Introduction Surgical treatment of kidney cancer with a tumor thrombus spreading through the inferior vena cava (IVC) up to the right atrium remains a challenge. The aim of this article was to 1. assess the safety and feasibility of four transdiaphragmatic surgical approaches to the right atrium from the abdominal cavity; 2. to evaluate the feasibility of palpation and displacement of thrombi below the diaphragm. Material and methods Four cadaveric specimens preserved with the Thiel method to assess each surgical access: 1) extrapericardial T-shaped diaphragmotomy, 2) extrapericardial T-shaped + circular diaphragmotomy, 3) transpericardial T-shaped diaphragmotomy with longitudinal pericardiotomy, 4) transpericardial T-shaped + circular diaphragmotomy with longitudinal and circular pericardiotomy. Different diameters and density of tumor thrombus simulators, placed at various levels from the cava-diaphragm junction, were used to evaluate the palpation and displacement of the thrombus. Two surgeons performed each assessment independently. Results Approaches 2, 3 and 4 were significantly better than approach 1, regarding the feasibility of palpation, according to both surgeons (surgeon 1 Chi-square 21.56, p = 0.001; surgeon 2 Chi-square 27.83, p <0.0001). Approach 1 also showed a significant higher number of impossible displacements recorded by both surgeons (surgeon 1 Chi-square 19.02, p = 0.004; surgeon 2 Chi-square 20.01, p = 0.003). Only surgeon 1 recorded a significant lower number of easy palpations at 4 cm from the cava-diaphragm junction (Chi-square 14.10, p = 0.007). There were no high-risk complications in any approach. Conclusions The transdiaphragmatic access to the right atrium from the abdominal cavity is feasible using three of the four surgical approaches. They are an adequate alternative to sternotomy.