Table 2.
Characteristics of patients, overall and by receipt of radiation therapy. P values for differences between patients who did and did not receive radiation therapy.
| All Patients | Received RT | Omission of RT | P | |
|---|---|---|---|---|
| N = 117 | N = 74 | N = 43 | ||
| Age – mean (SD) | 76.3 (5.68) | 74.7 (4.61) | 78.9 (6.41) | < 0.001 |
| Age -median (range) | 75 (70, 95) | 73 (70, 87) | 78 (70, 95) | < 0.001 |
| Age -no. (%) | ||||
| 70–74 | 58 (49.6) | 44 (59.5) | 14 (32.6) | 0.007 |
| 75 or older | 59 (50.4) | 30 (40.5) | 29 (67.4) | |
| Race -no. (%) | ||||
| Caucasian | 83 (72.2) | 54 (74) | 29 (69) | 0.408 |
| African American Asian | 25 (21.7) | 13 (17.8) | 12 (28.6) | |
| Other | 1 (0.9) | 1 (1.4) | 0 (0) | |
| Unknown | 6 (5.2) | 5 (6.8) | 1 (2.4) | |
| 2 | 1 | 1 | ||
| Tumor size (cm) -median (range) | 1 (0.2, 2) | 1.1 (0.2, 2) | 1 (0.2, 1.8) | 0.362 |
| Tumor grade -no. (%) | ||||
| I | 30 (25.9) | 18 (24.7) | 12 (27.9) | 0.675 |
| II | 77 (66.4) | 48 (65.8) | 29 (67.4) | |
| III | 9 (7.8) | 7 (9.6) | 2 (4.7) | |
| Unknown | 1 | 1 | 0 | |
| Tumor histology -no. (%) | ||||
| Ductal | 87 (74.4) | 55 (74.3) | 32 (74.4) | 0.353 |
| Lobular | 17 (14.5) | 13 (17.6) | 4 (9.3) | |
| Mixed | 11 (9.4) | 5 (6.8) | 6 (14) | |
| Other | 2 (1.7) | 1 (1.4) | 1 (2.3) | |
| LN Biopsy -no. (%) | ||||
| Not done, clinically negative | 21 (17.9) | 6 (8.1) | 15 (34.9) | < 0.001 |
| Done, negative | 96 (82.1) | 68 (91.9) | 28 (65.1) |
LN: lymph node
RT: radiation therapy
cm: centimeter