This dataset includes abdominal or pelvic enhanced CT images within 10 days before surgery of 230 patients with stage II colorectal cancer (CRC). The inclusion criteria were as follows: (i) patients with radical surgery for CRC (complete removal of the original tumor and regional lymphadenectomy); (ii) patients with stage II CRC confirmed by histology and pathology; (iii) abdominal or pelvic enhanced CT examination was performed within 10 days before surgery, with complete CT enhanced scan images. The exclusion criteria were as follows: (i) preoperative treatment (neoadjuvant chemotherapy or radiotherapy); (ii) patients with another tumor diseases at the same time; (iii) patients who died within 1 month after surgery due to acute surgical complications. 

All CT images were enhanced abdominal or pelvic CT scan, which were scanned by using a Sensation 64 (Siemens Healthcare, Erlangen, Germany) CT scanner or Brilliance (Philips Healthcare, Best, The Netherlands) CT scanner. The specific scanning parameters were as follows: 120kV tube voltage, 200mA tube current, 5 mm slice thickness, 0.5s/week rack speed, 1.4 or 0.9 pitch, 4.11 cm field of view and a 512×512 matrix. 80-100ml iodine contrast agent ioprolamine was injected through the cubital vein at a speed of 2-3mL/s. CT enhanced images were collected after 65-75s contrast agent injection.

The digital CT images were retrieved from the picture archiving and communication system (PACS), and exported with digital imaging and communication in medicine (DICOM) format. Patient identifying information has been removed. The publishing of this dataset follows the ethical and privacy rules of China. Other researchers can further analyze these CT images of stage II colorectal cancer or use the data as validation sets for their studies.