Oncologic efficacy of gonadotropin-releasing hormone agonist in hormone receptor-positive very young breast cancer patients treated with neoadjuvant chemotherapy

Table 1 Patient characteristics according to age group

Variable	≤ 35 yr group (n = 78), n (%)	> 35 yr group (n = 353), n (%)	P value
BMI			0.064
≤ 25	56 (71.8)	211 (59.7)
> 25	22 (28.2)	142 (40.23
Clinical tumor stage			0.187
cT1	8 (10.26)	15 (4.25)
cT2	36 (46.15)	184 (52.12)
cT3	26 (33.33)	120 (33.99)
cT4	8 (10.26)	34 (9.63)
Clinical node stage			0.237
cN1	14 (17.95)	96 (27.20)
cN2	40 (51.28)	162 (45.89)
cN3	24 (30.77)	95 (26.91)
Pathologic tumor stage			0.101
ypT0-is	15 (19.23)	34 (9.63)
ypT1	23 (29.49)	116 (32.86)
ypT2	25 (32.05)	111 (31.44)
ypT3	15 (19.23)	84 (23.80)
ypT4	0 (0.00)	8 (2.27)
Pathologic node stage			0.336
ypN0	25 (32.05)	110 (31.16)
ypN1	30 (38.46)	111 (31.44)
ypN2	18 (23.08)	86 (24.36)
ypN3	5 (6.41)	46 (13.03)
Lymphovascular invasion			0.739
Present	38 (48.72)	168 (47.59)
Absent	32 (41.03)	157 (44.48)
Unknown	8 (10.26)	28 (7.93)
Surgery			0.195
Breast conserving	43 (55.13)	166 (47.03)
Mastectomy	35 (44.87)	187 (52.97)
Nuclear grade			0.697
Low	11 (14.10)	37 (10.48)
Intermediate	32 (41.03)	165 (46.74)
High	27 (34.62)	121 (34.28)
Unknown	8 (10.26)	30 (8.50)
Radiation therapy			0.642
Yes	75 (96.15)	335 (94.90)
No	3 (3.85)	18 (5.10)
GnRH agonist			< 0.001
Yes	22 (52.4)	20 (11.2)
No	20 (47.6)	158 (88.8)

GnRH: Gonadotropin-releasing hormone; BMI: Body mass index.

Table 2 Patient characteristics according to gonadotropin-releasing hormone agonist treatment in equal to or younger than 35 years patients

Variable	GnRH agonist (n = 30), n (%)	No. of GnRH agonist (n = 48), n (%)	P value
BMI			0.999
≤ 25	25 (83.33)	40 (83.33)
> 25	5 (16.67)	8 (16.67)
Clinical tumor stage			0.150
cT1	2 (6.67)	6 (12.50)
cT2	13 (43.33)	23 (47.92)
cT3	14 (46.67)	12 (25.00)
cT4	1 (3.33)	7 (14.58)
Clinical node stage			0.185
cN1	8 (26.67)	6 (12.50)
cN2	12 (40.00)	28 (58.33)
cN3	10 (33.33)	14 (29.17)
Pathologic tumor stage			0.706
ypT0-is	7 (23.33)	8 (16.67)
ypT1	8 (26.67)	15 (31.25)
ypT2	8 (26.67)	17 (35.42)
ypT3	7 (23.33)	8 (16.67)
ypT4	0 (0.00)	0 (0.00)
Pathologic node stage			0.061
ypN0	9 (30.00)	16 (33.33)
ypN1	10 (33.33)	20 (41.67)
ypN2	7 (23.33)	11 (22.92)
ypN3	4 (13.33)	1 (2.08)
Lymphovascular invasion			0.754
Present	13 (43.33)	25 (52.08)
Absent	14 (46.67)	18 (37.50)
Unknown	3 (10.00)	5 (10.42)
Surgery			0.472
Breast conserving	15 (50.00)	28 (58.33)
Mastectomy	15 (50.00)	20 (41.67)
Nuclear grade			0.984
Low	4 (13.33)	7 (14.58)
Intermediate	13 (43.33)	19 (39.58)
High	10 (33.33)	17 (35.42)
Unknown	3 (10.00)	5 (10.42)
Radiation therapy			0.555
Yes	28 (93.33)	47 (97.92)
No	2 (6.67)	1 (2.08)

GnRH: Gonadotropin-releasing hormone; BMI: Body mass index.