Prostate cancer at the peripheral end of a prostate biopsy specimen as assessed by a novel marking technique may indicate increased risk of locally advanced disease.

The objective of this study was to test a novel technique of processing a prostate biopsy (PB) specimen by marking its peripheral end (PE) as a predictive tool for locally advanced prostate cancer (PC) or margin-positive resection (R1) after radical prostatectomy (RP). Prospective evaluation of a consecutive cohort of men who underwent PB and subsequent RP was carried out. Transrectal ultrasound-guided 10-20 core PB was performed according to a standardized protocol. Each biopsy core was inked at the PE and classified as PE positive or negative. The study cohort comprised 100 men with a mean age of 62.3 years (41-75 years). Overall, PE-positive cores were found in 71 men, postoperative tumour (pT)3/pT4 stages were diagnosed in 33 men and R1 status in 45 men after RP. In univariate analysis, the presence of at least one PE-positive core was correlated to an increased risk for pT3/pT4 stage (relative risk (RR): 3.15; 95% confidence interval (95% CI): 1.1-9.9; P = 0.03) and R1 status (RR: 2.9; 95% CI: 1.1-7.5; P = 0.03). In multivariate analysis including Gleason score, total number of positive cores, PE positivity and PSA, PE positivity was correlated to pT3/pT4 stage (P = 0.04). In conclusion, PC at the PE of a PB specimen predicts non-organ-confined tumour stage in subsequent prostatectomy. This simple, new technique may contribute to increasing the accuracy of risk stratification for curative treatment of PC.

Cryopreservation technique: comparison of Test yolk buffer versus SpermCryo and vapour versus computerised freezing.

Semen cryopreservation offers the possibility to maintain fertility over a long time period e.g. for male cancer patients. Although its use expands worldwide, there is no established method that can be referred to as an entrenched standard for routine laboratory use. Cryodamage is still a general phenomenon and the success of cryopreservation is affected on one side by the cryoprotective agent and on the other side by the technique of freezing. In this methodological study, we compared the newly offered SpermCryo (SC) with the standard used cryoprotectant Test yolk buffer (TYB). We could show that TYB is superior to SC. In addition, we compared the two mainly used techniques for cryopreservation: computerised slow-stage freezing versus nitrogen vapour fast freezing. Regarding the sperm post-thaw motility and viability, no significant difference was found between these two methods. In conclusion, TYB can be recommended as a cryomedium of first choice and the appropriate freezing technique can be selected according to the local facilities of the institution.

Mitochondrial DNA mutations in renal cell carcinomas revealed no general impact on energy metabolism.

Previously, renal cell carcinoma tissues were reported to display a marked reduction of components of the respiratory chain. To elucidate a possible relationship between tumourigenesis and alterations of oxidative phosphorylation, we screened for mutations of the mitochondrial DNA (mtDNA) in renal carcinoma tissues and patient-matched normal kidney cortex. Seven of the 15 samples investigated revealed at least one somatic heteroplasmic mutation as determined by denaturating HPLC analysis (DHPLC). No homoplasmic somatic mutations were observed. Actually, half of the mutations presented a level of heteroplasmy below 25%, which could be easily overlooked by automated sequence analysis. The somatic mutations included four known D-loop mutations, four so far unreported mutations in ribosomal genes, one synonymous change in the ND4 gene and four nonsynonymous base changes in the ND2, COI, ND5 and ND4L genes. One renal cell carcinoma tissue showed a somatic A3243G mutation, which is a known frequent cause of MELAS syndrome (mitochondrial encephalomyopathy, lactic acidosis, stroke-like episode) and specific compensatory alterations of enzyme activities of the respiratory chain in the tumour tissue. No difference between histopathology and clinical progression compared to the other tumour tissues was observed. In conclusion, the low abundance as well as the frequently observed low level of heteroplasmy of somatic mtDNA mutations indicates that the decreased aerobic energy capacity in tumour tissue seems to be mediated by a general nuclear regulated mechanism.

Prostate biopsy outcome using 29 mm cutting length.

OBJECTIVES: The aim of the study was to compare the prostate biopsy outcome by using either standard or extended cutting length of the needles. MATERIAL AND METHODS: A total of 74 consecutive prostates from radical prostatectomy were used. Two sextant biopsies were performed ex vivo. We developed a precise simulation of a transrectal biopsy procedure using ultrasound for guiding the needle. In the first set of biopsies an 18-gauge tru cut needle with 19 mm cutting length, powered by a automatic biopsy gun was used. In the second set a single use gun with an 18-gauge end-cutting needle and 29 mm cutting length was used. RESULTS: In the set of sextant biopsies using 19 mm cutting length 49 (66%) carcinomas were found. In the set of sextant biopsies using 29 mm cutting length 58 (78%) of the tumors were detected. 24 (32%) prostates showed tumor in the transition zones, but there was no transition-zone-only cancer in this study. Nevertheless taking longer cores led to an improvement in prostate cancer detection of 18%. CONCLUSIONS: In this ex vivo setting the use of 29 mm cutting length for prostate biopsy led to an significant improvement in cancer detection. As we found the end-cutting needle not suitable for use in the patient, these results support the idea to develop a longer tru cut needle and corresponding gun for further clinical investigations.

Fluorescence diagnosis: a novel method to guide radical inguinal lymph node dissection in penile cancer.

In penile cancer there is still a diagnostic dilemma between over treatment of lymph node-negative patients and the missing of occult metastases by watchful waiting. In the current study the value of fluorescence diagnosis during radical inguinal lymph node dissection was evaluated. Five patients with penile cancer were elected to undergo groin dissection. All patients received 5-aminolevulinic acid (5-ALA) orally before the operation for fluorescence diagnosis. Intraoperatively, fluorescence detection of the lymph nodes was performed by visual detection and spectroscopy. Two of the five patients had positive inguinal lymph nodes. Fluorescence in tumor-bearing tissue was detectable in the exposed lymph nodes. Protoporphyrin IX (PPIX) is accumulated in tumor-positive lymph nodes, making fluorescence diagnosis in penile cancer possible. More studies with higher patient numbers are necessary to evaluate optimal dosage and excitation conditions to detect tumor-bearing nodes in vivo.

Acrosome reaction in Chlamydia-positive and negative patients.

Chlamydia trachomatis infections might have a detrimental effect on various sperm functions. Data concerning the effect of C. trachomatis on the capacitation activity of sperms are lacking. The study was undertaken to evaluate whether chlamydial infection influences acromsome reaction (AR). Three groups of men were investigated for ARs -Chlamydia negative (n = 46) and positive (n = 30) patients, and healthy men (n = 53) undergoing vasectomy. The fluorescence technique for the evaluation of AR was applied. The normal range for the induction of AR was assumed DeltaAR > 12.5% for this technique. Seminal plasma was examined for IgA antibodies against C. trachomatis. There was a significant difference in AR between healthy volunteers, Chlamydia-negative and Chlamydia-positive patients. DeltaARs were 15.8 +/- 1.6% in healthy volunteers versus 12.15 +/- 2.4% in Chlamydia-negative and 9.08 +/- 1.8% in Chlamydia-postive patients, respectively (P < 0.05). Significant elevated titres of C. trachomatis-specific IgA in seminal plasma showed a negative correlation with the AR of spermatozoa. AR seems to be a valuable marker, especially in couples with idiopathic infertility.

One 10-core prostate biopsy is superior to two sets of sextant prostate biopsies.

OBJECTIVES: To compare the efficiency of different transrectal ultrasonography (TRUS)-guided prostate biopsy techniques for detecting prostate cancer. MATERIALS AND METHODS: In all, 81 prostates from radical prostatectomy were used and two consecutive sets of sextant biopsies and one 10-core biopsy taken in each specimen. The 10-core biopsy consisted of a sextant biopsy and four cores from the far lateral areas of the prostate. To simulate a transrectal biopsy procedure, all biopsies were taken under TRUS guidance. RESULTS: In the first set of sextant biopsies 44 prostate cancers (54%) were detected and in the second set 51 (63%). Combining both sets of sextant biopsies 57 (70%) of the carcinomas were detected. One set of 10-core biopsies detected 66 (82%) of all prostate cancers. Overall, with the 10-core biopsies 16% more prostate tumours were diagnosed than with two consecutive sets of sextant biopsies. To find the same number of prostate cancers as with the 10-core technique, 14% of patients undergoing sextant biopsy would require a second set and 11% at least a third set of biopsies. CONCLUSIONS: The 10-core prostate biopsy technique is superior to the commonly used sextant technique and could spare patients unnecessary repeated biopsy. Even after including a second set of sextant biopsies, the total detection rate with these 12 biopsies was inferior to the 10-core technique.

[Urological emergencies]. / Urologische Notfälle.

Urological emergencies that require specialist treatment include testicular torsion, gross hematuria, urogenital injuries and acute flank pain. After initial symptoms-adapted therapy, patients should be transferred immediately to an urological department for imaging (e.g. ultrasound, IVP, CT) and further specific examinations (e.g.blood tests, urine analysis, microbiology). Acute lower abdominal and scrotal pain in young men may be symptomatic of testicular torsion, which requires immediate urological surgery. Gross hematuria is usually not a life-threatening emergency. Nevertheless, urogenital tumor has to be ruled out by an urologist. Patients with urogenital injuries are triaged into surgical and non-surgical treatments. Differential diagnosis of acute flank pain falls into several medical fields. After initial symptom-related therapy, further diagnostic procedures have to be performed. Septic presentation may be symptomatic of infectious hydronephrosis which requires immediate urological intervention.

Prostate cancer detection with two sets of ten-core compared with two sets of sextant biopsies.

OBJECTIVES: To compare the cancer detection of two consecutive sets of prostate biopsies using either the sextant or the 10-core technique. METHODS: Ninety-one specimens after radical prostatectomy were used and consecutive sets of biopsies were performed ex vivo on each prostate after the operation. The sextant biopsies were taken paramedian and midlobular, three per side. For the 10-core biopsies, two cores per side from the lateral areas of the prostate were added. We developed a realistic simulation of a transrectal sonographic biopsy procedure. RESULTS: In the first set of sextant biopsies, 55 prostate cancers (60.4%) were found; in the second set, 13 additional tumors were detected. Two consecutive sets of sextant biopsies thus found 68 tumors (74.7%). Using one 10-core biopsy led to cancer detection in 71 of the prostates (78%). A second 10-core biopsy revealed 11 additional tumors, for a cumulative cancer detection rate of 90.1%. We found that 9 (9.9%) of all the cancers were not diagnosed by two consecutive sets of this extended biopsy protocol. Eight of these cancers (88.9%) were clinically significant as determined by a tumor volume larger than 0.5 cm(3). CONCLUSIONS: Although the 10-core protocol is far superior to the commonly used sextant protocol, a significant number of prostate cancers can still be found on a second similar set of prostate biopsies. Even after two consecutive sets of 10-core biopsies, approximately 10% of the prostate tumors remained undetected. Most of them were clinically significant.

Autofluorescence imaging to optimize 5-ALA-induced fluorescence endoscopy of bladder carcinoma.

OBJECTIVES: To design an optical system for detecting autofluorescence (AF) of bladder tumors and to determine the success of reducing the false-positive rate of 5-aminolevulinic acid-induced fluorescence endoscopy (AFE). AFE provides significantly higher sensitivity in detecting and localizing bladder carcinoma compared with white light endoscopy. The specificity of AFE is equivalent to white light endoscopy, mostly because of the false-positive fluorescence of chronic cystitis lesions. Laser-induced spectral autofluorescence detection is also an efficient method in the diagnosis of bladder carcinoma. METHODS: Bladder tissue was excited to AF using the D-Light (375 to 440 nm) after regular AFE with detection of fluorescence-positive areas. The optical image was produced using a special RGB camera. Biopsies were taken from AFE-positive areas, the peritumoral edges, and normal bladder mucosa. The AF images of the suspicious areas were compared with the AFE images and the histologic results. RESULTS: A total of 43 biopsies were histologically examined (24 benign and 19 neoplastic). AF imaging showed contrast differences between papillary tumors, flat lesions, and normal mucosa. The combination of AFE with AF raised the specificity of AFE alone from 67% to 88%. CONCLUSIONS: AF imaging is possible. The value of the method in reducing the false-positive rate of the highly sensitive AFE needs to be validated with higher numbers. The combination of AF with AFE had a 20% higher specificity than AFE alone in our study.

Nucleosomes in serum as a marker for cell death.

The concentration of nucleosomes is elevated in blood of patients with diseases which are associated with enhanced cell death. In order to detect these circulating nucleosomes, we used the Cell Death Detection-ELISAplus (CDDE) from Roche Diagnostics (Mannheim, Germany) (details at http:\\biochem.roche.com). For its application in liquid materials we performed various modifications: we introduced a standard curve with nucleosome-rich material, which enabled direct quantification and improved comparability of the values within (CVintraassay:3.0-4.11%) and between several runs (CVinterassay:8.6-13.5%), and tested the analytical specificity of the ELISA. Because of the fast elimination of nucleosomes from circulation and their limited stability, we compared plasma and serum matrix and investigated in detail the pre-analytical handling of serum samples which can considerably influence the test results. Careless venipuncture producing hemolysis, delayed centrifugation and bacterial contamination of the blood samples led to false-positive results; delayed stabilization with EDTA and insufficient storage conditions resulted in false-negative values. At temperatures of -20 degrees C, serum samples which were treated with 10 mM EDTA were stable for at least 6 months. In order to avoid possible interfering factors, we recommend a schedule for the pre-analytical handling of the samples. As the first stage, the possible clinical application was investigated in the sera of 310 persons. Patients with solid tumors (n=220; mean=361 Arbitrary Units (AU)) had considerably higher values than healthy persons (n=50; mean=30 AU; p=0.0001) and patients with inflammatory diseases (n=40; mean= 296 AU; p=0.096). Within the group of patients with tumors, those in advanced stages (UICC 4) showed significantly higher values than those in early stages (UICC 1-3) (p=0.0004).

Clinical outcome of microsurgical subinguinal varicocelectomy in infertile men.

The present study assesses the clinical outcome of microsurgical subinguinal varicocelectomy in infertile men, especially with regard to sperm count, motility and fertility. Between June 1990 and October 1998, 272 patients had subinguinal microsurgical varicocelectomy operations for clinical varicoceles, and their long-term results were assessed. In nearly all the patients there was a significant improvement in sperm count and sperm motility after 3 and 6 months. Very few complications arose from this procedure. We concluded that microsurgical subinguinal varicocelectomy is an effective treatment for clinical varicoceles in infertile men. The significant improvement in the quality of spermatozoa, the low complication rates and the remarkably high pregnancy rates make this a valuable alternative to in vitro reproduction techniques.

Nucleosomes in serum of patients with benign and malignant diseases.

High quantities of mono- and oligonucleosomes circulate in the blood of patients with malignant tumors. For their direct quantification in serum, we modified the Cell Death Detection(plus)-ELISA for its application in liquid materials. We examined sera samples from 590 persons, including 418 patients with malignant tumors, 109 patients with benign diseases and 63 healthy persons. We also observed the kinetics of the concentration of nucleosomes in serum samples from 20 patients undergoing chemotherapy and from 16 patients undergoing radiotherapy. Sera of patients with malignant tumors contained considerably higher concentrations of nucleosomes (mean = 350 arbitrary units [AU], median = 190 AU) compared with those of healthy persons (mean = 36 AU, median = 24 AU; p = 0.0001) and patients with benign diseases (mean = 264 AU, median = 146 AU; p = 0.072). Concerning the follow-up investigations, the concentration of nucleosomes in serum increased 24-72 hr after the first application of chemotherapy and 6-24 hr after the start of radiotherapy. A subsequent decrease was often correlated with regression of the tumor. In patients undergoing chemotherapy, an increase in the baseline values of circulating nucleosomes >50%, which were determined before each new therapeutic cycle, was correlated with progression of disease; all patients with disease regression showed a decrease >50% of the baseline values. In patients undergoing radiotherapy, an early decrease of the nucleosomal concentration (< or = 1 day after the initial peak during therapy) to low minimum levels (< or = 100 AU) correlated with good clinical outcome; a late decrease (>1 day) to higher minimum levels (>100 AU) was associated with a worse clinical outcome. Thus, the concentration of nucleosomes in serum might be a useful tool for monitoring the biochemical response during antitumor therapy, especially for the early estimation of therapeutic efficacy.

Nuclear mitotic apparatus protein (NuMA) in benign and malignant diseases.

Nuclear mitotic apparatus protein (NuMA) is a 239 kDa internal nuclear matrix protein described to be elevated in cancer patients, especially in colorectal carcinoma and early colorectal cancers. We tested the significance of NuMA as tumour marker in colorectal cancer and also the sensitivity/specificity profile in general. Therefore, we investigated in a retrospective clinical study 507 sera from patients suffering from solid tumours, with the main emphasis on colorectal carcinoma, and 418 sera from patients with benign diseases and healthy individuals. Testing was done with a double monoclonal enzyme immunoassay detecting head and rod domain of NuMA and results were compared to the established tumour associated antigens. Based on a specificity of 95% versus the benign reference group of gastrointestinal diseases, we found--at the time of primary diagnosis--a sensitivity for colorectal cancer of 8% for NuMA, 36% for CEA and 17% for CA 19-9. Regarding T-stages of colorectal cancer no marker detected T1 when regarding 95% specificity-cut-off value but NuMA showed little more sensitivity when based on a 95% specificity cut off value versus healthy. This could not be shown in Dukes' stages. Regarding all other solid tumours tested--all based on a specificity of 95% for the corresponding benign reference groups--no advantage of NuMA in sensitivity for all other solid tumours investigated was found. No additional sensitivity could be observed. Based on our results, the NuMA-assay in its present form has no clinical relevance.

BTA-TRAK--a useful diagnostic tool in urinary bladder cancer?

During recent years the BTA-TRAK-assay (Bard Diagnostics, Redmont, USA) has been described in several investigations to be of clinical utility for patients suffering from bladder cancer. In a prospective study we investigated over four months the voided urine samples of all consecutive patients undergoing cystoscopy independent of their clinical background (n = 244) with the BTA-TRAK-assay. With a specificity of 95% for benign urological diseases (cut off: 1300 U/mL) we found a sensitivity of 13% for active bladder tumours. Using healthy individuals as a reference group (cut off: 40 U/mL) we found a sensitivity of 56% (specificity 67%). Using the cut off value recommended by the manufacturer (14 U/mL) a specificity of 54% and a sensitivity of 62% was found. For patients without relapse (NED) versus patients with active bladder tumours we got a specificity of 55% and a sensitivity of 62%. Due to an insufficient specificity and sensitivity the BTA-TRAK-test is not able to replace cystoscopy nor to improve existing diagnostic strategies in bladder cancer.

Proliferation- and apoptosis-associated factors in advanced prostatic carcinomas before and after androgen deprivation therapy: prognostic significance of p21/WAF1/CIP1 expression.

The molecular mechanisms leading to androgen-independent growth in prostate cancer (PC) are poorly understood. Androgen deprivation therapy (ADT) results physiologically in a decrease in proliferation and an increase in programmed cell death (PCD)/apoptosis. The aim of our study was to get more insight into these processes in prostatic carcinomas before and after ADT. For this purpose, immunohistologic staining for the androgen receptor (AR) molecule, the Ki-67 antigen, the bcl-2 oncoprotein, the p53 protein and its physiologic effector, p21/WAF1, was performed on archival material. PCD was visualized by enzymatic detection of DNA fragmentation. Specimens from 69 PC patients after ADT were studied in correlation to histopathology and prognosis. In 42 cases, corresponding tumour tissue from the untreated primary tumours could be analysed comparatively. Before ADT, histologic grade was associated with Ki-67 index (P < 0.0001, Spearman correlation) and PCD rate (P < 0.05, Spearman correlation). Ki-67 index correlated with PCD rate (P < 0.05, Spearman correlation) and p21/WAF1 expression (P < 0.01, Fisher's exact test). p21/WAF1 expression was the only statistically significant prognostic factor for shorter survival (P < 0.002, log-rank test). All p21/WAF1-positive cases showed high Ki-67 index and high histologic grade. After ADT, loss of AR expression was associated with high Ki-67 index, whereas histologic signs of regression correlated negatively with Ki-67 index (P < 0.001, Pearson chi2 test). p21/WAF1 expression increased significantly (P < 0.02, McNemar test) and correlated with p53 accumulation (P < 0.0001, Pearson chi2 test). Most significant prognostic parameter after conventional ADT was high-rate p21/WAF1 expression (> 50% of tumour cells; P < 0.00001, log-rank test). This study demonstrates that p21/WAF1 overexpression before and after ADT characterizes a subgroup of advanced PC with paradoxically high proliferation rate and significantly worse clinical outcome. This finding might be clinically useful for planning therapy in these patients.

[Partial priapism. Case report and review of the literature of diagnostic and therapeutic measures]. / Partieller Priapismus. Kasuistik und Literaturübersicht über diagnostisches und therapeutisches Vorgehen.

Partial priapism is a rare condition which has been previously reported in the literature only in eight cases. Unlike the typical case of priapism, patial priapism generally shows erection only of the proximal corpora cavernosa. In most of the cases a well defined membrane separated the proximal erected and the distal flaccid part of the corpus. The origin of the fibrous membrane is not clear. Usually a painful segmental thrombosis of the corpora cavernosa was found proximal the membrane. Until 1985 diagnosis and therapy of this entity have principially involved invasiv methods. Later computed tomography (CT) and magnetic resonance (MR) were used for noninvasive imaging and conservative management was elected. We report a case of partial priapism and review the diagnostic and therapeutic procedure in the previous literature.

[Adjuvant therapy in lymph node positive prostate carcinoma?]. / Adjuvante Therapie bei lymphknotenpositivem Prostatakarzinom?

Few patients with prostate cancer metastatic to the lymphnodes can be cured by radiotherapy, radical prostatectomy or androgen deprivation. Inevitably serum PSA levels will rise after a few years whereas the clinical recurrence appears after 5 to 10 years. Prospective trials regarding adjuvant treatment of lymphnode positive prostate cancer do not exist. Retrospective studies involving adjuvant endocrine treatment reveal a prolonged disease free survival time. Scientific proof of the best treatment for prostate cancer with lymphnode metastasis does not exist. The decision how to treat is based on our personal experience and philosophy as well as on our knowledge and interpretation of the available literature. The art of medicine is the feeling for the best treatment of each individual patient.

A study of reflux in patients with an ileal orthotopic bladder.

OBJECTIVE: To determine whether there is vesico-ureteric reflux during voiding in patients who had undergone an ileal bladder substitution after cystectomy. PATIENTS AND METHODS: The study comprised 15 patients (13 men and two women) who had undergone radical cystectomy and construction of a Studer ileal neobladder. At 1-24 months (median 4) after the operation indirect radionuclide cystography (IRC) was performed after isotopic renography (using 99m-technetium mercapto-acetyltriglycine) and voiding cysto-urethrography (VCUG). RESULTS: None of the patients had reflux during voiding, either on IRC or on VCUG. Renal function and morphology remained stable in all patients. Despite bacteriuria occurring in four patients, no episode of pyelonephritis was reported. CONCLUSION: There was no vesico-ureteric reflux during voiding in patients with a Studer ileal bladder substitution. However, long-term follow-up is needed to finally determine whether an antirefluxive ureteric implantation is required to protect the upper urinary tract in patients with ileal low-pressure bladder substitutions.

Validity of predictions of residual retroperitoneal mass histology in nonseminomatous testicular cancer.

PURPOSE: To validate predictions of the histology (necrosis, mature teratoma, or cancer) of residual retroperitoneal masses in patients treated with chemotherapy for metastatic nonseminomatous testicular germ cell tumor. PATIENTS AND METHODS: We studied 172 testicular cancer patients who underwent resection while tumor markers were normal. Predictive characteristics for the residual histology were registered, including the presence of teratoma elements in the primary tumor, the prechemotherapy level of tumor markers (alpha-fetaprotein [AFP], human chorionic gonadotropin [HCG], lactate dehydrogenase [LDH]), the size of the residual mass, and the percentage of shrinkage in mass diameter. We calculated the predicted probability of necrosis and the ratio of cancer and mature teratoma with previously published logistic regression formulas. RESULTS: The distribution of the residual histology was necrosis in 77 (45%), mature teratoma in 72 (42%), and cancer in 23 (13%). Necrosis could be well distinguished from other tissue, with an area under the receiver operating characteristic (ROC) curve of 82%. No tumor was found in 15 patients with a predicted probability of necrosis over 90%. The predicted probabilities corresponded reliably with the observed probabilities (goodness-of-fit tests, P > .20), although a somewhat higher probability of necrosis was observed in patients treated with chemotherapy containing etoposide. Conversely, cancer could not reliably be predicted or adequately discriminated from mature teratoma. CONCLUSION: The predicted probabilities of necrosis have adequate reliability and discriminative power. These predictions may validly support the decision-making process regarding the need and extent of retroperitoneal lymph node dissection.