Using subsetting to identify factors significantly associated with breast cancer recurrence within patient populations based on MRI usage

Controversies remain as to how beneficial MRI (magnetic resonance imaging) can influence the association of recurrence with demographic and clinical factors of the patient population. Here, we examine this preposition by analyzing cross-tabulations of breast cancer recurrences within 586 patient documented as having had an MRI scan and within 500 patients documented with no prior MRI use from the Lynn Sage Cancer Research Foundation. Results indicate that MRI use appeared to be associated with lower recurrence rates among ER/PR positive patients in contrast to their ER/PR negative counterparts (5.34% versus 20.51%, p < 0.0001 in the MRI subset; 11.41% vs. 18.60% with no MRI) and with a lessened detrimental effect of palpable mass on recurrence (12.14% versus 6.32%, p = 0.02 in the MRI subset; 21.49% versus 9.7%, p = 0.001 with no MRI) but also with the lessened beneficial effect of optimal therapy (8.27% versus 11.11%, p = 0.66 in the MRI subset; 11.80% versus 23.53%, p = 0.06 with no MRI). MRI use did not appear to affect the association between recurrence and age, race, or histology. These outcomes lead us to recommend more investigation into how this technology influences breast cancer recurrence rates to determine which patient populations could benefit most from its use.