Risk factors for lymph node metastasis in clinically node-negative penile cancer patients

Factors Predicting Nodal Metastasis in Penile Cancer: Analysis from a Tertiary Center

INTRODUCTION

Lymph node metastasis is an important prognostic marker in penile cancer. Identification of occult metastasis is by lymphadenectomy based on the histological features of primary tumor; however, this leads to unnecessary surgical morbidity in node negative patients.

METHODS

A retrospective analysis of all surgically treated penile cancer patients managed at our institute from January 2011 to March 2014 was performed. Patient characteristics, histological factors, and lymph node involvement were identified. Logistic regression analysis was used to compute odds ratio (OR) in univariate and multivariate analysis.

RESULTS

Ninety seven patients underwent surgical management at our institute during the abovementioned period. Grade III tumor, presence of lymphovascular invasion, tumor thickness >10 mm, perineural invasion (PNI) and Ki67 >50% were significantly associated with nodal metastasis. On multivariate analysis, only presence of PNI was found to be significant (OR: 6.82) (95% confidence interval: 1.72-27.03) (p = 0.006).

CONCLUSION

PNI is a strong independent predictor of occult lymph node metastasis in penile cancers. Its inclusion in stratification of clinically node negative patients will identify high-risk patients who will benefit from prophylactic lymphadenectomy.

Prognostic predictors of lymph node metastasis in penile cancer: a systematic review

PURPOSE

Squamous cell carcinoma (SCC) of the penis is a rare disease in developed countries but is associated with significant morbidity and mortality. A crucial prognostic factor is the presence of inguinal lymph node metastases (ILNM) at the time of diagnosis. At least 25% of cases have micrometastases at the time of diagnosis. Therefore, we performed a literature review of studies evaluating factors, both clinical and pathological, predictive of lymph node metastases in penile SCC.

MATERIALS AND METHODS

Studies were identified using PubMed and search terms included the following: penile cancer, penile tumor, penile neoplasm, penile squamous cell carcinoma, inguinal lymph node metastasis, lymph node metastases, nodal metastasis, inguinal node metastasis, inguinal lymph node involvement, predictors, and predictive factor. The number of patients and predictive factors were identified for each study based on OR, HR, or RR in multivariate analyses, as well as their respective significance values. These were compiled to generate a single body of evidence supportive of factors predictive of ILNM in penile SCC.

RESULTS

We identified 31 studies, both original articles and meta-analyses, which identified factors predictive of metastases in penile SCC. The following clinical factors were predictive of ILNM in penile SCC: lymphovascular invasion (LVI), increased grade, increased stage (both clinical and pathological), infiltrative and reticular invasion, increased depth of invasion, perineural invasion, and younger patient age at diagnosis. Biochemically, overexpression of p53, SOD2, Ki-67, and ID1 were associated with spread of SCC to inguinal lymph nodes. Diffuse PD-L1 expression, increased SCC-Ag expression, increased NLR, and CRP >20 were also associated with increased ILNM.

CONCLUSIONS

A multitude of factors are associated with metastasis of SCC of the penis to inguinal lymph nodes, which is associated with poor clinical outcomes. The above factors, most strongly LVI, grade, and node positivity, may be considered when constructing a nomogram to risk-stratify patients and determine eligibility for prophylactic inguinal lymphadenectomy.

Role of dynamic sentinel node biopsy in carcinoma penis with or without palpable nodes

Introduction:

We aimed to evaluate the role of dynamic sentinel node biopsy (DSLNB) in patients diagnosed with carcinoma penis and clinically N0 disease using superficial inguinal dissection as the standard staging modality.

Materials and Methods:

Twenty consecutive men (40 groins) with carcinoma penis having clinically N0 status were enrolled in the study. Patients underwent DSLNB if fine needle aspiration cytology from the groin nodes was negative, followed by injection of radiocolloid and blue dye. The sentinel lymph node(s) were harvested. The inguinal incision was then extended and a modified superficial inguinal dissection was performed and all nodes were labeled separately and sent for frozen section. A completion deep inguinal with pelvic dissection was performed if any of the nodes were reported positive for malignancy.

Results:

The median age of the patients was 52.5 years. Ten patients were smokers. Phimosis was present in five patients. Lesions were present over the glans penis and shaft in 18 and two patients, respectively. Wide local excision, partial penectomy and total penectomy were performed in one, 15 and four patients, respectively. Clinically palpable nodes were found in 19 groins. Median follow-up was 26 months. Nodes were positive in 10 groins. DSLNB missed the sentinel node in one groin. The accuracy and false-negative rate of DSLNB was 97.5% and 10%, respectively.

Conclusion:

DSLNB is a useful and reliable technique to identify the involved node(s) in patients diagnosed as having carcinoma penis with clinical N0 status (with or without palpable nodes). It helps to avoid the morbidity associated with a staging inguinal dissection in these patients.