Selection of patients with breast cancer for routine follow-up bone scans.

Routine radionuclide bone scans have not been considered cost-effective for the routine follow-up after treatment of primary breast cancer. However subgroups of patients exist in whom early relapse in the skeleton is likely and this study examines again the role of the bone scan in routine follow-up. Serial radionuclide bone scans were performed every 6 months during the first 2 years of follow-up of 560 patients with breast cancer. Tumor characteristics which predict early relapse in bone were identified and the scan conversion rate from negative to positive determined for each prognostic group. A total of 199 (28%) of patients have relapsed, 50 (9%) with first recurrence in bone within two years of diagnosis. All were identified on the bone scan with a median lead time of 4 months over radiological evidence of bone involvement. The overall scan conversion rate was 2.8%. This was significantly higher in poor prognosis patients with T4 tumours (6.3%), more than four involved axillary lymph nodes (6.1%) and inoperable tumours (6.5%), than in good prognosis patients with T1 tumours (1.1%), negative axillary lymph node involvement (1.2%) or well-differentiated ductal grade tumours (1.1%). We do not recommend routine bone scans in the follow-up of all patients with breast cancer. In patients with a good prognosis after primary treatment they cannot be considered cost-effective. However, in those with features which predict early recurrence in the skeleton the frequency of scan conversion is sufficient to justify serial bone scanning during the first two years of follow-up.