Health care use among patients with breast cancer who were or were not referred to a Breast Assessment Site affiliated with the Ontario Breast Screening Program
| Type of encounter* | Non-O-BAS | O-BAS | ||
|---|---|---|---|---|
| No. (%) of patients n = 8862 | Days from encounter to diagnosis, median (IQR)† | No. (%) of patients n = 42 598 | Days from encounter to diagnosis, median (IQR)† | |
| Mammography | ||||
| Screening mammography | 2683 (30.3) | 25 (14 to 41) | 18614 (43.7) | 23 (14 to 39) |
| Diagnostic mammography (first) | 6929 (78.2) | 14 (3 to 28) | 38708 (90.9) | 11 (0 to 23) |
| Diagnostic mammography (second) | 3726 (42.0) | 6 (−2 to 20) | 25585 (60.1) | 0 (0 to 14) |
| Diagnostic mammography (third) | 1360 (15.3) | 0 (−32 to 0) | 12509 (29.4) | 0 (−30 to 0) |
| Any mammography | 7386 (83.3) | 17 (7 to 34) | 40858 (95.9) | 17 (7 to 32) |
| Other imaging | ||||
| Breast ultrasonography (first) | 7278 (82.1) | 8 (0 to 20) | 40155 (94.3) | 5 (0 to 17) |
| Breast ultrasonography (second) | 7114 (80.3) | 12 (1 to 23) | 39736 (93.3) | 9 (0 to 21) |
| Breast ultrasonography (third) | 3900 (44.0) | 0 (0 to 1) | 22379 (52.5) | 0 (0) |
| Abdominal or thoracic ultrasonography | 1832 (20.7) | 0 (−22 to 43) | 8129 (19.1) | −9 (−22 to 47) |
| Abdominal or thoracic computed tomography | 3368 (38.0) | −6 (−22 to 9.5) | 10547 (24.8) | −14 (−25 to 0) |
| Breast magnetic resonance imaging | 1168 (13.2) | −20 (−31 to −9) | 9635 (22.6) | −14 (−24 to −5) |
| Abdominal or thoracic magnetic resonance imaging | 1739 (19.6) | −15 (−27 to 2) | 11250 (26.4) | −13 (−23 to 0) |
| Chest radiography | 4300 (48.5) | 0 (−21 to 40) | 16738 (39.3) | −11 (−26 to 35) |
| Biopsy | ||||
| Breast biopsy | 7543 (85.1) | 0 (0 to 0) | 41160 (96.6) | 0 (0) |
| Lymph node biopsy | 789 (8.9) | 0 (−11 to 0) | 3711 (8.7) | 0 (−5 to 0) |
| Any biopsy | 7723 (87.1) | 0 (0) | 41804 (98.1) | 0 (0) |
| Consultations and visits | ||||
| General or general thoracic surgeon | 7690 (86.8) | −1 (−14 to 9) | 41300 (97.0) | −8 (−16 to 3) |
| Cardiac surgery consult | 52 (0.6) | 53 (−9 to 121) | 149 (0.3) | 87 (7 to 149) |
| Dermatology consult | 556 (6.3) | 86 (22 to 138) | 3088 (7.2) | 84 (27 to 140) |
| Cardiology consult | 632 (7.1) | 55 (0.5 to 128) | 2619 (6.1) | 63 (−2 to 127) |
| Primary care provider visit | 4337 (48.9) | 44 (3 to 115) | 17059 (40.0) | 59 (12 to 123) |
| Medical oncology consult | 2310 (26.1) | −22 (−36 to −11) | 6180 (14.5) | −19 (−30 to −11) |
| Internal medicine consult | 2131 (24.0) | 0 (−18 to 81) | 7529 (17.7) | 10 (−21 to 104) |
| Radiation oncology consult | 1443 (16.3) | −22 (−36 to −10) | 4117 (9.7) | −20 (−33 to −10) |
| First visit | ||||
| Earliest of any of the above until diagnosis | 8056 (90.9) | 53 (20 to 128) | 39822 (93.5) | 49 (19 to 125) |
| Earliest of any of the above until diagnosis (including diagnosis date) | 8862 (100.0) | 42 (14 to 121) | 42598 (100.0) | 42 (15 to 119) |
| Suspicion date until diagnosis | 7788 (87.9) | 39 (20 to 92) | 40052 (94.0) | 35 (18 to 79) |
Note: IQR = interquartile range, O-BAS = OBSP-affiliated breast assessment site, OBSP = Ontario Breast Screening Program,
↵* We collected health care encounter and timing of health care encounter relative to the diagnosis date from the Ontario Cancer Registry. We included encounters if they occurred within 6 months before diagnosis until the start of treatment (or 60 days after diagnosis, if no treatment). We identified encounters using billing codes from the Ontario Health Insurance Program, or procedural codes from the Discharge Abstract Database (inpatient) and the National Ambulatory Care Reporting System (outpatient).
↵† Positive values indicate the encounter occurred before diagnosis; negative values indicate the encounter occurred after diagnosis.