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Oncotype DX Colon Cancer Test Changes Treatment in Close to One-Third of Patients

By on January 23rd, 2012

A survey of oncologists suggests that the Oncotype DX colon cancer test changes treatment recommendations for 29 percent of patients with Stage II colon cancer. These results will be presented at the 2012 Gastrointestinal Cancers Symposium.

Gene expression profiling explores the patterns of genes that are active in tumor cells. Studies suggest that gene expression may provide important information about prognosis or likely response to treatment in several types of cancer. For example, among selected women with early-stage breast cancer, the Oncotype DX breast cancer test has been shown to predict the likelihood of cancer recurrence and the likelihood of benefit from chemotherapy. As a result, the test has been added to medical guidelines for early-stage breast cancer.

A similar test became available for patients with Stage II colon cancer in 2010. Stage II colon cancer refers to cancer that extends through the wall of the colon but has not invaded lymph nodes or spread to distant parts of the body. Many patients with this stage of disease have good outcomes with surgery alone, and routine adjuvant (post-surgery) chemotherapy is not currently recommended for Stage II colon cancer. Chemotherapy may, however, be considered for Stage II patients with a higher risk of cancer recurrence.

Previous research has demonstrated that the Oncotype DX colon cancer test provides information about the risk of recurrence among patients with Stage II colon cancer.[1] Researchers are now evaluating how this information affects treatment decisions.

In the current study, researchers surveyed US oncologists who had experience with the Oncotype DX colon cancer test.[2] All participating oncologists had ordered the test for at least three patients with Stage II colon cancer, and were asked to provide treatment information for the most recent patient. The study is ongoing, and the current, preliminary analysis includes information from 92 oncologists.

  • Among the patients who had an initial treatment plan (either chemotherapy or observation), 29 percent had a change in recommended treatment after the Oncotype DX test, including changes from chemotherapy to observation and vice-versa.

These results build upon previous studies of the Oncotype DX colon cancer test by demonstrating that use of the test can influence treatment decisions for Stage II colon cancer.

References:


 

[1] Gray RG, Quirke P, Handley K et al. Validation study of a quantitative multigene reverse transcriptase-polymerase chain reaction assay for assessment of recurrence risk in patients with stage II colon cancer.Journal of Clinical Oncology. 2011; 29(35):4611-9.

[2] Cartwright T, Chao C, Lopatin M, Bentley T, Broder M, Change E. Effect of Oncotype® DX Colon Cancer Test Results on Treatment Recommendations in Patients with Stage II Colon Cancer: Preliminary Results. Paper presented at: 2012 Gastrointestinal Cancers Symposium; January 19-21, 2012; San Francisco, CA. Abstract 398. …source …more about colon cancer

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Could the US have given Chavez cancer?

By on January 17th, 2012

Venezuela’s president has mused that the US may have given him and other leftist leaders cancer. That’s unlikely to be possible

Five South American presidents and former presidents, including Venezuela’s Hugo Chavez, have been recently diagnosed with cancer. Chavez speculated that US agents may be inducing the disease in South American leaders by feeding them or injecting them with an unspecified substance. The state department has rejected Chavez’s insinuation.

Can you give someone cancer? Not reliably. Injecting cancerous cells into a person isn’t enough to give him the disease. The abnormal tissue has to penetrate and grow in other areas of the body. If you injected someone with live cancer cells, their immune system would almost certainly attack and destroy the foreign tissue. In theory, secret agents might be able to induce cancer in a leftist South American president with a severely weakened immune system. Or perhaps they could harvest tissue from him, expose it to a carcinogen, and then reintroduce it into his body. As far as we know, however, these techniques have never successfully caused cancer in a human.

While it’s tough to induce cancer in an enemy, it’s certainly possible to increase his chances of developing the disease. The most effective option would be radiation. Oncologists implant radiation-emitting devices the size of a seed into some patients to combat existing cancers. It’s hard to say just how much the device would increase a healthy individual’s risk of cancer, but leaving a high-intensity model inside the body for weeks or months would result in a significant dose of radiation. The victim would likely notice the implant, though. They’re too big for an ordinary needle, and need to be inserted through a catheter.

You could, alternatively, contaminate the victim’s diet with high levels of aflatoxin, which is associated with liver cancer. Or you could infect her or him with any of a number of cancer-causing biological agents. Helicobacter pylori contributes to the development of gastric cancer, and human papillomaviruses can cause cervical, anal and a few other forms of cancer. But these tactics probably wouldn’t produce cancer in the short term and aren’t guaranteed to have any effect at all. In countries with high aflatoxin exposure, like China and parts of Africa, fewer than 1 in 1000 people develop liver cancer.

Most of the research on infusing cancer into humans is decades old. In the 1950s, Chester Southam gained notoriety by injecting hundreds of cancer patients and healthy prison inmates with live cancer cells. Southam wasn’t trying to give his subjects cancer. Rather, he was testing the efficiency with which the patients’ immune systems would reject the cells. He was so confident that the patients would fight off the invaders that he thought it unnecessary to tell them what he was doing. None of Southam’s patients seems to have developed metastatic cancer from his injections, and most modern oncologists believe the experiment posed little risk to the subjects. (One of the patients showed signs of a potentially spreading disease before dying of a separate illness.) Southam was sanctioned for fraudulent practices, however, and the case helped establish modern informed consent standards.

Southam’s experiments were abandoned in the 1950s, but he wasn’t the last doctor to inject a patient with live cancer cells. In 2009, a Taiwanese doctor was accused of implanting cancerous uterine cells into healthy patients as part of an insurance scam. While the insurance companies were out more than $660,000, none of the victims developed cancer.

Today, ethical physicians inject live cancer cells only into laboratory animals such as mice and rats. In most cases, the animals’ immune systems are compromised, or the rodents have been genetically engineered to rapidly spread mutant cells. …source …more about cancer

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New, Noninvasive Way To Identify Lymph Node Metastasis

By on January 16th, 2012

Using two cell surface markers found to be highly expressed in breast cancer lymph node metastases, researchers at Moffitt Cancer Center, working with colleagues at other institutions, have developed targeted, fluorescent molecular imaging probes that can non-invasively detect breast cancer lymph node metastases. The new procedure could spare breast cancer patients invasive and unreliable sentinel lymph node (SLN) biopsies and surgery-associated negative side effects.

Their study was published in a recent issue of Clinical Cancer Research (18:1), a publication of the American Association for Cancer Research.

“The majority of breast cancer patients, up to 74 percent, who undergo SLN biopsy are found to be negative for axillary nodal, or ALN, metastases,” said corresponding author David L. Morse, Ph.D., an associate member at Moffitt whose research areas include experimental therapeutics and diagnostic imaging. “Determining the presence or absence of ALN metastasis is critical to breast cancer staging and prognosis. Because of the unreliability of the SLN biopsy and its potential for adverse effects, a noninvasive, more accurate method to assess lymph node involvement is needed.”

The authors note that the postoperative complications to the SLN biopsy can include lymphedema, seroma formation, sensory nerve injury and limitations in patient range of motion. In addition, biopsies fail to identify disease in axillary lymph nodes in five to 10 percent of patients.

In developing targeted molecular probes to identify breast cancer in axillary lymph nodes, the research team from Moffitt, the University of Arizona and University of Florida used two surface cell markers – CAIX and CAXII. CAIX is a cell surface marker known to be “highly and broadly expressed in breast cancer lymph node metastases” and absent in normal tissues.

CAIX and CAXII are both integral plasma membrane proteins with large extracellular components that are accessible for binding of targeted imaging probes, explained Morse. In addition, several studies have shown that CAIX expression is associated with negative prognosis and resistance to chemo and radiation therapy for breast cancer. CAXII is a protein expressed in over 75 percent of axillary lymph node metastases.

The researchers subsequently developed their targeting agents by using monoclonal antibodies specific for binding CAIX and CAXII, both of which are known to promote tumor growth.

According to the researchers, a number of noninvasive optical imaging procedures for SLN evaluation have been investigated, but the approaches have lacked the ability to target tumor metastasis biomarkers.

“These methods provide only anatomic maps and do not detect tumor cells present in lymph nodes,” explained Morse. “Using mouse models of breast cancer metastasis and a novel, monoclonal anti-body-based molecular imaging agents, we developed a targeted, noninvasive method to detect ALN metastasis using fluorescence imaging.” …source …more about breast cancer