Abstract 726P
Background
Collecting duct carcinoma (CDC) and renal medullary carcinoma (RMC) are two rare and aggressive subtypes of kidney cancer that share a similar anatomic origin in the distal nephron. Due to their rarity, there is limited data on their epidemiology and outcomes. We used the Surveillance, Epidemiology, and End Results (SEER) database to describe the epidemiologic characteristics of these tumor and to provide contemporary prognostic information.
Methods
Using the SEER database, we conducted a retrospective analysis of all cases of CDC and RMC diagnosed between 2004-2015. We collected data on key demographic and tumor characteristics, including age, sex, race, stage, as well as treatment modalities. The primary endpoints were cancer specific (CSS) and overall survival (OS). We used Kaplan-Meier survival estimates to compare outcomes by histology and cox proportional hazard models to adjust for prognostic variables.
Results
We identified 273 cases of CDC and 74 cases of RMC. Patients with RMC were more likely to be younger (mean age 27.4 years vs 59.1 years, p<0.001) and of African-American ethnicity (81.1 % vs 23.1%, p<0.001). Compared with CDC, RMC was associated with more advanced disease at diagnosis, with 74.8% presenting with stage IV disease vs. 48.4% (p<0.001). RMC was also more likely to have regional lymph node metastases (60.8% vs. 38.1%, p<0.001) and distant metastases at diagnosis (75.7% vs. 38.3%, p<0.01). Surgery was more common in the CDC group (83.8% vs. 65.8%, p<0.001). Patients with RMC were more likely to receive chemotherapy (28.9% vs. 67.6%, p<0.001). The median OS in CDC was 19 months vs. 9 months in RMC. After controlling for age, sex, race, and stage, RMC was associated with significantly worse survival compared to CDC (HR 1.70, 95% CI 1.09-2.66, p=0.02).
Conclusions
Despite recent therapeutic advances in other subtypes of kidney cancer, the prognosis of CDC and RMC remains poor. Compared to CDC, RMC is associated with a particular poor prognosis with a median OS of less than one year. Further research focusing on prevention, early detection, and the development of novel treatment strategies is warranted.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
J. Graham: Advisory/Consultancy: Ipsen; Advisory/Consultancy: Janssen. M. Leveridge: Honoraria (self): Ipsen; Honoraria (self): Pfizer; Advisory/Consultancy: Abbvie. All other authors have declared no conflicts of interest.