Genetics and colon cancer

Genetics and colon cancer

A person's genetic background is an important factor in colon cancer risk. Among first-degree relatives of colon cancer patients, the lifetime risk of developing colon cancer is 18% (a threefold increase over the general population in the United States).

Even though family history of colon cancer is an important risk factor, majority (80%) of colon cancers occur sporadically in patients with no family history of colon cancer. Approximately 20% of cancers are associated with a family history of colon cancer. And 5 % of colon cancers are due to hereditary colon cancer syndromes. Hereditary colon caner syndromes are disorders where affected family members have inherited cancer-causing genetic defects from one or both of the parents.

Chromosomes contain genetic information, and chromosome damages cause genetic defects that lead to the formation of colon polyps and later colon cancer. In sporadic polyps and cancers (polyps and cancers that develop in the absence of family history), the chromosome damages are acquired (develop in a cell during adult life). The damaged chromosomes can only be found in the polyps and the cancers that develop from that cell. But in hereditary colon cancer syndromes, the chromosome defects are inherited at birth and are present in every cell in the body. Patients who have inherited the hereditary colon cancer syndrome genes are at risk of developing large number of colon polyps, usually at young ages, and are at very high risk of developing colon cancer early in life, and also are at risk of developing cancers in other organs.

What are the causes of colon cancer?

What are the causes of colon cancer?

Doctors are certain that colorectal cancer is not contagious (a person cannot catch the disease from a cancer patient). Some people are more likely to develop colorectal cancer than others. Factors that increase a person's risk of colorectal cancer include high fat intake, a family history of colorectal cancer and polyps, the presence of polyps in the large intestine, and chronic ulcerative colitis.

What is cancer of the colon and rectum?

What is cancer of the colon and rectum?

The colon is the part of the digestive system where the waste material is stored. The rectum is the end of the colon adjacent to the anus. Together, they form a long, muscular tube called the large intestine (also known as the large bowel). Tumors of the colon and rectum are growths arising from the inner wall of the large intestine. Benign tumors of the large intestine are called polyps. Malignant tumors of the large intestine are called cancers. Benign polyps do not invade nearby tissue or spread to other parts of the body. Benign polyps can be easily removed during colonoscopy and are not life-threatening. If benign polyps are not removed from the large intestine, they can become malignant (cancerous) over time. Most of the cancers of the large intestine are believed to have developed from polyps. Cancer of the colon and rectum (also referred to as colorectal cancer) can invade and damage adjacent tissues and organs. Cancer cells can also break away and spread to other parts of the body (such as liver and lung) where new tumors form. The spread of colon cancer to distant organs is called metastasis of the colon cancer. Once metastasis has occurred in colorectal cancer, a complete cure of the cancer is unlikely.

Globally, cancer of the colon and rectum is the third leading cause of cancer in males and the fourth leading cause of cancer in females. The frequency of colorectal cancer varies around the world. It is common in the Western world and is rare in Asia and Africa. In countries where the people have adopted western diets, the incidence of colorectal cancer is increasing.

Treatment

Improved understanding of breast tumor cell biology
and molecular genetics is enabling researchers to design
cancer therapies that are tailored to the unique characteristics
of each patient and tumor. Such “rational
therapeutics” may have greater efficacy and fewer side
effects than conventional chemotherapy.150 Clinical
trials of targeted therapies such as tyrosine kinase
inhibitors have demonstrated benefits in patients with
advanced disease and may also delay or reverse
hormone resistance. The tyrosine kinase inhibitor
Lapatinib®, may be effective in delaying disease progression
in women with HER2-positive advanced breast
cancer who have become resistant to tratuzumab.151
Metronomic therapy, a relatively new concept in antiangiogenic
therapy (drugs that block blood supply to the
tumor), uses much lower and less toxic doses of chemo-therapy agents than currently used in combination with
an antiangiogenesis drug.152 A recent study in experimental
animals suggests that bisphosphonates, which
are currently used to treat bone metastases in advanced
breast cancer patients, may also be able to prevent bone
metastases in women with early breast cancer.153
A recent combined analysis of data from three clinical
trials found that advances in chemotherapy have
substantially improved survival for patients with lymph
node-positive, ER-negative tumors.154 Advances in
chemotherapy have had less of an impact for women
with ER-positive tumors, although those who receive
adjuvant hormonal therapy still have better disease-free
and overall survival than ER-negative patients. Research
is underway to identify which women with ER-positive
disease truly benefit from the addition of chemotherapy
to hormonal therapy.155 This research includes a new
clinical trial that will use information on the expression
of 21 genes in breast tumor tissue (using a tool called
Oncotype DX) to assign women to treatment groups
based on their predicted likelihood of recurrence.

How is breast cancer treated?

Early detection
Research is underway to improve breast cancer
detection through mammography, as well as to identify
other radiologic approaches. Preliminary results from a
large clinical trial of digital versus film mammograms
reveal that women with dense breasts who are pre- or
perimenopausal (i.e., women who had a last menstrual
period within 12 months of their mammograms) or who
are younger than age 50 may benefit from having a
digital rather than a film mammogram.147 Women with
dense breast tissue have an increased risk of breast
cancer. Recent research indicates that increased breast
density over time may be a more accurate predictor of
future breast cancer.148 Future studies will focus on
identifying the best time to measure breast density.
Among women with newly diagnosed breast cancer, MRI
may be useful in detecting cancer in the contralateral
(opposite) breast.149 Diagnosing the second breast
cancer earlier could help women make treatment
decisions and might spare them from extra rounds of
surgery and chemotherapy later.

What are the signs and symptoms of breast cancer?

What are the signs and symptoms of breast cancer?

Early-stage breast cancer typically produces no symptoms
when the tumor is small and most treatable. It is
therefore very important for women to follow recommended
guidelines for finding breast cancer at an early
stage, before symptoms develop. When breast cancer
has grown to a size that can be felt, the most common
physical sign is a painless mass.41 Less common signs
and symptoms include breast pain or heaviness and
persistent changes to the breast, such as thickening,
swelling, redness, and nipple abnormalities such as
spontaneous discharge, erosion, inversion, or tenderness.
41 A woman should have any persistent abnormality
evaluated by her physician.

Can breast cancer be prevented?

Can breast cancer be prevented?
At this time, there is no guaranteed way to prevent breast
cancer, which is why regular mammograms are so
important. A woman’s best overall preventive health
strategy is to reduce her known risk factors as much as
possible by avoiding weight gain and obesity, engaging in
regular physical activity, and minimizing alcohol
intake.65 Women should consider the increased risk of
breast cancer associated with HRT use when evaluating
treatment options for menopausal symptoms. Treatment
with tamoxifen or raloxifene can also reduce the
risk of breast cancer among women at high risk (see page
12, section on chemoprevention).
Obesity
Obesity increases risk of postmenopausal (but not
premenopausal) breast cancer, as does weight gain
during adulthood.67-71 A recent study found that women
who gained 55 pounds or more after age 18 had almost
1.5 times the risk of breast cancer compared with those
who maintained their weight. A gain of 22 pounds or
more after menopause was associated with an increased
risk of 18%, whereas losing at least 22 pounds after
menopause and maintaining the weight loss was
associated with 57% lower breast cancer risk.71 In postmenopausal
women, circulating estrogen is primarily
produced in fat tissue. Thus, having more fat tissue
increases estrogen levels and the likelihood of develop-
Table 4. Age-Specific Probabilities of
Developing Invasive Breast Cancer*
The probability of
If current developing breast cancer
age is: in the next 10 years is: or 1 in:
20 0.05% 1,837
30 0.43% 234
40 1.43% 70
50 2.51% 40
60 3.51% 28
70 3.88% 26
Lifetime risk 12.28% 8
*Among those free of cancer at beginning of age interval. Based on
cases diagnosed 2002-2004. Percentages and “1 in” numbers may
not be numerically equivalent due to rounding.
Data source: DevCan Software, Version 6.2.1.165
American Cancer Society, Surveillance Research, 2007
ing breast cancer. Given the large percentage of women
in the US who are overweight or obese, strategies to
maintain a healthy body weight are important to reduce
the risk of both developing and dying from breast cancer.
Physical activity
Growing evidence supports a small protective effect of
physical activity on breast cancer.67,72-75 Although most
studies find reduced risk in women who exercise
vigorously for 45 to 60 minutes on 5 or more days per
week, one study suggests that regular physical activity,
regardless of intensity, may reduce the risk of breast
cancer in postmenopausal women.66,73 Overall, the
protective effect of physical activity may be greatest
among lean women, women who have carried children
to term, and premenopausal women. The underlying
mechanism of this potential protection is not well
understood, although it has been hypothesized that the
benefit may be due to the effects of physical activity on
hormones and energy balance.67,76
Alcohol consumption
Alcohol consumption is consistently associated with
increased breast cancer risk.77-80 A meta-analysis of more
than 40 epidemiologic studies suggests that the
equivalent of 2 drinks a day (or 24g of alcohol) may
increase breast cancer risk by 21%. This increased risk is
dose-dependent and exists regardless of the type of
12 Breast Cancer Facts & Figures 2007-2008
alcoholic beverage consumed. A recent review
concluded that the most likely mechanism by which
alcohol increases risk of breast cancer is by increasing
estrogen and androgen levels.81 Thus, reducing alcohol
intake may be a useful strategy for reducing breast
cancer risk among regular consumers of alcohol.

What are the known risk factors for breast cancer?

What are the known risk factors for breast cancer?


Many of the known breast cancer risk factors, such as
age, family history, age at first full-term pregnancy, early
menarche, late menopause, and breast density, are not
easily modifiable. However, other factors associated with
increased breast cancer risk (postmenopausal obesity,
use of post-menopausal hormones, alcohol consumption,
and physical inactivity) are modifiable. Some risk
factors directly increase lifetime exposure of breast
tissue to circulating ovarian hormones (early menarche,
late menopause, obesity, and hormone use), whereas
others, such as higher socioeconomic status, are only
correlates of reproductive behavior or other factors.
Established risk factors for breast cancer are listed in
Table 3 (page 10) in order of the strength of their
association.

Who gets breast cancer?

Who gets breast cancer?
Sex
• Excluding cancers of the skin, breast cancer is the most
common cancer among women, accounting for more
than 1 in 4 cancers diagnosed in US women.
• Men are generally at low risk for developing breast
cancer; however, they should report any change in
their breasts to a physician.
Age
• Breast cancer incidence and death rates generally
increase with age (Figure 1, page 2). During 2000-2004,
95% of new cases and 97% of breast cancer deaths
occurred in women aged 40 and older.
• During 2000-2004, women aged 20-24 years had the
lowest breast cancer incidence rate,

What is breast cancer?

What is breast cancer?
Cancers are a group of diseases that cause cells in the
body to change and grow out of control. Most types of
cancer cells eventually form a lump or mass called a
tumor and are named after the part of the body where
the tumor originates.
Breast cancer begins in breast tissue, which is made up
of glands for milk production, called lobules, and the
ducts that connect lobules to the nipple. The remainder
of the breast is made up of fatty, connective, and
lymphatic tissue.
• Most masses are benign; that is, they are not
cancerous, do not grow uncontrollably or spread, and
are not life-threatening.
• Some breast cancers are called in situ because they are
confined within the ducts (ductal carcinoma in situ) or
lobules (lobular carcinoma in situ) of the breast. Nearly
all cancers at this stage can be cured. Many oncologists
believe that lobular carcinoma in situ (also known as
lobular neoplasia) is not a true cancer but an indicator
of increased riskfor developing invasive cancer in the
future.
• Most cancerous breast tumors are invasive, or infiltrating.
These cancers start in the lobules or ducts of the
breast but have broken through the duct or glandular
walls to invade the surrounding tissue of the breast.
The seriousness of invasive breast cancer is strongly
influenced by the stage of the disease – the extent or
spread of the cancer when it is first diagnosed. There are
two main staging systems for cancer. The American Joint
Committee on Cancer’s classification of tumors uses
information on tumor size (T), lymph node involvement
(N), and the presence or absence of distant metastases
(M), and is commonly used in clinical settings.1 Once the
T, N, and M are determined, a stage of I, II, III, or IV is
assigned, with stage I being an early stage and stage IV
being the most advanced.

Cancer Astrology Forecast

What is cancer?

What is cancer?

Cancer is a group of more than 100 different diseases. They affect the body's basic unit, the cell. Cancer occurs when cells become abnormal and divide without control or order. Like all other organs of the body, the colon and rectum are made up of many types of cells. Normally, cells divide to produce more cells only when the body needs them. This orderly process helps keep us healthy.

If cells keep dividing when new cells are not needed, a mass of tissue forms. This mass of extra tissue, called a growth or tumor, can be benign or malignant.

Benign tumors are not cancer. They can usually be removed and, in most cases, they do not come back. Most important, cells from benign tumors do not spread to other parts of the body. Benign tumors are rarely a threat to life.

Malignant tumors are cancer. Cancer cells can invade and damage tissues and organs near the tumor. Also, cancer cells can break away from a malignant tumor and enter the bloodstream or lymphatic system. This is how cancer spreads from the original (primary) tumor to form new tumors in other parts of the body. The spread of cancer is called metastasis.

When cancer spreads to another part of the body, the new tumor has the same kind of abnormal cells and the same name as the primary tumor. For example, if colon cancer spreads to the liver, the cancer cells in the liver are colon cancer cells. The disease is metastatic colon cancer (it is not liver cancer).