Table 4.
Patient and Treating Surgeon Factors Associated With Number of Breast Surgeries (n = 12,013 surgeons; n = 88,272 patients)
| Predictor | No. of Patients | No. of Patients With Multiple Breast Cancer Surgeries | Unadjusted |
Adjusted |
||||
|---|---|---|---|---|---|---|---|---|
| RR | 95% CI | P* | RR | 95% CI | P* | |||
| Patient factors | ||||||||
| Type of biopsy | ||||||||
| Needle biopsy by nonsurgeon | 37,272 | 12,232 | 1 | 1 | ||||
| Needle biopsy by surgeon | 23,189 | 8,191 | 1.02 | 0.99 to 1.04 | .070 | 1.03 | 1.01 to 1.05 | .005 |
| No needle biopsy | 27,811 | 19,332 | 2.11 | 2.09 to 2.14 | < .001 | 2.10 | 2.07 to 2.12 | < .001 |
| Age, years | ||||||||
| < 70 | 17,755 | 8,532 | 1.25 | 1.22 to 1.28 | < .001 | 1.26 | 1.24 to 1.29 | < .001 |
| 70-79 | 51,279 | 23,666 | 1.21 | 1.19 to 1.23 | < .001 | 1.23 | 1.21 to 1.25 | < .001 |
| ≥ 80 | 19,238 | 7,557 | 1 | 1 | ||||
| Race/ethnicity | ||||||||
| White | 81,471 | 36,556 | 1 | |||||
| Black | 4,798 | 2,307 | 1.03 | 0.99 to 1.07 | .172 | NS | ||
| Other | 2,003 | 892 | 1.01 | 0.96 to 1.07 | .619 | NS | ||
| Medicaid coverage | ||||||||
| Yes | 5,363 | 2,379 | 1 | 1 | ||||
| No | 82,909 | 37,376 | 1.07 | 1.03 to 1.11 | < .001 | 1.11 | 1.08 to 1.15 | < .001 |
| Year of BCS | ||||||||
| 2003 | 19,630 | 7,917 | 1 | 1 | ||||
| 2004 | 18,502 | 8,514 | 1.16 | 1.13 to 1.18 | < .001 | 1.20 | 1.17 to 1.23 | < .001 |
| 2005 | 17,879 | 8,543 | 1.21 | 1.19 to 1.24 | < .001 | 1.29 | 1.26 to 1.32 | < .001 |
| 2006 | 17,959 | 8,516 | 1.20 | 1.17 to 1.23 | < .001 | 1.32 | 1.29 to 1.34 | < .001 |
| 2007 | 14,302 | 6,265 | 1.11 | 1.08 to 1.14 | < .001 | 1.25 | 1.22 to 1.28 | < .001 |
| Charlson comorbidity score | ||||||||
| ≤ 1 | 80,563 | 36,364 | 1.08 | 1.03 to 1.13 | .004 | 1.10 | 1.04 to 1.15 | < .001 |
| 2 | 5,340 | 2,370 | 1.04 | 0.98 to 1.10 | .183 | 1.05 | 0.99 to 1.11 | .106 |
| ≥ 3 | 2,369 | 1,021 | 1 | 1 | ||||
| Receipt of chemotherapy | ||||||||
| Yes | 12,137 | 5,949 | 1.10 | 1.07 to 1.12 | < .001 | 1.08 | 1.05 to 1.10 | < .001 |
| No | 76,135 | 33,806 | 1 | 1 | ||||
| County of residence | ||||||||
| Rural | 17,397 | 8,144 | 1 | < .001 | 1 | |||
| Urban | 70,875 | 31,611 | 0.95 | 0.93 to 0.98 | 1.04 | 1.01 to 1.06 | .004 | |
| Treating surgeon factors | ||||||||
| Board certified | ||||||||
| Yes | 84,321 | 37,684 | 1 | |||||
| No | 3,951 | 2,071 | 1.21 | 1.15 to 1.27 | < .001 | NS | ||
| US trained | ||||||||
| Yes | 78,462 | 34,917 | 1 | |||||
| No | 9,810 | 4,838 | 1.16 | 1.11 to 1.20 | < .001 | NS | ||
| Degree | ||||||||
| MD | 86,316 | 38,749 | 1 | |||||
| DO | 1,956 | 1,006 | 1.15 | 1.06 to 1.23 | < .001 | NS | ||
| Decade of medical school graduation | ||||||||
| Before 1980 | 37,056 | 16,626 | 1.15 | 0.97 to 1.34 | .107 | NS | ||
| 1980-1989 | 33,685 | 15,373 | 1.16 | 0.97 to 1.34 | .100 | NS | ||
| 1990-1999 | 17,239 | 7,637 | 1.11 | 0.93 to 1.30 | .243 | NS | ||
| 2000+ | 292 | 119 | 1 | |||||
| Case volume, No. of patients† | ||||||||
| ≤ 5 | 17,469 | 9,191 | 1.33 | 1.28 to 1.37 | < .001 | 1.08 | 1.04 to 1.13 | < .001 |
| > 5 and ≤ 10 | 16,578 | 7,856 | 1.17 | 1.12 to 1.22 | < .001 | 1.04 | 0.99 to 1.08 | .063 |
| > 10 and ≤ 20 | 20,914 | 9,449 | 1.12 | 1.07 to 1.17 | < .001 | 1.03 | 0.99 to 1.07 | .170 |
| > 20 | 33,311 | 13,259 | 1 | 1 | ||||
| Surgical specialty‡ | ||||||||
| Surgical oncologist | 14,356 | 5,489 | 1 | 1 | ||||
| General surgeon | 72,990 | 33,578 | 1.32 | 1.27 to 1.38 | < .001 | 1.14 | 1.09 to 1.19 | < .001 |
| Other | 926 | 688 | 1.98 | 1.92 to 2.02 | < .001 | 1.80 | 1.72 to 1.87 | < .001 |
| Sex | ||||||||
| Male | 66,227 | 30,587 | 1.14 | 1.10 to 1.18 | < .001 | NS | ||
| Female | 22,045 | 9,168 | 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 higher likelihood of multiple (two or more) breast cancer surgeries on separate dates before starting adjuvant radiation therapy. In this model, 392 surgeons and 1,440 patients were excluded as a result of unknown covariates. The ratio of the generalized χ2 statistic to its df was 0.91.
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.
Medical specialty was determined using the coded provider specialty in both the Carrier file and the American Medical Association Physician Masterfile, with either source considered sufficient to document a specialty of surgical oncology.