Purpose: Size criteria have been used as a gold standard for a long time in cancer staging of all kinds of solid tumors. However, real tumor mass is usually neither spherical nor symmetrical in shape. Therefore, single length (diameter) of tumor does not stand for the tumor volume exactly, because of its asymmetry and irregularity in shape. In this study, we conducted the feasibility test of volume criteria for T staging.
Methods: (1) From July 2005 until June 2006, 26 NSCLCa tumor masses were enrolled for the study. Estimated Tumor Volume (ETV-CT) was calculated using a formula from the lengths in three dimensions of the tumor from preoperative CT images, and Real Tumor Volume (RTV) was measured after complete tumor dissection in op room with measuring cylinder. We analyzed data sets between ETV and RTV to show the formula function well. The calculated tumor volume (ETV-CT) was compared to the measured tumor volume (RTV) in 26 tumor mass cases for consistency test by Pearson correlation coeffi cient. (2) From April 1998 to July 2012, 406 masses were enrolled. Among them, T1a, T1b, T2a, T2b, and T3 in N0 and N1, 228 cases were selected. From the reports of their tumor permanent biopsy, we calculated the estimated tumor volumes and analyzed survival data according to the volume ranges for staging: ~10cc, 10~30cc, 30~50cc and 50cc~.
Results: Pearson correlation coefficient (r) between measured tumor volume and calculated one in 26 cases is 0.9784. By comparing new volume (V) staging with the standard T staging, V staging shows higher results than T staging in overall survival function (log-rank p=.0012 vs. p=.0068), in N0 (p=.0231 vs. p=.0454), and in SQC subgroups (p=.0039 vs. p=.0580).
Conclusions: Volume staging criteria might be a feasible method to substitute the T staging size criteria.