Invasive breast carcinoma - IARC

tives, administrative and clerical jobs
{387}. A recent hypothesis deals with circadian
disruption through night work,
with an increased risk in women working
predominantly at night {632,2556}.
Over the last ten years concerns have
arisen as to the potential risks of exposure
to, not only hormones, but to art i f i c i a l
p roducts mimicking hormonal activities.
This led to the concept of xeno-hormones,
mostly re p resented so far by
x e n o - e s t rogens. The exact role they play
is unknown. Most epidemiological studies
deal with various pesticides, essentially
organochlorines which remain in the environment
for a very long time and the
residues of which may be found in adipose
tissue of various species, including
humans {628}. Studies have pro d u c e d
conflicting results with some suggesting a
possibly increased risk, some no risk and
others showing a negative effect. For the
time being, many consider these links as
speculative and unfounded {1951,2503}
or as markers of susceptibility {1951}.
Finally, based on animal experience, a
viral hypothesis has been put forward. In
mice, a retrovirus, the murine mammary
Table 1.02
Conditions requiring referral to a specialist clinic.
L u m p
Any new discreet mass
A new lump in pre-existing nodularity
Asymmetrical nodularity that persits at review
after menstruation
Abscess on breast inflammation which does not
settle after one course of antibiotics
Cyst persistently refilling or recurrent cyst (if the
patient has recurrent multiple cysts and the GP
has the necessary skills, then aspiration is
a c c e p t a b l e )
P a i n
If associated with a lump
Intractable pain that interferes with a patient’s
lifestyle or sleep and which has failed to respond to
reassurance, simple measures such as wearing a
well supporting brassiere and common drugs
Unilateral persistent pain in postmenopausal women
Nipple discharge
All women > 50
Women < 50 with:
bilateral discharge sufficient to stain clothes
bloodstained discharge
persistent single duct discharge
Nipple retraction, distortion, eczema
Change in skin contour
Family history of breast cancer
A
tumour virus, is a recognized cause of
mammary tumours, transmitted with milk
from mothers to daughters. Another candidate
is the Epstein-Barr virus, although
data from the USA are not particularly
supportive {1015}. Other potential viral
candidates remain to be searched for.
Localization
Breast carcinoma arises from the mammary
epithelium and most frequently the
epithelial cells of the TDLU. There is a
slightly higher frequency of invasive
breast cancer in the left breast with a
reported left to right ratio of approximately
1.07 to 1 {1096}. Between 40 and 50%
of tumours occur in the upper outer
quadrant of the breast and there is a
decreasing order of frequency in the
other quadrants from the central, upper
inner, lower outer to the lower inner quadrant
{1096}.
Clinical features
Symptoms and signs
The majority of women with breast cancer
present symptomatically, although
the introduction of breast screening has
led to an increasing proportion of asymtomatic
cases being detected mammographically.
Breast cancer does not have
specific signs and symptoms, which
allow reliable distinction from various
f o rms of benign breast disease.
However, the frequency distribution of
B
C
Fig. 1.08 A Mammogram of infiltrating carcinoma, clinically occult, less than 1 cm. B Mammographic detail
of small, non-palpable, infiltrating carcinoma (