Archive for the ‘Osteosarcoma Diagnosis’ Category

With Pediatric Sarcoma, No Need for Bone Scans. PET/CT Sufficient

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Posted 25 Jul 2011 — by James Street
Category Osteosarcoma, Osteosarcoma Diagnosis, Radiation
By Todd Neff | June 9, 2011

Children with pediatric sarcoma can be spared the additional radiation of single photon emission computed tomography (SPECT). PET/CT imaging alone does the trick, according to a study presented this week at the Society of Nuclear Medicine annual meeting in San Antonio.

Sarcomas of the bone and soft tissue make up more than 13 percent of tumors among children, with approximately 1,500 new cases in the United States each year.

The study, led by Franziska Walter, MD, of the University of California Los Angeles, compared the PET/CT scans and bone scans (technetium-99m methylene diphosphonate SPECT scans) of 29 pediatric patients (26 boys and six girls, average age 12 years). The study was retrospective, considering scans from January 2006 to February 2010. Twenty one of the patients (72 percent) had bone sarcoma; eight (28 percent) had tissue sarcoma.

A total of 39 paired scans were acquired, with some patients having been scanned more than once. Two observers read the SPECT scans, with two other readers simultaneously considered the PET/CT scans. Later, three readers assessed the PET/CT and SPECT scans side-by-side.

Twenty of the 39 studies showed malignant bone lesions, as established by reference standard. PET/CT found them all, the researchers found, compared to a SPECT accuracy of 80 percent. In three cases in which the disease was metastatic, SPECT scans spotted one; PET/CT identified them all.

“The current study strongly suggests that 99Tc-MDP bone imaging does not provide an additional diagnostic value over PET/CT imaging alone in pediatric sarcoma patients,” the researchers concluded, suggesting that physicians limit radiation exposure by omitting the SPECT scans.

 

(Reuters Health) – CT scans to measure lung tumors can be unreliable, potentially leading patients and doctors to believe the cancer is growing when it’s not, a new study suggests.

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Posted 09 Jul 2011 — by James Street
Category Diagnostic, Lung Cancer, Lung Metastases, Osteosarcoma Diagnosis, Osteosarcoma Outcomes, Relapse

By Frederik Joelving

NEW YORK | Fri Jul 8, 2011 5:27pm EDT

In principle, that could mean stopping a treatment that is actually keeping the tumor in check, researchers say.

“The patient and the doctor both need to understand that small changes don’t necessarily mean much,” Dr. Gregory Riely, a lung cancer specialist at Memorial Sloan-Kettering Cancer Center in New York, told Reuters Health.

“Changes of up to 10 percent can happen simply as a result of the inherent variability of CT imaging,” he added.

Riely’s study, published in the Journal of Clinical Oncology, is the first to test how reliable lung cancer scans are — work that’s long overdue, experts say, because CT scans have already become the gold standard for measuring cancer growth and treatment response.

“It’s the sense of, ‘Really? Is this first happening now?’” said Dr. Michael Maitland, an oncologist at the University of Chicago, who wrote an editorial about the findings.

“This is telling us scientifically how much noise is naturally there without any treatment or the cancer getting worse,” he told Reuters Health. “It’s an important thing to do whenever you are going to use any kind of marker for a disease.”

For the study, the Sloan-Kettering team asked patients with late-stage lung cancer if they’d be willing to have two chest CT scans done within minutes — 33 said yes.

Doctors normally scan such patients every few months to see if their tumor is growing, which might be a signal to try a new drug.

Then the researchers gave the images to three radiologists who had no idea the scans had been repeated before the tumors could have grown or shrunk appreciably.

According to the radiologists’ measurements, however, many tumors had changed, ranging from 23-percent shrinkage to 31-percent growth.

Overall, three percent of the tumors appeared to have grown so much that doctors would diagnose disease progression according to common criteria. And the smaller the tumor, the bigger the variation.

Riely said some doctors will make treatment decisions based on tiny changes seen on scans, although that might be a costly mistake, according to the new findings.

“We begin to put more and more stock in the data without really understanding the true variability of those measurements,” he said. “Small changes are not clinically meaningful and we should not alter clinical care based on them.”

Riely stressed, however, that his results don’t mean patients should get repeat scans, which would increase their radiation exposure.

Most likely, the results also apply outside of lung cancer, although patients’ breathing could make the chest scans extra variable.

Maitland said the findings will also help drug developers, who look at increasingly small changes in tumor size during drug tests, forgetting that the scans might be unreliable at that scale.

“Many of the individuals analyzing data that way perhaps are not aware of that limitation,” he explained.

With the new data, scientists can build better models of cancer progression that might save both time and money in clinical trials.

“There is a real opportunity here to update our systems and take advantage of the new technology,” said Maitland.

SOURCE: bit.ly/puOY5x Journal of Clinical Oncology, online July 5, 2011.

Tumor cell types in osteosarcoma as revealed by electron microscopy Implications for histogenesis and subclassification

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Posted 15 Jun 2011 — by James Street
Category Osteosarcoma Diagnosis

E. Grundmann, A. Roessner and M. Immenkamp

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Abstract

Ultrastructural studies in 26 osteosarcomas of high grade malignancy which were in diverse locations and of varied histological types revealed seven different tumor cell types. They were characterized by their features as follows: 1) anaplastic cells of malignant blast structure: 2) osteoblastic cells —some of them with dot-like intranuclear bodies ; 3) osteocytelike cells surrounded by mineralized matrix; 4) fibroblast-like cells; 5) cells of myofibroblastic differentiation ; 6) chondroblast-like cells in chondroblastic areas, and even 7) angioblastic cells that may be differentiated from the angioblastic and endothelial structures of capillaries. Histogenetically, osteosarcoma may be derived from stromal mesenchymal cells with a potential for differentiation into these seven tumor cell types, any tumor including, however, the osteoblastic and the osteocyte-like cells with tumor osteoid. This matrix serves as the specific criterion for identifying a tumor as „osteosarcoma“, but almost every osteosarcoma of high grade malignancy will show these seven tumor cell types. The predominance of one or the other cell in the population may provide the basic information for achieving a cytologic subclassification of osteosarcoma in order to obtain relevant morphologic criteria in terms of prognosis.