| 0 | Surgery of the primary site was performed. |
| 1 | Surgery of the primary site was not performed because it was not part of the planned first-course treatment. |
| 2 | Surgery of the primary site was not recommended/performed because it was contraindicated due to patient risk factors (comorbid conditions, advanced age, etc.). |
| 5 | Surgery of the primary site was not performed because the patient died prior to planned or recommended surgery. |
| 6 | Surgery of the primary site was not performed; it was recommended by the patient's physician, but was not performed as part of the first-course therapy. No reason was noted in the patient's record. |
| 7 | Surgery of the primary site was not performed; it was recommended by the patient's physician, but this treatment was refused by the patient, the patient's family member, or the patient's guardian. The refusal was noted in the patient record. |
| 8 | Surgery of the primary site was recommended, but it is unknown if it was performed. Further follow-up is recommended. |
| 9 | It is unknown if surgery of the primary site was recommended or performed. Death certificate-only cases and autopsy-only cases. |