RESUMEN
Objective:To investigate the association between bone lesions distribution and survival outcome and prognostic risk stratification in renal cell carcinoma bone metastasis (RCC-BM).Methods:The data of 122 RCC-BM patients admitted to Peking University People's Hospital between January 2009 and December 2019 were retrospectively reviewed. There were 100 males and 22 females, with a baseline age of (59.87±11.33) years old. According to the Memorial Sloan-Kettering Cancer Center (MSKCC)/Motzer score, patients were stratified into different risk groups using profiles at first bone metastasis diagnosis, with 20 (16.4%), 74 (60.6%) and 28 (23.0%) patients in favorable, intermediate and poor group, respectively. The spatial distribution of bone metastasis was investigated at the first bone metastasis diagnosis. The overall distribution patterns were as follows: locoregional group (lesions only involved thoracic and/or lumbar vertebrates) in 26 cases (21.3%), stochastic group (bone lesions randomly distributed) in 69 cases (56.6%), extensive group (with concomitant visceral metastasis) in 27 cases (22.1%). Metastatic site involvement was as follows: spine in 48 cases(39.3%), pelvis in 43 cases (35.2%), upper extremities in 22 cases (18.0%), and lower extremities in 20 cases (16.4%). Half (61 cases) of the enrolled patients had synchronous bone metastasis as their first bone metastases were diagnosed simultaneously with their renal tumors. Of all the patients, 99 (81.1%) accepted radical nephrectomy, 6 (4.9%) accepted partial nephrectomy, and the other 17 patients (13.9%) accepted the treatment of ablation or embolization. Eighty-two patients (67.2%) received definitive treatment for bone metastatic lesions, respectively. Forty patients (32.8%) accepted the palliative tumor reduction therapy. Thirty-two patients (26.2%) received tyrosine kinase inhibitor (TKI) or immune checkpoint inhibitor (ICI) medication, and 12 patients (9.8%) received local radiotherapy. Distribution variation and therapeutic strategies throughout the disease course until the last follow-up were recorded. Univariate analysis (chi-squared test, Mantel-Haenszel test), Kaplan-Meier survival analysis, and multivariate ordinal logistic regression were performed for the possible association.Results:Patients from the locoregional group (30.8%, 8/26) were prone to have higher risk stratification at first diagnosis than patients in the stochastic and extensive groups ( 20.8%, 20/96, P=0.107) as the marginal difference was found. At first bone metastasis diagnosis, RCC-BM patients with spinal involvement were more likely to have higher MSKCC risk stratification than those without spinal involvement [20.3%(15/48) vs. 17.6%(13/74), P<0.05]. Multivariate ordinal logistic regression showed that after adjusting for general data, bone metastasis sites, and concomitant visceral metastasis, RCC-BM patients with spinal involvement at first bone metastasis diagnosis were 3.3 times (95% CI 1.195-9.091, P<0.05)more likely to fall into the higher MSKCC risk group than those without spinal involvement.In those 93 cases with follow-up records, 20 (21.5%), 53 (57.0%), and 20 (21.5%) cases were in the locoregional group, stochastic group, and extensive group, respectively. The median overall survival time (mOS) of patients with pelvic involvement (36 cases) throughout the disease course was 32.0 months (95% CI 6.0-58.0), which was shorter than that of patients without pelvic involvement (57 cases, mOS 49.0 months, 95% CI 20.4-77.5, P<0.05). Conclusions:Spinal involvement (especially limited to thoracic and/or lumbar vertebrates) at first bone metastasis diagnosis and pelvic involvement throughout the disease course were associated with poor prognosis.