Survival benefits analyses of T1a renal cell carcinoma patients treated with microwave ablation

Abstract

PurposeThe individual decision-making reference of Microwave ablation (MWA) for T1a RCC treatment is not clear, and it may not benefit all the patients equally. Therefore, we quantitatively evaluated the distinct survival benefits of patients with T1a RCC stratified by survival predictors. Materials and methodsA total of 237 patients with T1a RCC who underwent MWA over the last 16 years were retrospectively reviewed for survival benefit analysis. Cox proportional hazard models were used to control for the prognostic variables of OS, CSS, and PFS. Survival rates were calculated using the Kaplan-Meier method and compared by log-rank analysis. Linear extrapolation was used to compute median survival periods. ResultsThe OS benefit was significantly dependent on age (HR:2.499, 95% CI: 1.245–5.016, p = 0.010) and age-adjusted Charlson comorbidity index (CCI) score (HR:3.956, 95% CI, 1.409–11.110, p = 0.009). OS in patients aged <75 years or with an age-adjusted CCI score <7 was significantly prolonged (44.68, 65.55 months) compared to OS in patients aged ≥75 years or with CCI score ≥7 (p < 0.001 for both). PFS benefit was significantly dependent on age-adjusted CCI (HR:3.325, 95% CI, 1.390–7.956, p = 0.007), patient type (HR:0.4, 95% CI, 0.214–0.745, p = 0.004), and tumour growth pattern (HR:12.562, 95% CI, 1.552–101.696, p = 0.018). PFS in incipient patients was significantly prolonged (33.75 months) compared to that in the relapsed patients (p = 0.037). Patients with an age-adjusted CCI score <7 or without tumour protruding into the renal pelvis, lived free from recurrence or metastasis (55.69 or 101.61 months) longer than that in patients with an age-adjusted CCI score ≥7 or with tumour protruding into the renal pelvis (p < 0.01 for both). None of the variables was associated with CSS benefit. ConclusionsThe OS and PFS benefits from MWA were not equal for all T1a RCC patients. Age ≥75 years and age-adjusted CCI ≥ 7 significantly shortened OS. Age-adjusted CCI ≥ 7, relapsed RCC, and RCC protruding into the renal pelvis significantly shortened the PFS period. For a better survival prognosis, appropriate patient triage is still needed.