Tuesday, March 1, 2011

Breast cancer: Symptoms, treatment & prevention

The chance of developing breast cancer for a woman in the United States over the course of her lifetime is about 1 in 8. However, the death rates from this much-publicized disease continue to drop with better early detection and constant advancements in treatment. 

More than 261,000 women are diagnosed with breast cancer each year, according to the American Cancer Society, making it the second most common malignancy in women after skin cancer. 

While all cancers arise from an uncontrolled growth of abnormal cells, each patient’s treatment and prognosis can differ radically depending on her type of breast cancer, how advanced it is and a variety of other factors. 

- Symptoms & Types 

All breast cancers are not created equal, either in symptoms or category. Though some cases emerge without any noticeable symptoms, breast changes that warrant a doctor’s attention include a lump, swelling or thickening; dimpling or skin irritation; breast pain; nipple pain or an inverted nipple; red or flaky nipple or surrounding skin; or a discharge other than breast milk, according to the National Breast Cancer Foundation. 

It's important to note that even these symptoms don’t necessarily mean a malignancy is present and often signal a benign condition, such as a cyst or infection. 

Just as breast cancer has many symptoms, the disease is comprised of many specific types. Defined by whether it begins in the lobules or ducts, the parts of the breast responsible for milk production, these types include: 

- DCIS, or Ductal Carcinoma in Situ. This non-invasive malignancy is the earliest and most curable form of the disease because is confined to the duct and rarely spreads. DCIS comprises about 20 percent of all breast cancers, invasive and non-invasive, diagnosed annually. 

- IDC, or Infiltrating Ductal Carcinoma, is an invasive malignancy because it has spread beyond the ducts. It accounts for almost 80 percent of all invasive breast cancers. IDC appears as rounded or star-shaped areas on mammograms, with the star-like lesions signaling a poorer prognosis. 

The remaining five types of invasive breast cancer comprise about 20 percent of all total cases. According to the National Breast Cancer Foundation, they include the rare and aggressive Inflammatory Breast Cancer, or IBC, which unlike other forms is often visible on the outside of the breast. IBC causes the breast to look red or inflamed due to blocked lymph vessels in the skin and mimics certain breast infections such as mastitis.  

Diagnosis & Tests 

Breast cancer screening tests, which are done on symptom-free women, can help to diagnose early cases. Early detection methods include clinical exams by medical professionals, self breast exams and screening mammograms, which are recommended for women age 40 and over, according to the American Cancer Society. Women with a family history of the disease can also undergo genetic testing to determine if they are at increased risk of developing it. 

If a screening method reveals possible breast cancer, several tests can help confirm or disprove the diagnosis. These include: 

- Imaging tests such as mammograms, MRI scans or breast ultrasound. Each of these methods produces internal pictures of the breast that help doctors see a potential mass. 

- Biopsies, which take cells from suspicious lumps to study in a pathology lab to determine if they are malignant. Cells are extracted through special needles or during surgery. 

If cancer is confirmed, doctors will assess the cells to determine key information such as the type of cancer and its grade, which signals how fast it is growing. They will also learn if the tumor is caused by a genetic mutation passed through families or is hormone receptive. 

According to the American Cancer Society, the presence of hormone receptors on breast cancer cells usually indicates a better prognosis because certain drugs can prevent estrogen or progesterone from promoting cancer growth. 

Typically, women with a positive breast cancer diagnosis will also undergo a battery of tests to determine if the cancer has spread to surrounding tissues, organs or bone. Common sites for breast cancer metastases are the bones, lungs or liver. 

Treatments & Medications 

With more than 2.5 million breast cancer survivors in the United States, it's clear that researchers have developed effective treatments and drugs that can either cure the disease or prevent it from quickly recurring. Treatments either target the cancer locally or systemically, depending on the location of the breast tumor, its size and the extent of the disease. 

Local treatments include surgery and radiation, which attempt to remove or destroy the cancer in the breast without affecting the rest of the body. Surgery can include a breast-sparing lumpectomy or the more aggressive mastectomy, which removes the entire breast and is usually done in more advanced cases, according to the National Breast Cancer Foundation. 

Systemic treatments are given by mouth or through the bloodstream and target cancer cells throughout the body. 

These include chemotherapy, which uses toxic drugs such as cyclophoshamide (sometimes referred to by its brand name, Cytoxan) or methotrexate. Cancer fueled by the hormones estrogen or progesterone can be treated with hormone suppressors such as tamoxifen or raloxifene (Evista). 

More recent systemic treatments include biological therapy, which use the immune system to fight the cancer and targets breast cancer cells containing high levels of a certain protein. Commonly used biologics are bevacizumab (Avastin) or trastuzumab (Herceptin). 

Depending on a variety of factors, including a patient’s age, type and stage of cancer, her care regimen might include only one of these treatments or a combination of several. 


Some breast cancer risks, such as age and heredity, can’t be controlled. But as with so many other diseases, eating right and exercising can help lower the chances of developing breast cancer. According to the Mayo Clinic, other risk-reducing tips include: 

- Limiting dietary fat - Maintaining a health weight - Foregoing hormone therapy at menopause - Limiting exposure to pesticides and antibiotics. 

(Source: myhealthnewsdaily.com) 

Monday, February 28, 2011

Dual-energy CT images cancer biomarkers

by : medicalphysicsweb 

Spectral CT, an emerging technique that images using X-rays of more than one energy, can differentiate multiple tissue types or contrast agents within the body. At the SPIE Medical Imaging conference, held last week in Lake Buena Vista, FL, Cristian Badea from Duke University Medical Center (Durham, NC) described the application of dual-energy microCT to simultaneously image iodine and gold probes in vivo.

Badea and colleagues examined two nanoprobes: liposomal iodine (Lip-I) and gold nanoparticles. The Lip-I probes comprised an aqueous iohexol core surrounded by a lipid bilayer and PEGylated to ensure retention in the blood. The gold probe was AuroVist, a commercial contrast agent comprising 15 nm nanoparticles. Both probes are cleared from the body via the liver and spleen.
As gold and iodine exhibit different attenuation coefficient profiles, with K-edges at different energies (81 and 33 keV, respectively), it should be possible to distinguish the two by comparing X-ray images at different energies. To determine the optimal imaging parameters, Badea's team built a dual-energy microCT system, containing two X-ray tubes and two detectors.
First, the researchers used the Spektr computational tool to model the microCT system's performance, using a phantom containing varying volumes of the two probes and imaging at voltages from 40 to 150 kVp. Plots of contrast versus voltage revealed that at 40 kVp, signals from regions containing gold nanoparticles were brightest, while iodine provided maximum enhancement at around 70 and 80 kVp.
They then performed phantom experiments to measure CT enhancement for the probes across the same voltage range. The measured images agreed with the simulated results, showing maximum CT enhancement at 40 kVp for the gold nanoparticles and 80 kVp for the Lip-I. On a mass-concentration basis, the relative average enhancement of gold to iodine was 2.75 at 40 kVp and 1.58 at 80 kVp.
The team also used the phantom images to determine the limits of detectability of the two probes. Calculating the contrast-to-noise ratio at different concentrations revealed a limit of 20 mg/ml for the Lip-I probes and 10 mg/ml for gold nanoparticles. The use of averaging to reduce the noise improved these values to 15 and 6 mg/ml for Lip-I, and gold respectively.

In vivo assessment

The researchers also used the dual-energy microCT system to perform in vivo imaging of mice with colon cancer tumours. Mice were injected with 0.1 ml gold nanoparticles (with a gold concentration of 200 mg/ml) and then imaged 72 hours later at 40 and 80 kVp. The mice were then injected with 0.4 ml of the Lip-I probe and rescanned.
Maximum intensity projection images showed that Lip-I probes visualized the blood vessels, while gold probes revealed the liver, spleen and some enhancement into the tumour due to extravasation of the nanoparticles.
"This dual-energy microCT provides a way to image 3D vasculature and permeability in tumours," concluded Badea, associate professor of radiology at Duke's Center for In Vivo Microscopy. "These are both important biomarkers in cancer studies."