Récidive testiculaire isolée d’un adénocarcinome prostatique révélée par TEP/TDM 18F-fluorocholine

With the development of new PET tracers, nuclear medicine has become a central element in the search for prostate cancer recurrence. A 75-year-old patient followed for a prostate adenocarcinoma was referred to our center for biological recurrence, with a gradual rise of prostatic specific antigen (PSA). A pelvic MRI and ¹⁸F-fluorocholine PET/CT were performed, both showing no strong evidence of local recurrence. This last examination however revealed an intense pathological radiotracer uptake only in the left testicle. After performing a complementary ultrasound imaging, orchiectomy revealed a metastatic testicular localization of the prostatic adenocarcinoma. PSA control after surgery had normalized. This case emphasizes one of the unusual presentations of metastatic prostatic disease to be aware of.     

TEP/TDM au 68Ga-PSMA-11 quand la 18F-fluorocholine ne localise pas la récidive biologique du cancer de la prostate : à propos d’un cas et revue de la littérature

A rise in prostate-specific antigen serum level (PSA) is an increasing issue, which occurs in more than one third of the patients who underwent radical prostatectomy. Thus, imaging these patients is of importance in order to localize residual disease and then to propose suitable therapy. The usefulness of ¹⁸F-fluorocholine (FCH) PET/CT in this indication has been demonstrated for several years. Recently, specific ligands of the prostate-specific membrane antigen (PSMA), which is expressed by almost all prostate cancers, were labelled with PET radionuclides. ⁶⁸Ga-PSMA-11 (PSMA-11) PET/CT has been described as superior to FCH and conventional imaging to detect prostate cancer recurrence. We present the case of a patient with history of prostate cancer, treated by surgery, referred for a rise in PSA serum level and without any residual disease targeted neither on FCH, nor on pelvic MRI. The PSMA-11 PET/CT demonstrated a pelvic lymph node, which was suspect of recurrence and allowed to initiate a specific curative therapy, replacing the “palliative” hormonotherapy, which was planned. A short review of the literature on this topic, focusing on the published PSMA-11 performances and main known interpretation pitfalls.     

Apport d’un nouveau score visuel en TEP/TDM au 18Fluorodeoxyglucose (18FDG) lors des récidives ganglionnaires de cancer ORL après traitement initial

New visual score in PET/CT 18Fluorodeoxyglucose (¹⁸FDG) to evaluate lymph node recurrence of head and neck cancer after initial treatment. Neck dissection for node recurrence of head and neck cancer is known for important morbidity after initial radiation therapy. ¹⁸FDG PET/CT in this situation looks interesting but needs standardized interpretation. Our objective was to develop a PET/CT interpretation method in suspicious locoregional head and neck recurrence. Twenty-seven patients with suspicious lymph node recurrence after initial radiation ± chemotherapy for head and neck cancer were retrospectively included. ¹⁸FDG PET/CT was performed before neck dissection and histological data. Initial PET records, binary visual scale, five-point visual scale “Deauville like” and semi-quantitative index were assessed by 2 reviewers. A lymph node recurrence was confirmed in 19 patients (70%) based on histological results. PET records analysis found 6 false positive (FP), 2 true negative (TN) and 19 true positive (TP), with a sensibility (Se), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) of 100%, 25%, 76% and 100%, respectively. Binary visual scale reclassified 1/6 FP. “Deauville like” criteria, reclassified 4/6 FP with the first reviewer (P < 0.001) and 5/6 with the second (P < 0.002), improving Sp and PPV of 66% and 95%, respectively. Kappa concordance coefficient for “Deauville like” scale was 0.88. Semi-quantitative index like SUVmax, SUVmean, SUVpeak, MTV, TLG and SAM showed no statistical value. Those preliminary results warrant a standardized visual scale, particularly the “Deauville like” criteria for ¹⁸FDG PET/CT interpretation in suspected lymph node recurrence of head and neck cancer.     

Intérêt de la TEP/TDM au 18F-FDG dans la neurofibromatose de type 1, expérience du centre national de référence Henri-Mondor sur 10 ans

ObjectiveMalignant peripherals nerve sheath tumours (MPNST) are one of the leading causes of death in neurofibromatosis type 1 (NF1). Given the temporal and spatial multiplicity of suspicious lesions, the histological diagnosis of certainty might require iterative and decaying surgical procedure. Our objective was to determine the threshold values of metabolic metrics determined on ¹⁸F-FDG PET/CT (SUV_max, total lesion glycolysis [TLG], total metabolic tumour volume [TMTV], tumour-to-liver [T/L] ratio and heterogeneity index [HI]) in order to distinguish at best MPNST from benign lesion (simple neurofibromas [NF] or dysplastic NF).Patients and methodsHundred and seven patients from the national reference centre of NF1 Henri-Mondor, clinically suspects of TMGN, underwent 160 ¹⁸F-FDG PET/CT over a period of 10 years, between 2005 and 2015. The hypermetabolics lesions identified on ¹⁸F-FDG PET/CT were confronted with pathological analysis or clinico-radiological and metabolic follow-up of more than 6 months.ResultsFour hundred and eight hypermetabolics lesions were identified, of which 112 were histologically confronted with 38 simple NF, 29 dysplastic NF, 39 TMGN and 6 incidentalomas. The remaining 296 hypermetabolics lesions experienced a median follow-up of 40.4 months [13.5–137 months]. The optimal cut-off values for malignant lesions, determined by ROC curves, were in order of decreasing performance: T/L ratio > 2.03 (sensitivity 96%, specificity 88%); SUVmax > 4.74 (sensitivity 93%, specificity 86%); TLG > 172 (sensitivity 84%, specificity 76%); TMTV > 53.5 (sensitivity 83%, specificity 68%); HI > 1.63 (sensitivity 84%, specificity 54%).Conclusions¹⁸F-FDG PET/CT is a powerful diagnostic and prognostic tool in the management of TMGN. Metabolic metrics allow with good sensitivity and specificity to identify lesions transformed into TMGN. The advent of PET/MRI will undoubtedly allow in the near future to reinforce the diagnostic and prognostic performances for the detection of transformations of neurofibromas in TMGN.     

Impact clinique et thérapeutique de l’acquisition corps entier en TEP/TDM au 18F-FDG chez les patients suivis pour mélanome malin

ObjectiveTo assess the added benefit of scanning lower limbs in addition to usual whole-body PET/CT scan in patients with no known or suspected primary or metastatic melanoma involving the lower limbs.Materials and methodsThis is a retrospective study of 133 consecutive patients (189 FDG PET/CT) who underwent FDG PET/CT for staging of melanoma at different time points in the course of disease from October 2005 to July 2009 at Brest University Hospital. Reports of whole-body PET/CT scans including lower limbs were reviewed. PET/CT abnormalities on the lower extremities were tabulated by location and correlated with pathology, other imaging studies and at least a 6-month clinical follow-up.ResultsAmong the 189 consecutive PET/CT scans performed in 133 patients, 34 scans in 29 patients highlighted abnormal FDG uptakes considered as equivocal or suggestive of malignancy on lower limbs. In 29 cases, uptakes were located both on lower limbs and on the rest of the body (lung, liver, mediastinal and sub-diaphragmatic lymph nodes, adrenal glands, bone) corresponding to disseminated disease. In five cases, PET/CT uptakes were located only on lower limbs; each pathological uptake corresponded to benign lesions. Lower limbs findings never impacted clinical and therapeutic decision.ConclusionLower limbs additional PET/CT acquisition appears to offer poor additional benefit with no unexpected solitary lesion detected and routine skull base to upper thigh images may be sufficient for this subset of patients.     

Tumeurs mammaires bilatérales chez une jeune femme : pensez à réaliser une TEP/TDM au FDG. À propos d’un cas de discordance entre l’imagerie sénologique et la TEP/TDM

This case report shows the potential role of FDG (18F) PET/CT in characterization of breasts tumors in a young female without any risk factor of malignancy.     

Radiothérapie interne vectorisée par 177Lu-PSMA-617 de l’adénocarcinome prostatique métastatique résistant à la castration : à propos d’un cas et revue de la littérature

The prostate-specific membrane antigen (PSMA) is a type II glycoprotein which is over-expressed in prostate cancer tissue, especially in high grade tumours, metastatic disease, as an effect of androgen-deprivation therapies and in castrate-resistant prostate cancer (CRPC). Recent studies about radioligand therapy using PSMA ligands labeled with lutetium-177 (¹⁷⁷Lu) in CRPC patients have suggested its interest as a third line of treatment after second generation anti-androgens and chemotherapy by taxane. We present the case of a CRPC patient who was treated by iterative radioligand therapy using PSMA-617 ligand labeled with ¹⁷⁷Lu. This case illustrates on the one hand the efficacy of the treatment, and on the other hand the fragility of the patients who are at an advanced stage of their disease. Then we present a short review of the literature on this topic, focusing on the published efficacy and tolerance of ¹⁷⁷Lu-PSMA radioligand therapy of CRPC patients.