Impact of the COVID-19 pandemic on diagnosis, stage, and initial treatment of breast cancer in the Netherlands: a population-based study

Table 3 Association between diagnosis period and type of initial treatment

	Not yet treated	BCS	Mx with IBR	Mx without IBR	Chemotherapy	Hormonal treatment	Other
DCIS^a
Weeks 2–8	2.04 (1.44–2.88)	0.81 (0.63–1.04)	0.87 (0.58–1.32)	0.95 (0.66–1.36)	0.71 (0.08–6.32)	0.27 (0.03–2.19)	NA
Weeks 9–11	2.18 (1.31–3.61)	0.72 (0.49–1.05)	0.56 (0.28–1.10)	1.36 (0.82–2.26)	NA	2.13 (0.40–11.33)	NA
Weeks 12–13	1.38 (0.61–3.13)	0.80 (0.47–1.36)	0.44 (0.15–1.29)	1.38 (0.70–2.72)	NA	18.32 (3.68–91.30)	NA
Weeks 14–17	1.07 (0.37–3.11)	0.53 (0.28–1.04)	1.92 (0.78–4.74)	1.40 (0.60–3.25)	5.98 (0.57–62.65)	2.13 (0.22–20.53)	NA
Invasive^b
Weeks 2–8	1.11 (0.84–1.48)	0.93 (0.83–1.04)	0.93 (0.74–1.16)	1.01 (0.88–1.16)	0.96 (0.82–1.12)	1.23 (1.05–1.44)	0.50 (0.25–0.98)
Weeks 9–11	0.95 (0.60–1.50)	0.93 (0.79–1.10)	0.97 (0.70–1.36)	1.11 (0.91–1.36)	0.59 (0.45–0.76)	1.92 (1.53–2.41)	NA
Weeks 12–13	0.63 (0.27–1.45)	0.91 (0.70–1.17)	0.52 (0.28–0.96)	0.90 (0.65–1.24)	0.66 (0.45–0.95)	3.01 (2.20–4.11)	NA
Weeks 14–17	0.83 (0.48–1.45)	0.75 (0.61–0.92)	1.08 (0.73–1.59)	1.11 (0.87–1.41)	1.31 (1.01–1.70)	1.26 (0.96–1.65)	0.42 (0.13–1.38)

Logistic regression calculating the odds ratios and 95% confidence intervals to investigate the association between period of diagnosis of the tumor (week 2–17 2018/2019 as a reference) and type of initial treatment, for DCIS and invasive tumors separately
BCS, breast conserving surgery; DCIS, ductal carcinoma in situ; IBR, immediate breast reconstruction; Mx, mastectomy; NA, not applicable
^aOdds ratios are adjusted for age groups, socioeconomic status, and region
^bOdds ratios are adjusted for age groups, socioeconomic status, stage, subtype, and region

ISSN: 1756-8722