Established and Validated Novel Nomogram for Predicting Prognosis of Post-Mastectomy pN0-1 Breast Cancer without Adjuvant Radiotherapy

Figures & data

Figure 1 Flow of patient selection and external validation.

Table 1 Baseline Characteristics of Included Patients

Group	Training Set (1316)	Validation Set (n=563)	P value
Age (median, range)	56 (28–92) years	58 (23–92) years
N stage
pN0	1115	475	0.90
pN1	201	88
CCI score	1 (0–8)	2 (0–7)
Location
Medial	409	191	0.25
Lateral	907	372
T size (median, range)	2 (0.01–14) cm	2 (0.02–12.5) cm
T stage
T1mic	36	11	0.65
T1a	77	26
T1b	172	72
T1c	521	221
T2	484	224
T3	26	9
Grade
1	119	58	0.57
2	742	321
3	455	184
Adjuvant chemotherapy
Yes	790	313	0.08
No	526	250
Adjuvant anti-HER-2 therapy
Yes	171	70	0.80
No	1145	493
Number of positive LN
0	1115	475	0.28
1	133	56
2	49	17
3	19	15
Number of resected LN	13 (1–46)	13 (1–38)
ER status
Positive	857	376	0.52
Negative	459	187
PR status
Positive	539	235	0.79
Negative	777	328
HER-2 status
Positive	294	123	0.79
Negative	1022	440
Adjuvant hormonal therapy
Yes	868	383	0.41
No	448	180
Sub-groups
ER positive/HER-2 negative	743	329	0.86
ER negative/HER-2 negative	279	111
ER positive/HER-2 positive	114	47
ER negative/HER-2 positive	180	76
Molecular types
Luminal A	457	186	0.60
Luminal B	413	194
HER-2 positive	178	76
Triple-negative	268	107

Figure 2 Feature selection using least absolute shrinkage and selection operator (LASSO) Cox regression for BCSS.

Table 2 Multi-Variable Cox Regression of Selected Variables in the Nomogram

Group	BCSS	LRR	DM
	HR (95% CI), p value	HR (95% CI), p value	HR (95% CI), p value
Age	1.03 (1.00–1.05), p=0.052	–	–
Number of positive LN	1.77 (1.29–2.46), p<0.001	1.71 (1.13–2.60), p=0.027	1.55 (1.17–2.06), p=0.002
T stage
pT1	Reference	–	Reference
pT2	2.25 (1.13–4.52), p=0.021	–	1.98 (1.18–3.32), p=0.01
pT3	13.04 (4.61–36.88), p<0.001	–	4.99 (1.77–14.06), p=0.002
Grade
1–2	Reference	–	Reference
3	1.38 (0.68–2.79), p=0.37	–	1.17 (0.68–2.04), p=0.55
Ki-67	1.02 (1.00–1.033), p=0.005	–	1.01 (1.00–1.02), p=0.020
Number of resected LN	–	–	1.04 (1.00–1.07), p=0.039
PR status
Positive	–	–	Reference
Negative	–	–	0.68 (0.37–1.23), p=0.20

Figure 3 Nomogram for predicting 5-year BCSS (A) and 5-year DM-free survival (B).

Figure 4 Calibration curves for 5-year BCSS and 5-year DM-free survival in the training, internal validation and external validation cohort: (A) the predicted and observed 5-BCSS in training set; (B) the predicted and observed 5-BCSS in internal validation set; (C) the predicted and observed 5-BCSS in external validation set; (D) the predicted and observed 5-year DM-free survival in training set; (E) the predicted and observed 5-year DM-free survival in internal validation set; (F) the predicted and observed 5-year DM-free survival in external validation set.