Table 1.

Characteristics of included studies

Study	No. of patients	No. of HR+HER2, HER2+, and TNBC	Type of study	Median follow-up, mo	Comparison groups by BMI, kg/m2	HR+HER2−			HER2+			TNBC
						DFS	OS	BCSS	DFS	OS	BCSS	DFS	OS	BCSS
Subset A1: studies comparing obese with nonobese, No. of studiesa	—	—	—	—	—	8	7	6	11	9	5	12	11	6
Jeon et al., 2015 (12)	41 021	21 094, 8005, 7436	Obs	92	≥30 vs <18.5-24.9	No	Yes	Yes	No	Yesc	Yesc	No	Yes	Yes
Pajares et al., 2013 (13) GEICAM/BCIR trial	5683	—	Int	93.4	35 vs <25	Yesd	Yes	Yes	Yesd	Yes	Yes	Yesd	Yes	Yes
Sparano et al., 2012 (5) ECOG1199 trial	4770	—	Int	94.8	≥30 vs <25	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Sun et al., 2015 (14)	1109	714, 72, 197	Obs	162	≥30 vs <25	No	Yes	Yes	No	No	No	No	Yes	Yes
Ademuyiwa et al., 2011 (15)	418	0, 0, 418	Obs	37.1	≥30 vs <25	No	No	No	No	No	No	Yes	Yes	No
Dawood et al., 2012 (16)	2311	0, 0, 2311	Obs	39	≥30 vs <25	No	No	No	No	No	No	Yes	Yes	No
Paul et al., 2016 (17)	74	0, 0, 74	Obs	68	≥30 vs <25	No	No	No	No	No	No	Yes	Yes	No
Tait et al., 2014 (18)	448	0, 0, 448	Obs	40.1	≥30 vs <25	No	No	No	No	No	No	Yes	No	No
Widschwendter et al., 2015 (19)	3754	2045, 883, 742	Int	65	≥30 vs <25	Yes	Yes	No	Yes	Yes	No	Yes	Yes	No
Cecchini et al., 2016 (20) NSABB-31 trial	2102	0, 2102, 0	Int	99.6e	≥30 vs <25	No	No	No	Yesc,g	Yesc	No	No	No	No
Crozier et al., 2013 (21) N9831 trial	3017	0, 3017, 0	Int	63.6	≥30 vs <25	No	No	No	Yes	No	No	No	No	No
Martel et al., 2018 (22) ALTTO trial	8381	0, 8381, 0	Int	na	≥30 vs <25	No	No	No	Yes	Yes	No	No	No	No
Mazzarella et al., 2013 (23)	1250	0, 1250, 0	Obs	98.4	≥30 vs <25	No	No	No	Yesc	Yesc	No	No	No	No
Turkoz et al., 2013 (4)	733	561, 65, 107	Obs	29	≥30 vs 18.5-24.9	Yes	No	Yes	Yes	No	Yes	Yes	No	Yes
Robinson et al., 2014 (24)	1155	1155, 0, 0	Obs	67.2	30-40 vs ≥18.5-24.9	Yes	No	No	No	No	No	No	No	No
Kawai et al., 2016 (25)	20 090	13 838, 1485, 2993	Obs	80.4	≥30 vs <18.5-21.8	Yesd	No	Yes	Yesd,f	No	Yesf	Yesd	No	Yes
Lara-Medina et al., 2011 (26)	1048	1167, 421, 477	Obs	17	≥30 vs <18.5-21.8	Yes	Yes	No	Yesf	Yes§	No	Yes	Yes	No
De La Cruz et al., 2017 (27)	1415	0, 0, 1495	Obs	61.2	≥30 vs <30	No	No	No	No	No	No	Yes	Yes	No
Liu et al., 2018 (28)	273	135, 94, 44	Obs	32.6	≥30 vs <30	Yes	Yes	No	Yes	Yes	No	Yes	Yes	No
Subset A2: studies comparing obese with nonobese, No. of studiesb	—	—	—	—	—	3	2	0	2	2	0	6	7	1
Bao et al., 2016 (29)	518	0, 0, 518	Obs	109.2	≥28 vs 18.5-23.9	No	No	No	No	No	No	Yes	Yes	No
Chen et al., 2016 (30)	206	0, 0, 206	Obs	59	≥25 vs <25	No	No	No	No	No	No	Yes	Yes	No
Cho et al., 2018 (6)	5668	3352, 1151, 793	Obs	na	≥25 vs <25	Yes	Yes	No	Yesc	Yesc	No	Yes	Yes	No
Sato et al., 2017 (31)	1924	1371, 258, 295	Obs	73	≥25 vs <25	Yes	Yes	No	Yesc	Yesc	No	Yes	Yes	No
Ohara et al., 2015 (32)	184	184, 0, 0	Obs	46.1	≥25 vs <25	Yesd	No	No	No	No	No	No	No	No
Al Jarroudi et al., 2017 (33)	115	0, 0, 115	Obs	na	≥ 25 vs <25	No	No	No	No	No	No	Yes	Yes	No
Hao et al, 2015 (34)	1106	0, 0, 1106	Obs	44.8	>24 vs ≤24	No	No	No	No	No	No	No	Yes	Yes
Asaga et al., 2013 (35)	135	0, 0, 135	Obs	49.2	>25 vs <18.5	No	No	No	No	No	No	Yes	Yes	No
Subset B: studies comparing overweight with nonoverweight, No. of studies	—	—	—	—	—	2	3	3	5	4	2	6	6	3
Sun et al., 2015 (14)	1109	714, 72, 197	Obs	162	25-29.9 vs <25	No	Yes	Yes	No	No	No	No	Yes	Yes
Ademuyiwa et al., 2011 (15)	418	0, 0, 418	Obs	37.1	25-29.9 vs <25	No	No	No	No	No	No	Yes	Yes	No
Dawood et al., 2012 (16)	2311	0, 0, 2311	Obs	39	25-29.9 vs <25	No	No	No	No	No	No	Yes	Yes	No
Paul et al., 2016 (17)	74	0, 0, 74	Obs	68	25-29.9 vs <25	No	No	No	No	No	No	Yes	Yes	No
Cecchini et al., 2016 (20) NSABP-31 trial	2102	0, 2102, 0	Int	99.6e	25-29.9 vs <25	No	No	No	Yesc,g	Yesc	No	No	No	No
Crozier et al., 2013 (21) N9831 trial	3017	0, 3017, 0	Int	63.6	25-29.9 vs <25	No	No	No	Yes	No	No	No	No	No
Mazzarella et al., 2013 (23)	1250	0, 1250, 0	Obs	98.4	25-29.9 vs <25	No	No	No	Yes	Yes	No	No	No	No
Jeon et al., 2015 (12)	41 021	21 094, 8005, 7436	Obs	92	25-29.9 vs 18.5-24.9	No	Yes	Yes	No	Yesc	Yesc	No	Yes	Yes
Kawai et al., 2016 (25)	20 090	13 838, 1485, 2993	Obs	80.4	25-29.9 vs <18.5-21.8	Yesd	No	Yes	Yesd,f	No	Yesf	Yesd	No	Yes
Tait et al., 2014 (18)	448	0, 0, 448	Obs	40.1	25-29.9 vs <25	No	No	No	No	No	No	Yes	No	No
Widschwendter et al., 2015 (19)	3754	2045, 883, 742	Int	65	25-29.9 vs <25	Yes	Yes	No	Yes	Yes	No	Yes	Yes	No

^aObese defined as BMI ≥30 kg/m². ALTTO = Adjuvant Lapatinib And/Or Trastuzumab Treatment Optimisation; BCR = breast cancer recurrence; BCSS = breast cancer–specific survival; BMI = body mass index; DFS = disease-free survival; ECOG = Eastern Cooperative Oncology Group; HR = hormone receptor; Int = interventional; NA = not available; NSABP = National Surgical Adjuvant Breast and Bowel Project; Obs = observational; OS = overall survival; RFS = recurrence-free survival; TNBC = triple-negative breast cancer; Yes = available outcomes according to each tumor subtype.

^bObese defined as BMI ≥28, 25, or 24 kg/m².

^cHER2+ further divided into HR+ and HR−.

^dRFS.

^eMean follow-up.

^fHER2+ HR− only.

^gBCR.