Table 4.
Clinical characteristics of left-sided and right-sided CRC in the SEER database
| RS | LS | Total | |
|---|---|---|---|
| Median age (min–max) | 71 (13–108) | 63 (11–106) | 67 (11–108) |
| Gender | |||
| Male | 22.99 | 27.58 | 50.57 |
| Female | 27.64 | 21.79 | 49.43 |
| Race (%) | |||
| White | 40.65 | 38.82 | 79.47 |
| Black | 6.52 | 4.99 | 11.51 |
| Asian | 2.84 | 4.73 | 7.57 |
| Other | 0.61 | 0.85 | 1.46 |
| Stage at presentation (%) | |||
| Stage 0 | 0.61 | 0.50 | 1.11 |
| Stage I | 10.67 | 11.23 | 21.90 |
| Stage II | 16.67 | 13.66 | 30.32 |
| Stage III | 15.53 | 17.53 | 33.06 |
| Stage IV | 7.14 | 6.46 | 13.60 |
| Histologic subtype (%) | |||
| Adenocarcinoma | 43.49 | 46.04 | 89.54 |
| Mucinous adenocarcinoma | 5.67 | 2.69 | 8.37 |
| Other | 1.45 | 0.64 | 2.10 |
| Histologic grade (%) | |||
| Well differentiated | 4.33 | 4.21 | 8.54 |
| Moderately differentiated | 33.63 | 37.77 | 71.40 |
| Poorly differentiated | 10.85 | 6.58 | 17.43 |
| Undifferentiated | 1.81 | 0.82 | 2.63 |
| Adequate lymph node examination (more than 12 nodes) (%) | |||
| Yes | 41.94 | 34.62 | 76.56 |
| No | 8.57 | 14.60 | 23.17 |
| Missing data | 0.11 | 0.16 | 0.27 |
| Type of surgery (%) | |||
| Local excision | 0.06 | 0.39 | 0.45 |
| Partial colectomy | 9.93 | 34.68 | 44.60 |
| Hemicolectomy | 39.34 | 8.43 | 47.77 |
| Total colectomy | 0.70 | 4.34 | 5.04 |
| Other colectomy | 0.55 | 1.38 | 1.94 |
| No surgery | 0.04 | 0.15 | 0.19 |
| Chemotherapy (%) | |||
| Yes | 15.59 | 24.48 | 40.07 |
| No/unknown | 35.03 | 24.90 | 59.93 |
| Radiation therapy (%) | |||
| Yes | 0.53 | 12.26 | 12.79 |
| No/unknown | 50.09 | 37.12 | 87.21 |
All patients diagnosed with colon and rectal adenocarcinoma from 2006 to 2015 in the SEER database were included. Right-sided (RS) CRC includes cancers located in the cecum, ascending colon, and transverse colon, and left-sided (LS) CRC includes those located in the descending colon, sigmoid colon, and rectum. A total of 179,323 CRC patients were included after screening