Nuclear Oncology

Archive for the ‘Brain Tumors’ Category

A small initial test in children with medulloblastoma (most common type of childhood malignant brain tumor) showed that an experimental drug developed by Swiss drugmaker Roche Holding AG, may have promising results.

Baptized under the name ‘GDC-0449′, this drug is part of a new class of drugs that block the so-called ‘Hedgehog Signaling Pathway, which involves several proteins that play a role in cell growth.

Presented at a meeting of the American Society of Clinical Oncology, the results of the test phase showed that the drug was well tolerated by 12 of 13 children with medulloblastomas constant or resistant to drugs, with one patient who remained with the drug for more than a year without achieving progress against the disease.

Amar Gajjar Dr., director of neuro-oncology at Children’s Research Hospital St. Jude in Memphis, Tennessee, and lead investigator of the study, stressed that: “Less than 5 percent of these children survive if primary treatment fails.”

Gajjar found that the ‘hedgehog pathway’ was responsible for about 20 percent of medulloblastomas and future trials will involve patients whose tumors have activated hedgehog ducts.

In addition, earlier studies have suggested that GDC-0449 could also be effective against basal cell carcinoma in adults and there is currently a two-phase test is performed in adults with medulloblastoma recurrent.

The following are some new types of radiation:

* Intensity Modulated Radiotherapy (IMRT, for its acronym in English [Intensity-modulated radiation therapy]) is an advanced form of radiation therapy that uses high-precision X-ray accelerators for computer-controlled precise radiation doses to a malignant tumor or specific areas within the tumor. The radiation dose is designed to conform to the three-dimensional (3D) of the tumor by modulating (control) the intensity of the radiation beam to focus a higher dose to the tumor while minimizing exposure to radiation on healthy cells.

* Stereotactic radiosurgery is a highly precise form of radiation therapy that directs narrow beams of radiation to the tumor from different angles. In this procedure the patient may put a rigid head. Computed tomography (CT) or nuclear magnetic resonance imaging (MRI) help the doctor identify the exact location of the tumor, and a computer helps regulate the dose of radiation. Stereotactic radiotherapy is physically similar to radiosurgery but involves fractionation (multiple treatments). This method would be recommended for tumors that are at or near critical brain structures that can not tolerate a single large dose of radiation or for larger tumors.

* The three-dimensional conformal radiotherapy (3D-CRT) is a conventional form of radiation therapy that uses a specific adaptation of the X-ray beams designed to conform to the shape of the tumor to maximize the tumor dose and minimize dose applied in the surrounding normal tissue. This form of treatment is tailored to the particular patient’s anatomy and tumor location. Often requires a CT and / or MRI for treatment planning. Read the rest of this entry »