Table 1.

The results of randomized clinical trials comparing the efficacy of D2 lymphadenectomy to D3 or D4 (D3+) lymphadenectomy

Author	Year	Number of patients	Country	Tumor depth	Comparative arma	Survival results	Morbidity D2 vs. D3 (%)
Maeta et al. [17]	1997	70	Japan	T3–T4	D2+ vs. D4 (D3+)	NS	26.0 vs. 40.0
Wu et al. [33]	2006	221	Japan, Korea, China, Taiwan	T2–T4/N1–3	D2 vs. D4 (D3+)	Unknown	7.3 vs. 17.1
Kulig et al. [18]	2007	550	Poland	T1–T3	D2 vs. D3	NS	27.7 vs. 21.6
Sasako et al. [16]	2008	523	Japan	T2–T4	D2 vs. D3	NS	20.9 vs. 28.1
Yonemura et al. [19]	2008	269	Japan, Korea, Taiwan	T2–T4	D2 vs. D3	NS	Mortality: 0.7 vs. 3.7

T, depth of tumor infiltration; N, number of metastasized lymph nodes; D, types of lymphadenectomy; NS: not significant

^aThe different types of lymphadenectomies performed in the comparative arms of the respective randomized clinical trials: D2+: D2 lymphadenectomy plus dissection of lymph nodes located at the hepatoduodenal ligament, in the retro-pancreatic space and along the vessels of the transverse mesocolon. D3: D2 lymphadenectomy plus dissection of lymph nodes located at the para-aortic lymph node dissection from the upper margin of the celiac trunk to the lower margin of the left renal vein. D4 (D3+): D2 lymphadenectomy plus dissection of lymph nodes located at the para-aortic lymph nodes from the aortic hiatus to the aortic bifurcation (hepatoduodenal ligament, in the retro-pancreatic space and along the vessels of transverse mesocolon)