Disease-free survival in patients with non-metastatic breast cancer

Breast cancer is the second most common malignancy in the world and the one with highest incidence in the female population; it is also a major cause of death from cancer among women.

Objective:

To analyze the disease-free survival (DFS) at 5 years and prognostic factors in women with non-metastatic invasive breast cancer treated at a referral center for cancer care located in a medium-sized city in the Southeast of Brazil.

Method:

Patients diagnosed with the disease between 2003 and 2005 and identified through the institution’s cancer hospital records were analyzed. The follow-up of cases was carried out through hospital records, and complemented by search in the database of the Mortality Information System (SIM) as well as telephone contact. The variables analyzed were distributed in the following blocks: socio-demographic data, tumor-related characteristics, and treatment-related characteristics. Survival functions were calculated using the Kaplan-Meier method and the prognostic factors were analyzed based on Cox proportional hazard model.

Results:

The study showed a DFS at 5 years of 72% (95CI 67.6-75.9). The main variables independently associated with DFS were lymph node involvement, use of hormone therapy, and education level.

Conclusion:

This study reinforces the importance of early diagnosis for DFS, pointing to the role of social aspects in this regard. The relevance of this research in the country is also highlighted, given the scarcity of studies on DFS in the Brazilian population.

Keywords
breast neoplasm’s; survival analysis; survival

	Disease recurrence
Variables	Present (N=129)		Absent (N=330)		p-value^* * Chi-squared test (or Fisher's exact test, wherever indicated); significant if p<0.05;
	N	%	N	%
Skin color^# # The sum is lower due to missing data on: skin color - 21 (4.5%), tumor size - 8 (1.7%); lymph node involvement - 9 (2.0%); type of surgery - 5 (1.1%).					0.004
White	90	72.6	262	84.5
Non white	34	27.4	48	15.5
Education					0.03
Higher education	12	9.3	68	20.6
Middle education	45	34.9	110	33.3
Low education	53	41.1	112	33.9
Unknown	19	14.7	40	12.1
Staging					<0.001
I	15	11.6	111	33.6
II	49	38.0	149	45.2
III	65	50.4	70	21.2
Tumor size^# # The sum is lower due to missing data on: skin color - 21 (4.5%), tumor size - 8 (1.7%); lymph node involvement - 9 (2.0%); type of surgery - 5 (1.1%).					<0.001
≤ 2 cm	33	26.4	152	46.6
> 2 cm	92	73.6	174	53.4
Lymph node involvement#					<0.001
No	44	35.8	200	61.2
Yes	79	64.2	127	38.8
Tumor grade					0.03
1	23	17.8	88	26.7
2	45	34.9	118	35.8
3	31	24.0	45	13.6
Unknown	30	23.3	79	23.9
Immunohistochemical profile					<0.001
Unknown	18	14.0	43	13.0
Luminal HER2-negative	54	41.9	204	61.8
Luminal HER2-positive	7	5.4	25	7.6
Overexpressed HER2	15	11.6	10	3.0
Triple negative	35	27.1	48	14.5
Type of surgery^# # The sum is lower due to missing data on: skin color - 21 (4.5%), tumor size - 8 (1.7%); lymph node involvement - 9 (2.0%); type of surgery - 5 (1.1%).					0.01
Conservative	51	41.1	180	54.5
Radical	73	58.9	150	45.5
Chemotherapy					<0.001
Use	106	82.2	217	65.8
Non-use	23	17.8	113	34.2
Hormone therapy					<0.001
Use	67	51.9	260	78.8
Non-use	62	48.1	70	21.2

Variables	Unadjusted HR	95CI^* * 95CI 95% confidence interval;	Adjusted HR^ Adjusted by age at diagn osis (continuous format), n addition to the three variables in the Table.	95CI^* * 95CI 95% confidence interval;
Education
Higher	1.00		1.00
Middle	2.19	1.16-4.15	1.60	0.84-3.08
Low	2.37	1.26-4.43	1.84	0.96-3.52
Unknown	2.48	1.20-5.10	2.05	0.97-4.34
Lymph node involvement
Absent	1.00		1.00
Present	2.38	1.64-3.44	2.35	1.61-3.42
Hormone therapy
Not performed	1.00		1.00
Performed	0.35	0.25-0.49	0.37	0.26-0.53

Associação Médica Brasileira R. São Carlos do Pinhal, 324, 01333-903 São Paulo SP - Brazil, Tel: +55 11 3178-6800, Fax: +55 11 3178-6816 - São Paulo - SP - Brazil
E-mail: ramb@amb.org.br

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[1] *Programa de Pós-graduação em Saúde Coletiva, Universidade Federal de Juiz de Fora (UFJF), Address: Campus Universitário, Bairro Martelos, Juiz de Fora, MG – Brazil. roberta_wolp@hotmail.com