Table 1.

Estimated change of number and rate for breast cancer surgery during COVID-19 pandemic.

	Time	Estimated change of number1			Estimated change of rate2			p-value
		Number	95% CI		%	95% CI
Total	Apr-2020	689	− 499	1877	9	− 7	26	0.256
	Jul-2020	− 657	− 1947	634	− 9	− 27	9	0.319
	Oct-2020	− 79	− 1385	1227	− 1	− 20	17	0.906
	Jan-2021	539	− 770	1849	8	− 11	26	0.420
BCS without ALND	Apr-2020	97	− 188	381	3	− 6	12	0.506
	Jul-2020	− 846	− 1190	− 502	− 28	− 39	− 16	< 0.001
	Oct-2020	− 540	− 861	− 218	− 17	− 27	− 7	0.001
	Jan-2021	8	− 384	401	0	− 13	14	0.967
Mastectomy without ALND	Apr-2020	134	− 438	707	5	− 18	28	0.645
	Jul-2020	− 136	− 771	500	− 5	− 31	20	0.676
	Oct-2020	124	− 568	817	5	− 23	33	0.725
	Jan-2021	154	− 591	900	6	− 24	36	0.685
BCS with ALND	Apr-2020	− 42	− 289	205	− 8	− 55	39	0.741
	Jul-2020	− 112	− 389	166	− 21	− 75	32	0.431
	Oct-2020	− 182	− 487	124	− 35	− 93	24	0.244
	Jan-2021	38	− 292	369	7	− 56	71	0.820
Mastectomy with ALND	Apr-2020	147	− 138	431	9	− 9	27	0.312
	Jul-2020	− 1	− 339	337	0	− 22	22	0.995
	Oct-2020	− 61	− 399	277	− 4	− 26	18	0.723
	Jan-2021	9	− 329	347	1	− 21	22	0.959

ALND axillary lymph node dissection, BCS breast-conserving surgery, CI confidence interval.

¹Estimated change of number represents the change during the COVID-19 pandemic under the control of underlying trends, autocorrelation, moving average, and seasonality.

²Estimated change of rate was calculated by dividing the estimated change of number by the predicted number in the absence of the pandemic (counterfactual number).