Recently, the incidence and mortality of colorectal cancer have increased, leading the second
prevalence after lung cancer. Local recurrence of mid/low rectal cancer is not only the poor
prognostic factor but also the threat of terrible quality of life. Although universal usage
of neoadjuvant chemo-radiotherapy (nCRT) and total mesorectal excision (TME) have decreased
local recurrence to 5%-10%, the ratio of local recurrence has occupied almost 30% of total
metastasis and recurrence incidences, which limited the therapeutic effect of rectal cancer.
Increasing evidences have demonstrated lateral pelvic lymph nodes (LLN) metastasis as one of
the prominent causes of local recurrence, accompanied with 10%-25% advanced rectal cancer.
Published researches also reminder us preoperative LLN involvement may lead to high local
recurrence and poor overall survival.
As for the treatment strategies on LLN metastasis, there are huge controversies on whether
lateral pelvic lymph nodes dissection (LLND) or LLND+TME after nCRT:
Eastern countries especially Japan favors LLND following TME with the reasons: 1) the
incidence of LLN metastasis reaches as high as 10%-25% and 27% of rectal patients who undergo
TME solely (without LLND) will develop into local recurrence. And the predictive pelvic
recurrence rate will decrease 50%; corresponding 5-year overall survival will increase 8%-9%.
2) efficacy of LLND equals to resection of "local lymph nodes metastases". A large cohort of
11567 cases from Japan demonstrates resection of iliac lymph nodes metastasis does not show
any difference from TME of cTxN2aM0 and resection of obturator and external iliac lymph nodes
favors that of liver metastasis. 3) Japanese Guidelines for treatment of colorectal in 2014
also recommends mid/low II/III rectal cancer under peritoneal reflex undergo regular
TME+LLND.
On the contrary, western countries favor sole TME after nCRT for LLN metastasis, holding
that: 1) rate of lymph nodes metastasis is relatively low and LLN metastasis is regarded as
systemic metastasis. 2) LLND experiences longer operative time, higher postoperative
complications, and poor quality of life. 3) American NCCN and European ESMO guidelines
recommend single TME for rectal cancer, if necessary, LLDN is added when LLN is indeed
metastasis.
However, there is a blank strict prospective randomized control study on the comparison of
nCRT and LLND. Present existing retrospective cohort mainly focus on all the mid/low advanced
cancer, not the specific individual of suspicious LLN metastasis. In fact, the results almost
indicate no differences on local recurrence and overall survival, except for less operation
time, blood loss, and perioperative complications in LLND. Although the latest researches
start to report their preliminary outcomes, the patients sample sizes are small and they
achieve varied recurrence and overall survival.
In conclusion, the treatment strategy for colorectal cancer has focused on individual and
precision. Massive of retrospective reports have indicated that rectal cancer patients with
LLN metastasis will benefit from LLND, however, there is hot controversy on the treatment of
whether TME+LLND or TME+nCRT for specific rectal patients with suspicious LLN metastasis.
Therefore, our trial will compare the efficacy and safety of the two strategies for mid/low
rectal cancer with suspicious LLN metastasis. The risk factors (such as radiologic factors,
pathologic factors, and serum protein) to predict local recurrence and overall survival will
be further investigated.
