Assessing the accuracy of 68 Ga-PSMA PET/CT compared with MRI in the initial diagnosis of prostate malignancy: A cohort analysis of 114 consecutive patients.

INTRODUCTION: Prostate cancer diagnosis is shifting towards a minimally invasive approach, maintaining accuracy and efficacy while reducing morbidity. We aimed to assess if PSMA-Ga68 PET/CT can accurately grade and localise prostatic malignancy using objective methods, compared with pathology and MRI. METHODS: Retrospective analysis on 114 consecutive patients undergoing staging PSMA PET/CT scans over 12 months was carried out. The SUVmax and site of highest PSMA activity within the prostate gland were recorded. Pathology/biopsy review assessed maximum Gleason score (and location). MRI analysis assessed the highest PIRADS score and location. The grade, location and size of malignant tissue on biopsy, and PSA, were correlated with the SUVmax and the PIRADS score. RESULTS: SUVmax was significantly elevated in cases with PSA ≥10 (P = 0.003) and Gleason score ≥8 (P = 0.0002). SUVmax demonstrated equivalent sensitivity to MRI-PIRADS in predicting Gleason ≥8 disease, with higher specificity when tested under a high-specificity regime (SUVmax ≥10, PIRADS = 5, P = 0.002). Furthermore, the region of highest SUVmax was superior to MRI-PIRADS for localising the highest grade tumour region, correctly identifying 71% of highest grade regions compared to 54% with MRI (P = 0.015). CONCLUSION: PSMA PET/CT is as effective as MRI in identifying high-grade prostate malignancy. Our findings also support previous studies in showing a significant relationship between SUVmax and Gleason grade. These benefits, along with the known advantage in identifying distant metastases and the reduced cost, further support the argument that PSMA PET/CT should be offered as an initial investigation in the workup of prostate cancer.

18-Fluoride labeled sodium fluoride positron emission tomography with computer tomography: the impact of pretreatment staging in intermediate- and high-risk prostate cancer.

BACKGROUND: 18-Fluoride labeled sodium fluoride (Na-18-F) positron emission tomography with computer tomography (PET/CT) has a better sensitivity and specificity than whole body bone scan (WBBS) in detecting osseous metastatic prostate cancer. We performed a pilot study of 20 men to examine what level of impact Na-18-F PET/CT has on management plans when used for staging newly diagnosed prostate cancer. MATERIALS AND METHODS: Twenty men were prospectively enrolled into the study in South Australia. Men were eligible if they had newly diagnosed, untreated, and biopsy-confirmed intermediate- or high-risk prostate cancer (D'Amico classification). WBBS and Na-18-F PET/CT scans were performed within 1 week of each other. Following review of the WBBS, treatment type and intent was documented by the treating urologist. The Na-18-F PET/CT scan was then reviewed. The impact of the Na-18-F PET/CT was measured on whether treatment modality or intent was subsequently altered: high impact = treatment intent or modality was changed; medium impact = treatment modality was modified; low impact = no change in treatment. RESULTS: In 18 men (90%), the WBBS and Na-18-F PET/CT were negative for osseous metastases. In one man (5%), the WBBS demonstrated widespread osseous metastases which were similarly demonstrated on the Na-18-F PET/CT. One man (5%) had a normal WBBS; however, the Na-18-F PET/CT demonstrated widespread osseous metastases. Subsequently, in 19 men (95%), the results of the two scans were congruent and the addition of the Na-18-F PET/CT scan demonstrated a low impact on management. In one man (5%), the addition of the Na-18-F PET/CT had a high impact as treatment type and intent was altered. CONCLUSIONS: Our pilot study is the first of its kind in Australia, and our findings suggest that Na-18-F PET/CT is a safe and feasible modality for staging prostate cancer. However, its true impact on prostate cancer management warrants further investigation.

Treatment of unresectable hepatocellular carcinoma with radiolabelled lipiodol.

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most common solid organ tumours, with approximately 500,000 new cases being reported each year. It has a very high prevalence in Asia, and almost two-thirds of all cases occur in this region. The incidence of this tumour in Australia has nearly doubled in the past decade. Surgical resection is the mainstay of treatment, but only 10-30% of HCC are amenable to surgical resection at the time of diagnosis. The prognosis for patients with unresectable HCC remains dismal. Internal radiotherapy with radiolabelled lipiodol has been used with some success in treatment of HCC. Several studies have validated its usefulness in an adjuvant setting, but it also appears to have a role in treating unresectable tumours. METHODS: Twenty-two patients with proven HCC, not amenable to or having failed surgical treatment, were evaluated for radiolabelled lipiodol treatment. Of these, 10 patients were excluded after initial evaluation and 12 patients underwent treatment. Patients were followed up every 3 months with physical examination, computed tomography scan and alpha-fetoprotein levels. Overall survival, change in tumour size and alpha-fetoprotein levels were used to evaluate the efficacy of treatment. RESULTS: The median overall survival in patients undergoing lipiodol therapy was 15 months. Tumour size was stabilized in most patients and very few side-effects of the treatment were observed. CONCLUSION: This study has shown that radiolabelled lipiodol is an effective method for the treatment of unresectable locally advanced HCC.

Assessment of radionuclide arthrography in the evaluation of loosening of knee prostheses.

BACKGROUND: Radionuclide arthrography (RNA) is an established technique in the evaluation of hip prostheses but there is scant literature on its role in knee prostheses and no data specifically related to unicompartmental knee prostheses. We reviewed our experience with radionuclide arthrography in total (TKRs) and unicompartmental (UKRs) knee arthroplasties. METHODS: A retrospective review of 66 consecutive RNA studies that either had direct surgical correlation or arthroscopic assessment in conjunction with at least 12 months of clinical and radiological follow-up. These formed the basis of our case note review. 26 studies had a confirmed diagnosis of prosthetic loosening. RESULTS: By using standardised criteria for diagnosis and an early and late imaging protocol at 30 min and 4 h, RNA had an overall sensitivity of 88% and a specificity of 88% for the diagnosis of prosthetic loosening. The individual sensitivities and specificities were 93% and 86% for TKRs and 82% and 92% for UKRs. The technique was unable to detect femoral component loosening unless a long femoral stem was present, although only 8% of episodes of prosthetic loosening did not involve the tibial component. CONCLUSION: Radionuclide arthrography should be considered as a useful diagnostic test for the evaluation of loosening of the tibial component of knee prostheses but requires early and late imaging and close attention to detail to achieve optimal results.

A systematic review of brachytherapy. Is it an effective and safe treatment for localised prostate cancer?

BACKGROUND: Brachytherapy is a promising treatment for prostate cancer as it may have reduced rates of impotence and incontinence. OBJECTIVE: General practitioners can influence the treatment patients receive by their referral patterns, so it is important they understand the effectiveness and safety of treatment. We reviewed the primary literature on brachytherapy as sole therapy for localised prostate cancer. DISCUSSION: Although there have been many studies on the safety and effectiveness of brachytherapy, there have been no trials of brachytherapy versus other treatments that would control for factors such as tumour stage, grade, or initial prostate specific antigen levels. Brachytherapy for localised prostate cancer appears to have equivalent survival rates to surgery and lower rates of impotence and urinary incontinence.