Treatment selection in metastatic renal cell carcinoma : Towards an individualised approach

Abstract: Renal cell carcinoma (RCC), a common malignancy worldwide, affects 1200 new patients yearly in Sweden. Metastatic RCC (mRCC) develops in one in three and is commonly incurable. Clear cell histology dominates followed by papillary histology. The mainstay of mRCC treatment is targeted agents (TA) against aberrantly signalling pro-angiogenic tyrosine kinase receptors, and recently also immune checkpoint inhibitors. Local metastatic therapy with stereotactic radiotherapy (SRT) or surgical metastasectomy may be considered for oligometastatic disease.The aims of this thesis were (1) to identify clinically relevant factors useful for prognostication in real-world patients with mRCC treated in the TA era, (2) to deepen the understanding of papillary mRCC, and (3) to evaluate local metastatic therapy in mRCC. The papers of this thesis were based on retrospective data from regional databases or patient records from 2005 and onwards to reflect the contemporary therapeutic landscape.Paper I was a single-centre study analysing inflammatory blood and clinical parameters in relation to overall survival (OS) in mRCC (n=84). Median OS (mOS) was 20 months. Hypoalbuminemia was a negative prognostic factor (HR 2.7), independently of patient performance status (PS) or Memorial Sloan Kettering Cancer Center risk criteria.Paper II included solely patients with papillary mRCC (n=86) treated at three centres. mOS was 11 months. Age ≥60 years (HR 2.2), ≥3 metastatic sites (HR 2.7), and Eastern Cooperative Oncology Group (ECOG) PS ≥2 vs 1 (HR 3.0) were independently associated with worse OS.Paper III included mRCC patients treated with local metastatic therapy (n=117). Survival was similar irrespective of SRT or surgical metastasectomy with a mOS of 51 months. Treatment with TA in close proximity to local therapy was well tolerated. ECOG PS 1 vs 0 (HR 2.9), intracranial treatment (HR 1.8), and watchful waiting ≥18 months prior to treatment (HR 0.3) were independently prognostic.  Paper IV was a follow-up of patients with ccRCC brain metastases treated with single fraction gamma knife radiosurgery (sf-GKRS) at three European centres (n=43). 1- and 3-year local control rates were 97% and 90%, and mOS was 16 months. Hypoalbuminemia (HR=5.3), corticosteroids prior to sf-GKRS (HR=5.8), and Karnofsky PS <80% (HR=9.1) were independently associated with worse OS, whereas previously described prognostic scores were not. Adverse radiation effects (ARE) were uncommon and associated with large target volumes and pre-treatment oedema.In conclusion, this thesis identifies several factors potentially useful for prognostication in mRCC, and indicates the usefulness of local metastatic therapy, in particular SRT, in selected patients. The results should be validated prospectively.