Upcoming event

Impact of tumor size on cancer specific mortality after local tumor ablation in T1a renal cell carcinoma

  • Carlotta Palumbo,
  • Sarah-Jeanne Cyr,
  • Elio Mazzone,
  • Francesco Alessandro Mistretta,
  • Sophie Knipper,
  • Angela Pecoraro,
  • Zhe Tian,
  • Shahrokh F Shariat,
  • Fred Saad,
  • Claudio Simeone,
  • Alberto Briganti,
  • Anil Kapoor,
  • Alessandro Antonelli,
  • Pierre I Karakiewicz

Publication: Journal of Endourology, April 2019

DOI: https://doi.org/10.1089/end.2019.0179

Introduction
Institutional studies suggested that tumor size (TS) might be an independent predictor of recurrence after local tumor ablation (LTA). However, limited data exist to ascertain whether larger TS may also predispose to worse cancer-specific mortality (CSM).

Materials and methods
Patients treated with LTA for T1a non-metastatic RCC were identified within the SEER database (2004-2015). Estimated annual proportion change methodology (EAPC), cumulative incidence plots and multivariable competing risks (CCR) regression models before and after 1:1 ratio propensity score (PS) adjustment were used to compare LTA for TS≤30mm vs TS>30 mm. A comparison of cryosurgery vs thermal ablation according to TS was also performed.

Results
Of 3,946 LTA patients, 2,974 (75.3%) patients harbored TS≤30mm vs 972 (24.7%) harbored TS>30mm. The latter were significantly older (median age 67 vs 71 years, p<0.001), compared to TS≤30 mm. No differences were recorded in annual rates over time. In unmatched CRR models, after adjustment for other-cause mortality (OCM), LTA for TS>30mm showed worse 5-year CSM (HR 2.3, p<0.001), relative to TS≤30 mm. In PS and OCM-adjusted CRR models, LTA for TS>30mm still showed worse 5-year CSM (HR 2.86, p<0.001), relative to TS≤30 mm. Thermal ablation was associated with higher 5-year CSM, compared to cryosurgery (7.6 vs 3.9%, p=0.02), but only when TS was >30 mm.

Conclusions
TS>30 mm is an independent predictor of higher 5-years CSM rates in patients treated with LTA, even after adjustment for OCM. In consequence, when LTA is considered it ideally should be performed for TS≤30 mm.

Carlotta Palumbo, MD and Pierre I. Karakiewicz, MD

NCCN guidelines recommend ablation for renal masses up to 30 mm, since above this threshold recurrence risk significantly increases. Within the SEER database, we investigated whether larger tumor size may also predispose to worse cancer-specific mortality.

Tumor size >30mm was associated with a 2.8-fold increase of cancer-specific mortality, even after propensity-score matching and other-cause mortality adjustment. This finding was highly consistent with our meta-analysis of previous studies, where we showed an almost 5-fold increase of recurrence.

Our findings validate NCCN guidelines recommendation and should be considered in clinical decision making when ablation is performed for renal masses above 30mm.