Trial Information

A Feasibility Study Using Fluorine-18-Labeled Fluoro-Misonidazole Positron Emission Tomography to Detect Hypoxia in Locally Advanced (T3-T4 and./or N1)Primary Rectal Cancer Patients

Hypoxia is a characteristic feature of malignant solid tumors associated with poor prognosis
and resistance to chemotherapy and radiation. It has also been shown (6) that the presence
of hypoxia may reduce long-term survival post surgery. Hypoxia renders tumor cells up to
three times more resistant to ionizing radiation than aerobic cells. The presence of hypoxic
regions within tumors may be one factor leading to local failure after treatment with
standard pre-operative radiotherapy doses. If these regions could be identified and verified
using a non-invasive imaging technique prior to surgery, they could be specifically targeted
using sophisticated planning techniques such as intensity modulated radiation therapy (IMRT)
to deliver higher doses ionizing radiation with preoperative radiotherapy. Future studies
using IMRT to "dose paint" areas of hypoxia within tumors will build upon the results of
this feasibility study. Ultimately, by the delivery of differential dose of radiation to the
tumor, in combination with surgery, the local control rates of rectal cancer patients may
further be improved.