The standard
approach to treatment if the cancer appears early (T1 or T2) is to do surgery
first and then decide on postOp chemoradiation based on the pathology findings. If the
tumor appears locally advanced then preOp chemoradiation is used (see NCCN guidelines, NCCN radiation guidelines,)
Some recents studies suggest that patient who may a complete response to
chemoradiation may avoid surgery altogether (go
here).
A long standing debate was whether preOp was better than PostOp
radiation. The recent New England Journal showed PreOp is superior
(see study.) Even
if a radical resection (total mesorectal excision) is performed with clear
margins, even a short course of PreOp radiation will decrease the risk of a
local relapse (see
Dutch study.) After preOp treatment the surgical resection should remove
the cancer with clear margins...if the margins are still involved the
outlook is less favorable (see
study.) After preOp radiation or preOp chemo radiation as many as
30% of the patients may have no concer found at the time of surgery
(called a pathologic complete response) see
here and
here.Generally if preOp is used for locally advanced cancers
then it should be combined with chemotherapy (see MD Anderson study.)
We have participated in the NSABP R-04 protocol which is a preOp
study combining radiation (45Gy + boost (5.4Gy non-fixed or 10.8Gy fixed)
with either one of 4 chemoRx arms (continuous infusion 5FU or 5FU +
oxaliplatin (Eloxatin) or capecitabine (Xeloda) or capecitabine +
oxaliplatin)
See CT picture below for a normal rectum and then these images of large,
locally advanced rectal cancer (picture#1
and picture #2) |
