Table 3.
Patient and Diagnosing Surgeon Factors Associated With Omission of Needle Biopsy Among Patients With Surgeon Consultation Before Biopsy (n = 10,981 diagnosing surgeons; n = 60,018 patients)
| Predictor | No. of Patients | No. of Patients With Needle Biopsy | Unadjusted |
Adjusted |
||||
|---|---|---|---|---|---|---|---|---|
| RR | 95% CI | P* | RR | 95% CI | P* | |||
| Patient factors | ||||||||
| Age, years | ||||||||
| < 70 | 11,836 | 6,436 | 1 | |||||
| 70-79 | 34,629 | 18,748 | 1.01 | 0.98 to 1.03 | .678 | NS | ||
| ≥ 80 | 13,553 | 6,994 | 1.07 | 1.04 to 1.11 | < .001 | NS | ||
| Race/ethnicity | ||||||||
| White | 55,317 | 29,869 | 1 | |||||
| Black | 3,396 | 1,679 | 1.10 | 1.05 to 1.15 | < .001 | NS | ||
| Other | 1,305 | 630 | 1.12 | 1.05 to 1.20 | .002 | NS | ||
| Medicaid coverage | ||||||||
| Yes | 3,935 | 1,825 | 1.14 | 1.09 to 1.18 | < .001 | 1.06 | 1.02 to 1.11 | .002 |
| No | 56,083 | 30,353 | 1 | 1 | ||||
| Year of BCS | ||||||||
| 2003 | 14,374 | 6,706 | 1.38 | 1.35 to 1.42 | < .001 | 1.34 | 1.30 to 1.37 | < .001 |
| 2004 | 13,021 | 6,527 | 1.28 | 1.24 to 1.31 | < .001 | 1.24 | 1.21 to 1.28 | < .001 |
| 2005 | 12,075 | 6,591 | 1.16 | 1.12 to 1.20 | < .001 | 1.15 | 1.11 to 1.18 | < .001 |
| 2006 | 11,814 | 6,998 | 1.02 | 0.99 to 1.06 | .207 | 1.02 | 0.99 to 1.06 | .187 |
| 2007 | 8,734 | 5,356 | 1 | 1 | ||||
| Charlson comorbidity score | ||||||||
| ≤ 1 | 54,491 | 29,366 | 1 | 1 | ||||
| 2 | 3,789 | 1,958 | 1.06 | 1.01 to 1.10 | .013 | 1.04 | 1.00 to 1.09 | .039 |
| ≥ 3 | 1,738 | 854 | 1.09 | 1.03 to 1.16 | .005 | 1.08 | 1.02 to 1.14 | .014 |
| Receipt of chemotherapy | ||||||||
| Yes | 8,622 | 4,879 | 1 | 1 | < .001 | |||
| No | 51,396 | 27,299 | 1.14 | 1.11 to 1.18 | < .001 | 1.15 | 1.12 to 1.18 | |
| County of residence | ||||||||
| Rural | 13,264 | 6,376 | 1.12 | 1.09 to 1.16 | < .001 | 1.07 | 1.03 to 1.10 | < .001 |
| Urban | 46,754 | 25,802 | 1 | 1 | ||||
| Distance to nearest radiologic facility performing needle biopsy, miles | ||||||||
| ≤ 0.6 | 14,739 | 8,112 | 1 | 1 | ||||
| 0.7-3.4 | 14,059 | 7,729 | 1.00 | 0.97 to 1.03 | .902 | 1.00 | 0.97 to 1.03 | .980 |
| 3.5-8.1 | 15,021 | 8,396 | 1.00 | 0.97 to 1.03 | .845 | 1.00 | 0.97 to 1.03 | .861 |
| ≥ 8.2 | 16,199 | 7,941 | 1.09 | 1.06 to 1.12 | < .001 | 1.04 | 1.01 to 1.07 | .017 |
| Mammography before surgical consultation or needle biopsy | ||||||||
| Yes | 51,529 | 28,109 | 1 | 1 | ||||
| No | 8,489 | 4,069 | 1.26 | 1.23 to 1.28 | < .001 | 1.26 | 1.23 to 1.29 | < .001 |
| Diagnosing surgeon factors | ||||||||
| Board certified | ||||||||
| Yes | 56,709 | 30,960 | 1 | 1 | ||||
| No | 3,309 | 1,218 | 1.51 | 1.45 to 1.57 | < .001 | 1.32 | 1.25 to 1.38 | < .001 |
| US trained | ||||||||
| Yes | 52,480 | 28,852 | 1 | 1 | ||||
| No | 7,538 | 3,326 | 1.38 | 1.32 to 1.43 | < .001 | 1.17 | 1.11 to 1.22 | < .001 |
| Degree | ||||||||
| MD | 58,385 | 31,522 | 1 | |||||
| DO | 1,633 | 656 | 1.40 | 1.30 to 1.50 | < .001 | NS | ||
| Decade of medical school graduation | ||||||||
| Before 1980 | 25,905 | 13,064 | 1.53 | 1.26 to 1.75 | < .001 | 1.49 | 1.25 to 1.69 | < .001 |
| 1980-1989 | 22,544 | 12,568 | 1.31 | 1.05 to 1.54 | .018 | 1.36 | 1.14 to 1.55 | .001 |
| 1990-1999 | 11,413 | 6,446 | 1.25 | 0.98 to 1.49 | .069 | 1.27 | 1.05 to 1.48 | .018 |
| 2000+ | 156 | 100 | 1 | 1 | ||||
| Case volume, No. of patients† | ||||||||
| ≤ 5 | 13,496 | 5,407 | 1.81 | 1.77 to 1.85 | < .001 | 1.66 | 1.62 to 1.70 | < .001 |
| > 5 and ≤ 10 | 12,069 | 5,968 | 1.49 | 1.43 to 1.54 | < .001 | 1.41 | 1.37 to 1.46 | < .001 |
| > 10 and ≤ 20 | 14,554 | 8,009 | 1.31 | 1.26 to 1.36 | < .001 | 1.27 | 1.22 to 1.32 | < .001 |
| > 20 | 19,899 | 12,794 | 1 | 1 | ||||
| Specialty | ||||||||
| Surgical oncologist | 7,944 | 5,055 | 1 | 1 | ||||
| General surgeon | 50,714 | 26,187 | 1.42 | 1.34 to 1.51 | < .001 | 1.11 | 1.04 to 1.19 | .001 |
| Other | 1,360 | 936 | 1.04 | 0.91 to 1.18 | .534 | 0.77 | 0.66 to 0.88 | < .001 |
| Sex | ||||||||
| Male | 46,545 | 23,938 | 1.40 | 1.34 to 1.46 | < .001 | NS | ||
| Female | 13,473 | 8,240 | 1 | |||||
Abbreviations: BCS, breast-conserving surgery; DO, doctor of osteopathy; MD, doctor of medicine; NS, not significant; RR, relative risk.
Statistical significance evaluated at the P = .05 level in both unadjusted and adjusted analyses. A RR > 1 indicates that the factor was associated with a lower likelihood of needle biopsy. In this model, 298 surgeons and 1,294 patients were excluded because of unknown covariates. The ratio of the generalized χ2 statistic to its df was 0.85, indicating no residual overdispersion in the model.
Surgeon case volume was defined for each surgeon as the number of patients in the cohort who underwent BCS performed by that surgeon during the time interval of the study.