Table 1.
Patient and tumor characteristics with respect to radiotherapy delivery
| Characteristics | Number (%) of patients
|
P-value* | ||
|---|---|---|---|---|
| Total (n=56,968) | No RT (n=21,876) | RT (n=35,092) | ||
| Age (years) | <0.001 | |||
| ≤50 | 15,554 (27.3) | 5,551 (25.4) | 10,003 (28.5) | |
| >50 | 41,414 (72.7) | 16,325 (74.6) | 25,089 (71.5) | |
| Year of diagnosis | <0.001 | |||
| 1998–2002 | 23,601 (41.4) | 9,975 (45.6) | 13,626 (38.8) | |
| 2003–2007 | 33,367 (58.6) | 11,901 (54.4) | 21,466 (61.2) | |
| Race | 0.013 | |||
| Black | 5,422 (9.5) | 2,137 (9.8) | 3,285 (9.4) | |
| White | 46,024 (80.8) | 17,626 (80.6) | 28,398 (80.9) | |
| Other† | 5,173 (9.1) | 1,896 (8.7) | 3,277 (9.3) | |
| Unknown | 349 (0.6) | 217 (1.0) | 132 (0.4) | |
| Marital status | <0.001 | |||
| Non-married‡ | 19,475 (34.2) | 7,934 (36.3) | 11,541 (32.9) | |
| Married | 35,283 (61.9) | 12,762 (58.3) | 22,521 (64.2) | |
| Unknown | 2,210 (3.9) | 1,180 (5.4) | 1,030 (2.9) | |
| % below poverty | <0.001 | |||
| <10 | 24,346 (44.5) | 8,859 (40.5) | 16,487 (47.0) | |
| 10–19.99 | 28,292 (49.7) | 11,708 (53.5) | 16,584 (47.3) | |
| ≥20 | 3,327 (5.8) | 1,307 (6.0) | 2,020 (5.8) | |
| Unknown | 3 (0.0) | 2 (0.0) | 1 (0.0) | |
| % with lower than high school education | <0.001 | |||
| ≤15.99 | 20,693 (36.3) | 7,174 (32.7) | 13,546 (38.6) | |
| 16–20.8 | 17,427 (30.6) | 6,441 (29.4) | 10,986 (31.3) | |
| 20.81–28.76 | 7,872 (13.8) | 3,021 (13.8) | 4,851 (13.8) | |
| >28.76 | 10,973 (19.3) | 5,265 (24.1) | 5,708 (16.3) | |
| Unknown | 3 (0.005) | 2 (0.003) | 1 (0.002) | |
| Poverty–high school index | <0.001 | |||
| Low SEP | 11,776 (20.7) | 5,542 (25.3) | 6,234 (17.8) | |
| Moderate SEP | 28,289 (49.7) | 10,522 (48.1) | 17,767 (50.6) | |
| High SEP | 16,900 (29.7) | 5,810 (26.6) | 11,090 (31.6) | |
| Unknown | 3 (0.0) | 2 (0.0) | 1 (0.0) | |
| Laterality | 0.755 | |||
| Left | 29,073 (51.0) | 11,140 (50.9) | 17,933 (51.1) | |
| Right | 27,874 (48.9) | 10,716 (49.0) | 17,158 (48.9) | |
| Unknown | 21 (0.037) | 20 (0.1) | 1 (0.0) | |
| Primary site | <0.001 | |||
| Single-quadrant lesions | 48,002 (84.3) | 17,269 (78.9) | 30,733 (87.6) | |
| Multi-quadrant lesions | 8,966 (15.7) | 4,607 (21.1) | 4,359 (12.4) | |
| ER status | <0.001 | |||
| Negative/borderline | 3,913 (6.9) | 1,035 (4.7) | 2,878 (8.2) | |
| Positive | 20,202 (35.5) | 6,298 (28.8) | 13,904 (39.6) | |
| Unknown | 32,853 (57.6) | 14,543 (66.5) | 18,310 (52.2) | |
| PR status | <0.001 | |||
| Negative/borderline | 6,145 (10.8) | 1,699 (7.8) | 4,446 (12.7) | |
| Positive | 16,470 (28.9) | 5,082 (23.2) | 11,388 (32.5) | |
| Unknown | 34,353 (60.3) | 15,095 (69.0) | 19,258 (54.9) | |
| Grade | <0.001 | |||
| I | 7,066 (12.4) | 3,616 (15.8) | 3,450 (10.3) | |
| II | 18,937 (33.2) | 7,706 (35.2) | 11,231 (32.0) | |
| III and IV | 19,730 (34.6) | 5,608 (25.6) | 14,122 (40.2) | |
| Unknown | 11,235 (19.7) | 5,112 (23.4) | 6,123 (17.4) | |
Notes:
*
P-value was calculated after unknown category was excluded.
†
Including American Indian/Alaskan Native and Asian/Pacific Islander.
‡
Including divorced, widowed, single (never married), and separated.
Abbreviations: RT, radiotherapy; SEP, socioeconomic position; ER, estrogen receptor; PR, progesterone receptor.