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Introduction
Breast cancer incidence has been
increasing in the general population all over the world,
particularly in areas of low incidence such as Asia.
The worldwide incidence of
breast cancer has increased from 720,000 cases per year
in 1985 to 1,000,000 new cases in the year 20001.
Nearly 1/3rd (32%) of all cancer cases
and 18% of all cancer deaths in women are reported to be
due to breast cancer1. The increase in
incidence is more noticeable in regions of the world,
which were previously considered to be areas of low
incidence such as the Asian continent.
Breast
Cancer is second to cancer of the Cervix among women in
India, but is considered the leading Cancer in certain
metros such as Mumbai and Bangalore. It is estimated
that approximately 80,000 cases occur annually; the age
adjusted incidence rates varying between 16 and 25/
100,000 population. Breast
cancer ranks first in incidence out of all cancers among
females in Mumbai and Thiruvananthapuram and constitutes
26.2% and 25.4% of all cancers respectively2.
The peak incidence of breast cancer is in the age group
of 45-49years in females, as noted from a five year data
(1994-1998), in Mumbai, Bangalore, Chennai and
Thiruvananthapuram2.
Timely
diagnosis of symptomatic disease relies on breast health
awareness in the potential patient population and in
primary health care professionals, and thus increased
breast health awareness in terms of risk factors and
recognition of symptoms is a key element of
interventions at all resource levels. Although awareness
is an elusive concept, it clearly has great potential
for improving the outcome of breast cancer patients. It
is important to be mindful that the great majority of
women in the world in whom breast cancer is diagnosed
each year are symptomatic at the time of diagnosis, and
that the majority of women in the world do not have
access to screening mammography. Thus, based on the
observation of the association between tumor size and
prognosis, it should be clear that the goal of early
detection is not simply the goal of detecting a greater
proportion of breast cancers when they are asymptomatic,
but also downsizing symptomatic breast cancers as well.
3
The
risk factors responsible for the causation of breast
cancer may be population or region specific. Moreover,
there are inherent factors that aid in the late
presentation of breast cancer patients to a hospital.
It is important to identify these factors in order to
bring down the incidence, morbidity and mortality due to
this disease. This study reviewed the breast cancer
patients at a tertiary care center with respect to their
socio-demographic characteristics, risk factors that
contributed to the development of the disease and stage
at which treatment was sought. We also tried to
determine the risk factors that contributed to a delayed
presentation.
Methodology
This case control study was carried out as a short term
student project funded by the Indian Council of Medical
Research (ICMR). Due clearance was obtained from the
Institutional Ethics Committee at the Kasturba Medical
College, Manipal, India.
Study Population
The study setting was the
Kasturba Hospital - a tertiary healthcare facility in
Manipal which is situated in southern India. Manipal is
a university town flanked by a predominant rural
population. Eligible cases
were histopathologically
confirmed female breast cancer patients admitted to the
hospital from June to September 2008.They were included
in the order of their
admission into the hospital during the study period.
The
controls were age matched and
selected at random within 2 year age range to cases.
They were healthy individuals either caregivers to a
case of breast cancer or neighbours, friends or
relatives accompanying other patients to the hospital.
Caregivers who were first degree relatives (mother,
sister, and daughter) of breast cancer cases were
excluded. The controls were also required to have no
personal history of breast disease.
Considering delayed age at first delivery a risk factor
with an expected exposure of 40% in the controls and an
anticipated OR of 2.24 the calculated number of cases
was 63 for a power of 80% and 5% level of significance.
For a 1:4 allocation ratio the required number of
controls were 252 and thus a total of 315 individuals
were included into the study.
Data Collection & Analysis
The cases and controls fulfilling the above mentioned
criteria were personally interviewed by the investigator
using a structured questionnaire. The questionnaire
included information on socio-demographic
characteristics, reproductive factors, type of diet,
physical activity, method of identification of the
disease and mode of referral. Women were classified as
menopausal if they had not had a menstrual cycle in the
last one year prior to the date of interview. Physical
activity was classified into regular exercise regimen
and household activity which was either vigorous or
moderate. Vigorous household activity referred to the
woman carrying out all activities at home manually
without any external help. Data pertaining to stage at
presentation, treatment and diagnostic modalities were
collected from the medical records.
A written Informed Consent was taken
from each individual before including them in the study.
The data was analysed using SPSS version XI and STATA
version IX.
Results
The demographic characteristics of the study population
are as illustrated in table 1. There does not appear to
be much of a difference between the cases and the
controls with regard to these traits. Of the 63 cases,
twenty nine (46%) were in the
45 – 54 age range while another 33% was in the 25 – 44
age range. The number of cases over the age of 54 was
relatively less (21%)
Most of
the cases were detected in stage III (46%) or stage IV
(36.5%) of the disease when treatment options are
limited and cure may not be possible. Nearly all the
cases (98.4%) had accidently identified the breast lump.
It is also noteworthy that none of the cases had ever
performed a breast self examination as compared to 8% of
the controls who were routinely doing it.
A
larger percentage of the controls (25.8%) were
vegetarians when compared to the cases (15.9%). There
was no difference between cases and controls with
respect to physical activity in terms of regular fitness
regimen as only 3% in both the groups were involved in
it. However, 96.4% of the controls engaged in rigorous
household activity whereas only 84% of the cases did so.
This suggests that the controls had a more physically
active life when we consider rigorous house work to be a
form of physical activity.
Risk factors for Breast cancer
Advancing age is considered to be a significant risk
factor in the western literature; however women in Asia
in particular appear to be at risk at an earlier age as
is illustrated from the age distribution of the cases in
this study as well. Some of the other notable risk
factors are age at first delivery more than 30 years,
menarche < 11 years, Body Mass Index (BMI) more than 25
and a predominantly non vegetarian diet. Table 2 shows
the association between the cases and controls with
respect to these parameters.
First
delivery > 30 years and non vegetarian diet showed an
association as reported in the literature; however the
diet factor was not found to be significant.
Interestingly, age at menarche < 11 years and a BMI > 25
were found to have a protective effect contrary to what
is reported in literature. It was observed that past
history of benign breast disease was present in a few of
the breast cancer cases. Menopause after 55 years is
another significant risk factor which however could not
be demonstrated since the controls were age matched.
Delay in seeking medical help
The study illustrated the fact that most cases reported
to the hospital only in stage III or IV of the disease.
Almost 98.4% of the cases were self diagnosed. Nearly
88% approached two or more independent primary care
practitioners prior to being referred to a cancer
detection center thereby delaying diagnosis.
Discussion
Much of the increase of breast cancer in India has been
associated with greater urbanization and changing life
styles. The population in this
study were predominantly from a rural background which
sustained on agriculture. This reaffirms the fact that
this disease is no longer
confined to an urban setting. However, despite the rural
status, women in this study were literate and nearly 25%
were employed which probably explains the increased
risk. Higher education level and income are shown to be
significant reasons for an increased risk 4, 5.
This is because economic independence may encourage
women to remain single or marry late thereby increasing
their risk of getting the disease.
The
Malaysian study 1 illustrated that
postponement of first pregnancy to as late as 35 years
as well as being menopausal had greater risk to the
occurrence of breast cancer. Our study also showed an
increased association with increasing age at first
delivery.
The
Malaysian study1 concluded that breast cancer
tended to occur earlier among Malaysian women1.
This seems to be illustrated in this study as well
wherein 33% of the cases were among those below the age
of 45 and another 46% were in the age range of 45 to 54
years. A study on Iranian women also reported nearly 30%
of cases to be less than 40 years of age6.
These findings reiterate the fact that Asian women get
the disease almost a decade earlier than their western
counterpart.
The
findings in a study on breast cancer risk within the
South Asian female population in England reveal
differences in breast cancer risk between South Asian
ethnic subgroups, which were not fully explained by
reproductive differences, but were partly accounted for
by diet and body size7. Our study showed more
number of controls to be vegetarians as compared to the
cases.
Obesity
and lack of physical activity are associated with
increased risk at various cancer sites, including breast
and endometrial cancer. Energy balance, which includes
maintaining ideal weight through physical exercise, has
been associated with decreased risk of breast cancer8.
However, our study showed a protective factor for BMI >
25. This is probably because the BMI for the cases were
the current estimates and they are likely to have lost a
lot of weight due to the illness and treatment.
Case-control studies that compared non-vegetarian and
vegetarian diets and alcohol and tobacco use in India
have reported that vegetarians have a reduced risk of
oesophageal and breast cancers9.
Large epidemiological studies have identified a possible
association between increased dietary fiber and a
decreased risk for cancers of the colon and breast.8
In this study non vegetarian diet did
show a risk association with an OR of 1.94, which was
however statistically not significant.
Late
presentation of Breast cancer is a major concern, as
large numbers of patients are still diagnosed in
clinical Stage III or IV. It was found that the
proportion of late-stage cancer was clearly decreased
when tumors were detected by screening 10.
Education/awareness campaigns, better access to
diagnostic resources, availability of higher standards
of health care, use of breast self-examination, and
screening mammography if implemented rationally would go
a long way towards increasing early diagnosis and
improved survival with a consequent possible rise in
detection of early cases as is seen in the West11.
Our study showed late presentation to the hospital to be
an area of concern. One factor contributing to this is
the fact that there is no organized screening program in
place for early detection. Almost 98.4% of the cases
were self diagnosed. Almost all of these were accidental
discovery and not secondary to any systematic self
examination. Secondly, awareness regarding the disease
was noted to be uniformly poor amongst the cases and
controls. Only 40% of the total subjects were aware. The
third factor is the delay in referral and diagnosis of
these cases by the health care providers. This is
reflected by the fact that nearly 88% of the cases had
to approach two or more primary care practitioners prior
to being diagnosed of the disease.
There
are some inherent limitations of this study. The
findings noted here may not be generalisable since the
women in this study were notably more literate and
employed as compared to a majority of rural population
elsewhere. Moreover, care should have been taken to
include the relevant weight for the cases as this would
have enabled more accurate calculation of the BMI. As
regards delay in presentation factors such as fear of
diagnosis, cultural inhibitions and affordability could
have played a role which was not specifically looked
for.
Conclusion
Although the literacy rate of the women in this study
was over 80%, their awareness pertaining to breast
cancer was not as good. Nearly all the cases had self
detected the breast lump and breast screening was not a
widespread term. Delay in referral of the cases was
another noteworthy finding.
A
targeted intervention creating more awareness is the
need of the hour. The awareness campaigns should not
only target the community but also health care providers
stressing on them the need for early referral to
appropriate care centers. Facilities for early detection
and diagnosis are the areas that need to be worked on.
Further studies evaluating an organized screening
modality suitable for a developing country may throw
more light in this direction. It would also be
worthwhile to see if women identified with the specific
risk factors noted in this study would benefit from
frequent screening.
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