There exists considerable biological and clinical variability between histologic variants of metastatic renal cell carcinoma (mRCC). Data reporting on patterns of metastasis in histologic variants of mRCC are sparse.
To characterize sites of metastasis and their association with survival across the 3 most common histologic variants of mRCC: clear cell (ccRCC), papillary (pRCC), and chromophobe (chrRCC).
In this multicenter, international cohort study, the International mRCC Database Consortium (IMDC) database was used to identify consecutive patients starting systemic therapy for mRCC between 2002 and 2019. Patients with mixed histologic subtype were excluded. Statistical analysis was performed from February to June 2020.
Data regarding histologic subtype and sites of metastatic involvement at the time of first systemic therapy initiation were collected.
The primary outcomes were prevalence of metastatic site involvement and overall survival (OS) from time of systemic therapy initiation. Patients with multiple sites of metastatic involvement were included in analyses of all groups to which they had metastases.
A total of 10 105 patients were eligible for analysis. Median (interquartile range) age at diagnosis was 60 (53-67) years, 7310 (72.4%) were men and 8526 (84.5%) underwent nephrectomy. Of these, 9252 (92%) had ccRCC, 667 (7%) had pRCC, and 186 (2%) had chrRCC. The median number of sites of metastasis was 2 (range, 0-7). In ccRCC, the most common sites of metastasis were lung (70%; 6189 of 8804 patients [448 missing]), lymph nodes (45%; 3874 of 8655 patients [597 missing]), bone (32%; 2847 of 8817 patients [435 missing]), liver (18%; 1560 of 8804 [448 missing]), and adrenal gland (10%; 678 of 6673 patients [2579 missing]). Sites of metastasis varied between subtypes. Lung, adrenal, brain, and pancreatic metastases were more frequent in ccRCC, lymph node involvement was more common in pRCC, and liver metastases were more frequent in chrRCC. Median OS for ccRCC varied by site of metastatic involvement, ranging between 16 months (95% CI, 13.7-18.8 months) for the pleura and 50 months (95% CI, 41.1-55.5 months) for the pancreas. Compared with ccRCC, patients with pRCC tended to have lower OS, regardless of metastatic site.
Sites of metastatic involvement differ according to histologic subtype in mRCC and are associated with OS. These data highlight the clinical and biological variability between histologic subtypes of mRCC. Patterns of metastatic spread may reflect differences in underlying disease biology. Further work to investigate differences in immune, molecular, and genetic profiles between metastatic sites and histologic subtypes is encouraged.
JAMA network open. 2021 Jan 04*** epublish ***
Shaan Dudani, Guillermo de Velasco, J Connor Wells, Chun Loo Gan, Frede Donskov, Camillo Porta, Anna Fraccon, Felice Pasini, Jae Lyun Lee, Aaron Hansen, Georg A Bjarnason, Benoit Beuselinck, Sumanta K Pal, Takeshi Yuasa, Nils Kroeger, Ravindran Kanesvaran, M Neil Reaume, Christina Canil, Toni K Choueiri, Daniel Y C Heng
Tom Baker Cancer Centre, University of Calgary, Calgary, Alberta, Canada., Department of Medical Oncology, University Hospital 12 de Octubre, Madrid, Spain., Department of Oncology,Aarhus University Hospital, Aarhus, Denmark., Department of Internal Medicine, University of Pavia, Pavia, Italy., CDC Pererzoli, Peschiera del Garda, Italy., Oncologia Medica Ospedale Santa Maria della Misericordia, Rovigo, Italy., Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea., Division of Medical Oncology and Hematology, Princess Margaret Cancer Centre, Toronto, Ontario, Canada., Division of Medical Oncology, Sunnybrook Research Institute, Toronto, Ontario, Canada., Leuven Cancer Institute, University Hospitals Leuven, Leuven, Belgium., City of Hope Comprehensive Cancer Center, Duarte, California., Cancer Institute Hospital of Japanese Foundation for Cancer Research, Tokyo, Japan., Department of Urology, University Medicine Greifswald, Greifswald, Germany., Department of Medical Oncology, National Cancer Centre Singapore, Singapore., The Ottawa Hospital Cancer Centre, University of Ottawa, Ottawa, Ontario, Canada., Dana-Farber Cancer Institute, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.