The majority of domestic kidney cancers are clear cell carcinomas, followed by renal papillary carcinomas and renal suspicious cell carcinomas. These common types of kidney cancer progress relatively slowly, are less malignant, and can be well controlled using current treatments (e.g., surgery, targeted therapy, etc.). In addition, there are rare disseminated kidney cancer types that are extremely malignant, progress rapidly, and lack effective treatments.
Renal collecting duct carcinoma
Renal collecting duct carcinoma is a rare pathologic subtype of renal cell carcinoma that originates in the collecting ducts of the renal medulla (bellini ducts) and accounts for less than 1% of all renal cell carcinomas.
The incidence of renal collecting duct carcinoma is characterized by more men than women (2:1), can occur at all ages, with an average age of 55 years, is mostly metastatic at the time of presentation, is extremely malignant, progresses rapidly, and has a short survival period.
The treatment of limited renal collecting duct carcinoma is primarily surgical, but the outcome is significantly worse than other subtypes of renal cancer, such as clear cell carcinoma. Most patients with renal collecting duct carcinoma metastasize and die within months after surgery, with 1-, 3-, and 5-year survival rates of 69.0%, 45.3%, and 34.3%, respectively.
There is a lack of effective postoperative adjuvant therapy for patients with renal collecting duct cancer. Metastatic renal collecting duct carcinoma is insensitive to radiotherapy and cytokine therapy, and the combination of gemcitabine and platinum is effective, with an objective response rate of 26%, a disease control rate of 70%, and an overall survival time of 10.5 months.
Medullary renal carcinoma
Medullary renal carcinoma, which most often occurs in young African Americans, is a relatively new subtype of kidney cancer with characteristic sickle cell anemia. The tumor originates in the epithelium of the calyces adjacent to the renal papillae and is extremely malignant. As with collecting ductal carcinoma, most patients are found to be advanced with distant metastases and most are treatment-naïve.
It is also considered to be a subtype of renal collecting duct carcinoma because of its many histologic features similar to those of renal collecting duct carcinoma.
Sarcomatoid renal carcinoma
Sarcomatoid renal carcinoma is not a separate subtype of kidney cancer, but a poorly differentiated type derived from other tissue subtypes that can occur in any other subtype of kidney cancer, including clear cell carcinoma, papillary carcinoma, suspicious cell carcinoma, and collecting duct carcinoma, and accounts for about 5% of all kidney cancers. The majority of patients die within 1 year because of widespread tumor metastasis.
The tumor is currently thought to be the result of bidirectional differentiation of stem cells with multidirectional differentiation potential into epithelial and mesenchymal tissues in response to pro-carcinogenic factors, and the clinical symptoms are mainly local pain, masses, hematuria, coughing or coughing up blood, lethargy, and fever, which lack specificity.
The diagnosis and treatment of sarcomatoid kidney cancer are still divided at home and abroad, but radical nephrectomy is still the mainstay, chemotherapy and radiotherapy are not effective, and targeted therapy is its main treatment modality.