DOI: https://doi.org/10.21203/rs.3.rs-232862/v1
Introduction
Until today, there is no clear cut off point for age in young breast cancer. Multiple studies have shown that breast cancer among women diagnosed before age of 40 is increasing in trend and have poorer survival rate. Incidence rate among Malaysian breast cancer from the age of 25 and below 40 is also increasing in trend. This is first paper in Malaysia to ascertain the risk factors among young breast cancer in mainland of Penang state, Malaysia
Method
This is a retrospective study which includes young women diagnosed with breast cancer from 1st January 2015 until 31st December 2019, from HSJ cluster hospitals. Inclusion criteria are 40 years old and below at the age of diagnosis of breast cancer, female and complete sociodemographic data.
Result
This study has shown that 17.07% of women with young breast cancer are age before 31 years old and most are age from 36 to 40 years old. Young age at menarche (12 years old and below), positive family history of breast cancer, use of oral contraceptive pill, breastfeeding history and pregnancy history (parity at least 1 and above) are strongly associated with increased risk of young breast cancer with P-value<0.05.
Conclusion
This is a small-scale study on young breast cancer patient. Larger population study should be performed to confirm this findings and dwell further on other possible risk factors.
Until today, there is no clear cut off point for the age of young breast cancer. In study by Carey et al, women diagnosed before age of 40 years old has shown to have poorer survival rate. Young breast cancer account for more than 40% of cancer at this age group. (1) In US Surveillance, Epidemiology and End Results (SEER) cancer statistic review from 2000 to 2005, 6.6% of breast cancer among American women were diagnosed before age of 40. (2) In a 30-year review study by Rebecca et al., there is 2-fold increasing in trend among young breast cancer patients to develop more advance stage breast cancer which is metastatic breast cancer. The number of cases went up almost 2.1% per year from 1976 to 2009. (3) In Malaysia, breast cancer has contributed to 19.0% of all newly diagnosed cancer from 2012 to 2016 regardless of gender, as compared to 17.7% from 2007 to 2011. Incidence rate among Malaysian has increased at the age of 25. In year 2012 to 2016, age-standardized rate (ASR) has increased to 34.1 per 100,000 population as compared to 31.1 per 100,000 from 2007 to 2011. (4) Hospital Seberang Jaya (HSJ) in Penang is the head of cluster hospitals, which include in Hospital Kepala Batas (HKB), Hospital Bukit Mertajam (HBM), and Hospital Sungai Bakap (HSB). HSJ covers most of the breast cancer cases in mainland of Penang. This is the first paper in Malaysia with aim to investigate the risk factors among young breast cancer in mainland of Penang state, Malaysia.
A case-control retrospective study was conducted which included women diagnosed with breast cancer from 1st January 2015 until 31st December 2019, from HSJ cluster hospitals. Inclusion criteria are 40 years old and below at the age of diagnosis of breast cancer, female, complete sociodemographic data and histopathological confirmed breast cancer. Exclusion criteria are breast cancer diagnosed after age of 40 years old, incomplete data and patients with unspecified laterality of tumors. We compare women diagnosed with breast cancer age 40 years old and below (cases) during this period with control of same age range who came in for consultation and/or treated in this service with sonographic evidence of negative for breast lesions. Each case was compared with 1 control. Socio-demographic data (age, ethnics) and clinical characteristics (age of menarche, oral contraceptive use, family history of breast cancer, gravidity, parity, age at first pregnancy, history of breast feeding, duration of breast feeding) were collected from patients’ medical record and breast cancer registry.
A total of 82 patients (41 cases and 41 controls) were recruited into this study. Women diagnosed with breast cancer at 40 years old and below (cases) are compared with women of same range of age who came for consultation and/or treated in these facilities with sonographic evidence of negative breast lesions. Sample size was calculated by using StatCalc from Centre for Disease Control and Prevention (CDC). Odd ratio of 10.11 is quoted from variable (family history of breast cancer) in study by Felix Essiben et. Al. Two-sided confidence level is 95% with power of study 98%. Each case was opposed with 1 control. Minimum sample size obtained was 41 cases and 41 controls.
Statistical analysis
Statistical analysis was done by using Statistical Product and Service Solutions (SPSS) version 24. Chi square test has been used to analyze the differences between cases and controls. The significance threshold was set at 0.05. Logistic regression was performed to eliminate confounders.
Table 1 Socio-demographic characteristic of cases and controls in HSJ Cluster
Variable |
Case (N = 41) |
Control (N = 41) |
||
N |
% |
N |
% |
|
Age |
|
|
|
|
16 – 20 |
0 |
0.0 |
5 |
12.2 |
21 – 25 |
1 |
2.4 |
7 |
17.1 |
26 – 30 |
4 |
9.8 |
6 |
14.6 |
31 – 35 |
11 |
26.8 |
11 |
26.8 |
36 – 40 |
25 |
61.0 |
12 |
29.3 |
Ethnicity |
|
|
|
|
Malay |
35 |
85.4 |
28 |
68.3 |
Chinese |
5 |
12.2 |
6 |
14.6 |
Indian |
1 |
2.4 |
7 |
17.1 |
Table 2 Exogenous hormonal, reproductive factor and menarche and their association with young breast cancer
Variable |
Case |
Control |
P-value |
||
|
N |
% |
N |
% |
|
OCP use |
|
||||
No |
12 |
29.3 |
35 |
85.4 |
0.000 |
Yes |
29 |
70.7 |
6 |
14.6 |
|
Full term pregnancy |
|
||||
Nulliparous |
5 |
12.20 |
18 |
43.9 |
0.003 |
Yes |
36 |
87.80 |
23 |
56.1 |
|
Breastfeeding |
|
||||
Never |
10 |
24.4 |
20 |
48.8 |
0.038 |
Ever |
31 |
75.6 |
21 |
51.2 |
|
Breastfeeding duration |
|
||||
< 12 months |
2 |
6.5 |
10 |
47.6 |
0.002 |
12 months and above |
29 |
93.5 |
11 |
52.4 |
|
Age of menarche |
|
||||
≤ 12 years old |
28 |
68.3 |
7 |
17.1 |
0.026 |
>12 years old |
13 |
31.7 |
34 |
82.9 |
|
Primary family history of breast cancer |
|
||||
No |
27 |
65.9 |
39 |
95.1 |
0.002 |
Yes |
14 |
34.1 |
2 |
4.9 |
Age group/median
Estrogen exposure
Menarche
Pregnancy
OCP
Breast feeding
Family history of breast cancer
This is a retrospective hospital based study with lots of extra data are not available (lifestyle, body mass index, environmental hazzard and etc.). A small number of cases can be recruited even though 5 years study had been conducted. A large populations study should be conducted in multiple centers in order to ascertain the risk factors among young breast cancer.
Ethical Approval
This study uses available data of patient in respective hospital. Hospital ethical committee has reviewed this study and has approve the study. No ethical committee references number available.
Consent for publication
Not applicable in this study
Availability of data and materials
The datasets generated during and/or analysed during the current study are not publicly available due data confidentiality protection reason are available from the corresponding author on reasonable request.
Competing Interests and Funding
There is no competing interest in this study and it is self-funding by the authors and co-authors.
Authors contribution
Authors and co-authors contributing in this study by designing the study, data collection and analysis and manuscript preparation.
Acknowledgement
I will like to extend my gratitude to all staff in Cluster Hospital Seberang Jaya involve in making this study possible. Their help is remarkable and the additional ideas they provided ease the study flow.