Improving IMDC criteria in patients with metastatic renal cell carcinoma through the addition of initial metastatic site in bone, brain, and liver.

Abstract

754 Background: IMDC criteria are largely adopted to estimate patient prognosis. In a retrospective study we assessed that the addition of first site of metastases in brain bone and liver (bbl) metastases as variable improves prognostic stratification of patients (pts) with metastatic renal cell carcinoma (mRCC). We performed a validation study in an external cohort of patients with mRCC. Methods: All consecutive mRCC pts treated at a single institute and included in the local IGReCC database. All pts received at least one line of targeted therapy or ICIs. Primary outcome was OS from first line start. Univariate and multivariate analysis (cox regression model) were performed. Bootstrap was also carried out for validation. Results: 1073 mRCC pts were analysed (808 with known IMDC score). Of 13 initial variables considered for prognostic model, the presence of bbl as first site/s of metastases plus the 6 variables included in IMDC resulted as statistically significant factors associated with OS (table). By including this new parameter we developed a 7-variables based score (IMDC-7). Patients with 0, 1-2 and≥3 positive variable/s were considered as good, intermediate and poor risk patients respectively. 56 (22%) pts moved from good (IMDC) to intermediate (IMDC-7) and 66 (15.4%) pts moved from intermediate (IMDC) to poor (IMDC-7) group (table). Final bias corrected concordance c-index was 0.69 and 0.71 in overall cohort and in pts treated with ICI (n=241). Conclusions: The addition of bbl primary metastases to the others IMDC variables improves prognostic predictive power of the model.[Table: see text]