Histopathological Subtypes and PD-L1 Expression in Primary Urethral Adenocarcinoma: A Series of 5 Cases

Reprint of: Female Urethral Carcinoma: A contemporary review of the clinicopathologic features, with emphasis on the histo-anatomic landmarks and potential staging issues

Primary female urethral carcinoma (PUC-F) accounts for less than 1% of all genitourinary malignancies and comprises a histologically diverse group of tumors that are usually associated with poor prognosis. The carcinomas documented at this site include adenocarcinoma (clear cell adenocarcinoma, columnar cell carcinoma, and Skene gland adenocarcinoma), urothelial carcinoma (UCa), and squamous cell carcinoma (SCC). Recent studies have shown adenocarcinomas to be the most common type of primary urethral carcinoma in females. As most of the urethral carcinomas morphologically resemble carcinomas arising from surrounding pelvic organs or metastases, these should be ruled out before making the diagnosis of PUC-F. These tumors are currently staged according to the 8th edition of the American Joint Committee on Cancer (AJCC) staging system. However, the AJCC system has limitations, including the staging of tumors involving the anterior wall of the urethra. Staging systems like the recently proposed histology-based female urethral carcinoma staging system (UCS) takes into account the unique histological landmarks of the female urethra to better stratify pT2 and pT3 tumors into prognostic groups, that correlate with clinical outcomes including recurrence rates, disease-specific survival and overall survival. Further larger multi-institutional cohorts are however required to validate the results of this staging system. There is very limited information regarding the molecular profiling of PUC-F. Thirty-one percent of clear cell adenocarcinomas have been reported to show PIK3CA alterations, whereas 15% of adenocarcinomas show PTEN mutations. Higher tumor mutational burden and PD-L1 staining have been reported in UCa and SCC. Although multimodality treatment is usually recommended in locally advanced and metastatic disease, the role of immunotherapy and targeted therapy is promising in select PUC-F cases.

Progress in the treatment of urethral adenocarcinoma

BACKGROUND

Urothelial adenocarcinoma (UA) is a rare subtype of primary urothelial carcinoma, which is more common in women and has a poor prognosis. Because of their low incidence, most of the existing literature is based on case reports and there is a lack of comprehensive literature on this type of tumor.

PURPOSE

This article provides a comprehensive and systematic review of the epidemiology, pathological types, treatment, and prognosis of UA. Especially in the treatment section, we reviewed the various treatment methods including surgery, radiotherapy, chemotherapy, immunotherapy and molecular targeted therapy. This review aims to provide a theoretical basis for the clinical diagnosis and management of UA.

METHODS

We reviewed the relevant literature of UA from Pubmed.

CONCLUSION

There is no standard treatment for UA. Multidisciplinary therapy, including surgery, radiotherapy and chemotherapy, is the current trend. Immunotherapy and molecular targeted therapy will also become viable options for the treatment of UA in future.

Female urethral carcinoma: a contemporary review of the clinicopathologic features, with emphasis on the histoanatomic landmarks and potential staging issues

Primary female urethral carcinoma (PUC-F) accounts for less than 1% of all genitourinary malignancies and comprises a histologically diverse group of tumors that are usually associated with poor prognosis. The carcinomas documented at this site include adenocarcinoma (clear cell adenocarcinoma, columnar cell carcinoma, and Skene gland adenocarcinoma), urothelial carcinoma (UCa), and squamous cell carcinoma (SCC). Recent studies have shown adenocarcinomas to be the most common type of primary urethral carcinoma in females. As most of the urethral carcinomas morphologically resemble carcinomas arising from surrounding pelvic organs or metastases, these should be ruled out before making the diagnosis of PUC-F. These tumors are currently staged according to the 8th edition of the American Joint Committee on Cancer (AJCC) staging system. However, the AJCC system has limitations, including the staging of tumors involving the anterior wall of the urethra. Staging systems like the recently proposed histology-based female urethral carcinoma staging system (UCS) takes into account the unique histological landmarks of the female urethra to better stratify pT2 and pT3 tumors into prognostic groups, that correlate with clinical outcomes including recurrence rates, disease-specific and overall survival. Further larger multi-institutional cohorts are however required to validate the results of this staging system. There is very limited information regarding the molecular profiling of PUC-F. Thirty-one percent of clear cell adenocarcinomas have been reported to show PIK3CA alterations, whereas 15% of adenocarcinomas show PTEN mutations. Higher tumor mutational burden and PD-L1 staining have been reported in UCa and SCC. Although multimodality treatment is usually recommended in locally advanced and metastatic disease, the role of immunotherapy and targeted therapy is promising in select PUC-F cases.

Chemotherapy combined with immunotherapy in primary female urethral squamous cell carcinoma: a case report

Primary female urethral carcinomas are uncommon and have a low morbidity rate. Most of these patients have advanced illness with high invasion and a poor prognosis. There is no standard treatment, and multimodal therapy is recommended. The use of radiotherapy and chemotherapy were mostly reported in previous studies on advanced female urethral squamous cell carcinoma. We report that chemotherapy combined with a programmed death-1 (PD-1) inhibitor was effective in treating metastatic female urethral squamous cell carcinoma. During four cycles, we used systemic chemotherapy of albumin-paclitaxel + carboplatin in combination with a PD-1 inhibitor (toripalimab 240 mg) every 3 weeks, and a complete response was achieved. We performed a genetic test on the patient who had a tumor mutation burden of 5.7 mutations/Mb, tumor proportion score of 20%, and combined positive score of 20% (22C3). No recurrence or distant metastasis was found after 20 months of follow-up. In conclusion, in patients with positive PD-1 ligand 1 expression in primary female urethral squamous cell carcinoma, chemotherapy combined with PD-1 inhibitors may be effective. Larger sample studies are required to determine PD-1 ligand 1 expression and the curative effect of PD-1 inhibitors, as well as their effect on survival.

Immune checkpoint inhibitor in a case with primary urethral adenocarcinoma with lung metastasis

Primary urethral adenocarcinoma is extremely rare, and the clinical experience in optimizing the management is limited. The efficacy of immune checkpoint inhibitors for these patients is not clear. Here, we describe a 52-year-old patient with primary urethral adenocarcinoma accompanied by inguinal lymph nodes and lung metastasis with progressive disease after radiotherapy and multiline chemotherapy. The expression of programmed cell death ligand-1 (PD-L1) was positive. Hence, this patient was treated with tislelizumab, an immune checkpoint inhibitor. The disease is well controlled and the overall survival time is 5 years. Moreover, the patient tolerated the treatment well. To our knowledge, this is the first reported case in which immunotherapy was used for primary urethral adenocarcinoma. The immune checkpoint inhibitors may be a novel option for the treatment of these patients.