False-positive fluorodeoxyglucose positron emission tomography results after chemotherapy in patients with metastatic seminoma

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.

Postchemotherapy retroperitoneal lymph node dissection (PC-RPLND) for seminoma: Limitations of surgical intervention after first-line chemotherapy

PURPOSE

Patients with relapsed seminoma after first-line chemotherapy can be treated with salvage chemotherapy or postchemotherapy retroperitoneal lymph node dissection (PC-RPLND). Based on prior experience, surgical management can have worse efficacy and increased morbidity compared to nonseminomatous germ cell tumor. Our aim was to characterize the surgical efficacy and difficulty in highly selected patients with residual disease after first-line chemotherapy.

MATERIALS AND METHODS

The Indiana University testis cancer database was queried to identify men who underwent PC-RPLND for seminoma between January 2011 and December 2021. Included patients underwent first-line chemotherapy and had evidence of retroperitoneal disease progression.

RESULTS

We identified 889 patients that underwent PC-RPLND, of which only 14 patients were operated on for seminoma. One patient was excluded for lack of follow-up. Out of 13 patients, only 3 patients were disease free with surgery only. Median follow up time was 29.9 months (interquartile ranges : 22.6-53.7). Two patients died of disease. The remaining 8 patients were treated successfully with salvage chemotherapy. During PC-RPLND, 4 patients required nephrectomy, 1 patient required an aortic graft, 2 patients required a partial ureterectomy, and 3 patients required partial or complete caval resection.

CONCLUSION

The decision between salvage chemotherapy and PC-RPLND as second-line therapy can be challenging. Salvage chemotherapy is effective but is associated with short and long-term morbidity. Surgical efficacy in this setting seems to be limited, but careful selection of patients may lead to surgical success without affecting the ability to receive any systemic salvage therapies if necessary or causing life-threating morbidity.

[Multimodal treatment of testicular cancer: chemotherapy, surgery or radiotherapy?]

BACKGROUND

Metastatic testicular germ cell tumors patients require histology- and stage-appropriate therapy to achieve optimal therapeutic outcomes.

OBJECTIVES

This work focuses on the interdisciplinary presentation of current recommendations for the treatment of metastatic germ cell tumor patients.

MATERIALS AND METHODS

The interdisciplinary recommendations were formulated based on the German S3 guideline and supplemented by recent literature.

RESULTS

Using a stage-specific and guideline-based treatment approach, interdisciplinary cooperation between urology, oncology, and radiotherapy is mandatory to successfully achieve a high rate of cure and, in the case of complex advanced tumors, also the most effective therapy possible. The question of optimal treatment approaches for seminoma in cSII A/B remains particularly challenging.

CONCLUSION

Since treatment of advanced or multiple relapsed germ cell tumor patients remains complex, patients should be referred for an online second opinion ( https://urologie.ekonsil.org ).

Serum Levels of MicroRNA-371a-3p (M371) Can Predict Absence or Presence of Vital Disease in Residual Masses After Chemotherapy of Metastatic Seminoma

Background

Radiological evaluation of postchemotherapy residual masses of metastatic seminoma is characterized by poor diagnostic accuracy. Serum levels of microRNA-371a-3p (M371) involve high specificity and sensitivity for the primary diagnosis of seminoma. We evaluated if M371 levels can indicate the presence of vital disease in postchemotherapy residual masses in patients with metastatic seminoma.

Methods

Twenty-three seminoma patients (median age 52 years) with residual masses had posttreatment measurements of serum M371 levels (group A), fourteen of whom had measurements also beforehand. The posttreatment results were compared with the clinical outcome during follow-up. Eleven patients with complete remission after treatment of metastatic seminoma (group B) and 33 men with non-malignant testicular diseases (group C) served as controls. M371 serum levels were measured by quantitative real-time PCR using miR-30b-5p as endogenous control. An evaluation was performed with descriptive statistical methods.

Results

Twenty-two patients of Group A had uneventful follow-up so far, twenty-one of whom had M371 level <5, and one other had a mildly elevated level below relative quantity (RQ) = 10. One patient with a level of RQ = 26.2 rapidly progressed. The median posttreatment M371 level of the non-progressing patients of group A is not significantly different from the median level of the control group with complete remission (B). Before treatment, the median M371 levels in groups A and B were 507.6 and 143.9, respectively. In both groups, significant drops in M371 levels resulted from treatment.

Conclusion

Normal M371 serum levels at the time of completion of treatment of metastatic seminoma indicate the absence of vital seminoma in residual masses, while elevated levels >RQ = 10 predict the presence of disease. The optimal timing of M371 measurement after chemotherapy and the appropriate cutoff level still need to be determined. Based on the present results, measuring serum M371 levels involves the potential of a novel tool for assessing postchemotherapy residual masses of metastatic seminoma.

Management of Stage II Germ Cell Tumors

There are several treatment approaches for stage II germ cell tumors (GCTs), and a thorough understanding of the staging classification and histologic differences in tumor biology and therapeutic responsiveness is critical to determine an effective, multimodal management strategy that involves urologists, medical oncologists, and radiation oncologists. This article discusses contemporary management strategies for stage II GCTs, including chemotherapy, radiotherapy, retroperitoneal lymph node dissection (RPLND), and surveillance. Patient selection, histology, and extent of lymphadenopathy drive management, and, as both treatment and detection strategies continue to emerge and be refined, the management of patients with stage II GCT continues to evolve.

Questioning the Value of Fluorodeoxyglucose Positron Emission Tomography for Residual Lesions After Chemotherapy for Metastatic Seminoma: Results of an International Global Germ Cell Cancer Group Registry

PURPOSE

Residual lesions after chemotherapy are frequent in metastatic seminoma. Watchful waiting is recommended for lesions < 3 cm as well as for fluorodeoxyglucose (FDG) positron emission tomography (PET)-negative lesions ≥ 3 cm. Information on the optimal management of PET-positive residual lesions ≥ 3 cm is lacking.

PATIENTS AND METHODS

We retrospectively identified 90 patients with metastatic seminoma with PET-positive residual lesions after chemotherapy. Patients with elevated α-fetoprotein or nonseminomatous histology were excluded. We analyzed the post-PET management and its impact on relapse and survival and calculated the positive predictive value (PPV) for PET.

RESULTS

Median follow-up time was 29 months (interquartile range [IQR], 10 to 62 months). Median diameter of the largest residual mass was 4.9 cm (range, 1.1 to 14 cm), with masses located in the retroperitoneum (77%), pelvis (16%), mediastinum (17%), and/or lung (3%). Median time from the last day of chemotherapy to PET was 6.9 weeks (IQR, 4.4 to 9.9 weeks). Post-PET management included repeated imaging in 51 patients (57%), resection in 26 patients (29%), biopsy in nine patients (10%) and radiotherapy in four patients (4%). Histology of the resected specimen was necrosis in 21 patients (81%) and vital seminoma in five patients (19%). No biopsy revealed vital seminoma. Relapse or progression occurred in 15 patients (17%) after a median of 3.7 months (IQR, 2.5 to 4.9 months) and was found in 11 (22%) of 51 patients on repeated imaging, in two (8%) of 26 patients after resection, and in two (22%) of nine patients after biopsy. All but one patient who experienced relapse were successfully treated with salvage therapy. The PPV for FDG-PET was 23%.

CONCLUSION

FDG-PET has a low PPV for vital tumor in residual lesions after chemotherapy in patients with metastatic seminoma. This cautions against clinical decisions based on PET positivity alone.