁸F-fluorohippurate, hippurate m-cyano-p-¹⁸F-fluorohippurate, and rubidium-82 chloride (typically used for myocardial perfusion imaging). Renal receptor imaging of the renal renin-angiotensin system with a variety of selective PET radioligands is also becoming available for clinical translation.

Anti-3-[(18)F]FACBC positron emission tomography-computerized tomography and (111)In-capromab pendetide single photon emission computerized tomography-computerized tomography for recurrent prostate carcinoma: results of a prospective clinical trial

PURPOSE

We prospectively evaluated the amino acid analogue positron emission tomography radiotracer anti-3-[(18)F]FACBC compared to ProstaScint® ((111)In-capromab pendetide) single photon emission computerized tomography-computerized tomography to detect recurrent prostate carcinoma.

MATERIALS AND METHODS

A total of 93 patients met study inclusion criteria who underwent anti-3-[(18)F]FACBC positron emission tomography-computerized tomography plus (111)In-capromab pendetide single photon emission computerized tomography-computerized tomography for suspected recurrent prostate carcinoma within 90 days. Reference standards were applied by a multidisciplinary board. We calculated diagnostic performance for detecting disease.

RESULTS

In the 91 of 93 patients with sufficient data for a consensus on the presence or absence of prostate/bed disease anti-3-[(18)F]FACBC had 90.2% sensitivity, 40.0% specificity, 73.6% accuracy, 75.3% positive predictive value and 66.7% negative predictive value compared to (111)In-capromab pendetide with 67.2%, 56.7%, 63.7%, 75.9% and 45.9%, respectively. In the 70 of 93 patients with a consensus on the presence or absence of extraprostatic disease anti-3-[(18)F]FACBC had 55.0% sensitivity, 96.7% specificity, 72.9% accuracy, 95.7% positive predictive value and 61.7% negative predictive value compared to (111)In-capromab pendetide with 10.0%, 86.7%, 42.9%, 50.0% and 41.9%, respectively. Of 77 index lesions used to prove positivity histological proof was obtained in 74 (96.1%). Anti-3-[(18)F]FACBC identified 14 more positive prostate bed recurrences (55 vs 41) and 18 more patients with extraprostatic involvement (22 vs 4). Anti-3-[(18)F]FACBC positron emission tomography-computerized tomography correctly up-staged 18 of 70 cases (25.7%) in which there was a consensus on the presence or absence of extraprostatic involvement.

CONCLUSIONS

Better diagnostic performance was noted for anti-3-[(18)F]FACBC positron emission tomography-computerized tomography than for (111)In-capromab pendetide single photon emission computerized tomography-computerized tomography for prostate carcinoma recurrence. The former method detected significantly more prostatic and extraprostatic disease.

Translational Molecular Imaging of Prostate Cancer

Prostate cancer is a heterogeneous disease, and its management is now evolving to become more personalized and to incorporate new targeted therapies. With these new changes comes a demand for molecular imaging techniques that can not only detect disease but also assess biology and treatment response. This review article summarizes current molecular imaging approaches in prostate cancer (e.g. 99mTc bone scintigraphy and 18F-fluorodeoxyglucose positron emission tomography) and highlights emerging clinical and preclinical imaging agents, with an emphasis on mechanism and clinical application. Emerging agents at various stages of clinical translation include radiolabeled analogs of lipid, amino acid, and nucleoside metabolism, as well as agents more specifically targeting prostate cancer biomarkers including androgen receptor, prostate-specific membrane antigen and others. We also highlight new techniques and targeted contrast agents for magnetic resonance imaging and spectroscopy. For all these imaging techniques, a growing and important unmet need is for well-designed prospective clinical trials to establish clear indications with clinical benefit in prostate cancer.

The dilemma of a rising prostate-specific antigen level after local therapy: what are our options?

Prostate cancer is the most common solid tumor diagnosed in men in the United States and Western Europe. Primary treatment with radiation or surgery is largely successful at controlling localized disease. However, a significant number (up to one third of men) may develop biochemical recurrence (BR), defined as a rise in serum prostate-specific antigen (PSA) level. A general presumption is that BR will lead to overt progression in patients over subsequent years. There are a number of factors that a physician must consider when counseling and recommending treatment to a patient with a rising PSA. These include the following (1) various PSA-based definitions of BR; (2) source of PSA (ie, local or distant disease, residual benign prostate); (3) available modalities to treat the disease with the least morbidity; and (4) timing of therapy. In this article we review the current and future factors that clinicians should consider in the diagnosis and treatment of recurrent prostate cancer.

Molecularly targeted agents as radiosensitizers in cancer therapy--focus on prostate cancer

As our understanding of the molecular pathways driving tumorigenesis improves and more druggable targets are identified, we have witnessed a concomitant increase in the development and production of novel molecularly targeted agents. Radiotherapy is commonly used in the treatment of various malignancies with a prominent role in the care of prostate cancer patients, and efforts to improve the therapeutic ratio of radiation by technologic and pharmacologic means have led to important advances in cancer care. One promising approach is to combine molecularly targeted systemic agents with radiotherapy to improve tumor response rates and likelihood of durable control. This review first explores the limitations of preclinical studies as well as barriers to successful implementation of clinical trials with radiosensitizers. Special considerations related to and recommendations for the design of preclinical studies and clinical trials involving molecularly targeted agents combined with radiotherapy are provided. We then apply these concepts by reviewing a representative set of targeted therapies that show promise as radiosensitizers in the treatment of prostate cancer.

Functional and molecular imaging: applications for diagnosis and staging of localised prostate cancer

Prostate cancer is currently the most common solid organ cancer type among men in the Western world. Currently, all decision-making algorithms and nomograms rely on demographics, clinicopathological data and symptoms. Such an approach can easily miss significant cancers while detecting many insignificant cancers. In this review, novel functional and molecular imaging techniques used in the diagnosis and staging of localised prostate cancer and their effect on treatment decisions are discussed.

Prostate-specific membrane antigen-based imaging

Prostate cancer (CaP) is the most common noncutaneous malignancy affecting men in North America. Despite significant efforts, conventional imaging of CaP does not contribute to patient management as much as imaging performed for other common cancers. Given the lack of specificity in conventional imaging techniques, one possible solution is to screen for CaP-specific antigenic targets and generate agents able to specifically bind. Prostate-specific membrane antigen (PSMA) is overexpressed in CaP tissue, with low levels of expression in the small intestine, renal tubular cells, and salivary gland. The first clinical agent for targeting PSMA was (111)In-capromab, involving an antibody recognizing the internal domain of PSMA. The second- and third-generation humanized PSMA binding antibodies have the potential to overcome some of the limitations inherent to capromab penditide (i.e., inability to bind to live CaP cells). One example is the humanized monoclonal antibody J591 (Hu mAb J591) that was developed primarily for therapeutic purposes but also has interesting imaging characteristics, including the identification of bone metastases in CaP. The major disadvantage of use of mAb for imaging is slow target recognition and background clearance in an appropriate time frame for diagnostic imaging. Urea-based compounds, such as small molecule inhibitors may also present promising agents for CaP imaging with single-photon emission computed tomography (SPECT) and positron emission tomography (PET). Two such small-molecule inhibitors targeting PSMA, MIP-1072, and MIP-1095 have exhibited high affinity for PSMA. The uptake of (123)I-MIP-1072 and (123)I-MIP-1095 in CaP xenografts have imaged successfully with favorable properties amenable to human trials. While advances in conventional imaging will continue, Ab and small molecule imaging exemplified by PSMA targeting have the greatest potential to improve diagnostic sensitivity and specificity.

Management of prostate cancer patients with lymph node involvement: a rapidly evolving paradigm

Although widespread PSA screening has inevitably led to increased diagnosis of lower risk prostate cancer, the number of patients with nodal involvement at baseline remains high (nearly 40% of high risk patients initially staged cN0). These rates probably do not reflect the true incidence of prostate cancer with lymph node involvement among patients selected for external beam radiotherapy (EBRT), as patients selected for surgery often have more favorable prognostic features. At many institutions, radical treatment directed only at the prostate is considered standard and patients known to have regional disease are often managed palliatively with androgen deprivation therapy (ADT) for presumed systemic disease. New imaging tools such as MR lymphangiography, choline-based PET imaging or combined SPECT/CT now allow surgeons and radiation oncologists to identify and target nodal metastasis and/or lymph nodes with a high risk of occult involvement. Recent advances in the field of surgery including the advent of extended nodal dissection and sentinel node procedures have suggested that cancer-specific survival might be improved for lymph-node positive patients with a low burden of nodal involvement when managed with aggressive interventions. These new imaging tools can provide radiation oncologists with maps to guide delivery of high dose conformal radiation to a target volume while minimizing radiation toxicity to non-target normal tissue. This review highlights advances in imaging and reports how they may help to define a new paradigm to manage node-positive prostate cancer patients with a curative-intent.

Review of salvage therapy for biochemically recurrent prostate cancer: the role of imaging and rationale for systemic salvage targeted anti-prostate-specific membrane antigen radioimmunotherapy

Despite local therapy with curative intent, approximately 30% of men suffer from biochemical relapse. Though some of these PSA relapses are not life threatening, many men eventually progress to metastatic disease and die of prostate cancer. Local therapy is an option for some men, but many have progression of disease following local salvage attempts. One significant issue in this setting is the lack of reliable imaging biomarkers to guide the use of local salvage therapy, as the likely reason for a low cure rate is the presence of undetected micrometastatic disease outside of the prostate/prostate bed. Androgen deprivation therapy is a cornerstone of therapy in the salvage setting. While subsets may benefit in terms of delay in time to metastatic disease and/or death, research is ongoing to improve salvage systemic therapy. Prostate-specific membrane antigen (PSMA) is highly overexpressed by the majority of prostate cancers. While initial methods of exploiting PSMA's high and selective expression were suboptimal, additional work in both imaging and therapeutics is progressing. Salvage therapy and imaging modalities in this setting are briefly reviewed, and the rationale for PSMA-based systemic salvage radioimmunotherapy is described.

Management of biochemical recurrence after primary localized therapy for prostate cancer

Clinically localized prostate cancer is typically managed by well established therapies like radical prostatectomy, brachytherapy, and external beam radiation therapy. While many patients can be cured with definitive local therapy, some will have biochemical recurrence (BCR) of disease detected by a rising serum prostate-specific antigen (PSA). Management of these patients is nuanced and controversial. The natural history indicates that a majority of patients with BCR will not die from prostate cancer but from other causes. Despite this, a vast majority of patients with BCR are empirically treated with non-curable systemic androgen deprivation therapy (ADT), with its myriad of real and potential side effects. In this review article, we examined the very definition of BCR after definitive local therapy, the current status of imaging studies in its evaluation, the need for additional therapies, and the factors involved in the decision making in the choice of additional therapies. This review aims to help clinicians with the management of patients with BCR. The assessment of prognostic factors including absolute PSA level, time to recurrence, PSA kinetics, multivariable nomograms, imaging, and biopsy of the prostatic bed may help stratify the patients into localized or systemic recurrence. Patients with low-risk of systemic disease may be cured by a salvage local therapy, while those with higher risk of systemic disease may be offered the option of ADT or a clinical trial. An algorithm incorporating these factors is presented.

Diagnostic performance of In-111 capromab pendetide SPECT/CT in localized and metastatic prostate cancer

PURPOSE

To determine the diagnostic performance of In-111 capromab pendetide single photon emission computed tomography/computed tomography (SPECT/CT), in the prostate gland, seminal vesicles, and lymph nodes via correlation to a gold standard of histopathology.

MATERIALS AND METHODS

In this study, we retrospectively reviewed all In-111 capromab pendetide SPECT/CT acquired at our institution for dedicated histopathology within a 4-month period. Statistical measures of performance were calculated in terms of glandular, seminal vesicle, and lymph node activity. The accuracies of glandular and seminal vesicle activity were then correlated to the indices of risk, including the stage, Gleason score, and prostate-specific antigen level, as well as the treatment history.

RESULTS

Of the 200 scans meeting the criteria of our study, 197 had prostate gland histopathology, 94 had bilateral seminal vesicle histopathology, and 5 had a total of 43 resected lymph nodes for comparison. The overall accuracies of the scan results were determined to be 77.7% (area under the receiver operating characteristic curve [AUC] = 0.539) for the gland, 67.0% (AUC = 0.510) for the seminal vesicles, and 93.0% (AUC = 0.787) for lymph nodes. For glandular activity alone, scan accuracy was found to significantly improve with increasing Gleason score (P < 0.0001), and in a setting prior to treatment (P = 0.0005). No statistically significant differences were found between different scan groups with regards to seminal vesicle activity.

CONCLUSIONS

The results of this study provide substantiating evidence In-111 capromab pendetide can be used to accurately diagnose lymph node metastases from primary cancers of the prostate; however, they also suggest the test may have limited utility in diagnosing tumors within the prostate gland and seminal vesicles.

Detection of recurrent prostate carcinoma with anti-1-amino-3-18F-fluorocyclobutane-1-carboxylic acid PET/CT and 111In-capromab pendetide SPECT/CT

PURPOSE

To compare the diagnostic performance of the synthetic amino acid analog radiotracer anti-1-amino-3-fluorine 18-fluorocyclobutane-1-carboxylic acid (anti-3-(18)F-FACBC) with that of indium 111 ((111)In)-capromab pendetide in the detection of recurrent prostate carcinoma.

MATERIALS AND METHODS

This prospective study was approved by the institutional review board and complied with HIPAA guidelines. Written informed consent was obtained. Fifty patients (mean age, 68.3 years ± 8.1 [standard deviation]; age range, 50-90 years) were included in the study on the basis of the following criteria: (a) Recurrence of prostate carcinoma was suspected after definitive therapy for localized disease, (b) bone scans were negative, and (c) anti-3-(18)F-FACBC positron emission tomography (PET)/computed tomography (CT) and (111)In-capromab pendetide single photon emission computed tomography (SPECT)/CT were performed within 6 weeks of each other. Studies were evaluated by two experienced interpreters for abnormal uptake suspicious for recurrent disease in the prostate bed and extraprostatic locations. The reference standard was a combination of tissue correlation, imaging, laboratory, and clinical data. Diagnostic performance measures were calculated and tests of the statistical significance of differences determined by using the McNemar χ(2) test as well as approximate tests based on the difference between two proportions.

RESULTS

For disease detection in the prostate bed, anti-3-(18)F-FACBC had a sensitivity of 89% (32 of 36 patients; 95% confidence interval [CI]: 74%, 97%), specificity of 67% (eight of 12 patients; 95% CI: 35%, 90%), and accuracy of 83% (40 of 48 patients; 95% CI: 70%, 93%). (111)In-capromab pendetide had a sensitivity of 69% (25 of 36 patients; 95% CI: 52%, 84%), specificity of 58% (seven of 12 patients; 95% CI: 28%, 85%), and accuracy of 67% (32 of 48 patients; 95% CI: 52%, 80%). In the detection of extraprostatic recurrence, anti-3-(18)F-FACBC had a sensitivity of 100% (10 of 10 patients; 95% CI: 69%, 100%), specificity of 100% (seven of seven patients; 95% CI: 59%, 100%), and accuracy of 100% (17 of 17 patients; 95% CI: 80%, 100%). (111)In-capromab pendetide had a sensitivity of 10% (one of 10 patients; 95% CI: 0%, 45%), specificity of 100% (seven of seven patients; 95% CI: 59%, 100%), and accuracy of 47% (eight of 17 patients; 95% CI: 23%, 72%).

CONCLUSION

anti-3-(18)F-FACBC PET/CT was more sensitive than (111)In-capromab pendetide SPECT/CT in the detection of recurrent prostate carcinoma and is highly accurate in the differentiation of prostatic from extraprostatic disease.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11102023/-/DC1.

Imaging of prostate cancer with PET/CT and radioactively labeled choline derivates

PET- and PET/CT using [(11)C]- and [(18)F]-labeled choline derivates are increasingly being used for imaging of prostate cancer. The value of PET- and PET/CT with [(11)C]- and [(18)F]-labeled choline derivates in biochemical recurrence of prostate cancer has been examined in many studies and demonstrates an increasing importance. PET/CT, in comparison to PET, improves especially the lesion localization as well as characterization. Primary prostate cancer can be detected with moderate sensitivity using PET and PET/CT using [(11)C]- and [(18)F]-labeled choline derivates--the differentiation between benign prostatic hyperplasia, prostatitis, or high-grade intraepithelial neoplasia (HGPIN) is not always possible. At the present time, [(11)C]-choline PET/CT is not recommended in the primary setting but may be utilized in clinically suspected prostate cancer with repeatedly negative prostate biopsies, in preparation of a focused re-biopsy. Promising results have been obtained for the use of PET and PET/CT with [(11)C]- and [(18)F]-labeled choline derivates in patients with biochemical recurrence. The detection rate of choline PET and PET/CT for local, regional, and distant recurrence in patients with a biochemical recurrence shows a linear correlation with PSA value at the time of imaging and reaches about 75% in patients with PSA > 3 ng/ml. Even at PSA values below 1 ng/ml, the recurrence can be diagnosed with choline PET/CT in approximately one-third of the patients. PET and PET/CT with [(11)C]- and [(18)F]-choline derivates can be helpful in the clinical setting for choosing a therapeutic strategy in the sense of an individualized treatment: an early diagnosis of recurrence is crucial to the choice of optimal treatment. Especially important for the choice of treatment is the exact localization of the site of recurrence: local recurrence, recurrence as lymph node metastasis, or systemic recurrence, as it has direct influence on individual therapy. This article reviews the use of PET and PET/CT with [(11)C]- and [(18)F]-labeled choline derivates in prostate cancer imaging with special emphasis on patients with biochemical recurrence. We briefly provide an overview of PET tracers for prostate cancer imaging, the rationale of using choline derivatives for prostate cancer imaging and discuss the contribution of choline PET/CT in patients suffering from prostate cancer with an emphasis on recurrent disease. Furthermore, we provide an outlook on future prospects of choline PET/CT imaging for therapy guidance and monitoring in the framework of therapy individualization.

Salvage radiotherapy for patients with PSA relapse following radical prostatectomy: issues and challenges

A progressively rising level of serum prostate specific antigen (PSA) after radical prostatectomy (RP) invariably indicates the recurrence of prostate cancer. The optimal management of patients with post-RP PSA relapse has remained uncertain due to a wide variability in the natural course of post-RP PSA relapse and the inability to separate a recurrent disease confined to the prostate bed from that with occult distant metastasis. Management uncertainty is further compounded by the lack of phase III clinical studies demonstrating which therapeutic approach, if any, would prolong life with no significant morbidity. Radiotherapy has been the main therapeutic modality with a curative potential for patients with post-RP PSA relapse. This review article depicts issues and challenges in the management of patients with post-RP PSA relapse, presents the literature data for the efficacy of salvage radiotherapy, either alone or in combination of androgen ablation therapy, and discusses future directions that can optimize treatment strategies.

Hybrid imaging (SPECT/CT and PET/CT): improving therapeutic decisions

The incremental diagnostic value of integrated positron emission tomography-computed tomography (PET/CT) or single-photon emission computed tomography (SPECT)/CT images compared with PET or SPECT alone, or PET or SPECT correlated with a CT obtained at a different time includes the following: (1) improvement in lesion detection on both CT and PET or SPECT images, (2) improvement in the localization of foci of uptake resulting in better differentiation of physiological from pathologic uptake, (3) precise localization of the malignant foci, for example, in the skeleton vs soft tissue or liver vs adjacent bowel or node (4) characterization of serendipitous lesions, and (5) confirmation of small, subtle, or unusual lesions. The use of these techniques can occur at the time of initial diagnosis, in assessing the early response of disease to treatment, at the conclusion of treatment, and in continuing follow-up of patients. PET/CT and SPECT/CT fusion images affect the clinical management in a significant proportion of patients with a wide range of diseases by (1) guiding further procedures, (2) excluding the need of further procedures, (3) changing both inter- and intramodality therapy, including soon after treatment has been initiated, and (4) by providing prognostic information. PET/CT fusion images have the potential to provide important information to guide the biopsy of a mass to active regions of the tumor and to provide better maps than CT alone to modulate field and dose of radiation therapy. It is expected that the role of PET/CT and SPECT/CT in changing management will continue to evolve in the future and that these tools will be fundamental components of the truly "personalized medicine" we are striving to deliver.

Challenges in clinical prostate cancer: role of imaging

OBJECTIVE

This article reviews a recent 2-day workshop on prostate cancer and imaging technology that was conducted by the Cancer Imaging Program of the National Cancer Institute. The workshop dealt with research trends and avenues for improving imaging and applications across the clinical spectrum of the disease.

CONCLUSION

After a summary of prostate cancer incidence and mortality, four main clinical challenges in prostate cancer treatment and management-diagnostic accuracy; risk stratification, initial staging, active surveillance, and focal therapy; prostate-specific antigen relapse after radiation therapy or radical prostatectomy; and assessing response to therapy in advanced disease-were discussed by the 55-member panel. The overarching issue in prostate cancer is distinguishing lethal from nonlethal disease. New technologies and fresh uses for established procedures make imaging effective in both assessing and treating prostate cancer.

[Which imaging methods should be used prior to salvage radiotherapy after prostatectomy for prostate cancer?]

Prostatectomy is one of the most widely used methods for treatment of adenocarcinoma of the prostate. According to anatomopathological criteria, between 10 and 40% of patients will display biochemical relapse in the absence of adjuvant radiotherapy. Anatomopathological and biochemical criteria are powerful tools for selecting patients for salvage radiotherapy. The aim of this article is to review literature on the latest progress in radiological and nuclear medicine techniques and their performance levels, in order to determine local, regional and metastatic relapses associated with the techniques and specify the radiotherapy target volume. Magnetic resonance imaging (MRI) displays the best sensitivity and specificity for examination of the prostate bed and enables simultaneous assessment of the pelvic region - thus diminishing the utility of computed tomography. The performance levels of MRI will probably continue to improve, with the use of dynamic MRI and MR spectroscopy. Despite the development of new markers like (11)C and (18)F choline and acetate, the sensitivity of positron emission tomography is still low. Prospective studies with an appropriate methodology are necessary for specifying the technique's value in this context.

Adjuvant and salvage radiotherapy after prostatectomy for prostate cancer: a literature review

PURPOSE

Given that postprostatectomy recurrence of prostate cancer occurs in 10-40% of patients, the best use of immediate postoperative radiotherapy (RT) in high-risk patients and salvage RT for biochemical recurrence remains a topic of debate. We assessed the levels of evidence (in terms of efficacy, prognostic factors, and toxicity) for the following treatment strategies: immediate postoperative RT alone, salvage RT alone, and the addition of androgen deprivation therapy to the two RT strategies.

METHODS AND MATERIALS

A systematic literature search for controlled randomized trials, noncontrolled trials, and retrospective studies between 1990 and 2008 was performed on PubMed, CancerLit, and MEDLINE. Only relevant articles that had appeared in peer-reviewed journals were selected. We report on the levels of evidence (according to the National Cancer Institute guidelines) supporting the various treatment strategies.

RESULTS

Immediate postoperative RT improves biochemical and clinical progression-free survival (Level of evidence, 1.ii) but has no significant effect on metastasis-free survival or overall survival. A pathologic review is of particular importance for correctly analyzing the treatment strategies. Low-grade morbidity has been significantly greater in the postoperative groups, but no severe toxicity has been observed. The influence of immediate postoperative RT on postprostatectomy continence appears to be slight; therefore, immediate postoperative RT should be considered in patients with major risk factors for local relapse (Level of evidence, 1.ii). On the basis of extensive retrospective data, salvage RT is effective in biochemical relapse after prostatectomy; some patients with few adverse prognostic factors might also benefit from salvage RT (Level of evidence, 3.ii). The addition of androgen deprivation therapy to immediate postoperative or salvage RT has only been supported by weak, retrospective data (Level of evidence, 3.ii).

CONCLUSION

Prospective randomized trials are needed to compare immediate postoperative RT with salvage RT and to assess the value of androgen deprivation therapy in this setting.

Indium-111 capromab pendetide in the management of recurrent prostate cancer

The provision of accurate prognostic information is a long-standing goal for effective management of prostate adenocarcinoma. Nontargeted imaging modalities are less efficient at detecting slow-growing prostate cancers. Prostate-specific membrane antigen has emerged as a superior biomarker, especially for the evaluation of metastatic spread. Advances in imaging technology have focused clinical interest on indium-111 capromab ((111)In capromab) pendetide, a radioimmunoconjugate that detects prostate-specific membrane antigen expression in vivo. Single-photon emission computed tomography capromab pendetide images, fused with those generated by computed tomography or magnetic resonance, have engendered improvements in localization accuracy by correlating high signal intensity with anatomic structures. In long-term outcomes studies, fused (111)In capromab pendetide scans have delivered significant benefits for patient selection and improved treatment of prostate cancer.

Is there a role for positron emission tomography imaging in the early evaluation of prostate cancer relapse?

The patient population with a rising prostate specific antigen (PSA) post-therapy with no evidence of disease on standard imaging studies currently represents the second largest group of prostate cancer patients. Little information is still available regarding the specificity and sensitivity of positron emission tomography (PET) tracers in the assessment of early biochemical recurrence. Ideally, PET imaging would allow one to accurately discriminate between local vs nodal vs distant relapse, thus enabling appropriate selection of patients for salvage local therapy. The vast majority of studies show a relatively poor yield of positive scans with PSA values < 4 ng ml(-1). So far, no tracer has been shown to be able to detect local recurrence within the clinically useful 1 ng ml(-1) PSA threshold, clearly limiting the use of PET imaging in the post-surgical setting. Preliminary evidence, however, suggests that 11C-choline PET may be useful in selecting out patients with early biochemical relapse (PSA < 2 ng ml(-1)) who have pelvic nodal oligometastasis potentially amenable to local treatment. The role of PET imaging in prostate cancer is gradually evolving but still remains within the experimental realm. Well-conducted studies comparing the merits of different tracers are needed.

ProstaScint and its role in the diagnosis of prostate cancer

Cancer of the prostate is the most common cancer in males accounting for 33% of newly diagnosed cases. It is the second leading cause of cancer death in American males. The prevalence of prostate cancer increases most rapidly with age and the incidence (unlike other cancers) continues to rise with advancing age. Death due to this cancer is almost invariably the result of failure to control metastatic disease. In addition, several studies have demonstrated that over 30% of patients will experience biochemical recurrence after surgery with long-term (more than 10 years) follow-up. Information regarding the location of the cancer is critical to the success of initial therapy when deciding between local versus systemic treatment options in the newly diagnosed patient. For patients who have already undergone definitive treatment, the localization of recurrent tumor, evidenced by an elevation of prostate-specific antigen, is difficult unless the tumor burden is large enough to be detected on conventional radiographic studies or digital rectal examination and prostatic fossa biopsy. ProstaScint is a diagnostic tool used to detect metastatic prostate cancer in lymph nodes or other sites. This article provides an overview on the uses of ProstaScint in the assessment of patients with recurrent or metastatic prostate cancer.

Central abdominal uptake of indium-111 capromab pendetide (ProstaScint) predicts for poor prognosis in patients with prostate cancer

OBJECTIVES

Central abdominal uptake (CAU) on immunoscintigraphy with capromab pendetide (CP) (ProstaScint) suggests the presence of metastases from prostate cancer, but tissue confirmation is difficult and invasive. We report the outcomes data from a cohort of patients with CAU on CP images obtained for staging.

METHODS

The records of 341 men with prostate cancer who underwent CP imaging at two institutions from 1994 to 1999 were reviewed. The patients were divided according to the presence or absence of CAU. Metastases were confirmed in 36 patients (52%) with CAU. The median follow-up was 4.1 years. Statistical analyses compared the differences in baseline characteristics, subsequent radiotherapy, intervention with androgen ablation, and survival.

RESULTS

CAU was detected in 69 patients (20%). A total of 262 patients underwent pelvic radiotherapy after the scan, 57 (83%) with CAU and 205 (75%) without (P = 0.2). Of the 69 patients with positive CAU findings and the 272 patients with negative CAU findings, 10 (14.5%) and 14 (5.1%) had died during the follow-up period (P = 0.007). Prostate cancer-specific death occurred in 5 (7.2%) of 69 patients with CAU-positive findings versus 2 of 272 with CAU-negative findings, for a rate 10 times greater in the CAU-positive group (P = 0.02). The results were independent of either the use or timing of androgen blockade.

CONCLUSIONS

The results of our study have shown that CAU on CP immunoscintigraphy is clinically important and correlates with a significantly greater risk of prostate cancer-specific death. These findings suggest that patients with CAU should be considered for earlier intervention with systemic therapy.

Management of asymptomatic rise in prostatic-specific antigen in patients with prostate cancer

Biochemical failure after curative-intent therapies is an increasingly common dilemma confronting patients and physicians. No definition of biochemical failure exists that can be applied to all forms of treatment and that is not to some degree affected by the follow-up interval, pretreatment prognostic factors, or the frequency of prostatic-specific antigen (PSA) testing. Available imaging techniques lack sensitivity in detection of occult micrometastases. Prognostic factors such as tumor characteristics and PSA kinetics should be considered when recommending second-line therapies. For those patients with suspected localized recurrence, second-line treatment with salvage therapies may provide long-term disease control. Hormonal therapy, although most commonly employed for PSA recurrence, is of palliative benefit only. Currently, the most appropriate therapeutic intervention for asymptomatic patients with evidence of biochemical failure remains undefined.

Predicting the outcome of salvage radiation therapy for recurrent prostate cancer after radical prostatectomy

PURPOSE

An increasing serum prostate-specific antigen (PSA) level is the initial sign of recurrent prostate cancer among patients treated with radical prostatectomy. Salvage radiation therapy (SRT) may eradicate locally recurrent cancer, but studies to distinguish local from systemic recurrence lack adequate sensitivity and specificity. We developed a nomogram to predict the probability of cancer control at 6 years after SRT for PSA-defined recurrence.

PATIENTS AND METHODS

Using multivariable Cox regression analysis, we constructed a model to predict the probability of disease progression after SRT in a multi-institutional cohort of 1,540 patients.

RESULTS

The 6-year progression-free probability was 32% (95% CI, 28% to 35%) overall. Forty-eight percent (95% CI, 40% to 56%) of patients treated with SRT alone at PSA levels of 0.50 ng/mL or lower were disease free at 6 years, including 41% (95% CI, 31% to 51%) who also had a PSA doubling time of 10 months or less or poorly differentiated (Gleason grade 8 to 10) cancer. Significant variables in the model were PSA level before SRT (P < .001), prostatectomy Gleason grade (P < .001), PSA doubling time (P < .001), surgical margins (P < .001), androgen-deprivation therapy before or during SRT (P < .001), and lymph node metastasis (P = .019). The resultant nomogram was internally validated and had a concordance index of 0.69.

CONCLUSION

Nearly half of patients with recurrent prostate cancer after radical prostatectomy have a long-term PSA response to SRT when treatment is administered at the earliest sign of recurrence. The nomogram we developed predicts the outcome of SRT and should prove valuable for medical decision making for patients with a rising PSA level.

The role of indium-111 radioimmunoscintigraphy in post-radical retropubic prostatectomy management of prostate cancer patients

Indium-111 radioimmunoscintigraphy (RIS) has an increasing role in the treatment of prostate cancer and is most commonly performed at this disease site using labeled monoclonal antibody against prostate-specific membrane antigen. There are many limitations of RIS, including low spatial resolution, low diagnostic yield and limited availability. Despite these limitations, the efficacy of RIS has been demonstrated in many clinical studies, including multi-institutional investigations. The highest sensitivity and specificity of RIS appears to be in the post-radical retropubic prostatectomy (post-RRP) setting. RIS has recently been explored for its role in clinical radiotherapy decision-making, and was found to have a significant impact in selecting patients for radiotherapy and for the general radiotherapy treatment volume definition. RIS has also recently been explored for its role in radiotherapy planning and was found to impact clinical target volume design. However, manual editing of the RIS volume is still necessary when projected into the radiotherapy-planning scan, as there is often overlap in the RIS-defined uptake regions with normal structures (rectum, bladder and symphysis bone marrow). The impact of RIS on biochemical control has been explored, with studies in this area yielding conflicting results. It appears that the maximum impact of RIS is possible when areas of labeled antibody uptake regions are co-registered with the radiotherapy-planning computed tomography scan. The larger RIS-guided target volumes do not appear to be prohibitive in increasing radiotherapy-related toxicity. Future directions of the use of RIS for post-RRP prostate cancer are discussed.

Long-term follow-up of 111In-capromab pendetide (ProstaScint) scan as pretreatment assessment in patients who undergo salvage radiotherapy for rising prostate-specific antigen after radical prostatectomy for prostate cancer

PURPOSE

To evaluate the long-term failure patterns in patients who underwent an (111)In-capromab pendetide (ProstaScint) scan as part of their pretreatment assessment for a rising prostate-specific antigen (PSA) level after prostatectomy and subsequently received local radiotherapy (RT) to the prostate bed.

METHODS

Fifty-eight patients were referred for evaluation of a rising PSA level after radical prostatectomy. All patients had negative findings for metastatic disease after abdominal/pelvis imaging with CT and isotope bone scans. All patients underwent a capromab pendetide scan, and the sites of uptake were noted. All patients were treated with local prostate bed RT (median dose 66.6 Gy).

RESULTS

Of the 58 patients, 20 had biochemical failure (post-RT PSA level >0.2 ng/mL or a rise to greater than the nadir PSA), including 6 patients with positive uptake outside the bed (positive elsewhere). The 4-year biochemical relapse-free survival (bRFS) rates for patients with negative (53%), positive in the prostate bed alone (45%), or positive elsewhere (74%) scan findings did not differ significantly (p = 0.51). The positive predictive value of the capromab pendetide scan in detecting disease outside the bed was 27%. The capromab pendetide scan status had no effect on bRFS. Those with a pre-RT PSA level of <1 ng/mL had improved bRFS (p = 0.003).

CONCLUSION

The capromab pendetide scan has a low positive predictive value in patients with positive elsewhere uptake and the 4-year bRFS was similar to that for those who did not exhibit positive elsewhere uptake. Therefore, patients with a postprostatectomy rising PSA level should considered for local RT on the basis of clinicopathologic factors.

Advances in the Treatment of Localized Prostate Cancer: The Role of Anatomic and Functional Imaging in Men Managed With Radiotherapy

Radiation therapy is an active modality in the management of local and regional prostate cancer, but can be curative only if all existing disease is encompassed within the treatment portal. In addition to the ability to deliver sufficient radiation dose, accurate targeting is critical to achieve better treatment outcomes. Failure to accommodate daily variations in setup and organ motion potentially limits the efficacy of sophisticated conformal techniques (three-dimensional conformal radiotherapy and intensity-modulated radiotherapy). Increased use of various online and real-time imaging techniques is an important step toward enhancing treatment accuracy. The incorporation of functional imaging techniques into treatment planning is another important step. The addition of biologic and metabolic information regarding the location and extent of disease combined with real-time online imaging will allow us to better determine where, how, and with what to treat appropriate targets and improve cure rates.

Salvage radiotherapy for biochemical relapse after complete PSA response following radical prostatectomy: outcome and prognostic factors for patients who have never received hormonal therapy

Objectives

To evaluate the results of salvage conformal radiation therapy (3DC-EBRT) for patients submitted to radical prostatectomy (RP) who have achieved complete PSA response and who have never been treated with hormonal therapy (HT).

To present the results of biochemical control, a period free from hormonal therapy and factors related to its prognosis.

Materials and methods

from August 2002 to December 2004, 43 prostate cancer patients submitted to RP presented biochemical failure after achieving a PSA < 0.2 ng/ml. They have never received HT and were submitted to salvage 3DC-EBRT. Median age was 62 years, median preoperative PSA was 8.8 ng/ml, median Gleason Score was 7. Any PSA rise above 0.2 was defined as biochemical failure after surgery. Median 3DC-EBRT dose was 70 Gy, biochemical failure after EBRT was defined as 3 consecutive rises in PSA or a single rise enough to trigger HT.

Results

3-year biochemical non-evidence of disease (BNED) was 71%. PSA doubling time lower than 4 months (p = 0.01) and time from recurrence to salvage EBRT (p = 0.04) were associated with worse chance of biochemical control. Biochemical control of 76% was achieved when RT had been introduced with a PSA lower than 1 ng/ml vs. 48% with a PSA higher than 1 (p = 0.19). Late toxicity was acceptable.

Conclusion

70% of biochemical control in 3 years can be achieved with salvage radiotherapy in selected patients. The importance of PSADT was confirmed in this study and radiotherapy should be started as early as possible. Longer follow up is necessary, but it is possible to conclude that a long interval free from hormonal therapy was achieved with low rate of toxicity avoiding or at least delaying several important adverse effects related to hormonal treatment.

Natural history of biochemical recurrence after radical prostatectomy: risk assessment for secondary therapy

PURPOSE

A persistently elevated or rising serum level of prostate-specific antigen (PSA) after radical prostatectomy is indicative of recurrent prostate cancer. The natural history of PSA-defined biochemical recurrence (BCR) is highly variable. While a rising PSA level universally antedates metastatic progression and prostate cancer-specific mortality (PCSM), it is not a surrogate for these endpoints. Thus, the management of patients with BCR is controversial.

METHODS

A literature review was conducted to determine the incidence and natural history of BCR, prognostic factors for clinical progression (CP), and the available evidence supporting local or systemic salvage therapy for these patients.

RESULTS

BCR is best defined as two successive PSA levels > or =0.4 ng/ml, as this correlates most accurately with CP. PSA doubling time (PSA-DT) and prostatectomy Gleason score are the variables that best predict the development of distant metastasis and PCSM. Prognostic models based on these and other variables are useful for assessing the need for salvage therapy and the anticipated outcome following local salvage therapy. A treatment algorithm for managing patients with post-prostatectomy BCR was devised.

CONCLUSIONS

Management of patients with BCR after prostatectomy continues to be a complex and challenging issue. Improved methods for risk stratification allow for identification of patients who require treatment. Furthermore, these methods aid in determination of the pattern of disease recurrence, thereby guiding treatment modality. Randomized trials are essential to determine the value of local or systemic salvage therapy strategies in this patient population.

Synergistic Value of Single-Photon Emission Computed Tomography/Computed Tomography Fusion to Radioimmunoscintigraphic Imaging of Prostate Cancer

The rationale on which positron emission tomography/computed tomography (PET/CT) imaging is based, combining the functional features of PET with the anatomic detail of CT, provides many advantages that are easily transferable to single-photon emission computed tomography (SPECT)/CT imaging. Our efforts have focused on applying fused SPECT/CT imaging to identify prostate cancer and its metastasis and recurrence through radioimmunoscintigraphy (RIS). This application of RIS to imaging prostate cancer requires 2 key components: (1) a well-defined target associated with the cancer and (2) a "magic bullet" to seek that target. A well-characterized RIS target for prostate cancer is prostate-specific membrane antigen, or PSMA, and finding the bullet to seek this target with high sensitivity and specificity has been the focus of intensive study for nearly two decades. One of the candidate bullets developed is capromab pendetide, which is a monoclonal antibody that seeks PSMA. This antibody is commercially available as ProstaScint, which can be labeled with indium-111 to localize prostate cancer via SPECT imaging. In the course of applying fused SPECT/CT ProstaScint imaging to more than 800 prostate cancer cases, numerous refinements to our protocol have evolved that are aimed at staging the cancer with utmost accuracy. In addition to optimizing the localization of prostate cancer and its metastasis, these refinements also have been extended toward guiding both the implantation of radioactive seeds in brachytherapy and in other types of radiation therapy which is illustrated through 5 case reports. Progress in the therapeutic targeting of PSMA is also being actively explored, which has more universal ramifications because PSMA is found in the neovasculature of other types of cancers.

Initial therapy with radical prostatectomy for high risk localized prostate cancer

PURPOSE

This study provides a perspective on initial treatment in select patients with high risk, localized prostate cancer.

MATERIALS AND METHODS

A select literature review was done with commentary on the philosophy of initial surgery followed by adjuvant or salvage therapies.

RESULTS

Early detection and associated stage migration identify a cadre of men with unfavorable but apparently localized prostate cancer who historically would not have been viewed as appropriate candidates for radical prostatectomy. Decreased morbidity from radical prostatectomy and data demonstrating improved outcomes in some patients treated with multimodal therapy protocols provide a rationale for including radical prostatectomy as part of an aggressive treatment plan to achieve optimal local elimination of cancer. Data suggest that radical prostatectomy and adjuvant or possibly even salvage radiation therapy may provide the best elimination of large local cancers. Whether such an approach provides results that are better than or even as good as those of the common standard of radiation therapy plus androgen deprivation therapy remains to be seen and, if so, at what cost to the patient in terms of adverse effects. However, it is likely that optimal elimination of local disease is needed to achieve the maximum benefit from adjuvant systemic endocrine, chemotherapy or targeted treatments. In other words optimal local therapy may be necessary but not sufficient.

CONCLUSIONS

Initial radical prostatectomy may have a role for treating high risk localized prostate cancer.

Variables which might predict the response to salvage radiotherapy in chinese patients with biochemical failure after radical prostatectomy

BACKGROUND/AIMS

To evaluate the relationship between the variables and the outcomes of salvage radiotherapy (sRT) to find some predictors of sRT.

METHODS

The medical records of 56 patients receiving sRT for biochemical failure after radical prostatectomy (RP) were available for retrospective review. sRT was defined as external beam radiotherapy for patients with a continuous increase in the prostate-specific antigen (PSA) level of >or=0.2 ng/ml after RP. Response was defined as achievement of a PSA nadir of <or=0.1 ng/ml.

RESULTS

The mean follow-up period after sRT was 31.6 months. The predictors of response to sRT were PSA doubling time (PSADT) and seminal vesicle invasion. The median PSADT in responders was 6.5 months versus 4.0 months in non-responders (OR=1.66, p=0.006). The patients with a PSADT of >6 months were all responders. The response rate in patients with seminal vesicle invasion was 42.9% (6/14) versus 76.2% (32/42) in patients without seminal vesicle invasion (OR=0.119, p=0.015).

CONCLUSION

PSADT and the state of seminal vesicle invasion were good predictors of response to sRT. sRT was especially effective when the PSADT was >6 months and in patients without seminal vesicle invasion.