Management of postchemotherapy residual mass in patients with advanced seminoma: Indiana University experience

End-of-Treatment FDG PET-CT (EOT-PET) in Patients with Post-Chemotherapy Masses for Seminoma: Can We Avoid Further Intervention?

Anjana JoelContext  Patients with seminoma present with advanced disease. End-of-treatment (EOT) positron emission tomography-computed tomography (PET-CT) is done to assess response and direct management of post-chemotherapy residual masses. Purpose  This article assesses the utility of EOT PET-CT in the management of post-chemotherapy residual lymph nodal masses seminoma. Materials and Methods  We analyzed all patients with seminoma who underwent an EOT PET-CT from January 2015 to January 2020 at our center and calculated the positive predictive value (PPV) and negative predictive value (NPV) of EOT PET-CT in the entire cohort of patients and among subgroups. Results  A total of 34 male patients underwent EOT PET-CT. Fourteen (41.2%) were stratified as good risk and 20 (58.8%) as intermediate risk. The median follow-up was 23 months (interquartile range: 9.75-53 months). In 23 patients there were residual masses of size more than 3 cm at the EOT PET scan. EOT PET was positive as per the SEMPET criteria in 18 (78%) out of 23 patients. None underwent retroperitoneal lymph node dissection. All four who underwent image-guided biopsy, showed only necrosis on pathology. One patient with positive mediastinal node (standardized uptake value 13.6) had granulomatous inflammation. There was no relapse or progression during this period of follow-up. The NPV for EOT PET-CT for the entire cohort, > 3 cm, and > 6 weeks cutoff were 100%, respectively. The PPV for EOT PET-CT for the entire cohort, > 3 cm residual mass, and > 6 weeks cutoff were 8.7, 11.11, and 6.67%, respectively. Conclusion  EOT PET-CT has a low PPV and high NPV in predicting viable tumor in post-chemotherapy residual masses among patients with seminomatous germ cell tumors. If required, EOT PET positivity can be confirmed by a biopsy or reassessed with a repeat PET-CT imaging to document persistent disease prior to further intervention.

Management of residual disease after chemotherapy in germ cell tumors

PURPOSE OF REVIEW

Although testicular cancer remains a highly curable malignancy, challenges and uncertainty still remain in certain aspects of management. Residual disease after chemotherapy in patients with germ cell tumors (GCT) remains one of these challenges. We aim to highlight the recent literature on the management of residual disease after chemotherapy in GCT and the emerging innovations that may provide further guidance into this area.

RECENT FINDINGS

A subset of patients with GCT will have residual disease after chemotherapy, and management of these patients involves highly skilled multidisciplinary experts including medical oncologists, surgeons, radiologists, and pathologists. Management options depend on histologic subtype, either seminoma or nonseminoma, and involve size criteria, possible further imaging modalities, and tumor markers. Even with these tools at highly specialized expert centers, uncertainty in management remains, and recent literature has explored the use of newer biomarkers to aid in these cases.

SUMMARY

Postchemotherapy residual masses in GCT can prove to be complicated cases to manage. Balancing survival with quality of life outcomes is important and requires a multidisciplinary team experienced in treating GCT.

Management of residual masses in testicular germ cell tumors

INTRODUCTION

About 50% of all patients with advanced testicular cancer demonstrate residual retroperitoneal or extraretroperitoneal masses. About two thirds of the masses harbour necrosis/fibrosis only whereas as about 10% and 40% harbour vital cancer or teratoma. Appropriate therapy will result in a high cure rate if performed properly. Areas covered: This review article covers the indication, the surgical technique and the oncological outcome of PC-RPLND and resection of extraretroperitoneal residual masses following chemotherapy in patients with advanced testis cancer. Expert commentary: Postchemotherapy retroperitoneal lymph node dissection (PC-RPLND) plays an integral part of the multimodality treatment in patients with advanced testicular germ cell tumours. Patients with nonseminomas, residual masses < 1cm and good prognosis can undergo active surveillance. In all other cases, PC-RPLND with or without resection of adjacent organs needs to be performed for curative intent. PC-RPLND requires a complex surgical approach and should be performed in experienced, tertiary referral centres only.

Current controversies on the role of lymphadenectomy for testicular cancer for the journal: Urologic Oncology: Seminars and Original Investigations for the special seminars section on the role of lymphadenectomy for urologic cancers

The role of surgery in the locoregional management of many solid tumors has long been established. For testicular cancer, the incorporation of lymphadenectomy has played an important part in generating long-term survival outcomes in excess of 90% for germ cell tumor patients. In this review, we address several clinical scenarios in which lymphadenectomy at times is underutilized, and others ill advised.

Testicular Cancer: Epidemiology, Diagnosis, and Management

There were an estimated 8720 new cases of testicular cancer (TC) in the United States in 2016. The cause of the disease is complex, with several environmental and genetic risk factors. Although rare, the incidence has been steadily increasing. Fortunately, substantial advances in treatment have occurred over the last few decades, making TC one of the most curable malignancies. However, because TC typically occurs in younger men, considerations of the treatment impact on fertility, quality of life, and long-term toxicity are paramount; an individualized approach must be taken with patients based on their clinical and pathologic findings.

A New Model to Predict Benign Histology in Residual Retroperitoneal Masses After Chemotherapy in Nonseminoma

BACKGROUND

Postchemotherapy retroperitoneal lymph node dissection (pcRPLND) is indicated in testicular cancer patients with normalised or plateaued serum tumour markers and residual retroperitoneal lesions >1cm. Challenges remain in predicting postchemotherapy residual mass (pcRM) histology, which may lead to unnecessary surgery.

OBJECTIVE

To develop an accurate model to predict pcRM histology in patients with nonseminomatous germ cell tumours (NSGCTs).

DESIGN, SETTING, AND PARTICIPANTS

A retrospective review of 335 patients undergoing pcRPLND for metastatic NSGCTs to develop a model to predict benign histology in retroperitoneal pcRM. Our model was compared with others and externally validated.

INTERVENTION

Chemotherapy and pcRPLND.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Multivariable logistic regression to evaluate the presence of benign histology, and fractional polynomials to allow for a nonlinear association between continuous variables and the outcome. The final Princess Margaret model (PMM) was selected based on the number of variables used, reliability, and discriminative capacity to predict benign pcRM.

RESULTS AND LIMITATIONS

PMM included the presence of teratoma in the orchiectomy, prechemotherapy α-fetoprotein, prechemotherapy mass size, and change in mass size during chemotherapy. Model specificity was 99.3%. Compared with Vergouwe et al's model, PMM had significantly better accuracy (C statistic 0.843 vs 0.783). PMM appropriately identified a larger number of patients for whom pcRPLND can safely be avoided (13.9% vs 0%). Validated in external cohorts, the model retained high discrimination (C statistic 0.88 and 0.80). Larger and prospective studies are needed to further validate this model.

CONCLUSIONS

Our clinical model, externally validated, showed improved discriminative ability in predicting pcRM histology when compared with other models. The higher accuracy and reduced number of variables make this a novel and appealing model to use for patient counselling and treatment strategies.

PATIENT SUMMARY

Princess Margaret model accurately predicted postchemotherapy benign histology. These results might have clinical impact by avoiding unnecessary retroperitoneal lymph node dissection and consequently changing the paradigm of advanced testicular cancer treatment.

Platinum-based Chemotherapy in Primary Advanced Seminoma-a Retrospective Analysis: Treatment Results at the Northern Israel Oncology Center (1989-2010)

OBJECTIVE

Over the past 30 years, great strides have been made in the treatment of disseminated testicular tumors. Despite the low number of patients and the rarity of studies concerning primary advanced seminoma, the efficacy of chemotherapy is clear, mainly 3-4-cisplatin-based chemotherapy. Aiming to contribute to the understanding and implementation of proper chemotherapeutic management in advanced seminoma patients, we retrospectively summarized our experience with 26 patients who were referred for platinum-based chemotherapy, post-orchiectomy to the Northern Israel Oncology Center between 1989 and 2010. Response rate, side effects, and long-term outcome were investigated.

METHODS

Before chemotherapy, meticulous staging was done, including tumor markers (B-human chorionic gonadotropin (B-HCG), alpha-fetoprotein (AFP), and lactic dehydrogenase (LDH)), and abdominal and pelvic computerized tomography (CT) scans were carried out.

RESULTS

All 26 treated patients achieved complete remission, clinically and symptomatically, with normalization of their CT scans. At a median follow-up of 120 months (range, 24-268 months) all patients are alive, without evidence of recurrent disease. One patient whose disease recurred twice achieved a third complete remission following salvage treatment with high-dose chemotherapy and autologous peripheral stem cell transplantation. Another patient, who preferred surveillance, relapsed abdominally after 9 months but achieved long-standing complete remission with cisplatin-based chemotherapy. Both these patients are alive with no evidence of disease. Three patients recovered uneventfully from bleomycin-induced pneumonitis.

CONCLUSIONS

Advanced seminoma is a highly curable disease using platinum-based chemotherapy. Our study confirms the efficacy and safety of cisplatin-based chemotherapy in the treatment of advanced seminoma.

Retroperitoneal lymphadenectomy and resection for testicular cancer: an update on best practice

Clinical stage I testicular nonseminomatous germ cell tumours (NSGCTs) are highly curable. Following orchidectomy a risk-adapted approach using active surveillance (AS), nerve-sparing retroperitoneal lymph node dissection (nsRPLND) and primary chemotherapy is recommended by the current guidelines. Clinical stage I is defined as negative or declining tumour markers to their half-life following orchidectomy and negative imaging studies of the chest, abdomen and retroperitoneum. Active surveillance can be performed in low-risk and in high-risk NSGCTs with an anticipated relapse rate of about 15% and 50%. The majority of patients will relapse with good and intermediate prognosis tumours which have to be treated with three to four cycles chemotherapy. About 25-30% of these patients will have to undergo postchemotherapy retroperitoneal lymph node dissection (PC-RPLND) for residual masses. Primary chemotherapy with one or two cycles of cisplatin (Platinol), etoposide and bleomycin (PEB) is a therapeutic option for high-risk clinical stage I NSGCT associated with a recurrence rate of only 2-3% and a minimal acute and long-term toxicity rate. nsRPLND, if performed properly, will cure about 85% of all high-risk patients with clinical stage I NSGCT without the need for chemotherapy. PC-RPLND forms an integral part of the multimodality treatment in patients with advanced testicular germ cell tumours (TGCTs). According to current guidelines and recommendations, PC-RPLND in advanced seminomas with residual tumours is only indicated if a positron emission tomography (PET) scan performed 6-8 weeks after chemotherapy is positive. In nonseminomatous TGCT, PC-RPLND is indicated for all residual radiographic lesions with negative or plateauing markers. Loss of antegrade ejaculation represents the most common long-term complication which can be prevented by a nerve-sparing or modified template resection. The relapse rate after PC-RPLND is around 12%, however it increases significantly to about 45% in cases with redo RPLND and late relapses. Patients with increasing markers should undergo salvage chemotherapy. Only select patients with elevated markers who are thought to be chemorefractory might undergo desperation PC-RPLND if all radiographically visible lesions are completely resectable. PC-RPLND requires a complex surgical approach and should be performed in experienced, tertiary referral centres only.

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.

Successful resection of mediastinal seminoma evaluated the response to induction chemotherapy with fluorodeoxyglucose-positron emission tomography

Mediastinal seminoma is a rare malignant tumor, and the current strategy for primary mediastinal seminomas is making a prompt diagnosis and achieving an appropriate chemotherapy. However, consensus regarding the optimal post-chemotherapy management has not been reached. We experienced a case of 26-year-old man who was diagnosed mediastinal seminoma and evaluated the response to induction chemotherapy with fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT). Complete surgical excision of the tumor was performed. Pathologic findings of the surgical specimen showed no viable cells in the tumor.

Results of retroperitoneal lymph node dissection after chemotherapy in patients with pure seminoma in the orchidectomy specimen but elevated serum alpha-fetoprotein

OBJECTIVE

To determine the incidence of necrosis, teratoma, and active cancer in specimens at retroperitoneal lymph node dissection (RPLND) after chemotherapy in patients who presented with a pure seminoma primary tumour and an elevated serum alpha-fetoprotein (AFP) level at diagnosis who underwent surgery.

PATIENTS AND METHODS

A retrospective review of the Indiana University testis cancer database from 1980 to 2004 was performed to identify all patients with metastasic germ cell cancer, pure seminoma in the orchidectomy specimen, and an elevated AFP level. In all, 42 patients were identified; two with nonseminomatous germ cell cancer in the contralateral testicle were excluded.

RESULTS

RPLND pathology in the 40 patients showed necrosis in 13 (32.5%), teratoma in 12 (30%), and cancer in 15 (37.5%). The histological subtype of the 15 cancer specimens at RPLND was pure seminoma in two, embryonal in three, yolk sac in seven, variant in one, and mixed elements in two (one with seminoma and yolk sac, and one with embryonal and variant). In all, 20 patients presented with a serum AFP level of <1000 microg/mL with nine (45%) having teratoma only in the retroperitoneum in contrast to 20 patients with an AFP level of >1000 microg/mL with three (15%) having teratoma only in the retroperitoneum (P = 0.04). The level of serum AFP did not predict for active cancer in the retroperitoneum (P = 0.5).

CONCLUSIONS

RPLND in patients after chemotherapy who presented with pure seminoma in the orchidectomy specimen and an elevated AFP do not have a high probability of finding necrosis only in the RPLND specimen. In fact, the prevalence of persistent cancer is higher compared with the general group of patients that have RPLND after chemotherapy.

Positron emission tomography (PET) in the urooncological evaluation of the small pelvis

Positron emission tomography (PET) with the use of ((18)F)2-fluoro-D: -2-desoxyglucose (FDG) has been investigated to be a highly sensitive and specific imaging modality in the diagnostic of primary and recurrent tumors and in the control of therapies in numerous non-urologic cancers. The aim of this review is to validate the significance of PET as a diagnostic tool in malignant urological tumors of the small pelvis. A systematic review of the current literature concerning the role of PET for malignant prostate, testicular and bladder tumors was carried out. The data indicate no additional role for PET in comparison with conventional imaging in tumor detection and local staging for prostate, bladder or testicular cancer. Tumor recurrence in prostate cancer seems to be more effectively identified with acetate and choline than with FDG, but this effect is more pronounced with higher PSA values. The value of PET in the identification of metastatic disease in either tumor entity can not be finally outlined as the clinical data are partly missing, controversial or in the process of evaluation. FDG-PET can be regarded as accepted imaging modality in the restaging of seminomatous germ cell tumors after chemotherapy.

Management of Recurrent Testicular Germ Cell Tumors

Although front-line chemotherapy cures most men with testicular germ cell tumors, salvage therapy is still important in a small but significant minority. Second-line conventional-dose or high-dose chemotherapy with stem cell rescue may cure 25%-50% of patients. New chemotherapeutic agents, including the taxanes gemcitabine and oxaliplatin, have added to the therapeutic armamentarium. Salvage surgical resection has an important role in selected patients. Cisplatin-refractory patients have a poor prognosis with current therapy, and novel chemotherapeutic and biologic agents need to be discovered for such patients.

Postchemotherapy residual masses in advanced seminoma: current management and outcomes

Although pure testicular seminoma is most often confined to the testis, it can present with advanced-stage bulky retroperitoneal metastases in nearly a quarter of cases. While highly treatable with cisplatin-based chemotherapy, up to 80% of patients with advanced disease are found to have a radiographically detectable residual mass after chemotherapy. The management of these postchemotherapy residual masses remains controversial. Surgical resection is technically challenging due to a desmoplastic reaction resulting from seminoma treatment and regression. In addition, these residual masses often demonstrate a protracted period of regression that can span several months to years. Surveillance protocols, therefore, may be appropriate for most patients. Several retrospective studies have supported surgical resection only for discrete, well-delineated masses over 3 cm in size. Despite the highly radiosensitive nature of seminoma, radiation therapy in this setting has not been shown to provide significant benefit, and may limit the tolerability of subsequent salvage chemotherapy. The incorporation of noninvasive imaging modalities, such as positron emission tomography, into the management algorithm may better delineate the presence of viable residual tumor and thus allow better risk stratification.

FDG PET is superior to CT in the prediction of viable tumour in post-chemotherapy seminoma residuals

AIM

In advanced seminoma the management of residuals after completion of chemotherapy is controversial. Some centres routinely perform surgery for lesions > or =3 cm diameter, others recommend surgery solely if the residual fail to shrink or show even growth. This study prospectively investigates whether FDG PET can improve the prediction of viable tumour in post-chemotherapy seminoma residuals.

MATERIALS AND METHODS

After an expansion of a previous study population, 54 patients from eight centres with metastatic seminoma and a CT-documented mass after chemotherapy were included in the study. Six patients were excluded from evaluation because of protocol violations. After PET, the patients underwent either surgery or were followed clinically. On follow-up the lesions were considered to be non-viable when there was unequivocal shrinking, or when the lesion remained morphologically stable for at least 24 months. Any lesion growth was assumed to be malignant. PET results were compared to CT discrimination (< or > or =3 cm) of the residual masses.

RESULTS

Fifty-two PET scans were evaluable. After adequate chemotherapy, there were 74 CT-documented residual masses ranging in size from 1 to 11 cm (median, 2.2 cm). Their dignities were confirmed histologically in 13 lesions, or by follow-up CT in 61 lesions. Four of forty-seven lesions <3 cm and 11/27 lesions > or =3 cm were viable. PET was true positive in one lesion <3 cm and in 11 lesions > or =3 cm, false negative in three lesions <3 cm, and true negative in 59 lesions (43 lesions <3 cm). No PET scan was false positive. In detecting viability the sensitivity and specificity was 73% (95% CI, 44-88), and 73% (59-83), respectively, for CT (< or > or =3 cm); and 80% (51-95), and 100% (93-100), respectively, for PET (specificity, P < 0.001).

CONCLUSION

In post-chemotherapy seminoma residuals, a positive PET is highly predictive for the presence of viable tumour. The specificity of PET is significantly higher than that of CT when using a > or =3 cm cut-off. A negative PET scan is excellent for the exclusion of disease in lesions > or =3 cm, with a somewhat higher sensitivity than CT (n.s.). PET can contribute to the management of residual seminoma lesions, especially in terms of avoiding unnecessary additional treatment for patients with lesions > or =3 cm.

Positronenemissionstomographie (PET) zur Diagnostik und zum Therapiemonitoring bei urologischen Tumoren

Positron emission tomography (PET) using ((18)F)2-fluoro-D-2-desoxyglucose (FDG) has been shown to be a highly sensitive and specific imaging modality in the diagnosis of primary and recurrent tumors and in the control of therapies in numerous non-urologic cancers. It was the aim of this review to validate the significance of PET as a diagnostic tool in malignant tumors of the urogenital tract. A systematic review of the current literature concerning the role of PET for malignant tumors of the kidney, testicles, prostate, and bladder was carried out. The role of FDG PET for renal cell cancer can be seen in the detection of recurrences after definitive local therapy and metastases. The higher sensitivity of PET in comparison to other therapeutic modalities (CT, ultrasound, MRI) in recurrent and metastatic renal cell cancer suggests a supplemental role of this diagnostic procedure to complement other imaging modalities.The clinical value of PET is established for the identification of vital tumor tissue after chemotherapy of seminomatous germ cell tumors. This diagnostic method has little significance for primary tumor staging and diagnosis of non-seminomatous germ cell tumor because of the high probability of false-negative results in adult teratomas. FDG PET is not sensitive enough in the diagnosis of primary or recurrent tumors in prostate or bladder cancer. Also PET did not prove to be superior to conventional bone scintigram in the detection of mostly osteoblastic metastases in prostate cancer. The recent use of alternative tracers, which are partly not eliminated by urinary secretion (acetate, choline) has increased the sensitivity and specificity of PET also in this tumor entity so that further clinical investigations are needed to validate these technical modifications in their significance for this imaging modality. PET appears to be sufficiently evaluated only for the diagnostic follow-up of patients with seminomatous germ cell tumors after chemotherapy to regard it is the diagnostic tool of first choice. For all other tumors of the urogenital tract this proof is still awaited.

Clinical parameters that predict histology of postchemotherapy retroperitoneal lymph node mass in testicular cancer

BACKGROUND

Since the advent of cisplatin-based chemotherapy, the majority of metastatic testicular cancers can be cured by chemotherapy followed by retroperitoneal lymph node dissection (RPLND). However, postchemotherapy RPLND confers no therapeutic benefit if the residual mass contains no viable cells. Therefore, to determine which parameters predict a patient's likelihood of having only necrosis in the residual mass, we retrospectively analyzed clinical parameters of patients who underwent postchemotherapy RPLND.

METHODS

Data from 27 patients with metastatic testicular cancer were analyzed. The histology of the primary tumor was seminoma in 11 cases and non-seminoma in 16 cases. All of the patients with non-seminoma showed a normalization of tumor markers after chemotherapy. Analysis of clinical parameters included data for the initial histology, pretreatment tumor marker levels, postchemotherapy retroperitoneal mass size, and the histology of the dissected RPLNs.

RESULTS

Histological examination of dissected RPLNs showed residual tumor in 27% of seminoma patients and 38% of non-seminoma patients. In seminoma patients, no viable cells were found in all six patients with pretreatment lactate dehydrogenase (LDH) levels below 7.5 times the upper limit of normal, or in all five of the patients with postchemotherapy RPLNs less than 2.5 cm. In non-seminoma patients, no viable cells were found in nine of 10 patients with pretreatment alpha-fetoprotein (AFP) levels less than 2700 ng/mL, or in eight of nine patients with residual mass less than 2.5 cm.

CONCLUSIONS

Both postchemotherapy RPLN mass size and pretreatment tumor marker levels are possible predictors for necrosis of the residual mass in testicular cancer patients.

Secondary surgery in germ cell tumors--when and how extensively should it be performed?

Postchemotherapy RPLND has been used for several decades. Two current issues relating to this surgery are discussed in this article. The selection for surgery and the extent of surgery to be performed continue to evolve.

The role of positron emission tomography in germ cell cancer

Positron emission tomography (PET) is a non-invasive tool for imaging regional metabolic processes, which adds another dimension to current anatomy-derived imaging techniques, i.e. metabolic imaging. To date, 2-(18)fluoro-2-deoxy-D-glucose (FDG) has been the only tracer used for imaging germ cell tumors (GCT), which can be distinguished from normal tissue by their different glucose utilization. However, FDG PET has several limitations: (1) inflammatory and granulomatous tissues also show extensive FDG uptake, (2) lesions <1 cm in size can often not be detected, and (3) mature teratoma is indistinguishable from normal and necrotic tissue. Studies assessing the clinical role of FDG PET in GCT suggest that the technique has a place as a standard tool in evaluating post chemotherapy seminoma residuals. Whether it also improves the assessment of the risks carried by clinical stage I non-seminoma patients and the early prediction of response to salvage chemotherapy is still under investigation, or at least needs to be confirmed by further trials. In relapsing patients with a mismatch between tumor markers and imaging data, FDG PET appears to be useful whenever salvage surgery is considered, although systematic trials are not yet available.

2-18fluoro-deoxy-D-glucose Positron Emission Tomography Is a Reliable Predictor for Viable Tumor in Postchemotherapy Seminoma: An Update of the Prospective Multicentric SEMPET Trial

Purpose

To define the clinical value of 2-18fluoro-deoxy-D-glucose positron emission tomography (FDG PET) as a predictor for viable residual tumor in postchemotherapy seminoma residuals in a prospective multicentric trial.

Patients and Methods

FDG PET studies in patients with metastatic pure seminoma who had radiographically defined postchemotherapy residual masses were correlated with either the histology of the resected lesion or the clinical outcome documented by computer tomography (CT), tumor markers, and/or physical examination during follow-up. The size of the residual lesions on CT, either > 3 cm or ≤ 3 cm, was correlated with the presence or absence of viable residual tumor.

Results

Fifty-six FDG PET scans of 51 patients were assessable. All 19 cases with residual lesions > 3 cm and 35 (95%) of 37 with residual lesions ≤ 3 cm were correctly predicted by FDG PET. The specificity, sensitivity, positive predictive value, and negative predictive value of FDG PET were 100% (95% CI, 92% to 100%), 80% (95% CI, 44% to 95%), 100%, and 96%, respectively, versus 74% (95% CI, 58% to 85%), 70% (95% CI, 34% to 90%), 37%, and 92%, respectively, for CT discrimination of the residual tumor by size (> 3 cm/≤ 3 cm).

Conclusion

This investigation confirms that FDG PET is the best predictor of viable residual tumor in postchemotherapy seminoma residuals and should be used as a standard tool for clinical decision making in this patient group.

Management of recurrence and follow-up strategies for patients with seminoma and selected high-risk groups

Seminoma is characterized by high sensitivity to both radiation and chemotherapy. Localized recurrences in the retroperitoneum after surveillance for stage I can be treated with radiotherapy; however, multiple or large bulky retroperitoneal recurrences or systemic metastasis requires cisplatin-based chemotherapy. Salvage chemotherapy for those who recur after initial CR to induction chemotherapy is based on ifosfamide- and cisplatin-containing regimens. Incomplete response or failure after induction chemotherapy requires high-dose chemotherapy and stem cell rescue. Patients with seminoma need long-term follow-up because of the possibility of late recurrence and the risk of a second primary tumor.

Use of fluorodeoxyglucose positron emission tomography scans in patients with advanced germ cell tumour following chemotherapy: single-centre experience with long-term follow up*

AIMS

Fluorodeoxyglucose positron emission tomography (FDG-PET) may detect residual or recurrent malignancy in patients with germ cell tumours (GCT) following chemotherapy. The objective of the present study was to evaluate the use of FDG-PET in the setting of advanced GCT, and to determine the influence of FDG-PET on subsequent patient management.

METHODS

A computerized search of the patient database of the Department of Medical Oncology, Guy's Hospital, London, United Kingdom, and a manual search of medical records, were conducted. All male patients with metastatic or extragonadal GCT treated with chemotherapy between July 1996 and June 1999 inclusive were identified. Data from patients that had a PET scan following chemotherapy were analysed. Reported PET scan findings were compared with subsequent clinical management and patient outcome.

RESULTS

A total of 30 patients with metastatic testicular GCT and three patients with extragonadal GCT were treated with chemotherapy. Of these, 15 patients (12 testicular; three extragonadal; 10 non-seminoma; and five seminoma) were investigated following chemo-therapy with at least one FDG-PET scan. Seven patients had two or more PET scans, and a total of 26 FDG-PET scans was performed. The most frequent indication for PET scan was evaluation of a residual mass (11 patients). Three patients had an FDG-PET to evaluate thymic prominence. Minimum follow up from first PET scan was 18 months. Three of 26 PET scans had false positive findings. Four PET scans yielded findings of equivocal significance with repeat PET scan recommended. Relapse of disease occurred in three patients; two of whom had normal previous PET scans and one had a previous equivocal result. PET had an impact on patient management in only one case where it 'prompted' surgical excision of a residual mass. Normal PET scans provided reassurance in patients with residual small masses but did not alter their subsequent -management.

CONCLUSIONS

A residual mass was the most common indication for PET. For the majority of patients PET did not have a discernible influence on clinical management. Oncologists should exercise caution in their interpretation of PET scan findings and guidelines for the appropriate use of PET in testicular cancer management need to be developed. Prospective trials are required to define the clinical role of PET in this setting.

Surgery in metastatic testicular cancer

Surgery in advanced testicular tumors is an integral part of the multimodality treatment. However, the indications for surgery in testis cancer have changed over the last 10 years. Patients with advanced seminoma only rarely will need surgery after chemotherapy whereas patients with advanced non-seminoma need to undergo the resection of residual disease in most of the cases. Surgery in metastatic disease may even be beneficial for patients with recurrent tumors, patients with persisting marker elevations during chemotherapy, or patients with late relapse of the disease. In view of late relapse, the extent and completeness of the primary resection is an important issue and, therefore, surgery should be performed in specialized centers. Most of the procedures are technically demanding and, therefore, individualized perioperative precautions are necessary to reduce morbidity of surgery. Nevertheless, in individual cases nerve-sparing techniques and laparoscopic approaches may be applicable to reduce surgery-related morbidity. This review will update the current indications and recommendations for post-chemotherapy surgery in advanced testis cancer.

Is post-chemotherapy resection of seminomatous elements associated with higher acute morbidity?

PURPOSE

A seminomatous element in patients undergoing retroperitoneal lymph node dissection for testicular cancer is associated with a desmoplastic reaction that renders retroperitoneal surgery more challenging. We examined the impact of seminomatous elements on the rate of complications and the need for additional intraoperative procedures in patients undergoing post-chemotherapy retroperitoneal lymph node dissection.

MATERIALS AND METHODS

The testis cancer data base at our institution was retrospectively reviewed and 1,366 patients were identified who underwent post-chemotherapy retroperitoneal lymph node dissection between 1973 and 2001. In 97 patients there was an element of seminoma in the dissection specimen and/or pure seminoma in the testicular primary specimen (seminoma group). The remaining 1,269 patients underwent post-chemotherapy retroperitoneal lymph node dissection for nonseminomatous testicular tumors. The rates of intraoperative complications and additional procedures as well as postoperative complications were analyzed.

RESULTS

Of the 97 patients in the seminoma group 37 (38.1%) required a total of 47 additional intraoperative procedures, including 25 nephrectomies, 9 inferior vena caval resections, 5 arterial grafts, 5 bowel resections and 3 hepatic resections/biopsies, compared with 340 of the 1,269 patients (26.8%) in the group without seminomatous elements (p = 0.02). Postoperatively complications occurred in 24 of 97 patients (24.7%) in the seminoma group versus 257 of 1,269 (20.3%) in the group without seminomatous elements (p = 0.29). One of the 97 patients in the seminoma group died secondary to postoperative complications.

CONCLUSIONS

A seminomatous element in patients undergoing post-chemotherapy retroperitoneal lymph node dissection is associated with a higher rate of additional intraoperative procedures and postoperative complications than in patients without seminomatous elements. However, resection is still possible with acceptable morbidity when indicated in appropriately selected patients.

Management of post-chemotherapy residual masses in advanced seminoma

PURPOSE

We studied the resection of post-chemotherapy residual masses (20% to 80%) of advanced seminoma complicated by extensive fibrosis, in which active disease appears in 10% to 20% of cases.

MATERIALS AND METHODS

We retrospectively analyzed (1986 to 2000) residual mass evolution according to size in 79 platinum treated patients.

RESULTS

There was an evaluable response in 78 patients, including toxic death in 1 after 1 chemotherapy cycle, a complete response in 34 (after chemotherapy in 15 and after complete residual mass resection in 19), a marker negative partial response in 42 (incomplete residual mass resection in 8), stable and progressive disease in 1 each. In 15 of 31 patients the resected residual mass was 3 cm. or greater, whereas in 12 of 29 it was less than 3 cm. No surgery was performed for 3 residual masses of unknown size. Of the 42 residual masses 21 disappeared at a median of 12.5 months. Progression occurred at the initial tumor site in 11 of 13 patients after a median of 3.5 months, including 3 with a complete response, 8 with a marker negative partial response (residual mass 3 cm. or greater in 3, less than 3 cm. in 4 and unknown size in 1) and treatment failure in 2 (residual mass 3 cm. or greater). At a median followup of 36.4 months 67 patients survived (no disease progression in 56 and nonevolving residual masses in 11), while 12 had died including 9 of progressive disease 1 of toxicity and 2 of other causes.

CONCLUSIONS

In our study there was incomplete surgical resection in 30% of cases. Relapse in 16.6% of cases occurred rapidly after the end of chemotherapy. Viable cells were only noted in residual masses 3 cm. or greater (13%) and 50% of residual masses disappeared during surveillance. We intend to perform a prospective cohort study with close followup of patients with residual masses less than 3 cm. using an indication for surgery tailored to positron emission tomography findings in those with residual masses 3 cm. or greater.

Chemotherapeutic and surgical strategies for germ cell tumors

Testicular cancer has become a model for a curable neoplasm. Studies of cisplatin combination chemotherapy performed by the author's group allow the following conclusions: (1) short-duration, intensive induction therapy with the most active agents in optimal dosage is more important than maintenance therapy; (2) a modest dose escalation increases toxicity without improving therapeutic efficacy; (3) it is possible to develop curative salvage therapy for refractory germ cell tumors; and (4) preclinical models predicting synergism, such as vinblastine plus bleomycin or cisplatin plus etoposide, have clinical relevance. Testicular cancer has also become a model for new drug development. Cisplatin has been approved by the US Food and Drug Administration for testis and ovarian cancer and VP-16 and ifosfamide for refractory germ cell tumors. The success of these studies confirms the importance of the continued search for new investigational drugs in all solid tumors.

Positron emission tomography in urologic oncology

BACKGROUND

Positron emission tomography (PET) is an emerging imaging modality that is being investigated for use in urologic oncology. PET scanning using the radioactive glucose analog FDG has proven to be a highly accurate imaging test for diagnosing and staging a variety of non-urologic cancer types. This review was performed to determine the role of PET imaging in genitourinary malignancies.

METHODS

A review of the literature focusing on PET and urologic oncology was performed. The role of PET imaging was reviewed in prostate, bladder, renal, and testicular cancer.

RESULTS

In testicular cancer, PET has a higher diagnostic accuracy than computed tomography (CT) for both staging and re-staging and should be the test of choice for the assessment of a CT-visualized residual mass following chemotherapy. In prostate, renal, and bladder cancer, the current role of PET is still being defined, but it has a high positive predictive value and can be used for problem solving in patients with indeterminate findings on conventional imaging. Its role in the diagnosis and staging of prostate cancer is hampered by the generally low glycolytic rate of most prostate tumors and their metastases. It has shown promise for staging and re-staging patients with advanced-stage disease and aggressive tumors suspected by a high tumor grade and high prostate-specific antigen velocity. PET has also demonstrated success when applied to renal cell carcinoma in classifying indeterminate renal masses as well as residual renal fossa masses following nephrectomy, gauging response to therapy, and staging and re-staging patients with a known diagnosis of renal cell carcinoma.

CONCLUSIONS

PET imaging has demonstrated great potential in certain applications, but further investigations are necessary to determine its eventual place as an imaging modality in genitourinary malignancies.

The role of (18)fluoro-2-deoxyglucose positron emission tomography in initial staging and re-staging after chemotherapy for testicular germ cell tumours

OBJECTIVE

To investigate the role of 18fluoro-2-deoxyglucose positron emission tomography (FDG-PET) in the initial staging of clinical stage I and II nonseminomatous germ cell tumours (NSGCTs) and in re-staging (non)seminomatous GCTs after chemotherapy.

PATIENTS AND METHODS

FDG-PET studies were undertaken in 50 patients. FDG uptake was interpreted visually and when possible the standardized uptake value was determined. A FDG-PET scan was taken in five patients with clinical stage I and in seven with stage II NSGCT. The scans were validated by histology. Stage I patients underwent a retroperitoneal lymph node dissection because of vascular invasion in the primary tumour. Thirty-eight scans were taken after completing chemotherapy (28 NSGCTs and 10 seminomatous GCTs), and validated by histology or clinical follow-up.

RESULTS

In stage I NSGCT, FDG-PET staging was equivalent to computed tomography (CT) staging. One small lesion, consisting of mature teratoma, was missed by both FDG-PET and CT. In stage II NSGCT, FDG-PET missed two lesions (mature teratoma and retroperitoneal mass with a small component of embryonal cell carcinoma) whereas CT correctly classified all. In 20 of 28 patients with NSGCT, histology was obtained after chemotherapy. In one of three patients with viable tumorous residual mass the FDG-PET scan was clearly positive; in four of 12 with mature teratoma and inflammation components retroperitoneally, the FDG-PET was also positive. In contrast, eight patients with solitary mature teratoma had a negative PET result. In four of five patients with necrosis after chemotherapy the PET result was correctly negative. All eight patients on surveillance had a negative PET scan and were free of disease at median (range) of 14 (8-18) months. Interestingly, of the 12 patients with a correct negative PET result, 11 had no mature teratoma in their primary tumour. Nine of 10 patients with SGCT were correctly staged. Two FDG-PET studies showed increased uptake; in one, a viable seminomatous mass was found and in the other there was inflammation in the residual mass. In all other patients the FDG-PET scan correctly predicted absence of viability in the residual mass.

CONCLUSIONS

In primary staging, FDG-PET has no benefit over CT. In re-staging, a negative FDG-PET result predicts fibrotic residual mass in seminomatous GCT. Moreover, it could be useful to predict fibrotic residual mass in NSGCT in those patients with no teratoma component in their primary tumour.

Predictive impact of 2-18fluoro-2-deoxy-D-glucose positron emission tomography for residual postchemotherapy masses in patients with bulky seminoma

PURPOSE

To establish the predictive potential of 2-18fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) for detecting viable tumor tissue in residual postchemotherapy masses of seminoma patients.

PATIENTS AND METHODS

In this prospective multicenter trial, results of FDG PET studies in seminoma patients with postchemotherapy masses > or = 1 cm were correlated with either the histology of the resected lesion or the clinical outcome on follow-up without resection. Negative PET scans of residual lesions that were devoid of viable tumor tissue on resection or disappeared, shrunk, or remained stable in size for at least 2 years were rated as true-negative (TN). Positive scans without histologic or clinical evidence of tumor tissue were classified as false-positive. In patients with histologically positive or progressive lesions, positive PET scans were defined as true-positive (TP) and negative scans, false-negative (FN).

RESULTS

Thirty-seven PET scans of 33 patients were assessable at a median follow-up time of 23 months (range, 2 to 46 months). Histologic data were available from nine patients who had undergone resection. Twenty-eight patients were followed-up clinically and radiologically. Twenty-eight scans were TN, eight were TP, and one was FN. All 14 residual lesions more than 3 cm and 22 (96%) of the 23 < or = 3 cm were correctly predicted by FDG PET. The specificity (100%; 95% confidence interval [CI], 87.7% to 100%), sensitivity (89%; 95% CI, 51.7% to 99.7%), positive predictive value (100%), and the negative predictive value (97%) of FDG PET were superior to data obtained by assessing residual tumor size (< or = or > 3 cm).

CONCLUSION

FDG PET is a clinically useful predictor of viable tumor in postchemotherapy residuals of pure seminoma, especially those greater than 3 cm.

A medical research council randomized trial of single agent carboplatin versus etoposide and cisplatin for advanced metastatic seminoma. MRC Testicular Tumour Working Party

The UK Medical Research Council conducted this trial of carboplatin chemotherapy in advanced seminoma to compare single agent carboplatin with a standard combination of etoposide with cisplatin. The use of single agent carboplatin was expected to be associated with reduced toxicity. A total of 130 patients with advanced seminoma were randomly assigned to treatment with either single agent carboplatin (C) at a dose of 400 mg/m(2)to be corrected for glomerular filtration rate outside the range 81-120 ml min(-1)and to be administered on day 1 of a 21 day cycle to a total of 4 cycles or to etoposide + platinum (EP). The trial was designed as an equivalence study aiming to exclude a reduction in the 3-year progression-free survival in patients allocated to carboplatin of between 10 and 15%, requiring initially a target accrual of 250 patients (90% power significance level 5% (one-sided)). The trial closed after 130 patients had been randomized following recommendation by an independent data monitoring committee. At a median follow-up time of 4.5 years, 81% of patients had been followed up for at least 3 years and 19 patients have died. The estimated PFS rate (95% Confidence Intervals (CI)) at 3 years was 71% (60-82%) in patients allocated C and 81% (71-90%) in those allocated EP; the 95% CI for the difference in 3 year PFS was - 6% to +19%. The hazard ratio of 0.64 (95% CI 0.32-1.28) favoured EP but the difference was not statistically significant (log rank chi-squared = 1.59 P = 0.21). The 3-year survival rate was 84% (75-92%) in those allocated C, and 89% (81-96%) in those allocated EP. The hazard ratio for survival was 0.85 with 95% CI, 0.35-2.10, log rank chi-squared = 0.12, P = 0.73. The trial has not demonstrated statistically significant differences in the major survival endpoints comparing single agent carboplatin with a combination of etoposide + cisplatin. This cannot be taken as an indication of equivalence since the limited size of this trial rendered it unable to exclude a 19% lower progression-free survival and survival in those treated with single agent carboplatin which would be important clinically. Standard initial chemotherapy for advanced seminoma should be based on cisplatin combinations and the role of carboplatin awaits the outcome of further studies.

Carcinoma of the kidney, testis, and rare urologic malignancies

The purpose of this symposium was to provide a forum for discussion on current information on the etiology and diagnosis of, and therapy for, tumors of the kidney, testis, and several uncommon malignancies of the genitourinary tract. The most recent contributions in epidemiology and molecular genetics were discussed with specific reference to their importance for clinical practice. Contemporary treatment approaches with the emphasis on multidisciplinary patient management of tumors commonly seen in the clinic as well as those that are only rarely diagnosed by urooncologists were presented. Major stress was given to the management optimization as it pertains to short- and long-term quality of life issues of patients treated for these tumors. Methods to reduce treatment toxicity including carcinogenic potential of chemotherapy, radiotherapy, or their combination were found to be of nearly equal importance to patient survival. Symposium participants reached consensus on a number of important points: 1) The management of patients with several malignancies discussed requires the presence of a multidisciplinary team of specialist who are interested in diagnosis and treatment of genitourinary tumors; 2) Patients managed in such an environment are expected to have optimal survival and the best possible quality of life; 3) Real advances in the management of patients can be best obtained through well-designed prospective clinical trials; and 4) There is a need for timely introduction of relevant advances in epidemiology and molecular genetics to clinics.

Intracranial dural metastasis of mediastinal seminoma--case report

A 24-year-old male presented with a rare intracranial dural metastasis from a mediastinal germ cell tumor infiltrating the superior vena cava, pericardium, ascending aorta, and lung. Routine chest radiography incidentally revealed the abnormal mediastinum, which was partially resected after median sternotomy, followed by radiotherapy. One year after the radiotherapy, magnetic resonance imaging revealed a right parasagittal tumor mimicking a meningioma. Partial tumor removal was performed. Two cycles of chemotherapy with carboplatin and etoposide were then performed, and the residual tumor almost completely disappeared. The histological diagnosis of both the mediastinal and intracranial tumors was pure seminoma. Sections of metastatic tumor revealed several thick fibrous septa and numerous epithelioid granulomas infiltrated by plasma cells, intermingled between the clusters of tumor cells. Follow up of patients apparently in remission from mediastinal seminoma without evidence of advanced or recurrent disease at other sites is recommended.

Positron emission tomography scans in the evaluation of postchemotherapy residual masses in patients with seminoma

PURPOSE

To assess the ability of positron emission tomography (PET) scans in differentiating between necrosis and viable seminoma in postchemotherapy (PC) residual disease.

PATIENTS AND METHODS

We conducted a prospective study of 29 patients with seminoma at Indiana University. All patients had PC residual disease. Computed tomography and PET scans were performed for 19 patients after primary chemotherapy (group A) and for 10 patients after salvage chemotherapy (group B).

RESULTS

In group A, the PC masses were >/= 3 cm in 14 patients, less than 3 cm in three patients, and not quantified in two patients. All of the patients in group A had negative PET scan results and have had stable or decreasing residual mass size (median follow-up duration, 11.5 months; range, 6 to 26 months). In group B, the PC masses were >/= 3 cm in four patients, less than 3 cm in five patients, and not quantified in one patient. One patient had a positive PET scan result for a posterior mediastinal mass. Pathologic diagnosis of the PET-positive mass showed only necrotic tissue. The same patient had a negative PET scan of the retroperitoneal mass but relapsed in that area. Overall, of patients in group B, five have stable or decreasing mass (median follow-up duration, 8 months; range, 7 to 22 months), and five had relapsed disease.

CONCLUSION

PET scans have no apparent benefit in PC evaluation of residual masses in bulky seminoma.