Editorial Comment to Significance of tumor shape irregularity: Radiomics analysis based on dynamic computed tomography for predicting pT3a upstaging in cT1b‐2N0M0 renal cell carcinoma

Shimada et al.1 reported the significance of tumor shape irregularity visualized with dynamic CT in predicting pT3a upstaging for renal cell carcinoma (RCC) by using radiomics analysis. Recent advances in robot-assisted surgery have enabled us to choose partial nephrectomy (RAPN) rather than the radical type for high-complexity tumors of clinical T1 and to expect feasible outcomes. Among cT1 RCCs, especially cT1a diseases, RAPN has lead to both excellent oncological and functional outcomes. In contrast, since the clinical aggressiveness of cT1b-T2 diseases is heterogenous, accurately predicting pathological upstaging through preoperative imaging may facilitate therapeutic decisions. Therefore, investigating predictive factors for this has been very important. The present study focused on tumor shape irregularity. Tumor shape irregularity has been an important piece of preoperative information to consider for patients scheduled for RAPN, and it will become even more important as a predictor of pathologic upstaging as RAPN is considered for most cT1 tumors. Our previous study also demonstrated the prediction of pathological upstaging to T3a done with the patterns of radiological morphology in preoperative CT scan imaging for patients with RCC.2 Although the relationship between radiological morphology and pathological upstaging seems to provide very insightful information, one of the problems was that it was very difficult to objectively evaluate tumor morphology on the basis of CT findings. The authors of the present study performed a radiomics analysis using the LIFEx software for dynamic CT in order to predict pT3a upstaging in patients with cT1b-2N0M0 RCC. A strong point of this study is that this system enabled tumor morphological irregularities to be objectively evaluated. In addition to the prediction of pathological upstaging, it would also be interesting to investigate the direct association of tumor shape irregularity assessed by the system in this study with the prognosis or the risk of recurrence, and the previous study showed such data.2 Further study will address this in the future using an expanded cohort with a longer follow-up period. Another interesting finding in this study is the effect of histological heterogeneity on the prediction of pathological upstaging based on the assessment of tumor shape irregularity. The study included eight cases with the chromophobe type and three cases with the papillary type. Tumors of different histologic types may differ in the significance of their morphological irregularities. Further analysis on a large number of cases of each histological type should clarify the significance of tumor shape irregularity or each histological type. None declared.