The role of positron emission tomography in the evaluation of residual masses after chemotherapy for advanced stage seminoma

Role of 18F-Fluorodeoxyglucose Positron Emission Tomography in Children With Germ Cell Tumor After Chemotherapy

BACKGROUND/AIM

18F-fluoro-2-deoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) is a diagnostic tool widely used in adult oncology and some pediatric oncological settings. There are no established recommendations for the use of this imaging modality in pediatric malignant germ cell tumors (mGCT), however. Our aim is to evaluate the role of 18F-FDG PET/CT in the restaging of mGCT after chemotherapy in children and adolescents.

METHODS

We retrospectively reviewed patients with mGCT treated in Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP) centers who underwent 18F-FDG PET/CT between 2011 and 2021.

RESULTS

Seventeen patients (median age 13 y) were included in the study. In 14 patients, 18F-FDG PET/CT was performed at diagnosis; 12 showed pathologic uptake. The 2 18F-FDG PET/CT negative cases were histologically defined as yolk sac tumor (YST) and mixed (chorioncarcinoma, YST). Nine of the 12 patients who had pathologic 18F-FDG PET/CT at diagnosis repeated the examination after neoadjuvant chemotherapy, before, second look surgery. In 5 cases, no pathologic uptake was evident. Histology showed necrosis alone in 4 cases and necrosis and mature teratoma in 1. In 3 of the 6 cases with pathologic uptake (2 of 6 patients did not perform the examination at diagnosis), histology showed persistence of malignant component, whereas in the remaining 3 cases, necrosis and mature teratoma were present.

CONCLUSION

In our review of a series of children with mGCT, 18F-FDG PET/CT after neoadjuvant chemotherapy showed 1 of 5 false negatives and was unable to discriminate between residual malignant component and mature teratoma.

Evaluation of post-chemotherapy residual seminomatous masses by 18F-fluorodeoxyglucose PET/CT using tumor-to-liver ratio - conundrum or solution?

OBJECTIVE

Assessment of diagnostic accuracy of FDG-PET/CT in the detection of viable disease in post-chemotherapy seminomatous residual masses using visual interpretation, SUVmax, and T/L ratio.

METHODS

This is a retrospective study assessing the post-chemotherapy seminomatous residual masses of size >3 cm. The PET/CT scan findings were interpreted visually for presence of residual disease which were validated from histopathology reports or imaging follow-up for a maximum of 3 years. SUVmax and T/L ratios were also determined for all the residual lesions. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value NPV were calculated and compared for all three parameters along with ROC analysis to obtain an optimal cutoff value for SUVmax and T/L ratio, respectively.

RESULTS

Sample size was 49. Out of these 49 patients, 8 had validation of PET results with histopathology. Rest was validated with imaging follow-up. FDG-PET was positive in 30 patients and negative in 19 patients by visual interpretation. The sensitivity, specificity, PPV, and NPV by this method were 100%, 62.5%, 73%, and 100%, respectively. The SUVmax and T/L ratios were also calculated for these lesions. The cutoff for these two variables was 4.56 and 1.21, respectively. The sensitivity, specificity, PPV, and NPV at these cutoffs were 76%, 87.5%, 86%, 77.7%, and 92%, 87.5%, 88%, 91%, respectively.

CONCLUSION

FDG-PET has a favorable diagnostic value in predicting viable disease in post-chemotherapy seminomatous residual masses and using T/L ratio cutoff of 1.21 will increase the specificity of the test.

Treatment de-escalation for stage II seminoma

International Germ Cell Cancer Collaborative Group good-risk metastatic seminoma has cure rates of >95%. Within this risk group, patients with stage II disease exhibit the best oncological outcomes with the standard-of-care treatment strategies of radiotherapy or combination chemotherapy. However, these treatments can be associated with substantial early and late toxic effects. Therapy de-escalation aims to reduce treatment morbidity whilst preserving oncological outcomes. The evidence supporting such approaches is largely from non-randomized institutional data, and therefore this strategy is not recognized as standard of care. Current de-escalation approaches for stage II seminoma include single-agent chemotherapy, radiotherapy and surgery based on early data from clinical studies. Increased recognition of emerging data on treatment modification to reduce morbidity whilst maintaining cure rates and consideration of therapy de-escalation could improve patient survivorship outcomes.

Outcomes of post-chemotherapy robot-assisted retroperitoneal lymph node dissection in testicular cancer: multi-institutional study

OBJECTIVE

To evaluate the perioperative and oncological outcomes after post-chemotherapy robot-assisted retroperitoneal lymph node dissection (PC-RARPLND).

MATERIALS AND METHODS

We retrospectively reported the perioperative and oncological outcomes of all the patients with testicular cancer who underwent PC-RARPLND at three tertiary teaching centers. Descriptive statistical measures were used to report demographic, clinical, intraoperative, postoperative and oncological outcomes.

RESULTS

There were 43 consecutive patients who underwent PC-RARPLND at the participating institutions. Mean patient age was 29.2 years (± 8.2), BMI was 26.6 kg/m² (± 6.2). The mean size of retroperitoneal mass was 4.1 cm (± 3.5). Full bilateral template dissection was performed in 38 (88.3%) patients. Nerve sparing was attempted in 19 (44.1%) patients. Mean operative time was 374 min (± 132) and estimated blood loss was 292 ml (± 445.6). The mean postoperative LOS was 2.8 days (± 5.9). There was a total of 12 complications in 10 patients (Clavien grade I = 5, II = 3, III = 3 and IV = 1). Postoperative pathology demonstrated 24 patients (55%) with necrosis/fibrosis, 16 (37%) with teratoma and 3 (7%) with viable tumor. Mean lymph node (LN) yield was 26.5 LNs (SD ± 16.1). Patients were followed for a mean of 30.7 months (± 24.7). No deaths were documented during follow-up and 2 pulmonary recurrences were identified. Antegrade ejaculation was preserved in 70.6% of patient who underwent nerve sparing. Limitations included retrospective nature and limited follow up.

CONCLUSION

PC-RAPLND is safe and technically reproducible. It provides improved morbidity and less convalescence.

A 25-year review of advances in testicular cancer: Perspectives on evaluation, treatment, and future directions/challenges

The year 2020 will be remembered for a number of different events, both good and bad. For the journal Urologic Oncology, Seminars and Original Investigations, this year represents the 25th anniversary of its inception and 1st publication. Under the encouragement of Editor-in-Chief Dr. Michael Droller, the collective editorial board has put together a reflection of the progresses made among the spectrum of genitourinary cancers across the entirety of therapeutic disciplines. In this review, we discuss the advances achieved in our knowledge and understanding of testicular germ cell tumors since 1995, and the challenges that lie ahead.

Radiotherapy for Post-Chemotherapy Residual Mass in Advanced Seminoma: A Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography-Based Risk-adapted Approach

AIMS

There is a lack of consensus regarding the management of post-chemotherapy residual mass in classical seminoma. The use of fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) may aid the detection of residual masses harbouring viable disease and help to tailor therapy. The aim of this study was to evaluate if PET-CT could identify patients who will benefit from locoregional radiotherapy.

MATERIALS AND METHODS

This ethics-approved study included patients with advanced classical seminoma primarily treated with standard platinum-based first-line chemotherapy. Patients were either observed or given adjuvant radiotherapy based on the clinician's preference and followed up. For this study, patients were stratified into two groups based on FDG PET-CT residual nodal maximum standardised uptake value (SUVmax): low risk (SUVmax <3) and high risk (SUVmax ≥3). Further subgroup analysis was carried out for patients with residual nodal size ≥3 cm and SUVmax ≥3, and this was considered as the very high risk group. The diagnostic accuracy of FDG PET-CT was assessed and survival was compared between the different groups.

RESULTS

Sixty-nine patients were included in the study: 48 patients were observed and 21 received radiotherapy. The low and high risk groups contained 50.7% and 49.3% of the patients, respectively. The very high risk subgroup had 24 patients. At a median follow-up of 44 months, locoregional failures in the radiotherapy and observation cohorts were 0% and 30% (P = 0.059) in the very high risk subgroup and 5.8% and 29.4% (P = 0.078) in the high risk group. The positive predictive value for the very high risk and high risk groups was 30% and 17.1%, respectively. The benefit of locoregional control failed to translate into overall survival benefit.

CONCLUSION

A tailored, FDG PET-based risk-adapted treatment approach can refine the management of post-chemotherapy residual masses in seminoma. In this study, with the largest cohort of advanced seminoma patients treated with radiotherapy reported to date, radiotherapy seems to benefit patients with post-chemotherapy residual mass SUVmax ≥3.

ESMO Consensus Conference on testicular germ cell cancer: diagnosis, treatment and follow-up

The European Society for Medical Oncology (ESMO) consensus conference on testicular cancer was held on 3-5 November 2016 in Paris, France. The conference included a multidisciplinary panel of 36 leading experts in the diagnosis and treatment of testicular cancer (34 panel members attended the conference; an additional two panel members [CB and K-PD] participated in all preparatory work and subsequent manuscript development). The aim of the conference was to develop detailed recommendations on topics relating to testicular cancer that are not covered in detail in the current ESMO Clinical Practice Guidelines (CPGs) and where the available level of evidence is insufficient. The main topics identified for discussion related to: (1) diagnostic work-up and patient assessment; (2) stage I disease; (3) stage II-III disease; (4) post-chemotherapy surgery, salvage chemotherapy, salvage and desperation surgery and special topics; and (5) survivorship and follow-up schemes. The experts addressed questions relating to one of the five topics within five working groups. Relevant scientific literature was reviewed in advance. Recommendations were developed by the working groups and then presented to the entire panel. A consensus vote was obtained following whole-panel discussions, and the consensus recommendations were then further developed in post-meeting discussions in written form. This manuscript presents the results of the expert panel discussions, including the consensus recommendations and a summary of evidence supporting each recommendation. All participants approved the final manuscript.

Role of surgical consolidation in metastatic urothelial carcinoma

Since the development of systemic combination chemotherapy, postchemotherapy extirpation has been performed in selected patients mainly with locally advanced and/or initially unresectable bladder cancer, and, in very selected patients, surgical consolidation for visceral metastases has also been performed. The purpose of this article was to review and summarize the current evidence for the role of surgical consolidation in metastatic urothelial carcinoma.

Foreign-body granuloma mimicking post-chemotherapy residual seminoma: A case of true-negative findings using diffusion-weighted whole-body magnetic resonance imaging with background suppression

Diffusion-weighted whole-body magnetic resonance imaging with background suppression (DWIBS) is increasingly used in cancer imaging. However, little is known about its usefulness in the management of metastatic seminoma, in which evaluation of the viability of postchemotherapy residual nodules is pivotal. To date, 2–18fluoro-deoxy-d-glucose positron emission tomography (FDG-PET) has been recommended for post-chemotherapeutic assessment. We describe a case of metastatic seminoma in a 27-year-old man in which the viability of post-chemotherapy residual nodules tested false-positive on FDG-PET, but true-negative on DWIBS. DWIBS may be a good alternative technique to evaluate post-chemotherapy seminoma, although further studies are required to determine its usefulness.

PET-CT and PET-MR in urological cancers other than prostate cancer: An update on state of the art

Hybrid positron emission tomography with computed tomography (PET/CT) and magnetic resonance imaging (PET/MRI) have enabled the combination of morphologic and functional imaging with the promise of providing better information in guiding therapy. Further advance has been made in the past decade with the development of newer radiotracers and optimization of the technical aspects. We performed a search in PubMed, Scopus, and Google Scholar for peer-reviewed literature concerning the advances and newer developments in the imaging of nonprostate urologic cancers between 2005 and 2017. This review aims at summarizing the current evidence on PET imaging in nonprostate urologic cancers and their impact on the diagnosis, staging, prognostication, response assessment, and restaging of these malignancies. However, much of the evidence is still in infancy and has not been incorporated into routine management or the practice guidelines of National Comprehensive Cancer Network or European Society for Medical Oncology (ESMO).

Clinico-pathological outcomes of post- primary and salvage chemotherapy retroperitoneal lymph node dissection for mixed germ cell tumors, King Hussein Cancer Center experience

OBJECTIVE

We sought to characterize clinical and pathologic outcomes of advanced mixed germ cell tumors after retroperitoneal lymph node dissection for post-chemotherapy residual masses.

MATERIAL AND METHODS

Between January 2006 and November 2015, 56 patients underwent retroperitoneal lymph node dissection (RPLND) for residual masses of greater than 1 cm after receiving either primary chemotherapy or salvage chemotherapy. Retrospective review of the patients' characteristics, clinical, pathological, and treatment outcomes were performed after institutional review board (IRB) and ethics committee approval.

RESULTS

The mean age at diagnosis was 30 years. Ninety percent of the patients received 3-4 cycles of BEP (bleomycin/etoposide/cisplatin) as primary chemotherapy, and 29% of them salvage chemotherapy prior to lymph node dissection. The mean size of the residual masses after chemotherapy was 6 cm. The histological findings were necrosis in 30%, viable tumor in 34% and teratoma in 36% of the retroperitoneal masses. The mean time to relapse after RPLND was 11 months, out of 9 relapses, 6 were in the retroperitoneum, 1 in the lung and 1 in the kidney and 1 in the contralateral testicle.

CONCLUSION

Our results indicated higher incidence of viable germ cell tumor in the retroperitoneal residual masses after primary and salvage chemotherapy when compared with previously reported global incidence rates.

The role of 18F-FDG PET/CT in the management of testicular cancers

OBJECTIVES

The aim of this study was to determine the utility of fluorine-18 fluorodeoxyglucose PET/computed tomography ((18)F-FDG PET/CT) in managing testicular cancer.

PATIENTS AND METHODS

Sixty-two patients (29 seminoma, 28 nonseminoma and five mixed) underwent 75 (18)F-FDG PET/CT scans (16 scans for primary staging, 44 for residual masses and 15 for rising tumour markers). Follow-up histology, clinical scans and tumour marker results were included for retrospective analysis.

RESULTS

(i) Primary staging: eight of 11 patients with equivocal CT scans had true-negative (18)F-FDG PET/CT scans. Five high-risk patients with normal stage 1 CT scans had negative (18)F-FDG PET/CT scans, but two subsequently relapsed. (ii) Residual masses: of the 20 scans interpreted as showing viable disease, five were false positive. Nineteen scans were negative (18 true negative and one false negative). (iii) Rising tumour markers: of the 15 scans, two were false negative and 13 were true positive.

CONCLUSION

(18)F-FDG PET/CT is helpful when primary staging CT scans are equivocal but insufficiently sensitive to predict relapse in high-risk patients with normal CT scans. With residual masses, a negative scan is rarely associated with relapse. (18)F-FDG PET/CT is helpful in defining recurrent disease in the majority of patients with rising tumour markers and negative CT scans.

PET/Computed Tomography in Renal, Bladder, and Testicular Cancer

Imaging plays an important role in the clinical management of cancer patients. Hybrid imaging with PET/computed tomography (CT) is having a broad impact in oncology, and in recent years PET/CT is beginning to have an impact in urooncology. In both bladder and renal cancers, there is a need to study the efficacy of other tracers than F-18 fluorodeoxyglucose (FDG), particularly tracers with limited renal excretion. Thus, new tracers are being introduced. This review focuses on the clinical role of FDG and other PET agents in renal, bladder, and testicular cancers.

Diagnostic accuracy of integrated (18)F-FDG PET/CT for restaging patients with malignant germ cell tumours

OBJECTIVE

Evaluation of utility of fluorine-18 fludeoxyglucose ((18)F-FDG) positron emission tomography/CT (PET/CT) for restaging patients with primary malignant germ cell tumours (GCTs).

METHODS

Data of 92 patients (age, 31.94 ± 10.1 years; male/female, 86/6) with histopathologically confirmed malignant GCTs (gonadal, 88; mediastinal, 4; seminomatous, 47 and non-seminomatous, 45) who underwent (18)F-FDG PET/CT for restaging (suspected recurrence/post-therapy evaluation) were retrospectively analysed. Two experienced nuclear medicine physicians reviewed the PET/CT images in consensus, qualitatively and semi-quantitatively [maximum standardized uptake value (SUVmax)]. Histopathology (if available) and clinical/imaging/biochemical follow-up (minimum of 6 months) were employed as the reference standard.

RESULTS

(18)F-FDG PET/CT was interpreted as positive in 59 and negative in 33 patients. Local disease was seen in 5, nodal disease in 50 and distant metastasis in 22 patients. PET/CT was true positive in 49, false positive in 10, true negative in 30 and false negative in 3 patients. (18)F-FDG PET/CT showed sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 94.2%, 75.0%, 83.0%, 90.9% and 85.8% overall; 90.0%, 74.0%, 72.0%, 90.9% and 80.8% in seminomatous GCT; and 96.8%, 76.9%, 91.1%, 90.9% and 91.1% in non-seminomatous GCT, respectively. Difference in PET/CT accuracy for seminomatous and non-seminomatous GCTs was not significant (p = 0.263). PET/CT demonstrated disease in 13 patients with negative/equivocal conventional imaging findings and in 9 patients with normal tumour markers. No site- or histology-based difference was seen in SUVmax.

CONCLUSION

(18)F-FDG PET/CT demonstrates high diagnostic accuracy for restaging patients with malignant GCTs. It has comparable diagnostic performance in both seminomatous and non-seminomatous malignant GCTs.

ADVANCES IN KNOWLEDGE

The present article demonstrates high diagnostic accuracy of (18)F-FDG PET/CT for restaging both seminomatous and non-seminomatous malignant GCTs in a large patient population.

Diagnostic performance of fluorine-18-fluorodeoxyglucose positron emission tomography in the postchemotherapy management of patients with seminoma: systematic review and meta-analysis

Objective. To meta-analyze published data about the diagnostic performance of fluorine-18-Fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) and PET/computed tomography (PET/CT) in the postchemotherapy management of patients with seminoma. Methods. A comprehensive literature search of studies published through January 2014 on this topic was performed. All retrieved studies were reviewed and qualitatively analyzed. Pooled sensitivity and specificity, positive and negative predictive values (PPV and NPV), accuracy, and area under the summary ROC curve (AUC) of ¹⁸F-FDG-PET or PET/CT on a per examination-based analysis were calculated. Subgroup analyses considering the size of residual/recurrent lesions were carried out. Results. Nine studies including 375 scans were selected. The pooled analysis provided the following results: sensitivity 78% (95% confidence interval (95% CI): 67–87%), specificity 86% (95% CI: 81–89%), PPV 58% (95% CI: 48–68%), NPV 94% (95% CI: 90–96%), and accuracy 84% (95% CI: 80–88%). The AUC was 0.90. A better diagnostic accuracy of ¹⁸F-FDG-PET or PET/CT in evaluating residual/recurrent lesions >3 cm compared to those <3 cm was found. Conclusions. ¹⁸F-FDG-PET and PET/CT were demonstrated to be accurate imaging methods in the postchemotherapy management of patients with seminoma; nevertheless possible sources of false-negative and false-positive results should be considered. The literature focusing on this setting still remains limited and cost-effectiveness analyses are warranted.

Suture Granuloma Showing False-Positive Findings on FDG-PET

We report a case of a 33-year-old male with a mixed germ-cell testicular tumor. Postoperative follow-up FDG-PET revealed concentration of FDG in the left inguinal area which is not tumor metastasis or local recurrence but suture reactivity granuloma. In this paper, we reviewed suture granulomas associated with false-positive findings on FDG-PET after surgery. If FDG-PET will be used more frequently in the future, it will be necessary to refrain from using silk thread in order to prevent any unnecessary surgery.

Laparoscopic and open postchemotherapy retroperitoneal lymph node dissection in patients with advanced testicular cancer--a single center analysis

Background

The open approach represents the gold standard for postchemotherapy retroperitoneal lymph node dissection (O-PCLND) in patients with residual testicular cancer. We analyzed laparoscopic postchemotherapy retroperitoneal lymph node dissection (L-PCLND) and O-PCLND at our institution.

Methods

Patients underwent either L-PCLND (n = 43) or O-PCLND (n = 24). Categorical and continuous variables were compared using the Fisher exact test and Mann–Whitney U test respectively. Overall survival was evaluated with the log-rank test.

Results

Primary histology was embryonal cell carcinomas (18 patients), pure seminoma (2 cases) and mixed NSGCTs (47 patients). According to the IGCCCG patients were categorized into “good”, “intermediate” and “poor prognosis” disease in 55.2%, 14.9% and 20.8%, respectively. Median operative time for L-PCLND was 212 min and 232 min for O-PCLND (p = 0.256). Median postoperative duration of drainage and hospital stay was shorter after L-PCLND (0.0 vs. 3.5 days; p < 0.001 and 6.0 vs. 11.5 days; p = 0.002). Intraoperative complications occurred in 21.7% (L-PCLND) and 38.0% (O-PCLND) of cases with 19.5% and 28.5% of Clavien Grade III complications for L-PCLND and O-PCLND, respectively (p = 0.224). Significant blood loss (>500 ml) was almost equally distributed (8.6% vs. 14.2%: p = 0.076). No significant differences were observed for injuries of major vessels and postoperative complications (p = 0.758; p = 0.370). Tumor recurrence occurred in 8.6% following L-PCLND and in 14.2% following O-PCLND with a mean disease-free survival of 76.6 and 89.2 months, respectively. Overall survival was 83.3 and 95.0 months for L-PCNLD and O-PCLND, respectively (p = 0.447).

Conclusions

L-PCLND represents a safe surgical option for well selected patients at an experienced center.

2-¹⁸fluoro-deoxy-D-glucose positron emission tomography (FDG-PET) for postchemotherapy seminoma residual lesions: a retrospective validation of the SEMPET trial

BACKGROUND

2-¹⁸fluoro-deoxy-D-glucose positron emission tomography (FDG-PET) has been recommended in international guidelines in the evaluation of postchemotherapy seminoma residuals. Our trial was designed to validate these recommendations in a larger group of patients.

PATIENTS AND METHODS

FDG-PET studies in patients with metastatic seminoma and residual masses after platinum-containing chemotherapy were correlated with either the histology of the resected lesion(s) or the clinical outcome.

RESULTS

One hundred and seventy seven FDG-PET results were contributed. Of 127 eligible PET studies, 69% were true negative, 11% true positive, 6% false negative, and 15% false positive. We compared PET scans carried out before and after a cut-off level of 6 weeks after the end of the last chemotherapy cycle. PET sensitivity, specificity, negative predictive value (NPV), and positive predictive value were 50%, 77%, 91%, and 25%, respectively, before the cut-off and 82%, 90%, 95%, and 69% after the cut-off. PET accuracy significantly improved from 73% before to 88% after the cut-off (P=0.032).

CONCLUSION

Our study confirms the high specificity, sensitivity, and NPV of FDG-PET for evaluating postchemotherapy seminoma residuals. When carried out at an adequate time point, FDG-PET remains a valuable tool for clinical decision-making in this clinical setting and spares patients unnecessary therapy.

Management of the residual post-chemotherapy retroperitoneal mass in germ cell tumors

The management of the residual mass in the retroperitoneum following induction chemotherapy for metastatic testicular cancer has evolved over the past three decades. A multidisciplinary approach involving cisplatin-based chemotherapy and postchemotherapy retroperitoneal lymph node dissection (PC-RPLND) has increased long-term survival rates above 80%. Advances into the appropriate patient selection and timing of surgery have lowered morbidity while improving oncologic outcomes. However, areas of controversy still exist within the field. Management of the small residual mass, predictors of the histology of the residual mass, the extent of PC-RPLND, the role of PC-RPLND in the setting of elevated serum tumor markers, and the role of positron-emission tomography are all topics of ongoing research and debate. We will discuss these issues and review the current guidelines for the management of the residual postchemotherapy retroperitoneal mass in this review.

[What is new in 2011 regarding testicular cancer]

The management of testicular cancer has already been standardized to the greatest extent by consistent performance of clinical trials. While the current aim is to reduce the therapy for early stage disease without jeopardizing the high cure rates, for patients in advanced stages the goal is to achieve further improvement of survival rates. This overview presents new aspects of organ-preserving primary tumor resection, prognostic factors in seminoma, secondary malignancies, high-dose therapy, residual tumor resection, aftercare, and PET/CT.

[Assessment of residual tumours after systemic treatment of metastatic seminoma: ¹⁸F-2-fluoro-2-deoxy-D-glucose positron emission tomography - meta-analysis of diagnostic value]

BACKGROUND

Meta-analysis evaluating the accuracy and sensitivity of FDG (2-[(18)F]-fluoro-2-deoxy-D-glucose) positron emission tomography (PET) to predict viable residual tumours in patients with metastatic seminoma.

MATERIAL AND METHODS

Altogether 5 studies with 130 patients were identified. Both FDG PET and the size of the residual lesions on conventional computed tomography (CT; lesions either ≤ or > 3 cm) were correlated with the presence or absence of viable residual tumour.

RESULTS

The specificity (92 vs 59%), sensitivity (72 vs 63%), positive (70 vs 28%) and negative (93 vs 86%) predictive value of FDG PET were superior to data obtained by assessing residual tumour size (either ≤ or > 3 cm) applying CT scans alone.

CONCLUSION

In view of the data currently available, FDG PET seems to be a clinically useful predictor of viable tumour in post-chemotherapy residuals of pure seminoma.

Update on management of seminoma

Testicular germ cell tumors and, in particular, seminomas are exquisitely radiation and chemotherapy-sensitive and most presentations are highly curable. In recent years the management focus has been on reducing late sequelae of treatment. For Stage I disease surveillance and adjuvant carboplatin, chemotherapy has become an option. The efficacy of combination chemotherapy has been established for advanced metastatic disease. Through a review of the available literature this article outlines the recent changes in the management of seminoma.

Testicular germ cell tumors: pathogenesis, diagnosis and treatment

Testicular germ cell tumors represent the most common solid malignancy of young men aged 15-40 years. Histopathologically, testicular germ cell tumors are divided into two major groups: pure seminoma and nonseminoma. The pathogenesis of testicular germ cell tumors remains unknown; however, cryptorchidism is the main risk factor, and molecular studies have shown strong evidence of an association between genetic alterations and testicular germ cell tumors. In cases of suspicion for testicular germ cell tumor, a surgical exploration with orchiectomy is obligatory. After completion of diagnostic procedures, levels of serum tumor markers and the clinical stage based on the International Union Against Cancer tumor-node-metastasis classification should be defined. Patients with early-stage testicular germ cell tumors are treated by individualized risk stratification within a multidisciplinary approach. The individual management (surveillance, chemotherapy or radiotherapy) has to be balanced according to clinical features and the risk of short-term and long-term toxic effects. Treatment for metastatic tumors is based on risk stratification according to International Germ Cell Cancer Collaborative Group classification and is performed with cisplatin-based chemotherapy and residual tumor resection in cases of residual tumor lesion. High-dose chemotherapy represents a curative option for patients with second or subsequent relapses.

[(18)F]2-fluoro-2-deoxy-D-glucose PET/CT in mediastinal masses

Computed tomography (CT) and magnetic resonance imaging (MRI) are excellent modalities for the localization of mediastinal masses and there are often features that may allow the correct diagnosis to be made. However, CT and MRI cannot usually assess the aggressiveness of masses or identify viable tumour in residual masses after chemotherapy. Metabolic imaging using [¹⁸F]fluorodeoxyglucose (FDG)-positron emission tomography/CT, although not required in many cases, may be helpful for further characterization of masses and to guide the most appropriate site for biopsy.

Lista de recomendações do Exame PET/CT com 18F-FDG em Oncologia: consenso entre a Sociedade Brasileira de Cancerologia e a Sociedade Brasileira de Biologia, Medicina Nuclear e Imagem Molecular

Apresentamos uma lista de recomendações sobre a utilização de 18F-FDG PET em oncologia, no diagnóstico, estadiamento e detecção de recorrência ou progressão do câncer. Foi realizada pesquisa para identificar estudos controlados e revisões sistemáticas de literatura composta por estudos retrospectivos e prospectivos. As consequências e o impacto da 18F-FDG PET no manejo de pacientes oncológicos também foram avaliados. A 18F-FDG PET deve ser utilizada como ferramenta adicional aos métodos de imagem convencionais como tomografia computadorizada e ressonância magnética. Resultados positivos que sugiram alteração no manejo clínico devem ser confirmados por exame histopatológico. A 18F-FDG PET deve ser utilizada no manejo clínico apropriado para o diagnóstico de cânceres do sistema respiratório, cabeça e pescoço, sistema digestivo, mama, melanoma, órgão genitais, tireoide, sistema nervoso central, linfoma e tumor primário oculto.

[Case report: simultaneous bilateral testicular tumors with different cell types]

A 29-year-old man was admitted to our hospital due to bilateral testicular tumors. The bilateral testicular tumors were palpated and visualized by ultrasound and magnetic resonance imaging (right 8 cm, left 6 cm in diameter). Bilateral high orchiectomies were performed after frozen storage of the sperm. Pathological examination revealed seminoma and immature teratoma in the right testis and seminoma in the left testis. Three months later, computed tomography (CT) showed multiple metastatic lung nodules. In addition, positron emission tomography (PET)-CT examination revealed peri-caval lymph node metastasis together with the lung metastases. Lung metastases disappeared, but the lymph node metastasis reduced and remained after 3 courses of combination chemotherapy with bleomycin, etoposide and cisplatin. PET-CT examination revealed that no uptake of FDG was seen in the lung and lymph nodes. Retroperitoneal lymph node dissection was performed. No viable tumor cells were histologically present in the excited lymph nodes. The postoperative course was good and uneventful at 10 months under androgen replacement therapy without disease recurrences.

[18F]Fluorodeoxyglucose Positron Emission Tomography in Nonseminomatous Germ Cell Tumors After Chemotherapy: The German Multicenter Positron Emission Tomography Study Group

Purpose

In patients with metastatic nonseminomatous germ cell cancer (NSGCT), residual masses after chemotherapy (CTX) can consist of vital carcinoma, mature teratoma, or necrosis. This prospective trial has evaluated the accuracy of [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) for the prediction of histology compared with computed tomography (CT) and serum tumor markers (STM).

Patients and Methods

A total of 121 patients with stage IIC or III NSGCT scheduled for secondary resection after cisplatin-based CTX were included. FDG-PET was performed after completion of CTX. All results were confirmed by histopathology and correlated to STM and CT.

Results

Prediction of tumor viability with FDG-PET was correct in 56%, which did not reach the expected clinically relevant level of 70%, and was not better than the accuracy of CT (55%) or STM (56%). Sensitivity and specificity of FDG-PET were 70% and 48%. The positive predictive values were not significantly different (55%, 61%, and 59% for CT, STM, and PET, respectively). Judging only vital carcinoma as a true malignant finding, the negative predictive value increased to 83% for FDG-PET.

Conclusion

The presence of vital carcinoma and mature teratoma is common (55%) in residual masses in patients with NSGCT, and CT and STM cannot reliably predict absence of disease. In contrast to prior studies, this prospective trial, which is the only with histologic confirmation in all patients, demonstrated that FDG-PET is unable to give a clear additional clinical benefit to the standard diagnostic procedures, CT and STM, in the prediction of tumor viability in residual masses.

[Surgical management of retroperitoneal metastases from germ cell cancers]

The surgery of residual retroperitoneal tumors is a compulsory prolongation of chemotherapy in non seminomatous germ cell tumors. The requirements of total resection must be respected. High morbidity of bilateral lymphadenectomy for large bulky disease is possible and implies specialised surgery. The extent of surgery can be limited to a template area in specific circumstances.