Prognostic factors among ER+ HER2- breast cancer patients in Malaysia

Y.Y. Lee1, N.A.M. Taib2, S.S. Yeoh1, C.H. Yip2, N. Bhoo-Pathy3 1Outcome and Evidence, Pfizer Malaysia , 2Surgery, University of Malaya Faculty of Medicine,3Social and Preventive Medicine, University of Malaya, Kuala Lumpur, MY

Background Results

Breast cancer is a multifaceted disease with diverse clinical, pathologic and molecular features which led to different prognostic outcomes. We aim to examine factors that influence survival outcome among ER+ HER2- patients from a single institution.

Methods

• Data of patients diagnosed between January 1, 2005 to December 1, 2011 was extracted from the University Malaya Medical Centre Breast Cancer Registry.

• Kaplan-Meier method was used to estimate overall survival. Overall survival was defined from date of diagnosis to date of death from any cause.

• Log rank tests and Cox hazards regression model were used to compare survival and identify prognostics factors.

• Stage 4 patients were excluded from univariate and multivariate analysis

Conclusion

• In this cohort, we found increasing age, tumor size and number of lymph node was associated with poorer survival outcome among ER+/HER2- breast cancer patients.

• Ethnic disparities in survival outcome were not apparent in this molecular subset.

• Women who undergone surgery had 71% greater survival outcome

Table 1 5 year survival probability among ER+/HER2- breast cancer patients

Results

• A total of 951 patients with ER+/HER2- breast cancer were available for analysis

• Median age at diagnosis was 54 years (range, 24-89) • Overall survival was 8.4 years (8.2-8.6) • Median follow up time was 5.2 years (0.08-10.1) • Ethnicity and grade were not associated with survival

outcome

N=951 5 year survival probability p-value

logrank % 95% CI Age, years <40 87.2 76.8-93.2 0.0021

40-49 88.9 84.4-92.2 50-59 81.2 75.9-85.5 60-69 82.5 76.3-87.2 >70 71.8 59.6-80.8

Race Chinese 85.4 81.6-88.4 0.83 Indian 77 67.9-83.8 Malay 83.3 78.7-87

Surgery No 43.8 32.3-54.7 <0.001 Yes 87.2 84.6-89.4 Lumpectomy 92 87.4-95 0.0016 Mastectomy 86.6 80.3-86.4

Adjuvant hormone therapy No 80.6 64.3-90 0.026 Yes 87.7 85-89.9

Adjuvant chemotherapy No 84.3 79.9-87.8 0.81 Yes 82.8 79-86 Anthracycline 82.7 78-86.5 0.41 Taxane based 86 78.7-90.0

Stage 1 95.4 91.7-97.4 <0.001 2 88.6 84.7-91.6 3 74.9 68.3-80.4 4 27.5 16.1-40.1

Grade 1 87.1 78.6-92.4 0.0072 2 85.2 81.2-88.3 3 77.8 70.8-83.4

Size, cm T1 (<2 cm) 94.8 90.9-97 <0.001 T2 (2-5 cm) 84 80.2-87.1 T3 (>5 cm) 64.2 55.9-71.3

Lymph node <0.001 Negative 95.2 92.6-96.8 Positive 75.9 71.1-80 N1 (1-3 LN) 80.5 73.8-85.7 <0.001 N2 (4-9 LN) 74.9 65.4-82.1 N3 (≥ 10 LN) 66.1 54.2-75.7

HR 95% CI p-value

Age 1.03 1.01-1.05 0.003

Hormone therapy 0.62 0.25-1.55 0.30

Surgery 0.29 0.13-0.64 0.002

Size T2 (2-5 cm) 2.57 1.33-4.96 0.005

Size T3 (>5 cm) 3.26 1.53-6.96 0.002

Lymph node, N1 (1-3 LN) 2.70 1.64-4.46 <0.001

Lymph node, N2 (4-9 LN) 2.26 1.27-4.03 0.006

Lymph node, N3 (≥ 10 LN) 3.67 2.01-6.69 <0.001

Grade 2 1.06 0.58-1.95 0.84

Grade 3 1.13 0.57-2.24 0.72

Table 2 Multivariate analysis of prognostic factors

73P

Figure 2 Univariate analysis of prognostic factors

Funding acknowledgement

Ministry of Education, Malaysia - High Impact Research Grant [UM.C/HIR/MOHE/06]

N3 (≥ 10 LN)

N2 (4-9 LN)

N1 (1-3 LN)

Positive lymph node

T3 (>5 cm)

T2 (2-5 cm)

Grade 3

Grade 2

Stage 3

Stage 2

Taxane based

Anthracycline

Chemotherapy

Hormone therapy

Mastectomy

Lumpectomy

Surgery

Malay

Indian

>70

60-69

50-59

40-49

Age, years

-4 -2 0 2 4 6 8 10

Hazard ratios

Reference groups: Hormone therapy – No, Surgery – No, Size - T1, Lymph node – N0, Grade 1