Postchemotherapy Retroperitoneal Lymph Node Dissection Research Articles

MP33-01 RISK OF RESIDUAL TERATOMA AFTER COMPLETE RESPONSE FOLLOWING FIRST-LINE CHEMOTHERAPY IN MEN WITH METASTATIC NON-SEMINOMATOUS GERM CELL TUMOR AND IGCCCG INTERMEDIATE/POOR PROGNOSIS: A MULTI-INSTITUTIONAL RETROSPECTIVE COHORT STUDY

MP33-01 RISK OF RESIDUAL TERATOMA AFTER COMPLETE RESPONSE FOLLOWING FIRST-LINE CHEMOTHERAPY IN MEN WITH METASTATIC NON-SEMINOMATOUS GERM CELL TUMOR AND IGCCCG INTERMEDIATE/POOR PROGNOSIS: A MULTI-INSTITUTIONAL RETROSPECTIVE COHORT STUDY

CT Rendering and Radiomic Analysis in Post-Chemotherapy Retroperitoneal Lymph Node Dissection for Testicular Cancer to Anticipate Difficulties for Young Surgeons.

Post-chemotherapy retroperitoneal lymph node dissection (PC-RPLND) in non-seminomatous germ-cell tumor (NSTGCTs) is a complex procedure. We evaluated whether 3D computed tomography (CT) rendering and their radiomic analysis help predict resectability by junior surgeons. The ambispective analysis was performed between 2016-2021. A prospective group (A) of 30 patients undergoing CT was segmented using the 3D Slicer software while a retrospective group (B) of 30 patients was evaluated with conventional CT (without 3D reconstruction). CatFisher's exact test showed a p-value of 0.13 for group A and 1.0 for Group B. The difference between the proportion test showed a p-value of 0.009149 (IC 0.1-0.63). The proportion of the correct classification showed a p-value of 0.645 (IC 0.55-0.87) for A, and 0.275 (IC 0.11-0.43) for Group B. Furthermore, 13 shape features were extracted: elongation, flatness, volume, sphericity, and surface area, among others. Performing a logistic regression with the entire dataset, n = 60, the results were: Accuracy: 0.7 and Precision: 0.65. Using n = 30 randomly chosen, the best result obtained was Accuracy: 0.73 and Precision: 0.83, with a p-value: 0.025 for Fisher's exact test. In conclusion, the results showed a significant difference in the prediction of resectability with conventional CT versus 3D reconstruction by junior surgeons versus experienced surgeons. Radiomic features used to elaborate an artificial intelligence model improve the prediction of resectability. The proposed model could be of great support in a university hospital, allowing it to plan the surgery and to anticipate complications.

Testicular radiomics correlated with pathology at time of post-chemotherapy retroperitoneal lymph node dissection for non-seminomatous germ cell tumor.

413 Background: Testicular germ cell tumors are the most commonly diagnosed malignancy in men aged 20 to 39 years old. Up to a third of patients will have metastatic disease at presentation typically managed with upfront chemotherapy. For many patients with metastatic non-seminomatous germ cell tumor (NSGCT), post-chemotherapy retroperitoneal lymph node dissection (PC-RPLND) is performed to further stage and treat residual disease in the retroperitoneum. Although 50% of patients will have viable GCT or teratoma, we do not have accurate tools to predict pre-operatively which patients will have residual disease after chemotherapy. Testicular radiomics is an emerging field that collects complex quantitative tumor imaging data from conventional imaging to aid in clinical decision making. Our aim was to use testicular radiomics data to predict pathology after PC-RPLND. Methods: We extracted radiomics data on 45 patients with metastatic NSGCT undergoing PC-RPLND from 2008-2019. Clinical and pathologic data were collected. Regions of interest (ROI) around metastatic nodes were drawn by a dedicated abdominal radiologist. PyRadiomics, an open-source imaging extraction software, was used to extract first order, shape, and second order statistics from each ROI. Multiple t-tests of testing difference in radiomic features between binary pathology type were performed. P values were adjusted using the BH method to control false discovery rate. Boxplot of features with adjusted p value < 0.05 were shown. Radiomic feature extraction was done in python 3.7 and statistical analyses were done in R 4.2.0. Results: There were 16 (36%) clinical stage II patients and 28 (62%) clinical stage III. 19 (42%) patients had necrosis on PC-RPLND pathology, while 24 (53%) and 2 (4%) patients had teratoma and viable germ cell tumor, respectively. First order statistics mean, median, 90th percentile and root mean squares were significant. Strong correlations were observed between these four features and a lower signal was associated with positive pathology (Table). No significant difference was observed in other first order, shape, or texture features. Conclusions: Testicular radiomics is an emerging tool that has the potential to help predict which patients with metastatic NSGCT are at higher risk of persistent disease after chemotherapy. This study found relatively few first order radiomic data that were correlated with post-operative pathology. Further precision of extraction of the radiomics data may improve clinical decision-making in patients with metastatic NSGCT after chemotherapy prior to RPLND. [Table: see text]

Relapse-free and overall survival in patients with non-seminomatous testicular germ cell tumours with teratoma-free primaries.

421 Background: Characteristics and outcome of non-seminomatous testicular germ cell tumours (NSGCT) with teratoma-containing primaries are still under debate. Methods: We performed a retrospective analysis including 557 patients with metastatic NSGCT as a registry study within the "German Testicular Cancer Study Group". Results: Of the eligible 557 patients with NSGCT, 237 (42%) of all orchiectomy specimens had teratoma-containing primaries, while 320 (58%) were teratoma-free. Teratoma-containing primaries had a significantly higher clinical stage (p=0.002) and worse prognosis (p=0.051) compared to teratoma-free specimens. Lymph node metastasis were significantly larger before (4.5 vs 2.5cm; p<0.001) and after chemotherapy (3.5 vs 2.5 cm; p<0.001) in teratoma-containing primaries. Post-chemotherapy retroperitoneal lymph node dissection was performed in 57% of all patients. As teratoma-containing specimens revealed a significantly lower number of complete responses after chemotherapy, PC-PRLND was more often performed, with teratomatous elements being more often present in the PC-RPLND specimens compared to non-teratoma containing primaries. Kaplan-Meier estimates revealed that 19% of all patients relapsed during a median follow-up of 56 months [29-112] with a median time to relapse of 10 months. Teratoma-containing had a significantly lower relapse-free survival (RFS) compared to teratoma-free NSGCT (relapse rate 24% vs 16%, p=0.020). 8% (45/533) of all patients died due to their disease. There was no difference regarding the tumour-specific survival between teratoma-containing NSGCT and teratoma-free NSGCT when looking at the entire cohort of patients (8% vs. 9%, p=0.563), however median overall survival was not reached. Conclusions: In our study, NSGCT patients with teratoma-containing primaries showed a significantly higher clinical stage and worse prognosis at time of presentation compared to teratoma-free primaries. Furthermore, patients with teratoma-containing primaries showed a significantly worse relapse-free survival. Consequently, treating physicians should be aware of these patients portending a dismal prognosis and the presence of teratomatous elements might act as a reliable stratification tool for treatment decision in TGCT patients.

Postchemotherapy robotic retroperitoneal lymph node dissection for non-seminomatous germ cell tumors in the lateral decubitus position: oncological and functional outcomes.

Retroperitoneal lymph node dissection (RPLND) is recommended for residual masses following chemotherapy for non-seminomatous germ cell tumors (NSGCT). Recently, aberrant recurrence patterns were reported in patients who underwent robotic RPLND. We aimed to evaluate perioperative safety in addition to functional and early oncological outcomes of postchemotherapy robotic RPLND (pcR-RPLND) for NSGCT. A total of 25 patients with NSGCT who underwent a pcR-RPLND between January 2011 and June 2022 were evaluated retrospectively. Descriptive statistics were provided for demographics, clinical characteristics, intraoperative and postoperative parameters. Functional and oncological outcomes were recorded. The median patient age was 28.9years (IQR 21.5-32.4). The median retroperitoneal tumor size was 2.6cm (IQR 1.5-3.5). Intraoperative complications occurred in only one case and the open conversion rate was 12%. There were seven cases with postoperative complications (Clavien grade II: 5 and IIIa: 2). Patients were followed for a median of 33.2months (IQR 14.8-43.0). Antegrade ejaculation was preserved in 85.7% of the patients. Two patients (8%) relapsed and both had out-of-field recurrences at unusual sites (perinephric fat and omentum). Of those, one patient died (4%) of testicular cancer. pcR-RPLND is a feasible and technically reproducible procedure with favorable perioperative morbidity, low rate of complications, and acceptable postoperative ejaculatory function. Although the recurrence rate was low (8%), recurrences were observed at unusual sites. Further studies are required to investigate any association between the robotic approach and aberrant recurrence patterns.

Outcomes of postchemotherapy retroperitoneal lymph node dissection: Comparison of two reference centres to a national data set

Outcomes of postchemotherapy retroperitoneal lymph node dissection: Comparison of two reference centres to a national data set

Analysis of 30-day complications in 225 post-chemotherapy RPLND’s for testicular germ cell tumors over a decade: A single centre experience

Analysis of 30-day complications in 225 post-chemotherapy RPLND’s for testicular germ cell tumors over a decade: A single centre experience

Outcomes of Arterial and Caval Resection During Post-Chemotherapy Retroperitoneal Lymph Node Dissection in Metastatic Testicular Cancer

Background/Objective:In the United States, testicular cancer is the most common solid tumor in men aged 15 to 34. Fortunately, testicular cancer has a cure rate greater than 90% and a 97% five-year survival rate. For the men not cured, a relapse to the retroperitoneum (RP) is most common. Of the patients with RP metastases, a minimal number may require post-chemotherapy retroperitoneal lymph node dissection (PC-RPLND) with resection of the aorta, external iliac, or inferior vena cava (IVC). We hypothesized this procedure would yield reasonable cure rates with acceptable levels of postoperative complications to warrant the indication for surgery.
 Methods:Between 2000 and 2020, 2,054 patients with metastatic testicular cancer underwent a PC-RPLND; of those men, 39 also underwent an aortic, external iliac, and/or IVC resection. For the men with a PC-RPLND and vascular resection, demographic, clinical, pathologic, and operative information were reviewed. Next, a Kaplan-Meier curve was created to determine overall survival
 Results:In this retrospective cohort study of 39 patients, PC-RPLND and vascular resection occurred at a median age of 40. The median follow-up of the cohort was 9 months. The median pre-operative mass size was 9 cm and 19 cm in the RP and pelvis, respectively. At PC-RPLND, 54%, 13%, 18%, and 15% of patients demonstrated cancer, teratoma, teratoma and cancer, and necrosis, respectively. Following PC-RPLND and vascular resection, 22 (56%) patients recurred. The median (IQR) time to relapse was 4.2 (2.5 – 8.2) months. Recurrence to the lung was most common, followed by the RP and liver. In total, 17 (44%) patients died of disease with a median overall survival of 14.8 months.
 Conclusion:With an overall survival rate of 45% at two years in this heavily pretreated patient population, PC-RPLND with resection of the aorta, external iliac, and/or IVC is reasonable in very select cases.

Risk of residual cancer after complete response following first-line chemotherapy in men with metastatic non-seminomatous germ cell tumour and International Germ Cell Cancer Cooperative Group intermediate/poor prognosis: A multi-institutional retrospective cohort study

IntroductionCurrent guidelines recommend surveillance in metastatic non-seminomatous germ cell tumour patients treated with first-line-chemotherapy and a complete clinical response (normalisation of serum tumour markers and residual masses <1 cm). However, this recommendation is based on a series including patients with good prognosis according to International Germ Cell Cancer Cooperative Group prognostic group (IGCCCG-PG). The aim of this study was to analyse the proportion of residual teratoma and survival among patients with intermediate/poor IGCCCG-PG and a complete clinical response after first-line-chemotherapy. Material & methodsThis is a retrospective study of men with intermediate/poor IGCCCG-PG, who had a complete clinical response after first-line chemotherapy. Patients were either followed by surveillance or treated with post-chemotherapy retroperitoneal lymph node dissection (pcRPLND). ResultsBetween 2009 and 2018, 143 men with intermediate (n = 83) or poor (n = 60) IGCCCG-PG were treated at 11 international centres. Among 33 patients treated with pcRPLND, the specimen showed teratoma and viable cancer in 16 (48%) and 4 (12%). During a median a 7-year follow-up, 20/110 (18%) patients managed with surveillance relapsed, of whom seven (6%) had a retroperitoneal-only relapse versus 2/33 patients managed with pcRPLND relapsed. No difference was observed regarding overall survival (OS) among men treated with pcRPLND or surveillance (5-year OS, 93% and 89%, p-value = 0.35). The median time-to-recurrence among men on surveillance was 1.3 years (range: 0.3–9.1), and the most common sites of relapses included retroperitoneum (11%), chest (5%), and bones (4%). ConclusionsWhile most men with intermediate/poor IGCCCG-PG harbour teratoma/cancer in the retroperitoneum despite a complete response to first-line-chemotherapy, only 6% managed with surveillance relapsed in the retroperitoneum. There was no significant difference in OS between the two groups.

Laparoscopic retroperitoneal lymph-node dissection in metastatic nonseminomatous germ-cell tumors.

To support laparoscopic post-chemotherapy retroperitoneal lymph-node dissection (L-PC-RPLND) as a potential new standard, we report on a large dataset of patients systematically undergoing L-PC-RPLND. Patients with unilateral residual mass (≥1cm), normalized markers, limited encasement (<30%) of gross retroperitoneal vessels underwent unilateral L-PC-RPLND with no adjuvant chemotherapy. Surgical performances, histology, hospital stay, complications within 30 days and follow-up visits were recorded. Multivariable linear and logistic regression models were used. Between February 2011 and January 2021, 151 consecutive patients underwent L-PC-RPLND. Median size of the residual mass was 25mm (interquartile range [IQR] 20-35mm). Overall median operative time was 208min (IQR 177-241) and was 51min longer (p-value <0.001) for right L-PC-RPLNDs. Eleven procedures were converted to open surgery. Median number of removed and positive nodes was 11 (IQR 8-16) and 1 (IQR 1-2), respectively. Mean hospital stay was 2 days (IQR 2-3). Nine complications (6%) occurred: two were Clavien-Dindo grade III. Definitive pathology revealed post-pubertal teratoma in 65.6%, fibro-necrotic tissue in 23.8%, teratoma with malignant somatic component in 6.6% and viable tumour in 4.0% patients. In multivariable linear regression models, fibro-necrotic tissue (32min, CI 8.5-55.5; p<0.01) and residual volume (1.05min, CI 0.24-1.85; p<0.01) achieved independent predictor status for longer operative time. All patients, but one, are alive and disease-free after a median follow-up of 22 months (IQR 10, 48). L-PC-RPLND, when adequately planned, is safe and effective for most patients with low to medium volume residual masses.

Differentially expressed messenger RNA/proteins can distinguish teratoma from necrosis in postchemotherapy retroperitoneal lymph node dissection tissue.

Before postchemotherapy retroperitoneal lymph node dissection (pcRPLND), in patients with metastasized germ cell tumors (GCTs), those harboring necrosis (NEC) cannot be distinguished from those who have teratoma (TER), resulting in relevant overtreatment, whereas microRNA-371a-3p may be predictive for viable GCT. The purpose of this study was to explore messenger RNA (mRNA) and proteins to distinguish TER from NEC in pcRPLND tissue. The discovery cohort consisted in total of 48 patients, including 16 each with TER, viable GCT, and NEC. Representative areas were microdissected. A NanoString panel and proteomics were used to analyze 770 genes and >5000 proteins. The most significantly and differentially expressed combination of both parameters, mRNA and its associated protein, between TER and NEC was validated using immunohistochemistry (IHC) in an independent validation cohort comprising 66 patients who were not part of the discovery cohort. The authors observed that anterior gradient protein 2 homolog (AGR2) and keratin, type I cytoskeletal 19 (KRT19) were significantly differentially expressed in TER versus NEC in mRNA and protein analyses (proteomics). The technical validation using IHC was successful in the same patients. These proteins were further validated by IHC in the independent patient cohort and exhibited significantly higher levels in TER versus NEC (p<.0001; area under the curve, 1.0; sensitivity and specificity, 100% each). The current study demonstrated that KRT19 and AGR2 mRNA and protein are overexpressed in TER versus NEC in pcRPLND tissue and might serve as a future diagnostic target to detect TER, for instance, by functional imaging, to avoid overtreatment. The proteins and the corresponding genes called AGR2 and KRT19 can differentiate between teratoma and necrosis in remaining tumor masses after chemotherapy in patients who have metastasized testicular cancer. This may be a way to improve presurgical diagnostics and to reduce the current overtreatment of patients with necrosis only, who could be treated sufficiently by surveillance.

Non-choriocarcinomatous trophoblastic tumors of testis in postchemotherapy retroperitoneal lymph node dissections.

Non-choriocarcinomatous trophoblastic tumors (NCTTs) are seldomly diagnosed in male genital tract. As they have been recently described among the testicular germ cell tumor (TGCT) variants, pathologists' familiarity with their morphology is limited. We searched our electronic hospital records covering the years 2000-2017 for post-chemotherapy retroperitoneal TGCT metastectomies. Slides of all cases with viable tumor were retrieved from the archives and reviewed. Cases suspected of N-CTT morphologies were subjected to immunohistochemistry. Twelve NCTTs were identified, 9 of which were unseen or misdiagnosed by the original pathologists: Cystic trophoblastic tumor (CTT) (n = 5), placental site trophoblastic tumor (n = 2), epithelioid trophoblastic tumor (ETT) (n = 4), and coinciding PSTT + ETT (n = 1). Eight of these were associated with mature teratoma components, and one case (ETT) contained embryonal carcinoma and yolk sac tumor in addition to teratoma. Ten patients were clinically N1 at the time of primary tumor detection and orchiectomy. One patient had burned-out primary testicular tumor. Six patients were clinical M1a at presentation, while one male was cM1b. Six patients had mildly elevated β-HCG (≤ 410 mIU/ml) just prior to retroperitoneal lymph node dissections (RPLND), while the others had normal β-HCG levels. All patients had follow-ups ranging from 8 to 118months (mean 42.3months). Three patients died of disease-related and two of unrelated causes. In conclusion, because NCTTs are rare and newly described tumor types, their diagnosis is difficult and most of them are missed in post-chemotherapy RPLNDs. The majority of patients exhibit normal or slightly elevated β-HCG levels. N-CTTs are usually accompanied by other components of TGCT, the most common being teratoma. Despite the high survival rate of the patients, our study points to the unpredictable evolution of NCTT cases, which may concur with a high-stage or progressive disease.

Decreased Muscle Mass Prior to and Following Chemotherapy Predicts Morbidity in Testicular Cancer Patients Undergoing Post-Chemotherapy Retroperitoneal Lymph Node Dissection.

The importance of nutritional status before oncologic surgery has been demonstrated in several solid malignancies. Testicular cancer primarily effects young men, and therefore clinicians may not consider sarcopenia as a factor in this population. We therefore sought to determine the impact of decreased muscle mass, measured by psoas muscle diameter, on outcomes in patients undergoing post-chemotherapy retroperitoneal lymphadenectomy (PC-RPLND) for metastatic germ cell tumors (mGCTs). Records of all patients undergoing PC-RPLND for mGCTs at our institution were reviewed. Muscle mass was assessed by measuring cross-sectional area of the psoas muscle on pre-chemotherapy and pre-operative computerized tomography. Psoas Index (PSI) was calculated by adjusting total psoas area for patient height (cm2/m2). Univariate and multivariate analysis was performed to assess the predictive value of sarcopenia for morbidity and mortality following PC-RPLND. From 2014-2019, 95 patients underwent PC-RPLND, of whom 64 patients had both pre-chemo and pre-operative cross-sectional imaging. Prior to chemotherapy, mean PSI was 7.36 cm2/m2, which decreased to 7.06 cm2/m2 (P=.041) following chemotherapy. Patients with Stage III disease had a lower mean PSI than patients with Stage I disease (6.84 cm2/m2 vs 7.46 cm2/m2, P=.047). Patients who suffered post-operative complications had a lower mean PSI (6.39 cm2/m2 vs 7.37 cm2/m2, P=.020). Decreased muscle mass was predictive of morbidity in patients undergoing PC-RPLND. Patients with higher disease burden had lower pre-operative muscle mass. Further assessment of pre-operative nutritional status in this population may reduce morbidity following PC-RPLND.

Robotic post-chemotherapy retroperitoneal lymph node dissection for testicular cancer: A multicenter collaborative study

To evaluate the perioperative and oncological/functional outcomes of robotic post-chemotherapy retroperitoneal lymph node dissection for testicular cancer. In this retrospective study, we included patients who underwent robotic post-chemotherapy retroperitoneal lymph node dissection at 7 academic centers between 2011 and 2021. Patients' characteristics, perioperative findings, as well as oncological and functional outcomes are reviewed. Relationships with the main outcome (90-day complications) were analyzed using multivariable logistic regression. A total of 90 patients with a median (IQR) age of 30 (25-37) years were included. The main primary histologic type was non-seminomatous germ cell tumor (89%). Seven patients (8%) were electively converted to open. Median estimated blood loss, operative time, and length of hospital stay were 150 ml, 5.6 hours, and 2 days, respectively. Final pathology revealed teratoma in 49 (55%), necrosis/fibrosis in 29 (32%), and viable germ cell tumor in 12 (13%) patients. The 90-day complication rate was 16.7%, most of which were low-grade (Clavien-Dindo < III) and managed conservatively. On multivariable analysis, pure seminoma (odds ratio 17.4) and bilateral dissection template (odds ratio 4.2) were independently associated with 90-day complications. No 90-day hospital readmission was recorded. With a median (IQR) follow-up of 16 (4-32) months, 6 (6.7%) patients had disease recurrence and there was 1 cancer-related death. With appropriate patient selection at centers with expertise in testicular cancer and minimally invasive surgery, robotic post-chemotherapy retroperitoneal lymph node dissection appears safe and effective, although longer follow-up is warranted.

Need for organ preservation in postchemotherapy retroperitoneal lymph node dissection (PC-RPLND).

5031 Background: The aim ofPC-RPLND for advanced nonseminomatous germ cell tumors is to resect all remaining metastatic tissue. So far, the resection of adjacent visceral or vascular organs is also commonly performed to achieve complete resection of the residual mass. To determine the possibility of more organ preservation, we aimed to analyze the pathohistology of patients with adjunctive surgery as the frequency of metastatic involvement in those organs with teratoma or vital cancer is currently unknown. Methods: We reviewed a cohort of 1204 patients who underwent PC-RPLND between 2008 and 2021 as a 2-center study and identified 242 (20.1%) cases of adjunctive surgery during PC-RPLND. We analysed the pathohistological presence of germ cell tumor elements in the resected organs: viable tumor (V), teratoma (T) or necrosis / fibrosis (N). Surgery associated complications were reported according to the Clavien-Dindo classification. Outcomes of subgroups were compared by using log-rank test. Results: V, T and N were present in 54 (22%), 94 (39%) and 94 (39%) of all patients with adjunct resected organs. In 242 patients, 325 adjunct organs were resected with 66 (27.3%) of these patients receiving a resection of multiple organs. The kidney was the most often resected organ (n = 77; V: 29% T: 39% N: 32%), followed by V. Cava (n = 67; V: 25% T: 36%, N: 39%) and partial liver resections (n = 50; V: 16%, T: 30%, N: 54%). Postoperative complications occurred in 30% of which 22% were Clavien grade III-V, showing no significant differences between V, T and N; p = 0.093. 27% of all patients suffered from a relapse during a median follow-up of 22 months [0-180]. Patients with T or V in the resected specimens had a significantly reduced 5-year RFS compared to patients with only N (39%, 81%, p &lt; 0.001). Conclusions: This study shows tremendous need for more organ preservation as 40% of all resections of adjunct organs are oncologically unnecessary due to the presence of N only in the pathological specimens. Therefore, in case of doubt, we should increase intraoperative frozen section to avoid oncologically unnecessary adjunctive surgeries, especially nephrectomies and vascular resections. Additionally, serological or image-based means for a more accurate presurgical workup are required to spare patients with N from PC-RPLND in general.

Postchemotherapy retroperitoneal residual mass resection for germ cell testicular tumors: a single-center experience.

Postchemotherapy retroperitoneal lymph node dissection (PC-RPLND) plays an important role in the management of advanced germ cell testicular tumors. Bilateral template lymph node dissection is considered a standard treatment in postchemotherapy residual masses; however, modified unilateral templates have gained acceptance in patients with unilateral residual disease. In this study, we aimed to demonstrate the perioperative and oncological outcomes of the patients with advanced testicular cancer who underwent unilateral modified template PC-RPLND in our center. This is a retrospective study in which patients who underwent PC-RPLND in a referred center between 2004 and 2021 were investigated. All patients had three or four cycles of chemotherapy and retroperitoneal residual masses. Data were retrospectively collected from medical, operative, radiology, and pathology records and analyzed. A total of 57 patients underwent PC-RPLND. The mean age was 32.7±8.1 years (19-50). According to the disease stage at presentation, there were 39 patients with stage 2 and 18 patients with stage 3. The average tumor size after chemotherapy was 57.6±2.7 mm (25-117). The overall complication rate was 35% (20/57 patients). No grade 4 and 5 complications were observed. Pathologic review demonstrated the presence of teratoma in 28 (49.1%) patients, fibrosis and/or necrosis in 15 (26.3%) patients, and viable germ cell tumor in 14 (24.5%) patients. The mean follow-up was 69.4 months (8-201). During follow-up after surgery, 14 (24.5%) deaths occurred due to advanced disease. PC-RPLND is a major component of the management of advanced testicular germ cell cancer. Our study demonstrated that modified unilateral template is an effective and safe procedure in the postchemotherapy setting for selected patients.

Role of preoperative albumin in predicting risk of postoperative complications in patients undergoing post-chemotherapy retroperitoneal lymph node dissection (PC-RPLND).

416 Background: Testicular cancer with retroperitoneal metastases is often treated with chemotherapy, with subsequent post-chemotherapy retroperitoneal lymph node dissection (PC-RPLND) performed for residual masses after chemotherapy. While the cure rate is high, the surgery is associated with significant morbidity. Unlike in other genitourinary cancers, perioperative nutritional optimization is typically not prioritized as most patients are young, otherwise healthy men. Albumin is a systemic marker of nutritional status and has been shown to predict adverse outcomes in other urological cancers. We sought to assess whether preoperative albumin level is associated with postoperative outcomes in patients undergoing PC-RPLND. Methods: A database of patients who received PC-RPLND at our institution between 2007 and 2019 was created. Pre-RPLND albumin was obtained and correlated with postoperative outcomes using univariate and multivariable regression models. The primary outcome was the presence of major (Clavien-Dindo grade ≥ III) complications within 90 days of surgery. Results: Of 76 patients who underwent PC-RPLND, 70 patients had preoperative albumin values available. The median age (IQR) of patients at the time of surgery was 26 years (22 - 32) and median (IQR) preoperative albumin level was 4.4 g/dL (4.1 - 4.6). Patients with major postoperative complications had lower median preoperative albumin than those without a complication (4.1 g/dL vs. 4.4 g/dL; p = 0.03). Greater albumin level (per g/dL) was associated with a lower risk of major postoperative complications on multivariable logistic regression (OR = 0.12; p = 0.03). Other preoperative serum markers such as hemoglobin and creatinine did not associate with postoperative complications. Conclusions: To our knowledge, this is the first study to demonstrate that preoperative albumin is an independent predictor of major postoperative complications in patients undergoing PC-RPLND. This finding demonstrates the importance of nutritional optimization even in young, otherwise healthy individuals prior to undergoing this morbid surgery. Additional studies are warranted to more reliably predict which patients may experience complications.

Viable germ cell tumor and teratoma can be distinguished from necrosis in postchemotherapy retroperitoneal lymph node dissection specimens by a combination of microRNA-371a-3p and 375-5p.

421 Background: Our objective was to identify a combination of microRNAs (miRNA) to differentiate between viable tumor (V) or teratoma (T) and necrosis/fibrosis (N) in pcRPLND specimens of metastatic nonseminomatous germ cell tumor (NSGCT) patients with residual masses ≥1cm after chemotherapy. Our hypothesis is that a biomarker guided therapy could reduce overtreatment with pcRPLND in patients with only N. Methods: Forty-eight patients were identified, n = 16 each with T/V/N. Representative regions of T/V/N were microdissected, subsequently total RNA was isolated and miRNA expression was analyzed for miR-371a-3p, 375-3p, and 375-5p using qPCR. ROC analysis was performed for each miRNA and for all combinations in order to determine the discriminatory capacity of V and T vs. N. Results: For the group comparisons of V vs. N miR-371a-3p achieved the highest fold change (FC) of 31.1 (p = 0.023) while for T vs. N miR-375-5p performed best (FC 64,2; p &lt; 0.001). Likewise, the most accurate AUC for V was 0.75 using miR-371a-3p, for T 0.80 using miR-375-5p. Combining the best performing miRNAs for V and T resulted in an AUC of 0.94 with a sensitivity of 93.75, specificity of 93.75, PPV of 96.8 and NPV of 83.3. Conclusions: In pcRPLND tissue samples V and T could be distinguished from necrosis/fibrosis by combining miR-371a-3p and miR-375-5p with great accuracy. This combination of miRNAs might serve as new biomarker in the future, in order to spare miRNA-negative patients from pcRPLND. However, further studies analyzing patient’s serum are needed to confirm the clinical impact of these biomarkers.

Evaluating the discriminatory capacity of miR-371A-3P in the context of pure seminomatous testicular cancer metastases.

424 Background: Conventional serum tumor markers (STMs) are noted to have poor specificity in detecting seminomatous germ cell tumors (SGCTs). Recent publications have suggested that miR-371a-3p may offer improved performance for these cases. However, miR-371a-3p’s performance in detecting pure seminoma at retroperitoneal lymph node dissection (RPLND) has yet to be elucidated in any publicly available study. This lack of data is in part due to the rare occurrence of such cases, and it represents a distinct path for exploring miR-371a-3p’s clinical utility. Methods: Pre-surgical serum samples were collected prospectively from patients prior to RPLND. Within the 15-patient cohort, 6 were assigned as ‘Control’ and 9 were assigned as ‘Seminoma’ based on pathological confirmation of viable GCT. Out of all 15 patients, 10 were chemotherapy naïve prior to RPLND. Post-chemotherapy patients made up 5/6 ‘Control’ patients. MiR-371a-3p levels were quantified by RT-qPCR. Using 2−∆∆Cq method, miR-371a-3p expression was first normalized to the miR-30b-5p reference gene and then calculated relative to the mean target expression across a collection of RNA extracts from healthy male donors’ serum. The Cq values were statistically evaluated to obtain performance characteristics (sensitivity and specificity). Results: Although assay results revealed no significant difference in miR-371a-3p expression between groups, median relative expression in the seminoma group trended higher than the control group (Rq = 3705 and 241 respectively, p = 0.2844). Out of all chemotherapy naïve patients, 9/10 had viable GCT at RPLND whereas 7/10 showed elevated miR-371a-3p. Among the five post-chemotherapy patients, 0/5 had viable GCT at RPLND and 2/5 had elevated miR-371a-3p. The assay provided 7/9 true positive designations in the seminoma group and 4/6 true negatives in the control group. The two false positive results were from post-chemotherapy patients. Of the two optimal thresholds calculated by Youden’s J statistic, the lower threshold of 28.62 (78% sensitivity ad 67% specificity) was selected because it was more in line with previously published data. ROC analysis provided an AUC of 0.704 (95% confidence interval: 0.43-0.98, p = 0.1949). STMs performance was poorer at 67% sensitivity and 17% specificity. Conclusions: Performance metrics for miR-371a-3p exceed those of STMs but were substantially lower than previous reports that evaluated performance in pre-orchiectomy and primary RPLND settings. A possible explanation for this disparity is that miR-371a-3p’s performance is hindered in the post-chemotherapy RPLND setting. However, any strong conclusions from these results are limited by the small sample size which is partly due to the rarity of this clinical scenario. These results suggest that pure seminoma at RPLND may be a key clinical context wherein the miRNA assay may require further refinement.

A0561 - Utility of CT rendering and Radiomic Features analysis in post-chemotherapy retroperitoneal lymph node dissection

A0561 - Utility of CT rendering and Radiomic Features analysis in post-chemotherapy retroperitoneal lymph node dissection