What dose and upper field border would you use following transanal excision for rectal cancer found to be T2 by final pathology but without LVSI or perineural invasion?

So this is a rectal adenocarcinoma that was was locally excised and found to be T2 with no otherwise concerning pathologic findings. I use S.P. Bach et al (British Journal of Surgery 2009; 96: 280–290) to estimate risk of LF with no further therapy. The Bach paper is a report of the British TEM regi...