Performance, clinical utility, and cost-effectiveness of selective use of staging investigations in early breast cancers.

Background: International guidelines do not recommend routine staging of EBCs. However, most clinicians still perform staging investigations (SI) selectively for several reasons. We examined our practice of selective use of SI to determine its performance, clinical utility, and cost-effectiveness.

Methods: We performed this retrospective study on patients who had treatment for AJCC stage I or stage II breast cancer through Eastern health Breast and cancer centre, Melbourne, for 50 months from January 2012.

Result: Our practice of selective use resulted in SI in 41% of all EBCs (95% CI 37-46%). Overall yield was 3% (95% CI 0.4-5.4%) with a false positive rate of 22% (95% CI 1628%) and a false-negative rate of 45% (95% CI 11-79%). The sensitivity of SI is 55% (95% CI 21-89%) with a negative predictive value of 97% (95% CI 94.8-99.9%). None of the treatment components was found to be significantly changed based on findings on SI. There was no significant difference in all-cause mortality or new distant recurrence in the staged and non-staged groups. Identification of six new metastases cost at least 422 021 AUD. The approximate cost to stage one EBC is 2069 AUD. 'Number needed to scan' to detect one new metastasis is 34 at the expense of 70337AUD.

Conclusion: Selective use of SI results in better yield. However, the clinical utility of these results is not significant. It is debatable if this level of expenditure is cost-effective. Our results point to a need for change in practice.