The role of imaging in the detection of prostate cancer local recurrence after radiation therapy and surgery

Literature review: Imaging in prostate cancer

Imaging plays an increasingly important role in the detection and characterization of prostate cancer (PC). This review summarizes the key conventional and advanced imaging modalities including multiparametric magnetic resonance imaging (MRI) and positron emission tomography (PET) imaging and tries to instruct clinicians in finding the best image modality depending on the patient`s PC-stage. We aim to give an overview of the different image modalities and their benefits and weaknesses in imaging PC. Emphasis is put on primary prostate cancer detection and staging as well as on recurrent and castration resistant prostate cancer. Results from studies using various imaging techniques are discussed and compared. For the different stages of PC, advantages and disadvantages of the different imaging modalities are discussed. Moreover, this review aims to give an outlook about upcoming, new imaging modalities and how they might be implemented in the future into clinical routine. Imaging patients suffering from PC should aim for exact diagnosis, accurate detection of PC lesions and should mirror the true tumor burden. Imaging should lead to the best patient treatment available in the current PC-stage and should avoid unnecessary therapeutic interventions. New image modalities such as long axial field of view PET/CT with photon-counting CT and radiopharmaceuticals like androgen receptor targeting radiopharmaceuticals open up new possibilities. In conclusion, PC imaging is growing and each image modality is aiming for improvement.

18F-Fluciclovine Parameters on Targeted Prostate Biopsy Associated with True Positivity in Recurrent Prostate Cancer

We evaluated ¹⁸F-fluciclovine uptake parameters that correlate with true positivity for local recurrence in non-prostatectomy-treated patients. Methods: Twenty-one patients (prostate-specific antigen level, 7.4 ± 6.8 ng/mL) with biochemical recurrence after nonprostatectomy local therapy (radiotherapy and cryotherapy) underwent dual-time-point ¹⁸F-fluciclovine (364.1 ± 37.7 MBq) PET/CT from pelvis to diaphragm. Prostatic uptake over background was delineated and coregistered to a prostate-biopsy-planning ultrasound. Transrectal biopsies of ¹⁸F-fluciclovine-defined targets were completed using a 3-dimensional visualization and navigation platform. Histologic analyses of lesions were completed. Lesion characteristics including SUV_max, target-to-background ratio (TBR), uptake pattern, and subjective reader's suspicion level were compared between true-positive (malignant) and false-positive (benign) lesions. Univariate analysis was used to determine the association between PET and histologic findings. Receiver-operating-characteristic curves were plotted to determine discriminatory cutoffs for TBR. Statistical significance was set at a P value of less than 0.05. Results: Fifty lesions were identified in 21 patients on PET. Seventeen of 50 (34.0%) targeted lesions in 10 of 21 patients were positive for malignancy. True-positive lesions had a significantly higher SUV_max (6.62 ± 1.70 vs. 4.92 ± 1.27), marrow TBR (2.57 ± 0.81 vs. 1.69 ± 0.51), and blood-pool TBR (4.10 ± 1.17 vs. 2.99 ± 1.01) than false-positive lesions at the early time point (P < 0.01) and remained significant at the delayed time point, except for blood-pool TBR. Focal uptake (odds ratio, 12.07; 95% confidence interval, 2.98-48.80; P < 0.01) and subjective highest suspicion level (odds ratio, 10.91; 95% confidence interval, 1.19-99.69; P = 0.03) correlated with true positivity. Using the receiver-operating-characteristic curve, optimal cutoffs for marrow TBR were 1.9 (area under the curve, 0.82) and 1.8 (area under the curve, 0.85) at early and delayed imaging, respectively. With these cutoffs, 15 of 17 malignant lesions were identified at both time points; however, fewer false-positive lesions were detected at the delayed time point (5/33) than at the early time point (11/33). Conclusion: True positivity of ¹⁸F-fluciclovine-targeted prostate biopsy in non-prostatectomy-treated patients correlates with focal uptake, TBR (blood pool and marrow), and subjective highest suspicion level. A marrow TBR of 1.9 at the early time point and 1.8 at the delayed time point had optimal discriminating capabilities. Despite the relatively low intraprostate positive predictive value (34.0%) with ¹⁸F-fluciclovine, application of these parameters to interpretative criteria may improve true positivity in the treated prostate.

68Ga-PSMA PET/CT in Patients with Rising Prostatic-Specific Antigen After Definitive Treatment of Prostate Cancer: Detection Efficacy and Diagnostic accuracy

RATIONALE AND OBJECTIVES

⁶⁸Ga-prostate-specific membrane antigen-11 (⁶⁸Ga-PSMA-11) is a recently developed positron emission tomography (PET) tracer that can detect prostate cancer (PC) relapses and metastases with high contrast resolution. The aim of this study was to assess the detection efficacy and diagnostic accuracy of ⁶⁸Ga-PSMA PET/CT image in patients with rising prostatic-specific antigen (PSA) after treatment of PC.

MATERIALS AND METHODS

The present prospective study included 188 patients who exhibited rising of PSA level on a routine follow-up examination after definitive treatment of PC. All patients underwent a ⁶⁸Ga-PSMA PET/CT examination. For each patient, we determined the disease stage, the Gleason score, and the maximum standardized uptake value of the local recurrence and extraprostatic metastases. The detection efficacy and diagnostic accuracy of ⁶⁸Ga-PSMA PET/CT were established by histopathology and clinical and imaging follow-up as the reference standards.

RESULTS

⁶⁸Ga-PSMA PET/CT detected tumour relapse in 165 patients (35 patients had local recurrence, 106 patients had extraprostatic metastases, and 24 patients had combined lesions). The sensitivity, specificity, and accuracy values of ⁶⁸Ga-PSMA PET/CT examination in the detection of PC recurrence were 98.8%, 100%, and 98.8%, respectively. ⁶⁸Ga-PSMA PET/CT revealed an overall detection rate of 87.8% (165/188) in patients with rising PSA (median of 2.2 ng/mL, and range of 0.01-70 ng/mL).

CONCLUSION

⁶⁸Ga-PSMA PET/CT is a valuable tool for the detection of PC local recurrence or extraprostatic metastases following rising PSA levels after primary definitive therapy and should be incorporated during routine work-up.

Dramatic polarization in genitourinary expert opinions regarding the clinical utility of positron emission tomography (PET) imaging in prostate cancer

Objectives:

To ascertain the opinions of North American genitourinary (GU) experts regarding inclusion of technologies such as prostate - specific membrane antigen (PSMA) and C – 11 choline positron emission tomography (PET) into routine practice.

Materials and Methods:

A survey was distributed to North American GU experts. Questions pertained to the role of PSMA and C – 11 PET in PCa management. Participants were categorized as “supporters” or “opponents” of incorporation of novel imaging techniques. Opinions were correlated with practice patterns.

Results:

Response rate was 54% and we analyzed 42 radiation oncologist respondents. 17 participants (40%) have been in practice for > 20 years and 38 (90%) practice at an academic center. 24 (57%) were supporters of PSMA and 29 (69%) were supporters of C – 11. Supporters were more likely to treat pelvic nodes (88% vs. 56%, p < 01) and trended to be more likely to treat patients with moderate or extreme hypofractionation (58% vs. 28%, p = 065). Supporters trended to be more likely to offer brachytherapy boost (55% vs. 23%, p = 09), favor initial observation and early salvage over adjuvant radiation (77% vs. 55%, p = 09), and to consider themselves expert brachytherapists (69% vs. 39%, p = 09).

Conclusions:

There is a polarization among GU radiation oncology experts regarding novel imaging techniques. A correlation emerged between support of novel imaging and adoption of treatment approaches that are clinically superior or less expensive. Pre - existing biases among GU experts on national treatment - decision panels and leaders of cooperative group studies may affect the design of future studies and influence the adoption of these technologies in clinical practice.

MRI guided focal HDR brachytherapy for localized prostate cancer: Toxicity, biochemical outcome and quality of life

PURPOSE

To describe toxicity, biochemical outcome and quality of life after MRI guided focal high dose rate brachytherapy (HDR-BT) in a single fraction of 19 Gy for localized prostate cancer.

MATERIALS AND METHODS

Between May 2013 and April 2016, 30 patients were treated by MRI-guided focal HDR-BT. Patients with visible tumour on MRI were included. All patients were ≥65 years, T-stage <T3, Gleason ≤7, PSA <10 ng/mL and IPSS <15. Focal irradiation was delivered in a single fraction of 19 Gy to the D95 of the clinical target volume. Toxicity was reported using the Common Terminology Criteria for Adverse Events version 4. Biochemical failure was defined according to the Phoenix criteria and quality of life was measured using validated questionnaires.

RESULTS

Median follow up was 24 months. One patient developed a grade 2 and 3 GU toxicity after treatment. In the other 29 patients, no grade 2 or higher perioperative complications occurred. Five patients developed a biochemical recurrence. For all measured time points, there was no statistically significant deterioration in quality of life.

CONCLUSION

Focal MRI guided HDR-BT confers low toxicity rates and maintains quality of life. Biochemical recurrence is rather high, 5 patients developed a biochemical recurrence according to the Phoenix definition. Longer evaluation of these patients is necessary and caution is warranted before implementing focal HDR-BT in patients with localized prostate cancer.

Image-Guided Robotic Radiosurgery as Salvage Therapy for Locally Recurrent Prostate Cancer after External Beam Irradiation: Retrospective Feasibility Study on Six Cases

Aims and background

Technological advances in treatment planning and execution are providing new potential opportunities in the treatment of recurrent prostate cancer. This study was conducted to evaluate the feasibility and safety of reirradiation with image-guided radiosurgery using CyberKnife, a robotic arm-driven compact linear accelerator, for intraprostatic recurrence after external beam radiotherapy (EBRT).

Methods

Between September 2007 and May 2008, 6 patients diagnosed with locally recurrent prostate cancer after EBRT were treated using the CyberKnife system. The total reirradiation dose was 30 Gy in five fractions. Prior to radiosurgery four patients were treated with androgen-deprivation therapy. Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer criteria and the Houston-Phoenix definition (PSA nadir + 2 ng/mL) were used for toxicity and biochemical failure evaluation, respectively.

Results

After a median follow-up of 11.2 months (range, 9.6–18.6 months), all patients are alive with no evidence of severe urinary or rectal acute morbidity. Local control cannot be exactly determined due to the short follow-up and the bias of the use of androgen ablation. Four patients had biochemical failure, three of them with clinical failure evidence (lymph node, bone and lung metastasis, respectively): none of these patients had clinical evidence of tumor persistence in the prostate.

Conclusions

Salvage radiosurgery with CyberKnife after irradiation is feasible with low urinary and rectal morbidity. A longer follow-up and a larger number of patients are necessary to evaluate its effectiveness and optimal patient selection criteria.

Focal MRI-Guided Salvage High-Dose-Rate Brachytherapy in Patients With Radiorecurrent Prostate Cancer

Introduction:

Whole-gland salvage treatment of radiorecurrent prostate cancer has a high rate of severe toxicity. The standard of care in case of a biochemical recurrence is androgen deprivation treatment, which is associated with morbidity and negative effects on quality of life. A salvage treatment with acceptable toxicity might postpone the start of androgen deprivation treatment, might have a positive influence on the patients’ quality of life, and might even be curative. Here, toxicity and biochemical outcome are described after magnetic resonance imaging–guided focal salvage high-dose-rate brachytherapy in patients with radiorecurrent prostate cancer.

Materials and Methods:

Seventeen patients with pathologically proven locally recurrent prostate cancer were treated with focal high-dose-rate brachytherapy in a single 19-Gy fraction using magnetic resonance imaging for treatment guidance. Primary radiotherapy consisted of external beam radiotherapy or low-dose-rate brachytherapy. Tumors were delineated with Ga-68–prostate-specific membrane antigen or F18-choline positron emission tomography in combination with multiparametric magnetic resonance imaging. All patients had a prostate-specific antigen level of less than 10 ng/mL at the time of recurrence and a prostate-specific antigen doubling time of ≥12 months. Toxicity was measured by using the Common Terminology Criteria for Adverse Events version 4.

Results:

Eight of 17 patients had follow-up interval of at least 1 year. At a median follow-up interval of 10 months (range 3-40 months), 1 patient experienced a biochemical recurrence according to the Phoenix criteria, and prostate-specific membrane antigen testing revealed that this was due to a distant nodal metastasis. One patient had a grade 3 urethral stricture at 2 years after treatment.

Conclusion:

Focal salvage high-dose-rate brachytherapy in patients with radiorecurrent prostate cancer showed grade 3 toxicity in 1 of 17 patients and a distant nodal metastasis in another patient. Whether this treatment option leads to cure in a subset of patients or whether it can successfully postpone androgen deprivation treatment needs further investigation.

Impact of 68Ga-PSMA-11 PET on Management in Patients with Biochemically Recurrent Prostate Cancer

The purpose of this prospective study was to estimate the effect of ⁶⁸Ga-labeled prostate-specific membrane antigen (PSMA)-11 PET on the intended management of patients with biochemically recurrent prostate cancer. Methods: Pre- and postimaging surveys were filled out by the referring providers for patients with biochemical recurrence who were imaged using ⁶⁸Ga-PSMA-11 PET. The inclusion criterion for this study was a prostate-specific antigen (PSA) doubling time of less than 12 mo after initial treatment (NCT02611882). Of the 150 consecutive patients imaged, 126 surveys were completed (84% response rate). The responses were categorized as major change, minor change, no change, or unknown change. Results: There were 103 patients (82%) with disease detected on ⁶⁸Ga-PSMA-11 PET. On the basis of the survey results, there were 67 patients (53.2%) with major changes in management and 8 patients (6.4%) with minor changes. The proportion of cases resulting in a change in management did not significantly differ by baseline PSA level. In patients with PSA levels below 0.2 ng/dL, 7 of 12 patients had disease detected on ⁶⁸Ga-PSMA-11 PET, 5 of whom had a major change in management. Conclusion:⁶⁸Ga-PSMA-11 PET resulted in a major change in management in 53% of patients with biochemical recurrence. Further studies are warranted to investigate whether PSMA-based management strategies result in improved outcomes for patients.

Anatomical patterns of recurrence following biochemical relapse after post-prostatectomy salvage radiation therapy: a multi-institutional study

OBJECTIVES

To characterise the frequency and detailed anatomical sites of failure for patients receiving post-radical prostatectomy (RP) salvage radiation therapy (SRT).

PATIENTS AND METHODS

A multi-institutional retrospective study was performed on 574 men who underwent SRT between 1986 and 2013. Anatomical recurrence patterns were classified as lymphotrophic (lymph nodes only), osteotrophic (bone only), or multifocal if both were present. Isolated first failure sites were defined as sites of initial clinically detected recurrence that remained isolated for at least 3 months.

RESULTS

The median follow-up after SRT was 6.8 years. The 8-year rates of local, regional, and distant failure for patients undergoing SRT were 2%, 6%, and 21%, respectively. Of the 22% men (128 of 574) who developed a clinically detectable recurrence, 17%, 50%, and 31% were lymphotrophic, osteotrophic, and multifocal, respectively. The trophic nature of metastases was prognostic for distant metastases-free survival (DMFS) and prostate cancer-specific survival (PCSS); the 10-year rates of DMFS were 18%, 5%, and 7% (P < 0.01), and PCSS were 78%, 68%, and 56% (P < 0.01), for lymphotrophic, osteotrophic, and multifocal failure patterns, respectively.

CONCLUSIONS

We demonstrate that trophism for metastatic site has significant prognostic impact on PCSS in men treated with SRT. Radiographic local failure is an uncommon event after SRT when compared to historical data of patients treated with surgery monotherapy. However, distant failure remains a challenge in this patient population and warrants further therapeutic investigation.

Practical aspects of prostate MRI: hardware and software considerations, protocols, and patient preparation

The use of multiparametric MRI scans for the evaluation of men with prostate cancer has increased dramatically and is likely to continue expanding as new developments come to practice. However, it has not yet gained the same level of acceptance of other imaging tests. Partly, this is because of the use of suboptimal protocols, lack of standardization, and inadequate patient preparation. In this manuscript, we describe several practical aspects of prostate MRI that may facilitate the implementation of new prostate imaging programs or the expansion of existing ones.

Innovations in diagnostic imaging of localized prostate cancer

PURPOSE

In recent years, various imaging modalities have been developed to improve diagnosis, staging, and localization of early-stage prostate cancer (PCa).

METHODS

A MEDLINE literature search of the time frame between 01/2007 and 06/2013 was performed on imaging of localized PCa.

RESULTS

Conventional transrectal ultrasound (TRUS) is mainly used to guide prostate biopsy. Contrast-enhanced ultrasound is based on the assumption that PCa tissue is hypervascularized and might be better identified after intravenous injection of a microbubble contrast agent. However, results on its additional value for cancer detection are controversial. Computer-based analysis of the transrectal ultrasound signal (C-TRUS) appears to detect cancer in a high rate of patients with previous biopsies. Real-time elastography seems to have higher sensitivity, specificity, and positive predictive value than conventional TRUS. However, the method still awaits prospective validation. The same is true for prostate histoscanning, an ultrasound-based method for tissue characterization. Currently, multiparametric MRI provides improved tissue visualization of the prostate, which may be helpful in the diagnosis and targeting of prostate lesions. However, most published series are small and suffer from variations in indication, methodology, quality, interpretation, and reporting.

CONCLUSIONS

Among ultrasound-based techniques, real-time elastography and C-TRUS seem the most promising techniques. Multiparametric MRI appears to have advantages over conventional T2-weighted MRI in the detection of PCa. Despite these promising results, currently, no recommendation for the routine use of these novel imaging techniques can be made. Prospective studies defining the value of various imaging modalities are urgently needed.

Anatomical Patterns of Recurrence Following Biochemical Relapse in the Dose Escalation Era of External Beam Radiotherapy for Prostate Cancer

PURPOSE

We provide a comprehensive analysis of anatomical patterns of recurrence following external beam radiotherapy in patients with localized prostate cancer.

MATERIALS AND METHODS

This retrospective analysis included 2,694 patients with localized prostate cancer who received definitive, dose escalated external beam radiotherapy from 1991 to 2008. First recurrence sites were defined as initial sites of clinically detected recurrence and any subsequent clinically detected recurrence within 3 months. Anatomical recurrence patterns were classified as local (prostate/seminal vesicles only), lymphotropic (lymph nodes only) and osteotropic (bones only) in patients with disease confined only to these respective sites for at least 2 years from the initial clinically detected recurrence.

RESULTS

Prostate was the most common first recurrence site in the low, intermediate and high risk groups with an 8-year cumulative incidence of 3.5%, 9.8% and 14.6%, respectively. The 8-year risk of isolated pelvic lymph node relapse as the first recurrence site was 0%, 1.0% and 3.3%, respectively. In the 474 patients with clinically detected recurrence the most common first recurrence site was local in 55.3%, bone in 33.5%, pelvic lymph nodes in 21.3% and abdominal lymph nodes in 9.1%. Patients showed unique relapse distributions, including a pattern that was local in 41.6%, lymphotropic in 9.7%, osteotropic in 20.3% and multiorgan/visceral in 28.5%. Anatomical recurrence pattern was the strongest predictor of prostate cancer specific mortality on multivariate analysis of patients with clinically detected recurrence.

CONCLUSIONS

The most common first recurrence site after dose escalated external beam radiotherapy for prostate cancer is in the prostate and seminal vesicles in all risk groups. In contrast, patients treated without elective pelvic lymph node irradiation are at relatively low risk for isolated pelvic lymph node relapse. Recurrence patterns revealed a tropism for specific anatomical distributions with divergent prognoses, suggesting underlying biological differences among tumors.

Identifying Quantitative In Vivo Multi-Parametric MRI Features For Treatment Related Changes after Laser Interstitial Thermal Therapy of Prostate Cancer

Laser interstitial thermal therapy (LITT) is a new therapeutic strategy being explored in prostate cancer (CaP), which involves focal ablation of organlocalized tumor via an interstitial laser fiber. While little is known about treatment-related changes following LITT, studying post-LITT changes via imaging is extremely significant for enabling early image-guided intervention and follow-up. In this work, we present the first attempt at examining focal treatment-related changes on a per-voxel basis via quantitative comparison of MRI features pre- and post-LITT, and hence identifying computerized MRI features that are highly sensitive as well as specific to post-LITT changes within the ablation zone in the prostate. A retrospective cohort of 5 patient datasets comprising both pre- and post-LITT T2-weighted (T2w) and diffusion-weighted (DWI) acquisitions was considered, where DWI MRI yielded an Apparent Diffusion Co-efficient (ADC) map. Our scheme involved (1) inter-protocol registration of T2w and ADC MRI, as well as inter-acquisition registration of pre- and post-LITT MRI, (2) quantitation of MRI parameters by correcting for intensity drift in order to examine tissuespecific response, and (3) quantification of the information captured by T2w MRI and ADC maps via texture and intensity features. Correction of parameter drift resulted in visually discernible improvements in highlighting tissue-specific response in different MRI features. Quantitative, voxel-wise comparison of the changes in different MRI features indicated that steerable and non-steerable gradient texture features, rather than the original T2w intensity and ADC values, were highly sensitive as well as specific in identifying changes within the ablation zone pre- and post-LITT. The highest ranked texture feature yielded a normalized percentage change of 186% within the ablation zone and 43% in a spatially distinct normal region, relative to its pre-LITT value. By comparison, both the original T2w intensity and ADC value demonstrated a markedly less sensitive and specific response to changes within the ablation zone. Qualitative as well as quantitative evaluation of co-occurrence texture features indicated the presence of LITT-related effects such as edema adjacent to the ablation zone, which were indiscernible on the original T2w and ADC images. Our preliminary results thus indicate great potential for non-invasive computerized MRI imaging features for determining focal treatment related changes, informing image-guided interventions, as well as predicting long- and short-term patient outcome.

Retreatment for prostate cancer with stereotactic body radiation therapy (SBRT): Feasible or foolhardy?

The most popular therapeutic option in the management of radio-recurrent prostatic carcinoma is represented by the androgen deprivation therapy, that however should be considered only palliative and hampered by potential adverse effects of testosterone suppression. Local therapies such as surgery, cryoablation or brachytherapy might be curative choices for patients in good conditions and with a long-life expectancy, but at cost of significant risk of failure and severe toxicity. The administration of stereotactic body radiation therapy (SBRT) in this setting have come about because of tremendous technologic advances in image guidance and treatment delivery techniques that enable the delivery of large doses to tumor with reduced margins and high gradients outside the target, thereby reducing the volume of rectum which already received significant doses from primary radiotherapy. So far, very modest data are available to support its employment. Rationale, clinical experience, and challenges are herein reviewed and discussed.

Evaluation of 3 T pelvic MRI imaging in prostate cancer patients receiving post-prostatectomy IMRT

PURPOSE

The purpose of the study was to evaluate the utility of a 3 T pelvic magnetic resonance imaging (MRI) in detecting a local recurrence in post-prostatectomy prostate cancer patients prior to receiving adjuvant or salvage intensity-modulated radiation therapy (IMRT).

METHODS

Ninety prostate cancer patients status post-prostatectomy with rising prostate-specific antigen (PSA) had a 3 T pelvic MRI prior to IMRT. The following variables were analyzed for predicting positive findings on MRI: initial presenting and initial post-op PSA, PSA at the time of imaging, PSA velocity, surgical margins, Gleason score, pathological stage, pre-RT digital rectal examination, and type of surgical prostatectomy.

RESULTS

The only significant variable predictive of a positive MRI was positive margins. Specifically, 15 of 46 (33 %) patients with positive margins had a positive MRI, while 5 of 44 (11 %) patients with negative margins had a positive MRI. In the MRI positive group, the location of the positive findings on MRI corresponded with the pathology report in 9 of 12 (75 %) cases.

CONCLUSION

Post-prostatectomy patients with pathologic positive margins are three times more likely to have positive findings on a 3 T MRI.

A paradigm shift from anatomic to functional and molecular imaging in the detection of recurrent prostate cancer

Approximately a third of men with localized prostate cancer who are treated with external beam radiation therapy (EBRT) or radical prostatectomy (RP) develop biochemical failure (BF). Presumably, BF will progress to distant metastasis and prostate cancer-specific mortality in some patients over subsequent years. Accurate detection of recurrent disease is important because it allows for appropriate treatment selection (e.g., local vs systemic therapy) and early delivery of therapy (e.g., salvage EBRT), which affect patient outcome. In this article, we discuss the paradigm shift in imaging technology in the detection of recurrent prostate cancer. First, we discuss the commonly used morphological and anatomical imaging modalities and their role in the post-RP and post-EBRT settings of BF. Second, we discuss the accuracy of functional and molecular imaging techniques, many of which are under investigation. Further studies are needed to establish the role of imaging techniques for detection of cancer recurrence and clinical decision-making.

Acute toxicity, biochemical and haematological study of Aframomum melegueta seed oil in male Wistar albino rats

ETHNOPHARMACOLOGICAL RELEVANCE

Aframomum melegueta is a popular medicinal plant in Nigeria believed to have many agents acting in different ways to bring about human health benefits. This study aimed to determine the acute toxicity, identify some phytochemicals known to be present in this plant and the possible effects on lipid profile, haematological indices and biomarker of prostate and cardiac dysfunction.

MATERIALS AND METHODS

Twenty four Wistar rats (284-326 g) were used in four groups of six animals. Group 1 (control) received normal saline; groups 2, 3 and 4, received intraperitoneal injection of 27.39, 54.77 and 82.16 mg/kg body weight of the extract respectively for 7 days. Haematological and biochemical parameters were measured.

RESULTS

Alkaloids, flavonoids, saponins, tannins, cardiac glycosides, terpenoids and steroids were identified in this plant extract. The LD₅₀ was 273.86 mg/kg body weight. Prostate Specific Antigen (PSA) decreased significantly in group 2. Testosterone increased significantly in all the test groups compared to the control. Cardiac troponin I (0 ng/dl) was recorded for the test groups while the control had 1.69 ± 0.12 ng/dl. Lipid profile results showed increase in HDL and decrease in total cholesterol and LDL-cholesterol. Haemoglobin (Hb) and Red Blood Cells count (RBC) decreased significantly in group 4. White Blood Cells count (WBC), Mean Cell Volume (MCV), Mean Cell Haemoglobin (MCH) and Mean Cell Haemoglobin Concentration (MCHC) did not change significantly.

CONCLUSION

Aframomum melegueta seed oil has the potential of ameliorating benign prostatic hyperplasia (BPH) and cardiac dysfunction as indicated by testosterone, PSA, lipid profile and troponin I levels. The LD₅₀ of 273.86 mg/kg body weight is indicative of mild toxicity. The lower than normal Hb, RBC confirms the possibility of toxicity.

[Single center experience of (18F)-fluorocholine positron emission tomography: analysis of its impact on salvage local therapy in patients with prostate adenocarcinoma]

PURPOSE

To assess usefulness of ((18)F)-fluorocholine positron emission tomography (PET) for localizing relapse in patients with biochemical relapse from prostate adenocarcinoma and its impact on indications of salvage local therapy.

PATIENTS AND METHODS

An ((18)F)-fluorocholine PET coupled with computed tomography was performed in 28 patients with biochemical progression from prostate adenocarcinoma. At the time of ((18)F)-fluorocholine PET, median prostate specific antigen (PSA) was 3.0 ng/mL (from 0.34 to 93 ng/mL) and 17 patients (60.7%) received hormone therapy. Eighteen patients from this cohort were potentially candidates to salvage radiotherapy.

RESULTS

A pathologic uptake was shown in 11 patients (39.3%) and 17 patients (60.7%) had no pathologic uptake. Median PSA was 2.4 ng/mL (0.33 to 36 ng/mL) in case of negative ((18)F)-fluorocholine PET, versus 6.75 ng/mL (1.21 to 93 ng/mL) in case of pathologic uptake (P=0.04). Among the 17 patients candidates to salvage radiotherapy, ((18)F)-fluorocholine PET helped deciding for salvage radiotherapy in five patients, since it showed only centropelvic pathologic uptake (27.7%). In one patient, it showed metastatic and radiotherapy was contraindicated. After prostatectomy, ((18)F)-fluorocholine PET was positive in only one patient candidate to salvage radiotherapy (9.1%), showing anastomotic relapse.

CONCLUSION

((18)F)-fluorocholine was positive in about a third of patients with biochemical progression. Its clinical impact is being prospectively investigated.

Analysis of intraprostatic therapeutic effects in prostate cancer patients using [(11)C]-choline pet/ct after external-beam radiation therapy

PURPOSE

The objective of the present study was to analyze, with relatively high sensitivity and specificity, uptake properties of [(11)C]-choline in prostate cancer patients by means of positron-emission tomography (pet)/computed tomography (ct) imaging using objectively defined pet parameters to test for statistically significant changes before, during, and after external-beam radiation therapy (ebrt) and to identify the time points at which the changes occur.

METHODS

The study enrolled 11 patients with intermediate-risk prostate cancer treated with ebrt, who were followed for up to 12 months after ebrt. The [(11)C]-choline pet scans were performed before treatment (baseline); at weeks 4 and 8 of ebrt; and at 1, 2, 3, 6, and 12 months after ebrt.

RESULTS

Analysis of [(11)C]-choline uptake in prostate tissue before treatment resulted in a maximum standardized uptake value (suvmax) of 4.0 ± 0.4 (n = 11) at 40 minutes after injection. During week 8 of ebrt, the suvmax declined to 2.9 ± 0.1 (n = 10, p < 0.05). At 2 and 12 months after ebrt, suvmax values were 2.3 ± 0.3 (n = 10, p < 0.01) and 2.2 ± 0.2 (n = 11, p < 0.001) respectively, indicating that, after ebrt, maximum radiotracer uptake in the prostate was significantly reduced. Similar effects were observed when analyzing the tumour:muscle ratio (tmr). The tmr declined from 7.4 ± 0.6 (n = 11) before ebrt to 6.1 ± 0.4 (n = 11, nonsignificant) during week 8 of ebrt, to 5.6 ± 0.03 (n = 11, p < 0.05) at 2 months after ebrt, and to 4.4 ± 0.4 (n = 11, p < 0.001) at 12 months after ebrt.

CONCLUSIONS

Our study demonstrated that intraprostatic [(11)C]-choline uptake in the 11 analyzed prostate cancer patients significantly declined during and after ebrt. The pet parameters SUVmax and tmr also declined significantly. These effects can be detected during radiation therapy and up to 1 year after therapy. The prognostic value of these early and statistically significant changes in intraprostatic [(11)C]-choline pet avidity during and after ebrt are not yet established. Future studies are indicated to correlate changes in [(11)C]-choline uptake parameters with long-term biochemical recurrence to further evaluate [(11)C]-choline pet changes as a possible, but currently unproven, biomarker of response.

Quantitative Evaluation of Treatment Related Changes on Multi-Parametric MRI after Laser Interstitial Thermal Therapy of Prostate Cancer

Laser interstitial thermal therapy (LITT) has recently shown great promise as a treatment strategy for localized, focal, low-grade, organ-confined prostate cancer (CaP). Additionally, LITT is compatible with multi-parametric magnetic resonance imaging (MP-MRI) which in turn enables (1) high resolution, accurate localization of ablation zones on in vivo MP-MRI prior to LITT, and (2) real-time monitoring of temperature changes in vivo via MR thermometry during LITT. In spite of rapidly increasing interest in the use of LITT for treating low grade, focal CaP, very little is known about treatment-related changes following LITT. There is thus a clear need for studying post-LITT changes via MP-MRI and consequently to attempt to (1) quantitatively identify MP-MRI markers predictive of favorable treatment response and longer term patient outcome, and (2) identify which MP-MRI markers are most sensitive to post-LITT changes in the prostate. In this work, we present the first attempt at examining focal treatment-related changes on a per-voxel basis (high resolution) via quantitative evaluation of MR parameters pre- and post-LITT. A retrospective cohort of MP-MRI data comprising both pre- and post-LITT T2-weighted (T2w) and diffusion-weighted (DWI) acquisitions was considered, where DWI MRI yielded an Apparent Diffusion Co-efficient (ADC) map. A spatially constrained affine registration scheme was implemented to first bring T2w and ADC images into alignment within each of the pre- and post-LITT acquisitions, following which the pre- and post-LITT acquisitions were aligned. Pre- and post-LITT MR parameters (T2w intensity, ADC value) were then standardized to a uniform scale (to correct for intensity drift) and then quantified via the raw intensity values as well as via texture features derived from T2w MRI. In order to quantify imaging changes as a result of LITT, absolute differences were calculated between the normalized pre- and post-LITT MRI parameters. Quantitatively combining the ADC and T2w MRI parameters enabled construction of an integrated MP-MRI difference map that was highly indicative of changes specific to the LITT ablation zone. Preliminary quantitative comparison of the changes in different MR parameters indicated that T2w texture may be highly sensitive as well as specific in identifying changes within the ablation zone pre- and post-LITT. Visual evaluation of the differences in T2w texture features pre- and post-LITT also appeared to provide an indication of LITT-related effects such as edema. Our preliminary results thus indicate great potential for non-invasive MP-MRI imaging markers for determining focal treatment related changes, and hence long- and short-term patient outcome.

The PROCAINA (PROstate CAncer INdication Attitudes) Project (Part I): a survey among Italian radiation oncologists on postoperative radiotherapy in prostate cancer

PURPOSE

Radiotherapy (RT) has an established role in the postoperative treatment of prostate cancer patients with extracapsular extension, positive surgical margins or a detectable post-operative prostate-specific antigen (PSA). Despite the large number of patients treated with postoperative RT, some issues about optimal technique, doses, volumes, timing and association with androgen deprivation are still subject of debate. The aim of this survey was to determine the patterns of choice of Italian radiation oncologists in two different clinical cases of postoperative prostate cancer patients.

STUDY DESIGN

During the 2010 National Congress of the Italian Association of Radiation Oncology (AIRO), four clinical cases were presented to the attending radiation oncologists. Two of them were cases of postoperative prostate cancer, differing in T stage of the primary tumour according to the TNM classification, preoperative staging procedures, preoperative PSA (iPSA), Gleason score of biopsies and definitive pathological specimen after surgery and postoperative PSA. For each clinical case, the radiation oncologists were asked to: (a) give indication to new pre-treatment procedures for staging; b) give indication to postoperative treatment; (c) to define specifically, where indicated, the total dose, type of fractionation, treatment volumes, type of technique, type of image-guided setup control; (d) indicate whether adjuvant hormonal therapy should be prescribed; (e) define criteria that mostly influenced the prescription. A descriptive statistical analysis was then performed.

RESULTS

A total of 300 questionnaires were distributed amongst radiation oncologists attending the congress; 128 were completed and considered for this analysis (41%). Some important differences were shown in prescribing and performing postoperative radiotherapy, and some significant differences with international guidelines and data available from the literature were also reviewed and discussed.

CONCLUSIONS

Despite the results of clinical trials, significant differences still exist among Italian radiation oncologists in deciding postoperative treatment in prostate cancer patients. These patients probably deserve a more uniform approach based on updated, detailed and evidence-based recommendations.

Prostate cancer imaging: what the urologist wants to know

No consensus exists at present regarding the use of imaging for the evaluation of prostate cancer. Ultrasonography is mainly used for biopsy guidance and magnetic resonance imaging is the mainstay in evaluating the extent of local tumor. Computed tomography and radionuclide bone scanning are mainly reserved for assessment of advanced disease. Positron emission tomography is gaining acceptance in the evaluation of treatment response and recurrence. The combination of anatomic, functional, and metabolic imaging modalities has promise to improve treatment. This article reviews current imaging techniques and touches on the evolving technologies being used for detection and follow-up of prostate cancer.

The incremental value of contrast-enhanced MRI in the detection of biopsy-proven local recurrence of prostate cancer after radical prostatectomy: effect of reader experience

OBJECTIVE

The purpose of this study is to retrospectively assess the incremental value of contrast-enhanced MRI (CE-MRI) to T2-weighted MRI in the detection of postsurgical local recurrence of prostate cancer by readers of different experience levels, using biopsy as the reference standard.

MATERIALS AND METHODS

Fifty-two men with biochemical recurrence after prostatectomy underwent 1.5-T endorectal MRI with multiphase contrast-enhanced imaging and had biopsy within 3 months of MRI. Two radiologists (reader 1 had 1 year and reader 2 had 6 years of experience) independently reviewed each MRI study and classified the likelihood of recurrent cancer on a 5-point scale. Areas under receiver operating characteristic curves (A(z)) were calculated to assess readers' diagnostic performance with T2-weighted MRI alone and combined with CE-MRI. Interobserver agreement was assessed using Cohen kappa statistics.

RESULTS

Thirty-three patients (63%) had biopsy-proven local recurrence of prostate cancer. With the addition of CE-MRI to T2-weighted imaging, the A(z) for cancer detection increased significantly for reader 1 (0.77 vs 0.85; p = 0.0435) but not for reader 2 (0.86 vs 0.88; p = 0.7294). The use of CE-MRI improved interobserver agreement from fair (κ = 0.39) to moderate (κ = 0.58).

CONCLUSION

CE-MRI increased interobserver agreement and offered incremental value to T2-weighted MRI in the detection of locally recurrent prostate cancer for the relatively inexperienced reader.

Advances in imaging and in non-surgical salvage treatments after radiorecurrence in prostate cancer: what does the oncologist, radiotherapist and radiologist need to know?

OBJECTIVES

In this article the state of art the of prostate cancer (Pca) imaging and non-surgical salvage treatments (STs) is surveyed in order to explore the impact of imaging findings on the identification of radiorecurrent Pca after external beam radiotherapy (EBRT).

METHODS

A computerised search was performed to identify all relevant studies in Medline up to 2012. Additional articles were extracted based on recommendations from an expert panel of authors.

RESULTS

Definitive EBRT for Pca is increasingly used as treatment. After radiorecurrent Pca, non-surgical STs are emerging and shifting from investigational status to more established therapeutic options. Therefore, several scientific societies have published guidelines including clinical and imaging recommendations, even if the timing, efficacy and long-term toxicity of these STs have to be established. In some measure, accurately delineating the location and the extent of cancer is critical in selecting target lesions and in identifying patients who are candidates for STs. However, there is increasing awareness that anatomical approaches based on measurements of tumour size have substantial limitations, especially for tumours of unknown activity that persist or recur following irradiation

CONCLUSIONS

To date, the main focus for innovations in imaging is the combination of excellence in anatomical resolution with specific biological correlates that depict metabolic processes and hallmarks at the tumour level. The emergence of new molecular markers could favour the development of methods that directly determine their presence, thereby improving tumour detection.

KEY POINTS

Imaging may influence therapeutic decisions during non-surgical STs. MRI findings correlate with parametric maps derived from multiple functional techniques. Non-surgical salvage treatments allow local tumour control in patients with radiorecurrent PCa.

Diffusion-weighted MRI for locally recurrent prostate cancer after external beam radiotherapy

OBJECTIVE

The objectives of our study were to establish the apparent diffusion coefficients (ADCs) of tumor and nontumor irradiated tissues in patients with suspected postradiation recurrence of prostate cancer and to determine the sensitivity and specificity of a combination of T2-weighted and diffusion-weighted imaging (DWI) for detecting local recurrence.

MATERIALS AND METHODS

Twenty-four patients with rising prostate-specific antigen levels after having completed radiation therapy 30-130 months earlier (median, 62 months) underwent endorectal T2-weighted imaging and DWI (b = 0, 100, 300, 500, and 800 s/mm(2)) followed by transrectal ultrasound (TRUS)-guided biopsy. Images were scored prospectively as positive for tumor if a region of low signal intensity on T2-weighted imaging within the prostate corresponded with a focally restricted area on the ADC map. A region of interest (ROI) was drawn around the suspicious lesion on a single slice of the ADC map and a corresponding ROI was drawn around presumed nontumor irradiated peripheral zone and central gland tissues on the opposite side of the prostate. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were determined against TRUS-guided biopsy reference standard (octant, n = 17; sextant, n = 5; two samples, n = 1; 12 samples, n = 1).

RESULTS

Sixteen of 24 patients (66.7%) had positive histology findings. The median tumor ROI area was 0.37 cm(2) (quartiles, 0.30 and 0.82 cm(2)). The sensitivity, specificity, PPV, and NPV for detecting tumor were 93.8%, 75%, 88.2%, and 85.7%, respectively. A cutoff ADC of 1216 × 10(-6) mm(2)/s could predict tumor with 100% sensitivity and 96% specificity (area under the receiver operating characteristic curve = 0.992).

CONCLUSION

An ADC derived from DWI is a useful adjunct to T2-weighted MRI for detecting local tumor recurrence larger than 0.4 cm(2) within the prostate.

ACR Appropriateness Criteria® posttreatment follow-up of prostate cancer

Although prostate cancer can be effectively treated, recurrent or residual disease after therapy is not uncommon and is usually detected by a rise in prostate-specific antigen. Patients with biochemical prostate-specific antigen relapse should undergo a prompt search for the presence of local recurrence or distant metastatic disease, each requiring different forms of therapy. Various imaging modalities and image-guided procedures may be used in the evaluation of these patients. Literature on the indications and usefulness of these radiologic studies and procedures in specific clinical settings is reviewed. The ACR Appropriateness Criteria(®) are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

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.

Lymph Node Staging with Choline PET/CT in Patients with Prostate Cancer: A Review

Due to its prevalence, prostate cancer represents a serious health problem. The treatment, when required, may be local in case of limited disease, locoregional if lymph nodes are involved, and systemic when distant metastases are present. In order to choose the best treatment regimen, an accurate disease staging is mandatory. However, the accuracy of conventional imaging modalities in detecting lymph node and bone metastases is low. In the last decade, molecular imaging, particularly, choline PET-CT has been evaluated in this setting. Choline PET represents the more accurate exam to stage high-risk prostate cancer, and it is useful in staging patients with biochemical relapse, in particular when PSA kinetics is high and/or PSA levels are more than 2 pg/ml. The present paper reports results of available papers on these issues, with particular attention to lymph node staging.

Synthesis of oncological [11C]radiopharmaceuticals for clinical PET

Positron emission tomography (PET) is a nuclear medicine modality which provides quantitative images of biological processes in vivo at the molecular level. Several PET radiopharmaceuticals labeled with short-lived isotopes such as (18)F and (11)C were developed in order to trace specific cellular and molecular pathways with the aim of enhancing clinical applications. Among these [(11)C]radiopharmaceuticals are N-[(11)C]methyl-choline ([(11)C]choline), l-(S-methyl-[(11)C])methionine ([(11)C]methionine) and 1-[(11)C]acetate ([(11)C]acetate), which have gained an important role in oncology where the application of 2-[(18)F]fluoro-2-deoxy-d-glucose ([(18)F]FDG) is suboptimal. Nevertheless, the production of these radiopharmaceuticals did not reach the same level of standardization as for [(18)F]FDG synthesis. This review describes the most recent developments in the synthesis of the above-mentioned [(11)C]radiopharmaceuticals aiming to increase the availability and hence the use of [(11)C]choline, [(11)C]methionine and [(11)C]acetate in clinical practice.

Translational imaging endpoints to predict treatment response to novel targeted anticancer agents

Response Evaluation Criteria in Solid Tumors (RECIST) and World Health Organization (WHO) Criteria have been traditionally used for the evaluation of therapeutic response to chemotherapeutic treatment regimens. They determine anatomic criteria for patients response to anti-cancer therapy based on morphological measurements of each target lesion. While this assessment is justified for cytotoxic (chemotherapeutic) drugs, it is now recognized that morphological imaging protocols are poorly suited to the evaluation of the efficacy of novel signal transduction inhibitors (STIs) which exhibit cytostatic rather than cytotoxic properties. New imaging technologies are now designed to evaluate, in a functional manner, modifications in tumor metabolic activity, cellularity, and vascularization before a reduction in tumor volume can be detected. Introduction of physiological imaging end-points, derived from dynamic contrast-enhanced (DCE) imaging protocols--including magnetic resonance imaging (MRI), computed tomography (CT) and ultrasound (US)--allow for early assessment of disruption in tumor perfusion and permeability for targeted anti-angiogenic agents. Diffusion-weighted MRI (DWI) provides another physiological imaging end-point since tumor necrosis and cellularity are seen early in response to anti-angiogenic treatment. Changes in glucose and phospholipid turnover, based on metabolic MRI and positron emission tomography (PET), provide reliable markers for therapeutic response to novel receptor-targeting agents. Finally, novel molecular imaging techniques of protein and gene expression have been developed in animal models followed by a successful human application for gene therapy-based protocols.

CADOnc©: An Integrated Toolkit For Evaluating Radiation Therapy Related Changes In The Prostate Using Multiparametric MRI

The use of multi-parametric Magnetic Resonance Imaging (T2-weighted, MR Spectroscopy (MRS), Diffusion-weighted (DWI)) has recently shown great promise for diagnosing and staging prostate cancer (CaP) in vivo. Such imaging has also been utilized for evaluating the early effects of radiotherapy (RT) (e.g. intensity-modulated radiation therapy (IMRT), proton beam therapy, brachytherapy) in the prostate with the overarching goal being to successfully predict short- and long-term patient outcome. Qualitative examination of post-RT changes in the prostate using MRI is subject to high inter- and intra-observer variability. Consequently, there is a clear need for quantitative image segmentation, registration, and classification tools for assessing RT changes via multi-parametric MRI to identify (a) residual disease, and (b) new foci of cancer (local recurrence) within the prostate. In this paper, we present a computerized image segmentation, registration, and classification toolkit called CADOnc^©, and leverage it for evaluating (a) spatial extent of disease pre-RT, and (b) post-RT related changes within the prostate. We demonstrate the applicability of CADOnc^© in studying IMRTrelated changes using a cohort of 7 multi-parametric (T2w, MRS, DWI) prostate MRI patient datasets. First, the different MRI protocols from pre- and post-IMRT MRI scans are affinely registered (accounting for gland shrinkage), followed by automated segmentation of the prostate capsule using an active shape model. A number of feature extraction schemes are then applied to extract multiple textural, metabolic, and functional MRI attributes on a per-voxel basis. An AUC of 0.7132 was achieved for automated detection of CaP on pre-IMRT MRI (via integration of T2w, DWI, MRS features); evaluated on a per-voxel basis against radiologist-derived annotations. CADOnc^© also successfully identified a total of 40 out of 46 areas where disease-related changes (both absence and recurrence) occurred post-IMRT, based on changes in the expression of quantitative MR imaging biomarkers. CADOnc^© thus provides an integrated platform of quantitative analysis tools to evaluate treatment response in vivo, based on multi-parametric MRI data.

The role of choline positron emission tomography/computed tomography in the management of patients with prostate-specific antigen progression after radical treatment of prostate cancer

CONTEXT

Choline positron emission tomography (PET)/computed tomography (CT) is a currently used diagnostic tool in restaging prostate cancer (PCa) patients with increasing prostate-specific antigen (PSA) after either radical prostatectomy (RP) or external-beam radiation therapy (EBRT). However, no final recommendations have been made on the use of this modality for patient management.

OBJECTIVE

To critically analyse the current evidence for the use of choline PET/CT scanning in the management of patients with a progressive increase in PSA after radical treatment for PCa, evaluating its diagnostic accuracy in the detection of recurrences, the clinical predictors of positive PET/CT examinations, and the modalities' role as a guide for tailored therapeutic strategies.

EVIDENCE ACQUISITION

Data on recently published (2003-2010) original articles, review articles, and editorials concerning the role of choline PET/CT in this scenario were analysed.

EVIDENCE SYNTHESIS

The diagnostic accuracy of choline PET in detecting sites of PCa relapse has been investigated by several authors, and the overall reported sensitivity ranges between 38% and 98%. It has been demonstrated that choline PET technology's positive detection rate improves with increasing PSA values. The routine use of choline PET/CT cannot be recommended for PSA values <1 ng/ml. However, in addition to PSA serum value, PSA doubling time (PSA DT), and other clinical and pathologic features-including locally advanced tumour (pT3b-T4) or lymph node involvement at initial staging-should be considered to refer patients to choline PET/CT study. Choline PET/CT may be also proposed as a image guide either for experimental surgical or radiation therapy treatments.

CONCLUSIONS

According to the current available data, choline PET/CT plays a role in the management of biochemical relapse. Its accuracy is correlated to PSA value, PSA DT, and other pathologic features. Choline PET/CT may be proposed as a guide for individualised treatment of recurrence.

Clinical evidence on PET/CT for radiation therapy planning in prostate cancer

The present chapter is focused on the role of positron emission tomography/computed tomography (PET/CT) and [11C]-labelled Choline ([11C]Choline) for the management of prostate cancer patients for radiation therapy planning. Although still a matter of debate, PET/CT with [11C]Choline is not routinely recommended for selecting patients for prostate cancer primary radiation treatment. However, due to its high accuracy in detecting and localizing recurrences when a biochemical failure occurs, [11C]Choline PET/CT may play a role in the re-staging phase to distinguish patients with local versus distant relapse, thus influencing patient management (curative versus palliative therapy). Limited data are currently available on the role of [11C]Choline PET/CT in target volume selection and delineation. According to available literature, [11C]Choline PET/CT is not clinically recommendable to plan target volume both for primary prostate treatment and for local recurrence. Nevertheless, promising data suggested a potential role of [11C]Choline PET/CT as an image guide tool for the irradiation of prostate cancer relapse.

[Locally recurrent prostate cancer following radiation therapy: radical salvage prostatectomy]

Radical salvage prostatectomy represents a secondary local treatment with curative intent in patients with organ-confined prostate cancer (PC) recurrences following radiation therapy. Preoperative risk factors predicting organ-confined disease are initial low dose rate (LDR) brachytherapy, preoperative Gleason biopsy score<or=6, <or=50% biopsy cores involved with cancer, and a prostate-specific antigen (PSA) doubling time>12 months. Metastatic disease should be ruled out preoperatively by skeletal scintigraphy, abdominal computed tomography or magnetic resonance imaging, and/or choline-PET/CT. Functionality of the lower urinary tract needs to be preoperatively evaluated by urethrocystoscopy and urodynamics. With appropriate patient selection, oncological control can be achieved in 80% of patients. A continence rate of 83%-96% depending on the type of previous radiation therapy is achievable.