Accuracy of sentinel lymph node biopsy for inguinal lymph node staging of penile squamous cell carcinoma: systematic review and meta-analysis of the literature

[CCAFU Recommendations 2013: Penile cancer]

INTRODUCTION

Malignant tumours of the penis are rare tumours. The objective of this article is to propose guidelines for the management of these tumours.

MATERIAL AND METHODS

A review of the literature was performed by selecting articles on penile cancer published in PUBMED.

RESULTS

The most common histological type is squamous cell carcinoma. Clinical examination of the penis is usually sufficient to assess local extension of the primary tumour, but it can be completed by MRI to assess deeper extension. Inguinal lymph nodes must be systematically palpated on both sides to assess regional extension. In the presence of palpable lymph nodes, aspiration cytology is recommended in combination with abdomen and pelvis computed tomography and (18)F-FDG PET-CT. Sentinel lymph node biopsy is recommended in the case of penile cancer at high risk of lymph node extension with no palpable lymph nodes. Treatment of the primary tumour is usually surgical. It must be as conservative as possible while ensuring negative surgical margins. Brachytherapy or local treatment (laser, cytotoxic cream, etc.) can be proposed in some cases. Bilateral lymph node chains must be systematically treated at the time of diagnosis of the disease. Inguinal lymphadenectomy alone has a curative role in patients with metastatic invasion of a single lymph node (stage pN1). In the case of more extensive lymph node involvement, multimodal management combining chemotherapy, surgery and possibly radiotherapy, must be considered.

CONCLUSION

The treatment of penile cancer is usually surgical possibly in combination with chemotherapy in the presence of lymph node extension. The main prognostic factor is lymph node involvement, requiring appropriate management right from the time of diagnosis.

Mapping lymph nodes in cancer management - role of (99m)Tc-tilmanocept injection

Two decades ago, lymphatic mapping of sentinel lymph nodes (SLN) was introduced into surgical cancer management and was termed sentinel node navigated surgery. Although this technique is now routinely performed in the management of breast cancer and malignant melanoma, it is still under investigation for use in other cancers. The radioisotope technetium (^99mTc) and vital blue dyes are among the most widely used enhancers for SLN mapping, although near-infrared fluorescence imaging of indocyanine green is also becoming more commonly used. ^99mTc-tilmanocept is a new synthetic radioisotope with a relatively small molecular size that was specifically developed for lymphatic mapping. Because of its small size, ^99mTc-tilmanocept quickly migrates from its site of injection and rapidly accumulates in the SLN. The mannose moieties of ^99mTc-tilmanosept facilitate its binding to mannose receptors (CD206) expressed in reticuloendothelial cells of the SLN. This binding prevents transit to second-echelon lymph nodes. In Phase III trials of breast cancer and malignant melanoma, and Phase II trials of other malignancies, ^99mTc-tilmanocept had superior identification rates and sensitivity compared with blue dye. Trials comparing ^99mTc-tilmanocept with other ^99mTc-based agents are required before it can be routinely used in clinical settings.

Prognostic significance of sentinel lymph node mapping in Merkel cell carcinoma: systematic review and meta-analysis of prognostic studies

Aim. To assess through a systematic review and meta-analysis of the literature the prognostic implication of sentinel lymph node mapping in Merkel cell carcinoma (MCC). Materials and Methods. PubMed and SCOPUS databases were searched by using “Merkel AND sentinel” as keywords. All studies with prognostic information regarding SLN mapping in cN0 MCC patients were included. Hazard ratio (HR) for overall survival (OS) and disease free survival (DFS) was used as effect size. Results. SLN biopsy predicted better DFS and OS as compared to the nodal observation in cN0 MCC patients (pooled HR for DFS: 1.61 (95% CI: 1.05–2.46), P = 0.028; pooled HR for OS: 1.08 (95% CI: 0.55–2.10), P = 0.8). Pathologically negative SLN (SLN−) patients had better OS (pooled HR: 4.42 (95% CI: 1.82–10.7), P = 0.0009) and DFS (pooled HR: 2.58 (95% CI: 1.78–3.73)) as compared to SLN+ patients. Conclusion. SLN mapping can provide strong prognostic information regarding OS and DFS in cN0 MCC patients. More importantly, SLN mapping can improve DFS and possibly OS in cN0 MCC patients as compared to nodal observation. As MCC is a rare tumor, large multicenter prospective studies are still needed to validate the survival benefit of SLN mapping.

Investigation of publication bias in meta-analyses of diagnostic test accuracy: a meta-epidemiological study

Background

The validity of a meta-analysis can be understood better in light of the possible impact of publication bias. The majority of the methods to investigate publication bias in terms of small study-effects are developed for meta-analyses of intervention studies, leaving authors of diagnostic test accuracy (DTA) systematic reviews with limited guidance. The aim of this study was to evaluate if and how publication bias was assessed in meta-analyses of DTA, and to compare the results of various statistical methods used to assess publication bias.

Methods

A systematic search was initiated to identify DTA reviews with a meta-analysis published between September 2011 and January 2012. We extracted all information about publication bias from the reviews and the two-by-two tables. Existing statistical methods for the detection of publication bias were applied on data from the included studies.

Results

Out of 1,335 references, 114 reviews could be included. Publication bias was explicitly mentioned in 75 reviews (65.8%) and 47 of these had performed statistical methods to investigate publication bias in terms of small study-effects: 6 by drawing funnel plots, 16 by statistical testing and 25 by applying both methods. The applied tests were Egger’s test (n = 18), Deeks’ test (n = 12), Begg’s test (n = 5), both the Egger and Begg tests (n = 4), and other tests (n = 2). Our own comparison of the results of Begg’s, Egger’s and Deeks’ test for 92 meta-analyses indicated that up to 34% of the results did not correspond with one another.

Conclusions

The majority of DTA review authors mention or investigate publication bias. They mainly use suboptimal methods like the Begg and Egger tests that are not developed for DTA meta-analyses. Our comparison of the Begg, Egger and Deeks tests indicated that these tests do give different results and thus are not interchangeable. Deeks’ test is recommended for DTA meta-analyses and should be preferred.

Micrometastatic cancer cells in lymph nodes, bone marrow, and blood: Clinical significance and biologic implications

Cancer metastasis may be regarded as a progressive process from its inception in the primary tumor microenvironment to distant sites by way of the lymphovascular system. Although this type of tumor dissemination often occurs in an orderly fashion via the sentinel lymph node (SLN), acting as a possible gateway to the regional lymph nodes, bone marrow, and peripheral blood and ultimately to distant metastatic sites, this is not a general rule as tumor cells may enter the blood and spread to distant sites, bypassing the SLN. Methods of detecting micrometastatic cancer cells in the SLN, bone marrow, and peripheral blood of patients have been established. Patients with cancer cells in their SLN, bone marrow, or peripheral blood have worse clinical outcomes than patients with no evidence of spread to these compartments. The presence of these cells also has important biologic implications for disease progression and the clinician's understanding of the process of cancer metastasis. Further characterization of these micrometastatic cancer cells at each stage and site of metastasis is needed to design novel selective therapies for a more "personalized" treatment.

Pelvic kidney visualization on the lymphoscintigraphy images of a patient with uterine cervix cancer: importance of the delayed imaging

We reported an unusual visualization of a pelvic kidney on the lymphoscintigraphy images of a patient with uterine cervix cancer, which was mistaken with para-aortic sentinel nodes. Delayed imaging clearly showed the nature of this activity. Our case underscores the importance of delayed pelvic lymphoscintigraphy imaging in the sentinel node mapping of gynecological cancers.

A hybrid radioactive and fluorescent tracer for sentinel node biopsy in penile carcinoma as a potential replacement for blue dye

BACKGROUND

Sentinel node (SN) biopsy in penile cancer is typically performed using a combination of radiocolloid and blue dye. Recently, the hybrid radioactive and fluorescent tracer indocyanine green (ICG)-(99m)Tc-nanocolloid was developed to combine the beneficial properties of both radio-guidance and fluorescence imaging.

OBJECTIVE

To explore the added value of SN biopsy using ICG-(99m)Tc-nanocolloid in patients with penile carcinoma.

DESIGN, SETTING, AND PARTICIPANTS

Sixty-five patients with penile squamous cell carcinoma were prospectively included (January 2011 to December 2012). Preoperative SN mapping was performed using lymphoscintigraphy and single-proton emission computed tomography supplemented with computed tomography (SPECT/CT) after peritumoural injection of ICG-(99m)Tc-nanocolloid. During surgery, SNs were initially approached using a gamma probe, followed by patent blue dye and/or fluorescence imaging. A portable gamma camera was used to confirm excision of all SNs.

SURGICAL PROCEDURE

Patients underwent SN biopsy of the cN0 groin and treatment of the primary tumour.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The number and location of preoperatively identified SNs were documented. Intraoperative SN identification rates using radio- and/or fluorescence guidance were assessed and compared with blue dye. Statistical evaluation was performed using a two-sample test for equality of proportions with continuity correction.

RESULTS AND LIMITATIONS

Preoperative imaging after injection of ICG-(99m)Tc-nanocolloid enabled SN identification in all patients (a total of 183 SNs dispersed over 119 groins). Intraoperatively, all SNs identified by preoperative SN mapping were localised using combined radio-, fluorescence-, and blue dye guidance. Fluorescence imaging enabled visualisation of 96.8% of SNs, while only 55.7% was stained by blue dye (p<0.0001). The tissue penetration of the fluorescent signal, and the rapid flow of blue dye limited the detection sensitivity. A tumour-positive SN was found in seven patients.

CONCLUSIONS

ICG-(99m)Tc-nanocolloid allows for both preoperative SN mapping and combined radio- and fluorescence-guided SN biopsy in penile carcinoma patients and significantly improves optical SN detection compared with blue dye.

Upregulation of nucleus HDGF predicts poor prognostic outcome in patients with penile squamous cell carcinoma bypass VEGF-A and Ki-67

Hepatoma-derived growth factor (HDGF) has been verified to serve as a credible prognostic marker for several types of cancers, but its role in urologic carcinomas remains undetermined. In this study, we analyzed the significance of HDGF, as well as its relative factors such as vascular endothelial growth factor-A (VEGF-A) and Ki-67, in penile squamous cell carcinoma (PSCC). Formalin-fixed paraffin-embedded PSCC samples from 54 patients receiving surgery at Qilu Hospital of Shandong University were included in the retrospective study. The expressions of HDGF, VEGF-A, and Ki-67 were detected by immunohistochemistry of a non-biotin polymerized horseradish peroxidase method. The relationships between the expressions of HDGF and VEGF-A, Ki-67 were assessed. Moreover, their correlations with clinical pathologic characteristics and disease prognosis were, respectively, evaluated. HDGF, VEGF-A, and Ki-67 were positively expressed in 28 (51.9%), 29 (53.7%), and 26 (48.1%) patients, respectively. The expressions of VEGF-A and Ki-67 were closely correlated with PSCC type (P < 0.05). A statistically significant relationship between the expressions of HDGF and VEGF-A in PSCC was observed (P = 0.03). Patients with symptom interval of more than 6 months had a significantly poorer survival rate than those with symptom interval less than 6 months (43.3 vs. 70.8%, P = 0.043). Patients with positive HDGF expression also showed a significantly poorer survival rate than those with negative HDGF expression (39.3 vs. 73.1%, P = 0.013). Logistic regression demonstrated that the expression level of HDGF was an independent predictor for the prognosis of postoperative patients. The expression of HDGF significantly correlated with VEGF-A, but not Ki-67 expression. Overexpression of HDGF, rather than VEGF-A or Ki-67, was confirmed to be an independent prognosticator of poor outcome for PSCC patients.

Accuracy of sentinel node biopsy in esophageal carcinoma: a systematic review and meta-analysis of the pertinent literature

The use of sentinel node surgery for esophageal carcinoma is still under investigation. We evaluated the data available in the literature on this topic, and herein present the results in a systematic review format. PUBMED, SCOPUS, the ISI web of knowledge and the information from the annual meetings of the Japan Esophageal Society were searched using the search terms: "(esophagus OR esophageal) AND sentinel". The outcomes of interest were the detection rate and sensitivity. Overall, 18 studies were included. The pooled detection rate was 89.2% [82.6-93.5]. Patients with T1 and two tumors had a 17% higher detection rate compared to those with T3 and four tumors. The pooled sensitivity was 84% [78-88%]. The sensitivity was higher for adenocarcinoma compared to squamous cell carcinoma (SCC) (91 vs. 81%). In the SCC patients, there was a trend toward decreased sensitivity associated with an increasing tumor depth (T1:88%, T2:76%, T3:50%). Our analysis indicated that sentinel node biopsy is useful in adenocarcinoma patients. For SCC patients, including only cN0 patients (preferably T1 and 2) would increase the detection rate and sensitivity. Due to the limited number of high-quality studies, drawing any more definite conclusions is impossible. Large cohort studies with a standardized and consistent design will be needed in the future.

[Therapeutic strategies in penile cancer: state of the art]

A systematic review of the current treatment options and of the outcomes of penile carcinoma has been performed with special focus on controversial issues. A MedLine search using specified search terms was done during the period 1988 - January 2013. Demolitive surgery is considered as the "gold standard" treatment of invasive penile carcinoma staged higher than T2, but negative psychological outcomes were reported. On the other hand, conservative surgical techniques have been associated with higher recurrence rates. Potency-sparing technique (glansectomy and apexes sparing) preserves penile length: the reconstruction of glans anatomy and function is a key point to restore anatomy and sexual functions. Techniques such as glanduloplasty have given satisfactory anatomic, functional and sexual outcomes. Lymphadenectomy is indicated in any case of inguinal palpable nodes that persist after a course of antibiotic therapy, but also in all the cases staged T2 or higher, or in any high-grade penile cancer. It is still being debated the extension of inguinal lymphadenectomy for penile cancer: unilateral, bilateral, and extended to pelvic lymph nodes. Due to the specific radioresistance of penile cancer, radiation therapy is currently indicated in case of unresectable penile cancers with palliative intent. Chemotherapy is indicated as adjuvant therapy for stage T1-T3, N1-3, M0, or as neo-adjuvant therapy in the event of extensive pelvic and inguinal lymphadenopathies, or as palliative treatment in patients with unresectable or metastatic cancers. New chemotherapy agents such as Cis - platinum and Taxanes have shown promising results in early trials.

Dynamic sentinel lymph node biopsy in patients with invasive squamous cell carcinoma of the penis: a prospective study of the long-term outcome of 500 inguinal basins assessed at a single institution

BACKGROUND

Dynamic sentinel node biopsy (DSNB) in combination with ultrasound scan (USS) has been the technique of choice at our centre since 2004 for the assessment of nonpalpable inguinal lymph nodes (cN0) in patients with squamous cell carcinoma of the penis (SCCp). Sensitivity and false-negative rates may vary depending on whether results are reported per patient or per node basin, and with or without USS.

OBJECTIVE

To determine the long-term outcome of patients undergoing DSNB and USS-guided fine-needle aspiration cytology (FNAC) in our cohort of newly diagnosed cN0 SCCp patients, as well as to analyse any variation in sensitivity of the procedure.

DESIGN, SETTING, AND PARTICIPANTS

A series of consecutive patients with newly diagnosed SCCp, over a 6-yr period (2004-2010), were analysed prospectively with a minimum follow-up period of 21 mo. All patients had definitive histology of ≥ T1G2 and nonpalpable nodes in one or both inguinal basins. Patients with persistent or untreated local disease were excluded from the study.

INTERVENTION

All eligible patients had DSNB and USS with or without FNAC of cN0 groins.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary end point was no nodal disease recurrence on follow-up. The secondary end point was complications after DSNB. Sensitivity of the procedure was calculated per node basin, per patient, with DSNB alone, and with USS with DSNB combined.

RESULTS AND LIMITATIONS

Five hundred inguinal basins in 264 patients underwent USS with or without FNAC and DSNB. Seventy-three positive inguinal basins (14.6%) in 59 patients (22.3%) were identified. Four inguinal basins in four patients were confirmed false negative at 5, 8, 12, and 18 mo. Two inguinal basins had positive USS and FNAC and negative DSNB results. Sensitivity of DSNB with USS, with and without FNAC, per inguinal basin was 95% and per patient was 94%. Sensitivity of DSNB alone per inguinal basin and per patient was 92% and 91%, respectively. The DSNB morbidity rate was 7.6%.

CONCLUSIONS

DSNB in combination with USS has excellent performance characteristics to stage patients with cN0 SCCp, with a 5% false-negative rate per node basin and a 6% false-negative rate per patient.