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Tumor markers alpha-fetoprotein, human chorionic gonadotropin, and lactate dehydrogenase assume a key role in the management of testicular germ cell tumors. While alpha-fetoprotein and human chorionic gonadotropin have modest sensitivity and specificity for germ cell tumors, lactate dehydrogenase has weak sensitivity and specificity. We explored the utility of lactate dehydrogenase in identifying relapse among stage I seminomatous and nonseminomatous germ cell tumors on surveillance.Patients with a history of stage I testicular germ cell tumors were identified from a prospectively maintained database at the Princess Margaret Cancer Centre from December 1980 to May 2021 and surveyed according to established institutional algorithm guidelines. The utility of lactate dehydrogenase elevation to independently detect germ cell tumor relapse was examined.Among 1,014 seminoma and 676 nonseminomatous germ cell tumor patients, 176 and 176 patients relapsed with a median time to relapse of 13.6 and 8.9 months, respectively. Imaging alone was the most common mode of relapse detection in 144 and 74 of seminoma and nonseminomatous germ cell tumor patients, respectively. Lactate dehydrogenase was elevated in 49 cases of seminoma and 38 cases of nonseminomatous germ cell tumors at relapse, but was never the sole relapse indicator. Among 350 seminoma and 311 nonseminomatous germ cell tumor patients who never relapsed, 210 and 233, respectively, had at least 1 elevated lactate dehydrogenase value.Lactate dehydrogenase alone did not independently contribute to early relapse detection in stage I seminoma or nonseminomatous germ cell tumor. Elevated lactate dehydrogenase values were documented in a high proportion of nonrelapsing seminoma and nonseminomatous germ cell tumor cases.

Background: Although metastatic germ cell tumor (GCT) is highly curable with initial cisplatin-based chemotherapy (CT), 20–30% of patients relapse. Salvage CT options include conventional (CDCT) and high dose chemotherapy (HDCT), however definitive comparative data remain lacking. We aimed to characterize the contemporary practice patterns of salvage CT across Canada. Methods: We conducted a 30-question online survey for Canadian medical and hematological oncologists with experience in treating GCT, assessing treatment availability, patient selection, and management strategies used for relapsed GCT patients. Results: There were 30 respondents from 18 cancer centers across eight provinces. The most common CDCT regimens used were TIP (64%) and VIP (25%). HDCT was available in 13 centers (70%). The HDCT regimen used included carboplatin and etoposide for two cycles (76% in 7 centers), three cycles (6% in 2 centers), and the TICE protocol (11%, in 2 centers). “Bridging” CDCT was used by 65% of respondents. Post-HDCT treatments considered include surgical resection for residual disease (87.5%), maintenance etoposide (6.3%), and surveillance only (6.3%). Conclusions: HDCT is the most commonly used GCT salvage strategy in Canada. Significant differences exist in the treatment availability, selection, and delivery of HDCT, highlighting the need for standardization of care for patients with relapsed testicular GCT.

Background Men using cholesterol-lowering statin medications have been found to have lower risks of both advanced and fatal prostate cancer in multiple registry-based studies and prospective cohort studies. Statin use has also been associated with longer survival among men already diagnosed with prostate cancer. Mechanisms responsible for purported anti-cancer effects of statins are not well understood but may offer insight into prostate cancer biology. Methods We summarise epidemiological data from studies of statins and prostate cancer and discuss to what extent these findings can be interpreted as causal. Additionally, lipid-mediated and non-lipid-mediated mechanisms that may contribute to potential anti-cancer effects of statins are reviewed. Finally, we consider treatment settings and molecular subgroups of men who might benefit more than others from statin use in terms of prostate cancer-specific outcomes. Results Data from prospective observational studies generally reported a lower risk of fatal prostate cancer among statin users. There is some evidence for serum cholesterol-lowering as an indirect mechanism linking statins with advanced and fatal prostate cancer. Window-of-opportunity clinical trials show measurable levels of statins in prostate tissue highlighting potential for direct effects, whilst observational data suggest possible statin-driven modulation of prostate microenvironment inflammation. Additionally, emerging data from registry studies support a potential role for statins within the context of androgen deprivation therapy and anti-androgen treatment. Conclusion Prospective and registry-based studies support a lower risk of advanced and fatal prostate cancer in statin users relative to non-users, as well as better outcomes among prostate cancer patients. The few randomised-controlled trials conducted so far have short follow-up, lack identified molecular subgroups, and do not provide additional support for the observational results. Consequently, additional evidence is required to determine which men may experience greatest benefit in terms of prostate cancer-specific outcomes and how statin effects may vary according to molecular tumour characteristics.

Supplementary data from Clinical and Genome-wide Analysis of Cisplatin-induced Tinnitus Implicates Novel Ototoxic Mechanisms

Demographic features and clinical characteristics of 511 genetically European male germ cell tumor (GCT) survivors at the time of audiometry.

The design of the study, GWAS results, clinical characteristics are included in the supplemental data.

Robustness of the enrichment of top GWAS SNPs in Mendelian deafness genes.

Purpose:Cisplatin, a commonly used chemotherapeutic, results in tinnitus, the phantom perception of sound. Our purpose was to identify the clinical and genetic determinants of tinnitus among testicular cancer survivors (TCS) following cisplatin-based chemotherapy.Experimental Design:TCS (n = 762) were dichotomized to cases (moderate/severe tinnitus; n = 154) and controls (none; n = 608). Logistic regression was used to evaluate associations with comorbidities and SNP dosages in genome-wide association study (GWAS) following quality control and imputation (covariates: age, noise exposure, cisplatin dose, genetic principal components). Pathway over-representation tests and functional studies in mouse auditory cells were performed.Results:Cisplatin-induced tinnitus (CisIT) significantly associated with age at diagnosis (P = 0.007) and cumulative cisplatin dose (P = 0.007). CisIT prevalence was not significantly greater in 400 mg/m2-treated TCS compared with 300 (P = 0.41), but doses >400 mg/m2 (median 580, range 402–828) increased risk by 2.61-fold (P < 0.0001). CisIT cases had worse hearing at each frequency (0.25–12 kHz, P < 0.0001), and reported more vertigo (OR = 6.47; P < 0.0001) and problems hearing in a crowd (OR = 8.22; P < 0.0001) than controls. Cases reported poorer health (P < 0.0001) and greater psychotropic medication use (OR = 2.4; P = 0.003). GWAS suggested a variant near OTOS (rs7606353, P = 2 × 10−6) and OTOS eQTLs were significantly enriched independently of that SNP (P = 0.018). OTOS overexpression in HEI-OC1, a mouse auditory cell line, resulted in resistance to cisplatin-induced cytotoxicity. Pathway analysis implicated potassium ion transport (q = 0.007).Conclusions:CisIT associated with several neuro-otological symptoms, increased use of psychotropic medication, and poorer health. OTOS, expressed in the cochlear lateral wall, was implicated as protective. Future studies should investigate otoprotective targets in supporting cochlear cells.

Purpose:Serum platinum is measurable for years after completion of cisplatin-based chemotherapy (CBC). We report the largest investigation of serum platinum levels to date of 1,010 testicular cancer survivors (TCS) assessed 1–35 years after CBC and evaluate genetic contributions to these levels.Experimental Design:Eligible TCS given 300 or 400 (±15) mg/m2 cisplatin underwent extensive audiometric testing, clinical examination, completed questionnaires, and had crude serum platinum levels measured. Associations between serum platinum and various risk factors and toxicities were assessed after fitting a biexponential model adjusted for follow-up time and cumulative cisplatin dose. A genome-wide association study (GWAS) was performed using the serum platinum residuals of the dose and time-adjusted model.Results:Serum platinum levels exceeded the reference range for approximately 31 years, with a strong inverse relationship with creatinine clearance at follow-up (age-adjusted P = 2.13 × 10−3). We observed a significant, positive association between residual platinum values and luteinizing hormone (age-adjusted P = 6.58 × 10−3). Patients with high residual platinum levels experienced greater Raynaud phenomenon than those with medium or low levels (age-adjusted ORhigh/low = 1.46; P = 0.04), as well as a higher likelihood of developing tinnitus (age-adjusted ORhigh/low = 1.68, P = 0.07). GWAS identified one single-nucleotide polymorphism (SNP) meeting genome-wide significance, rs1377817 (P = 4.6 × 10−8, a SNP intronic to MYH14).Conclusions:This study indicates that residual platinum values are correlated with several cisplatin-related toxicities. One genetic variant is associated with these levels.

Purpose: Cisplatin is one of the most commonly used chemotherapy drugs worldwide and one of the most ototoxic. We sought to identify genetic variants that modulate cisplatin-associated ototoxicity (CAO).Experimental Design: We performed a genome-wide association study (GWAS) of CAO using quantitative audiometry (4–12 kHz) in 511 testicular cancer survivors of European genetic ancestry. We performed polygenic modeling and functional analyses using a variety of publicly available databases. We used an electronic health record cohort to replicate our top mechanistic finding.Results: One SNP, rs62283056, in the first intron of Mendelian deafness gene WFS1 (wolframin ER transmembrane glycoprotein) and an expression quantitative trait locus (eQTL) for WFS1 met genome-wide significance for association with CAO (P = 1.4 × 10−8). A significant interaction between cumulative cisplatin dose and rs62283056 genotype was evident, indicating that higher cisplatin doses exacerbate hearing loss in patients with the minor allele (P = 0.035). The association between decreased WFS1 expression and hearing loss was replicated in an independent BioVU cohort (n = 18,620 patients, Bonferroni adjusted P < 0.05). Beyond this top signal, we show CAO is a polygenic trait and that SNPs in and near 84 known Mendelian deafness genes are significantly enriched for low P values in the GWAS (P = 0.048).Conclusions: We show for the first time the role of WFS1 in CAO and document a statistically significant interaction between increasing cumulative cisplatin dose and rs62283056 genotype. Our clinical translational results demonstrate that pretherapy patient genotyping to minimize ototoxicity could be useful when deciding between cisplatin-based chemotherapy regimens of comparable efficacy with different cumulative doses. Clin Cancer Res; 23(13); 3325–33. ©2016 AACR.

Purpose:Cisplatin is a first-line chemotherapeutic for many cancers, but causes neurotoxicity including hearing loss, tinnitus, and peripheral sensory neuropathy. However, no study has comprehensively characterized risk factors for developing multiple (>1) severe neurotoxicities.Experimental Design:The relationship between multiple severe neurotoxicities and age, cumulative cisplatin dose, medical history, and lifestyle/behavioral factors was evaluated in 300 cisplatin-treated testicular cancer survivors using logistic regression. Case–control genome-wide association study (GWAS; cases, n = 104 and controls, n = 196) was also performed.Results:Age at clinical examination (P = 6.4 × 10−16) and cumulative cisplatin dose (P = 5.4 × 10−4) were positively associated with multiple severe neurotoxicity risk, as were high serum platinum levels (P = 0.02), tobacco use (ever smoker, P = 0.001 and current smoker, P = 0.002), and hypertension (P = 0.01) after adjustment for age and cumulative cisplatin dose. Individuals with multiple severe neurotoxicities were more likely to experience dizziness/vertigo (P = 0.01), Raynaud phenomenon (P = 3.7 × 10−9), and symptoms consistent with peripheral motor neuropathy (P = 4.3 × 10−14) after age and dose adjustment. These patients also reported poorer overall health (P = 2.7 × 10−5) and a greater use of psychotropic medications (P = 0.06). GWAS identified no genome-wide significant SNPs. Gene-based association analysis identified RGS17 (P = 3.9 × 10−5) and FAM20C (P = 5.5 × 10−5) as near genome-wide significant. Decreased FAM20C expression was associated with increased cisplatin sensitivity in tumor cell lines.Conclusions:Certain survivors are more susceptible to cisplatin-induced neurotoxicity, markedly increasing likelihood of developing numerous neuro-otological symptoms that affect quality of life. Genome-wide analysis identified genetic variation in FAM20C as a potentially important risk factor.

Purpose: Our purpose was to characterize the clinical influences, genetic risk factors, and gene mechanisms contributing to persistent cisplatin-induced peripheral neuropathy (CisIPN) in testicular cancer survivors (TCSs).Experimental Design: TCS given cisplatin-based therapy completed the validated EORTC QLQ-CIPN20 questionnaire. An ordinal CisIPN phenotype was derived, and associations with age, smoking, excess drinking, hypertension, body mass index, diabetes, hypercholesterolemia, cumulative cisplatin dose, and self-reported health were examined for 680 TCS. Genotyping was performed on the Illumina HumanOmniExpressExome chip. Following quality control and imputation, 5.1 million SNPs in 680 genetically European TCS formed the input set. GWAS and PrediXcan were used to identify genetic variation and genetically determined gene expression traits, respectively, contributing to CisIPN. We evaluated two independent datasets for replication: Vanderbilt's electronic health database (BioVU) and the CALGB 90401 trial.Results: Eight sensory items formed a subscale with good internal consistency (Cronbach α = 0.88). Variables significantly associated with CisIPN included age at diagnosis (OR per year, 1.06; P = 2 × 10−9), smoking (OR, 1.54; P = 0.004), excess drinking (OR, 1.83; P = 0.007), and hypertension (OR, 1.61; P = 0.03). CisIPN was correlated with lower self-reported health (OR, 0.56; P = 2.6 × 10−9) and weight gain adjusted for years since treatment (OR per Δkg/m2, 1.05; P = 0.004). PrediXcan identified lower expressions of MIDN and RPRD1B, and higher THEM5 expression as associated with CisIPN (P value for each < 5 × 10−6) with replication of RPRD1B meeting significance criteria (Fisher combined P = 0.0089).Conclusions: CisIPN is associated with age, modifiable risk factors, and genetically determined expression level of RPRD1B. Further study of implicated genes could elucidate the pathophysiologic underpinnings of CisIPN. Clin Cancer Res; 23(19); 5757–68. ©2017 AACR.

Supplementary Figures and Tables for Clinical and Genome Wide Analysis of Cisplatin-Induced Peripheral Neuropathy in Survivors of Adult-Onset Cancer Figure S1. Diagram of Data Collection Pipeline. Table S1. EORTC-CIPN20 questionnaire. Figure S2. Flow diagram of GWAS Quality Control Pipeline. Table S2. Additional Diagnosis and Treatment Characteristics of TCS cohort. Figure S3. Response frequencies for the EORTC-CIPN20 questionnaire from 680 patients. Figure S4. Principal Component Analysis (PCA) of EORTC-CIPN20 items. Figure S5. SNP-level GWAS. Table S3. Top 100 GWAS Results (p < 2.25 x 10-5) Table S4. Review of candidate gene studies implicating SNPs in cisplatin-induced neuropathy and their replication in the TCS study. Table S5. Review of previous GWAS of CIPN implicating SNPs and their replication in the TCS study. Table S6. Top PrediXcan results (P < 0.001).

Purpose:Randomized trials from Africa demonstrate that circumcision reduces the risk of acquiring human immunodeficiency virus (HIV) among males. However, few studies have examined this association...

Background Testicular cancer survivors often have impaired gonadal function possibly related to chemotherapy. Platinum is a heavy metal that can be detected at low levels in serum many years after treatment, it is not known whether platinum also persists in semen and if platinum persistence in semen is associated with impaired fertility. Methods Adult cisplatin‐treated testicular cancer survivors were enrolled. High‐Performance Liquid Chromatography‐tandem mass spectrometry was used to measure semen and serum platinum levels. Semen quality and DNA Fragmentation Index (DFI) were assessed. Results From 11/2017 to 12/2019, 38 patients (median age 32 years; range: 19–52) were enrolled. Median cumulative cisplatin dose was 301 mg/m2 (range: 274–404). Platinum levels were higher in semen than in blood (p = 0.03). Semen platinum levels were not significantly associated with time from last cisplatin dosing (r = −0.34; p = 0.09) nor cumulative dose (r = −0.10, p = 0.63). Sperm concentration was correlated with time from last cisplatin dosing (r = 0.58, p

Background The hypothesis of a curable oligometastatic prostate cancer (PCa) state remains to be clinically-proven. Conventional imaging often fails to localize early recurrences, hampering the potential for radical approaches. Objective We hypothesize that prostate-specific membrane antigen (PSMA)-targeted PET-MR/CT allows for earlier detection and localization of oligorecurrent-PCa, unveiling a molecularly-defined state amenable to curative-intent metastasis-directed treatment (MDT). Design/setting/participants Single-institution single-arm phase-two study. Patients with rising PSA (0.4-3.0 ng/mL) after maximal local therapy (radical prostatectomy and post-operative radiotherapy), negative conventional staging, and no prior salvage hormonal therapy (HT) were eligible. Interventions All patients underwent [18F]DCFPyL PET-MR/CT. Patients with molecularly-defined oligorecurrent-PCa had MDT (stereotactic ablative body radiotherapy [SABR] or surgery) without HT. Outcome measurements/statistical analysis Primary endpoint was biochemical response (complete, i.e. biochemical ‘no evidence of disease’ [bNED], or partial response [100% or ≥50% PSA decline from baseline, respectively]) after MDT. Simon’s two-stage design was employed (null and alternate hypotheses 20% response rate, respectively), with α and β of 0.1. Results Seventy-two patients were enrolled (May/2017-July/2019). Thirty-eight (53%) had PSMA-detected oligorecurrent-PCa amenable for MDT. Thirty-seven (51%) agreed to MDT: 10 and 27 underwent surgery and SABR, respectively. Median follow-up was 15.9 months (IQR 9.8-19.1). Of patients receiving MDT, the overall response rate was 60%, including 22% rendered bNED. One (2.7%) grade 3 toxicity (intra-operative ureteric injury) was observed. Conclusions PSMA-defined oligorecurrent-PCa can be rendered bNED, a necessary step towards cure, in 1 of 5 patients receiving MDT alone. Randomized trials are justified to determine if MDT +/− systemic agents can expand the curative therapeutic armamentarium for PCa. Patient summary We studied men treated for prostate cancer with rising PSA. We found PSMA imaging detected recurrent cancer in three-quarters of patients, and targeted treatment to these areas significantly decreased PSA in half of patients.

Despite excellent outcomes with modern multidisciplinary care, clinicians caring for patients with testicular germ cell tumour (TGCTs) face clinical dilemmas across the spectrum of disease. Wrong treatment choices can lead to undertreatment or overtreatment of these young men. Unfortunately the currently available biomarkers alpha-fetoprotein and human chorionic gonadotropin, lack sufficient sensitivity and specificity to reliably aid in these clinical dilemmas. Thus, a sensitive and specific biomarker is desperately needed. Serum or plasma miRNA, in particular, miR-371a-3p, has shown great promise in discriminating the presence of TGCT and may represent a breakthrough for this disease. In this review, we discuss the potential role of miRNA across clinical states of TGCTs. We review their discovery, methods of assay, limitations and future potential.

Importance: Statins appear to lower serum prostate-specific antigen (PSA) and improve prostate cancer (PCa) outcomes through cholesterol-dependent and independent mechanisms. While dietary modifications have an established role in serum cholesterol reduction, whether diet-driven cholesterol reductions yield similar PCa benefits to that observed with statins is unclear. We aimed to study the effect of diet-driven cholesterol reduction on serum PSA and estimated-PCa risk. Methods: A total of 291 men from six published randomized controlled trials of dietary interventions were included. Men were aged ≥40 years, free of PCa, and had baseline PSA

The role of retroperitoneal lymph node dissection (RPLND) in testicular cancer is well established in both the primary and post-chemotherapy setting. The aim of this study was to report our 2 years oncological outcomes of robotic RPLND. A retrospective review was performed of all patients undergoing robotic RPLND by a single surgeon at Princess Margaret Cancer Centre. Demographic, perioperative, and oncologic data were analyzed using descriptive statistics. Between September 2014 and June 2020, 141 patients underwent an RPLND [33 (23.4%) were primary, 108 (76.6%) were post-chemotherapy]. 27 (19.1%) patients underwent a robotic bilateral template nerve-sparing RPLND. RPLND indication was primary (i.e. pre-chemotherapy) in 18 (66.7%), and post-chemotherapy in 9 (33.3%) patients. Stage at RPLND was 2A (n = 15, 55.6%), 2B (n = 9, 33.3%), 2C (n = 1, 3.7%) and 3 (n = 2, 7.4%). Median OR time (incision to closure) was 525 min and blood loss was 200 ml. Nerve sparing was performed in all but one case. Six (22.2%) adjuvant procedures were performed including two (7.4%) vascular repairs. Median length of stay was 2 days. Viable tumor was detected in 17 (63%) and teratoma in 9 (33.3%). Median follow-up was 31.3 months. No adjuvant chemotherapy was given. Three patients (11.1%) relapsed: 2 out-of-field and 1 with both in-field and out-of-field disease. Robotic RPLND can be performed safely. Long-term follow-up of series such as ours, enriched with patients with viable disease and/or teratoma, and not treated with adjuvant chemotherapy is required to ensure oncological outcomes are comparable to the open approach.

Traditionally, intervention was recommended for angiomyolipomas (AMLs)4 cm due to the risk of catastrophic hemorrhage.To delineate the natural history of AMLs, including growth rates and need for intervention.A retrospective review was performed of an AML series from 2002 to 2013, which have been followed prospectively until 2018. We defined lesion size by maximum axial diameter and categorized lesion size at baseline.A total of 458 patients with 593 AMLs, with a median follow-up of 65.2 mo, were identified. At diagnosis, 534 (90.1%) lesions were ≤4 cm. Forty-three interventions were required for 34 (5.7%) AMLs: 30 were treated with embolization, seven surgery, two with radiofrequency ablation (RFA), three with mammalian target of rapamycin (mTOR) inhibitors, and one with nivolumab when epithelioid AML was confirmed. The median size at intervention was 4.9 cm (range 1.1-29 cm).Most (94%) of the lesions grew slowly (growth rate of0.25 cm/yr) during the period of observation. The number of AMLs4 cm needed to treat (NNT) prophylactically to prevent one emergent bleed would have been 136 or that to prevent one blood transfusion would have been 205. The NNT (4 cm) prophylactically to prevent one elective intervention would have been 82. On multivariate analysis, there were significant differences in intervention rates based on tuberous sclerosis complex, size at presentation, and clinical presentation.This large single-institution updated series of renal AMLs demonstrates that early intervention is not required, regardless of the traditional 4 cm cut-off. The vast majority of AMLs are indolent lesions that are predominantly asymptomatic and slow growing. Follow-up should be no more frequent than annually.The majority of angiomyolipomas (AMLs) are indolent, slow-growing lesions that do not require intervention, regardless of size at presentation. We suggest that surveillance is a safe initial approach for patients presenting with AMLs.

145 Background: Studies are conflicting regarding the association between statin use and biochemical recurrence after surgery or radiotherapy for localized prostate cancer. A handful of studies have observed favorable associations between statins and prostate cancer-specific (PCSM) and overall mortality (OS), however, this has not been studied in an advanced disease cohort nor has the combination of statins and androgen deprivation therapy (ADT) been specifically studied. Methods: Patients with PSA >3 ng/mL after >1 year following primary or salvage radiotherapy (RT) were enrolled in a randomized trial of intermittent (IAD) vs. continuous (CAD) ADT (NCT00003653). Statin use at baseline and during the study was captured and modeled as a time-dependent covariate. The primary end-point was OS. Models were adjusted for age, time from RT to ADT and PSA at baseline. As results were nearly identical between the IAD and CAD arms they are reported as aggregates unless otherwise indicated. Results: Of 1,364 patients enrolled, 585 (43%) reported statin use during the study. Statin users were younger (72.7 vs. 73.8, p=0.001) and less likely to have PSA >15 (20 vs. 25%, p=0.04). Median follow-up was 6.9 years and 524 deaths occurred. Statin use was associated with a reduced risk of overall death (HR: 0.64; 95% C.I. 0.53 – 0.78, p

BACKGROUND The therapeutic role of extended (ePLND) versus nonextended pelvic lymph node dissection (nePLND) to remove occult micrometastases in men undergoing radical prostatectomy for localized prostate cancer (PC) is conflicting. Therefore, our aim was to quantify the direct effect of ePLND versus nePLND (removal of occult micrometastases), which is not mediated through the detection of nodal disease and potential adjuvant therapy (indirect effect). METHODS Retrospective, bi-center cohort study of consecutive patients undergoing radical prostatectomy and PLND for PC (January 2006 and December 2016). Patients were followed until April 2018 for the occurrence of either biochemical recurrence or secondary therapy (composite outcome). ePLND was compared to nePLND by unweighted and weighted survival analysis (total effect) as well as by causal mediation analysis (direct and indirect effect). RESULTS Positive nodal disease was detected in 71 (7%) out of 1008 patients undergoing radical prostatectomy and PLND for PC (ePLND: 368 [36.5%]; nePLND: 640 [63.5%]). Survival analysis demonstrated results in favor of ePLND (unweighted hazard ratio: 0.77 [95% confidence interval: 0.59-1.01], p = .056; weighted hazard ratio: 0.75 [0.56-0.99], p = .044). The causal mediation analysis confirmed the total effect of 0.77 (0.71-0.82). After disentangling this total effect into an indirect effect (via detection of nodal disease and potential adjuvant therapy) and a direct effect (via removal of occult micrometastases), we identified an even more protective direct effect of 0.69 (0.63-0.75). CONCLUSIONS Our results not only indicate the utility of ePLND but also that its impact is not restricted to a staging benefit and probably involves a therapeutic benefit mediated through the removal of occult micrometastases.