Breast imaging and needle biopsy in women with clinically evident breast cancer: does combined imaging change overall diagnostic sensitivity?

Combining mammography and ultrasound improves the sensitivity of imaging diagnosis. In the context of clinical masses, where percutaneous needle biopsy is routinely incorporated into the diagnostic pathway, little is known about the incremental gain in sensitivity where using single relative to combined imaging. We examined the sensitivity of imaging and needle biopsy combinations in a cohort of 1000 women with clinically evident (clinically presenting and/or clinically palpable) breast cancer. We report the distribution of age, tumour stage and node status, clinical findings, and individual test outcomes in all subjects. Sensitivity--true positive rate for cancer detection--of different test combinations (with the number of cases missed in 1000 subjects given in parentheses) is: mammography and ultrasound 97.9% (21); mammography with needle biopsy 99.5% (5); ultrasound with needle biopsy 99.5% (5); combined imaging with needle biopsy 99.6% (4). Using only one imaging test (irrespective of whether that is mammography or ultrasound) in combination with needle biopsy provides the same sensitivity, with an incremental gain in sensitivity of 0.1% where combined imaging is included into the diagnostic pathway. This is largely due to needle biopsy identifying most cancers missed on single imaging thus negating the effect of additional imaging on overall sensitivity.