Observation of MRD Detection for Preoperative Sensitivity and Postoperative Positive Rate in Common Risk Stage II Colorectal Cancer
Conditions: Stage II Colorectal Cancer
Sponsor: First Affiliated Hospital Xi'an Jiaotong University

Project Name
Observation of MRD Detection for General Risk Stage II Colorectal Cancer
of preoperative sensitivity and postoperative positive rate
NCT ID not yet assigned
Date: February 25, 2023

1. Project approval basis and research status
Colorectal cancer is the third malignant tumor with the highest
incidence rate in the world, and its mortality rate is the second [1]. The
incidence rate and mortality of colorectal cancer in China rank the third
and fifth in all malignant tumors, respectively, and the incidence rate has
shown a significant upward trend in recent years [2].
The adjuvant treatment for colorectal cancer after surgery is
currently based on postoperative pathological staging. According to the
"NCCN Guidelines for Rectal Cancer 2022. V1", for rectal cancer with
T3N0M0, there is also a choice between postoperative chemotherapy
and observation. Similarly, the requirements for "follow-up observation"
are: highly differentiated or moderately differentiated, involving<2mm of
the mesorectum, without lymphatic or vascular invasion, located in the
upper rectum. In China's "CSCO Guidelines for the Diagnosis and
Treatment of Colorectal Cancer (2022)", for patients with pMMR (90% of
colorectal cancer are pMMR patients), if they are of general risk type,
adjuvant chemotherapy can be performed after surgery, and follow-up
observation can also be considered. High risk factors include: T4 stage,
poor histological differentiation (poorly differentiated or
undifferentiated), vascular infiltration, neural infiltration, preoperative
intestinal obstruction or tumor site perforation, positive or unknown
surgical margin, insufficient safety distance from the surgical margin, and

less than 12 lymph nodes submitted for examination. In other words,
when the patient is a colorectal cancer T3N0M0 patient without high risk
factors, doctors have difficulty selecting adjuvant treatment after
surgery.
Figer 1
excerpted from page REC-4 of the "NCCN Guidelines for Rectal Cancer 2022. V1"
Although the article published in the New England Journal in June
2022 has already been applied to Phase II colorectal cancer with
Signature
＠MRD detection product, and has proven its role in guiding
postoperative chemotherapy[3]. However, there are still two problems: 1.
There is no independent distinction between the common risk types of
stage II colorectal cancer, and there is no answer to the question of the
postoperative positive rate of MRD in patients with stage II colorectal
cancer common risk types; 2. There are no similar studies in the Asian
population.
Therefore, we designed an observational study to observe the
sensitivity and postoperative positive rate of this method in patients with
general risk stage II colorectal cancer, with the aim of answering the
positive rate of MDR testing in patients with general risk stage II

colorectal cancer after surgery, and laying a foundation for exploring the
guidance of this method for postoperative adjuvant treatment.
Reference:
[1] Bray, F., et al. (2018). "Global cancer statistics 2018: GLOBOCAN estimates of
incidence and mortality worldwide for 36 cancers in 185 countries." CA Cancer J Clin
68(6): 394-424.
[2] Deng, Y. (2017). "Rectal Cancer in Asian vs. Western Countries: Why the
Variation in Incidence?" Curr Treat Options Oncol 18(10): 64.
[3] Jeanne Tie, et al. “Circulating Tumor DNAAnalysis Guiding Adjuvant Therapy in
Stage II Colon Cancer.” N Engl J Med, 2022 Jun 16;386(24):2261-2272.

2. Objects and contents
2.1 Objective
To observe the sensitivity of Huajian micro MRD detection in
preoperative diagnosis of patients with general risk stage II colorectal
cancer, and to study its positive rates at one and three months after
surgery.
2.2 Contents
Preoperative venous blood and intraoperative tumor tissue samples
were reserved for patients with colorectal cancer who were estimated as
stage II general risk through pelvic magnetic resonance imaging. Patients
with colorectal cancer who were confirmed as stage II general risk type
by postoperative pathological reports began to be enrolled. To observe
the sensitivity of preoperative Huajian micro MRD detection and the
postoperative positive rate of this type of patients.
2.3 Research steps
1) Patients who meet the inclusion and exclusion criteria for
preoperative examinations, especially pelvic magnetic resonance
imaging, are enrolled.
2) Informed consent signed by patients or family members before
surgery.
3) Before surgery, 20 ml of venous blood was collected, and the
dedicated anticoagulant tube was provided and stored by BGI Gene

manufacturer.
4) During the operation, tissue samples, about the size of soybeans, were
kept in vitro for 30 minutes, and were routinely fixed with formalin
before being handed over to BGI Gene manufacturer.
5)Due to the storage by the manufacturer, the samples shall be disposed
according to the sample destruction procedure after testing.
6) After the postoperative pathological report is released, the patient is
evaluated as a general risk type II colorectal cancer patient, and the BGI
Gene manufacturer is notified for testing.
7) Complete exon sequencing and preoperative MRD detection.
8) Peripheral blood MRD testing was performed one month and three
months after surgery under the same conditions as 5).
2.4 Evaluation indicators
Key point:
Sensitivity of preoperative MRD detection (sensitivity=number of truly
positive patients/pathologically diagnosed as general risk stage II
colorectal cancer)
Secondary points:
Positive rate of MRD testing at 1 month after surgery
Positive rate of MRD testing at 3 months after surgery
DFS of 2-years in patients with two MRD outcomes
2.5 Follow up

1) Implement a unified follow-up plan: All patients will be followed up
every 3 months for the first 2 years after surgery; Observation end point
is PFS of 2 years. Follow up every six months from the second to fifth
year after surgery; Thereafter, a follow-up visit will be conducted
annually. The follow-up includes: Finger rectal examination, blood
routine, biochemical routine, tumor markers, pelvic MRI, chest and
abdominal CT, endoscopy, etc.
2) Follow up time nodes: 3, 6, 9, 12, 18, and 24 months after surgery.
3) Outside the time node for the return visit, a dedicated person will
conduct the follow-up by phone, letter questionnaire, email, etc
Sample size estimation
2.6 Sample number estimation
According to existing literature, the positive rate of MRD detection is
85%, and the expected sensitivity is 80% α= 0.05，1- β= 0.90, the
statistical difference can be obtained by calculating 48 cases. 50 cases
were planned to be enrolled.

3. Inclusion and exclusion criteria
3.1 Inclusion criteria
Age 18-75;
Pathologically confirmed rectal adenocarcinoma;
Pathological differentiation is highly or moderately differentiated;
The pathological stage was pT3N0, that is, invasion of the proper
muscular layer of the intestinal wall without lymph node metastasis;
No new adjuvant treatment before operation
There was no vascular infiltration and nerve infiltration in
postoperative pathology;
No preoperative intestinal obstruction or tumor site perforation;
No postoperative pathological margin was positive or unknown;
The distance between the pathological cutting edge and the tumor
was more than 1 cm;
Invasion of mesentery of intestinal wall ≤2mm;
More than 12 lymph nodes were submitted for examination;
Nonlocal recurrence and distant metastasis;
No multiple primary carcinoma of colon and rectum;
Physical condition score PS ≤2 points;
Patients and their families can understand and are willing to
participate in this study and provide written informed consent.
3.2 Exclusion criteria

Multiple intestinal carcinomatosis
Previous history of malignant tumor,
There are concurrent malignant tumors in the whole body except for
colorectal cancer
Colorectal cancer with preoperative anti-tumor treatment
Pregnant or lactating women
There are serious complications during or after operation, affecting
the prognosis
Hepatitis B or Hepatitis C antibody positive
HIV antibody positive
Other diseases considered by the research doctor to affect the
prognosis and survival
Other conditions that the research doctor believes are not consistent
with this study.
3.3 Termination criteria
Termination of study treatment does not represent withdrawal from the
study. Subjects who terminate the study must continue to complete the
remaining tasks according to the protocol requirements
Research visits. The study treatment must be terminated if the subject
meets any of the following criteria:
Subjects voluntarily withdraw from the study, terminate testing, or
withdraw their informed consent;

Subjects have poor compliance and cannot be tested on time;
The subject is missing a visit or has a pregnancy event;
Other situations where the researcher believes it is necessary to end
the research and testing.