This is a nested cohort study of OAMBP-01. Patients over 70 years old were enrolled into the data-analysis.

The purpose of this study was to examine the feasibility and safety of laparoscopic colorectal resection in elderly patients from a single center, and to explore if there are advantages in laparoscopic surgery.

Surgical resection remains the primary treatment for CRC. Despite advancements in surgical techniques, treating elderly cancer patients remains challenging for surgeons. Perioperative risk increases as elderly patients are susceptible to cardiovascular and respiratory diseases. In addition, it has been demonstrated that elderly individuals come with more locally advanced tumor and are more likely to have obstructive or disseminated disease at the time of presentation. In addition, aging diminishes a person's physiological capacity to withstand a major operation. Therefore, surgeons preferred to choose laparotomic colorectal resection to reduce surgical duration and morbidity..

The benefits of laparoscopic colorectal resections over laparotomic surgery have been clearly demonstrated in the general population. However, previous clinical trials comparing surgical approach between laparoscopy and laparotomy restricted the patient's age <75 years, we have limited information on short- and long-term safety and efficacy of elderly patients underwent laparoscopic colorectal resection.

The purpose of this study was to examine the feasibility and safety of laparoscopic colorectal resection in elderly patients from a single center, and to explore if there are advantages in laparoscopic surgery.

This is a nested cohort study of OAMBP-01. Patients over 70 years old were enrolled into the data-analysis.

Inclusion Criteria:

• 1. Patient underwent elective laparoscopic or laparotomic colorectal resection for cancer treatment; 2. Patient baseline characteristics and surgical information were available; 3. Patients with complete follow-up data.

Exclusion Criteria:

• 1. Emergency surgery for causes including bowel obstruction, bleeding, or perforation; 2. Multiple primary malignancies; 3. Failure to follow-up.

This is a nested cohort study of OAMBP-01, patients over 70 years old underwent laparotomic surgery were enrolled into the data analysis, compared with the laparotomic colorectal resection in the same time period. All eligible patients were identified by searching the database of the Gastrointestinal Surgery Centre, Third Affiliated Hospital of Sun Yat-sen University.