TABLE 1.
Description of the 30 Population-based Studies Included in the Review
| Author, year | Population, Country | Number of Patients | Included Patients | Tumor Characteristics | Treatment Data | Comorbidity | Follow-up Months | Survival Data | Stratified Analysis |
|---|---|---|---|---|---|---|---|---|---|
| Mahmood et al 201230 |
SEER, USA 1990–2009 |
14,764: B 6640, M 8124 |
T1-2N0-1M0 Age 20–39 |
TS (10 mm groups), LN, type, grade, ER, PgR |
RT | No | 68 mo | 5-yr OS: B 92.5% M 83.5% |
Age |
| Hwang et al 20137 |
California, USA 1990–2004 |
112,514: B 61,771, M 50,383 |
T1-2N0-1M0 | TS, LN, grade | RT | No | 110 mo | 10-yr OS: age <50/HR– B 81%, M 75% Age ≥50/HR+ B 92%, M 87% |
<50HR–, <50HR+, ≥50HR–, ≤50HR+ |
| Jeon et al 201342 | South Korea 1988–2006 |
3512 B 1951 M 1561 |
T1N0-1M0 Age ≤40 |
T-stage (T1a, T1b, T1c), N-stage (N0, N1) | CT ET |
No | 111 | 10-yr BCSS B 96.9%, M 94.9% |
N-stage (N0, N1) |
| Agarwal et al 201431 |
SEER, USA 1998–2009 |
132,149: B 92,671, M 34,999 (4479) |
T≤40 mm, N0-1M0 |
TS (0-2, 2-4), LN ER, PgR, grade |
No | No | ? | 5-yr BCSS: B 97%, M 94%, M+RT 90% 10-yr BCSS: B 95%, M 90%, M+RT 83% |
Mx-RT, Mx+RT |
| Hartmann-Johnsen et al 20158 |
Norway 2002–2010 |
13,015: B 8065, M 4950 |
T1-2N0-1M0 | TNM-stage, type, grade | No | No | 87–104 mo | 5-yr OS: B 95% M 80% |
Age < 50 |
| Fisher et al 201517 |
Alberta, Canada 2005–2011 |
14,939: B alone 805, B 5722, M 8412 (?) |
T1-4N0-3M0 | T-stage, N-stage, ER, PR | CT (adjuvant, neoadjuvant), ET; (RT) |
No | 50 mo | 5-yr OS: B alone 74% B 94% M 83% |
Stage (I, II, III), Mx-RT, Mx+RT |
| Hofvind et al 201539 |
Norway 2005–2011 |
9547: B 5906, M 3641 |
T1-4N0-3M0 | T-stage, N-stage, molecular subtypes, grade | CT, ET, RT | No | ? | 6-yr OS: B 97.1% M 89.3% |
No |
| Chen, Liu et al 201543 |
NCDB, USA 2004–2011 |
160,880: B 126,569, M 34,311 (8181) |
T1-2N0-3M0 | T-stage, N-stage, ER, PR, grade, localization, LVI | CT | Yes | 43.4 mo | 5-yr OS: B 93.2% M 83.5% |
N-stage (N0, N1, N2), Age (<50; ≥) and N-stage, CCI and N-stage, Mx-RT, Mx+RT |
| Ye et al 201532 |
SEER, USA 1998–2003 |
6671: B 3249, M 3422 (795) |
T1-3N0-1M0 Age < 40 |
Stage, T-stage (T1-T3), LN (N0, N1), ER | CT, ET | No | 111 MO | 10-yr OS: B 82% M 65% |
Age, stage, Mx-RT, Mx+RT |
| van Maaren et al 201613 |
Netherlands 2000–2004 |
37,207: B 21,734, M 15,473 |
T1-2N0-1M0 | Size, LN, ER, PR, grade, localization | CT, ET | No | 10-yr OS: B 82% M 65% |
T1N0, T1N1, T2N0, T2, N1 | |
| van Maaren et al 201641 |
Netherlands 2000–2004 |
3071: B 1055, M 2016 (2016) |
T1-2N2M0 | Size, LN, type, grade, ER | CT, ET | No | 126 MO | 10-yr OS: B 63% M 52% |
T1N2, T2N2 |
| Bleicher et al 201634 |
SEER, USA 1992–2009 |
5685: B 887, M 4798 |
T3N0-3M0 Age 65 |
Stage II-III, LN, type, grade, size, ER | CT, RT; NACT | Yes | 5-yr OS: B 51.8 M 49.6 |
||
| Chen, Wang et al 201733 |
SEER, USA 2010–2013 |
11,514: B 5469, M 6045 |
T1-4N0-3M0 TNBC |
Grade, stage, TNM | RT | No | 22 mo | 4-yr OS: B 91% M 82% |
Grade, stage, T-stage, N-stage, age |
| Hartmann-Johnsen et al 201740 |
Norway 1998–2009 |
6387: B 4449, M 1938 |
T1-2N0-1M0 | Size, LN, type, grade, ER-stratification in TNM | No | No | 72 mo | 10-yr OS: B 96% M 92% |
T1N0, T2N0, T1N1, T2N1 |
| Lagendijk et al* 2017(1)9 |
Netherlands 1998–2005 |
60,381: B 31,413, M 4950 |
T1-2N0-2M0 | Tumor localization, T-stage, N-stage, type, grade | CT, ET, RT | Yes | 144 mo | T1-2N0-1 10-yr OS: B 89% M 78% |
T1-2N0-1, T1-2N2, T1-2N0-1; age; ER/PgR; adjuvant therapy; comorbidity |
| Lagendijk et al* 2017(2)9 |
Netherlands 2006–2012 |
69,311: B 41,580, M 27,731 |
T1, 2N0-2M0 | Tumor localization, T-stage, N-stage, type, grade. HR, HER2, focality | CT, ET, RT | Yes | 84 mo | T1-2N0-1 10-yr OS: B 94% M 87% |
T1-2N0-1, T1-2N2, T1-2N0-1; age; ER/PgR; adjuvant therapy; comorbidity |
| Mogal et al 201736 |
SEER, USA 1998–2009 |
1784: B alone 270, B 918, M 596 |
T1-2N01M0 Age 70+ |
Size, LN | RT | Yes | BCS+RT 10-yr OS: B alone 63% B 73% M 63% |
||
| Grover et al 201737 |
SEER, USA 1995–2009 |
150,171: B 94,477 M 51,219 |
T1-2 (≤30 mm), N0M0 Age ≥50 |
Size (5 mm groups), ER, PgR | RT | No | 61/63 | 10-yr OS B 79.5 B (APBI) 78.8 M 67.4 |
|
| Christiansen et al 201810 |
DBCG, Denmark 1995–2012 |
58,331: B 26,958, M 27,143 (6556) |
T1-3N1-3M0 | Size, LN, type, grade, ER, HER2, LVI, focality | CT, ET, RT | Yes | 138 mo | 10-yr OS: B 82% M 57% |
N-stage (N0, N1, N2, N2; age, year of incl. CCl, adjuvant treatment, Mx-RT, Mx+RT |
| Lazow et al 201944 |
NCDB, USA 2004–2014 |
11,859: B 5074, M 6785 |
T1N0M0 Age <40 |
Grade, “subtypes” based on HR and HER2 | CT, ET, anti-HER2, RT, bilat mastectomy, reconstruction | Yes | 62 mo | ||
| Mazor et al 201911 |
NCDB, USA 2004–2011 |
30,324: B 3296, M 27,028 |
T3N0-3M0 | Size, LN, grade, type | CT, RT | Yes | ? | 5-yr OS: B 68% M 69% |
|
| Landercasper et al 201912 |
NCDB, USA 2004–2013 |
845,136: B 464,053, M 381,084 |
T0-4N0-3M0 | T-stage, N-stage, grade, type, ER | CT, RT | Yes | ? | 5-yr OS: B 88.6% M 83% |
Stage (I, II, III); HR (positive, negative) |
| Li et al 201935 |
SEER, USA 2010–2014 |
14,910: B 7381, M 7529 (562) |
T1-2N0M0 TNBC |
Size, grade, stage, type (HR, HER2) | CT, (RT) | No | ? | 5-yr OS: B 88.6% M 83% |
Age; size; grade; stage, Mx-RT, Mx+RT |
| Almahariq et al 202045 |
NCDB, USA 2006–2014 |
231,642: B 144,263, M 87,379 |
T1-2N0M0 | T-stage, ER, PgR, HER2, grade, LVl, no LN evaluated, localization, RS | CT, ET | Yes | B 49 M 47 |
5-yr OS: B 94.4% M 91.8% |
Age, RS |
| Wrubel et al 202046 |
NCDB, USA 2004-2014 |
202,376: B 101,188, M 101,188 |
T1-2N0-1M0 | Size, No pos. nodes, type, grade, ER, PgR, HER2, LVl | CT, ET | No | B 43 M 41 |
5-yr OS: B 92.9% M 89.7% |
|
| de Boniface et al 202114 |
NKBD, Sweden 2008–2017 |
48,986: B 29,367, M 19,616 (7206) |
T1-2N0-2M0 | T-stage (T1mi, T1a etc.), N-stage, ER, PR, HER2, type, grade, | RT, CT, ET, HER2, (NACT) | Yes | 75 | 5-yr OS B 95.1% M 84.5% M+R 86.0 |
T1N0, T1N1, T1N2, T2N0, T2N1, T2N2, Mx-RT, Mx+RT |
| Guo et al 202138 |
SEER, USA 2010–2015 |
13,986: B 6116, M 7146 (2663) |
T1-4N0-3M0 TNBC |
T-stage, N-stage, grade, laterality, tumor site (HR, HER2) | RT | No | ? | 5-yr OS B 87.9% M 79.6% M+R 65.5% |
Age, T-stage, N-stage, Mx-RT, Mx+RT |
| Zhang et al 202147 |
SEER, USA 2001–2016 |
2412: B 881 M 1531 |
T1-3N0-3M0 Metaplastic BC |
T-stage, N-stage, HR, grade | RT, CT | No | 73 | 5-yr OS 84.3 vs 62.5 | |
| Chu et al 202148 |
Lousianna, USA 2004–2016 |
18,260: B 9968, M 8292 |
T1-2N0-1M0 T3N0M0 | T-stage, N-stage, grade, type, ER, focality | (RT), CT, ET | Yes | 81 | 5-yr OS B 92.0% M 84.8% |
|
| Abrahimi et al 202149 |
New Zealand 2000–2015 |
6384: B 4608, M 1776 (269) |
T1-2 (size < 30 mm) N1-2M0 | T-stage (T1. T2), N-stage, ER, PgR, type, grade, LVI | RT, CT, ET | No | 106 | Mx-RT, Mx+RT | |
| Kim et al 202150 |
South Korea 1998–2012 |
45,770: B 28,623, M 17,147 |
T1-2N0-1M0 | T-stage, N-stage, grade, LVI, subtype (ER HER2) | No | No | 68 | 10-yr OS B 93.2% 87.9% |
*Lagendijk et al includes 2 distinct periods and is therefore included as 2 separate studies. Numbers in parentheses represent subgroups of patients having mastectomy plus radiation therapy included in separate comparison with BCS plus radiation therapy.
B, breast-conserving surgery + RT; BCSS, breast cancer-specific survival; CT, chemotherapy; DBCG, Database of Danish Breast Cancer Group; ER, estrogen receptor; ET, endocrine therapy; HR, hormone receptor status; LN, lymph node status; LVI, lymphovascular invasion; M, Mastectomy; M+R, mastectomy + RT; MO, months; NCDB, National Center Data Base; OS, overall survival; PgR, progesteron receptor; RS, recurrence score; RT, radiation therapy; SEER, Database of Surveillance, Epidemiology, and End Results Program; TNBC, triple negative breast cancer; Type, histological type.