Table 2.
Hazard ratios for recurrence-free interval and overall and breast cancer–specific survival for omission vs receipt of radiotherapy
| Study endpoints | No. | No. of events/Total No. of women |
HR (95% CI) | P* | |
|---|---|---|---|---|---|
| No RT | RT | ||||
| RFI | |||||
| Unweighted (no RT vs RT)† | 1778 | 53/373 | 91/1405 | 2.59 (1.38 to 4.89) | .003 |
| Propensity weighted (no RT vs RT) ‡ | 1778 | 2.75 (1.67 to 4.54) | <.001 | ||
| Competing risk model (no RT vs RT)† | 1778 | 2.63 (1.40 to 4.92) | .003 | ||
| Locoregional RFI§ | |||||
| Unweighted (no RT vs RT) † | 1741 | 38/366 | 30/1375 | 3.91 (1.81 to 8.45) | .001 |
| Propensity weighted (no RT vs RT) ‡ | 1741 | 3.92 (1.87 to 8.20) | <.001 | ||
| Competing risk model (no RT vs RT) † | 1741 | 3.97 (1.85 to 8.50) | <.001 | ||
| Distant RFI‖ | |||||
| Unweighted (no RT vs RT) † | 1710 | 7/335 | 30/1375 | 0.90 (0.26 to 3.10) | .90 |
| Propensity weighted (no RT vs RT)‡ | 1710 | 0.84 (0.30 to 2.34) | .81 | ||
| Competing risk model (no RT vs RT) † | 1710 | 0.82 (0.24 to 2.75) | .75 | ||
| Mortality outcomes | |||||
| All-cause mortality † | 1778 | 44/373 | 104/1405 | 0.88 (0.53 to 1.44) | .61 |
| Breast cancer–specific mortality † | 1778 | 6/373 | 19/1405 | 1.14 (0.30 to 4.43) | .85 |
*
Two-sided P values are based on Student t test. RFI = recurrence-free interval; CI = confidence interval; RT = radiotherapy.
†
Adjusted for patient age, tumor grade (low, moderate, high, or unknown), ER/PR status (ER+ and PR+ or other), HER2 (negative or unknown), initial hormonal treatment (tamoxifen, aromatase inhibitors or other), tumor size, trial, and Oncotype DX recurrence score.
‡
Inverse probability of treatment weighted (IPTW) analysis.
§
Excluding distant recurrence events.
‖
Excluding locoregional recurrence events.