| primary tumors | Number of cases |
| lung cancer | 26 |
| breast cancer | 22 |
| prostate cancer | 17 |
| nasopharyngeal carcinoma | 3 |
| esophageal cancer | 4 |
| rectal cancer | 2 |
| liver cancer | 2 |
| renal carcinoma | 1 |
| gastric cancer | 1 |
| colon cancer | 1 |
| cervical cancer | 1 |