however , adenocarcinoma with concomitant adenoma ( i.e. , presumably arising in adenoma ) was observed in 14.3 % of cancers of the left colon , in 17.7 % of rectal tumors , but in only 5.7 % of neoplasms of the proximal colon ( p less than 0.05 and p less than 0.01 , respectively , vs. left colon and rectum ) .
C0034885
of rectal tumors
C0034896
rectum