Table 3. Risk of icSBC After a First DCIS Diagnosisa.
| Characteristics, first DCIS | Women, No. (%)b | Odds ratio (95% CI) | ||
|---|---|---|---|---|
| No SBC (n = 5777) | icSBC (n = 254) | Unadjusted | Adjustedc | |
| Age, y | ||||
| ≥50 | 4496 (78) | 192 (76) | 1 [Reference] | NA |
| <50 | 1281 (22) | 62 (24) | 1.13 (0.84-1.52) | NA |
| Race and ethnicity | ||||
| White | 1333 (23) | 49 (19) | 1 [Reference] | 1 [Reference] |
| Chinese | 467 (8) | 14 (6) | 0.82 (0.45-1.49) | 0.82 (0.45-1.50) |
| Filipino | 777 (13) | 39 (15) | 1.37 (0.89-2.10) | 1.70 (1.10-2.63) |
| Japanese | 2094 (36) | 105 (41) | 1.36 (0.97-1.93) | 1.30 (0.92-1.84) |
| Native Hawaiian | 736 (13) | 40 (16) | 1.48 (0.96-2.27) | 1.69 (1.10-2.61) |
| Minority race and ethnicityd | 370 (6) | 7 (3) | 0.52 (0.23-1.15) | 0.63 (0.28-1.40) |
| Year of diagnosis | ||||
| 1973-1989 | 485 (8) | 34 (13) | 1 [Reference] | 1 [Reference] |
| 1990-1999 | 1075 (19) | 83 (33) | 1.10 (0.73-1.67) | 1.06 (0.70-1.62) |
| 2000-2009 | 2131 (37) | 105 (41) | 0.70 (0.47-1.05) | 0.57 (0.36-0.91) |
| 2010-2017 | 2086 (36) | 32 (13) | 0.22 (0.13-0.36) | 0.17 (0.09-0.30) |
| Gradee | ||||
| Well or moderately differentiated, No./total No. (%) | 2424/4341 (56) | 86/154 (56) | 1 [Reference] | NA |
| Poorly differentiated or undifferentiated, No./total No. (%) | 1917/4341 (44) | 68/154 (44) | 1.00 (0.72-1.38) | NA |
| DCIS histologic characteristics | ||||
| Noninfiltrating, intraductal (NOS) | 2158 (37) | 124 (49) | 1 [Reference] | 1 [Reference] |
| Cribriform | 555 (10) | 23 (9) | 0.72 (0.46-1.14) | 1.37 (0.83-2.28) |
| Duct carcinoma, solid type | 410 (7) | 12 (5) | 0.51 (0.28-0.93) | 1.25 (0.65-2.42) |
| Comedocarcinoma | 807 (14) | 21 (8) | 0.45 (0.28-0.72) | 0.69 (0.43-1.12) |
| Intraductal or carcinoma in situ | 1386 (24) | 49 (19) | 0.62 (0.44-0.86) | 1.42 (0.93-2.17) |
| Other | 461 (8) | 25 (10) | 0.94 (0.61-1.47) | 1.22 (0.78-1.92) |
| Laterality, No./total No. (%)e | ||||
| Right breast | 2848/5776 (49) | 118/254 (46) | 1 [Reference] | NA |
| Left breast | 2928/5776 (51) | 136/254 (54) | 0.89 (0.69-1.15) | NA |
| ER status, No./total No. (%)e | ||||
| Positive | 2915/3472 (84) | 103/126 (82) | 1 [Reference] | NA |
| Negative | 557/3472 (16) | 23/126 (18) | 1.16 (0.74-1.85) | NA |
| PR status, No./total No. (%)e | ||||
| Positive | 2635/3447 (76) | 90/123 (73) | 1 [Reference] | NA |
| Negative | 812/3447 (24) | 33/123 (27) | 1.19 (0.79-1.79) | NA |
| First course of treatment | ||||
| BCS only | 534 (9) | 20 (8) | 1 [Reference] | NA |
| BCS and RT | 1220 (21) | 52 (21) | 1.14 (0.67-1.93) | NA |
| BCS and systemic treatment with or without RTf | 1240 (22) | 30 (12) | 0.65 (0.36-1.15) | NA |
| Mastectomy only | 1869 (32) | 100 (39) | 1.43 (0.88-2.33) | NA |
| Mastectomy and systemic treatment | 736 (13) | 44 (17) | 1.60 (0.93-2.74) | NA |
| No treatment | 106 (2) | 6 (2) | 1.51 (0.59-3.85) | NA |
| Other treatmentg | 72 (1) | 2 (1) | 0.74 (0.17-3.24) | NA |
Abbreviations: BCS, breast-conserving surgery; DCIS, ductal carcinoma in situ; ER, estrogen receptor; icSBC, invasive contralateral SBC; NA, not applicable; NOS, not otherwise specified; PR, progesterone receptor; RT, radiotherapy; SBC, second breast cancer.
Excludes invasive breast cancers diagnosed less than 6 months after DCIS diagnosis.
Column percentage totals may be slightly less than or greater than 100 owing to rounding.
Adjusted for variables significant in univariate analysis: race and ethnicity, diagnosis year, and histologic characteristics.
Asian ethnic subgroups (eg, Korean, Vietnamese, and Thai), Other Pacific Islander ethnicities (eg, Samoan, Micronesian, and Tongan), Black, and American Indian and Alaska Native.
Missing data: grade (n = 1607), laterality (n = 1), ER (n = 2305), and PR (n = 2330).
Systemic treatment includes chemotherapy and/or endocrine therapy.
Other treatment includes radiotherapy only, surgery (unspecified) with or without other therapy, and systemic treatment with no surgery.