PET and CT Scans in Patients With Locally Advanced Primary Rectal Cancer That Can Be Removed During Surgery

OBJECTIVES:

• Determine if fludeoxyglucose F 18 positron emission tomography (FDG-PET) is superior to CT scan at monitoring rectal cancer response to radiation and chemotherapy by identifying residual rectal cancer in the rectal wall or pelvic lymph nodes in order to optimize selection of patients suitable for a sphincter preserving rectal cancer resection or a local excision.
• Determine the accuracy of FDG-PET in detecting extrapelvic metastatic disease in primary rectal cancer patients considered operable on the basis of currently accepted diagnostic work-up, including abdominal CT scan and chest x-ray.

OUTLINE: This is a diagnostic study conducted concurrently with multimodality management.

Within 1-2 weeks prior to starting preoperative radiotherapy/chemotherapy, patients undergo baseline positron emission tomography (PET) imaging of the thorax, abdomen, and pelvis. Patients receive fludeoxyglucose F 18 (FDG) IV followed 45 minutes later by PET imaging. Patients also undergo baseline CT imaging of the abdomen and pelvis. A CT scan of the chest is obtained if the prestudy chest x-ray is abnormal.

Patients receive preoperative radiotherapy/chemotherapy. Within 4-6 weeks of completion of radiotherapy/chemotherapy, patients undergo repeat FDG-PET imaging and CT scan. Patients undergo surgical resection 1-2 weeks later.

PROJECTED ACCRUAL: A total of 125 patients will be accrued for this study within 3 years.

DISEASE CHARACTERISTICS:

• Primary resectable rectal cancer as determined by currently accepted diagnostic work-up, including CT scan and endorectal ultrasound (EUS)
• Must meet criteria for preoperative radiotherapy and chemotherapy:

• Bulky tumors and/or EUS evidence of T3-4 and/or N1 disease

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• Not specified

Life expectancy:

• Not specified

Hematopoietic:

• Not specified

Hepatic:

• Not specified

Renal:

• Not specified

Other:

• Not pregnant or nursing
• No uncontrolled diabetes mellitus (i.e., greater than 175 mg/dL)
• No intolerance of being inside PET scanner for duration of study
• No vulnerable patients (e.g., mentally retarded or prisoners)

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• See Disease Characteristics

Endocrine therapy:

• Not specified

Radiotherapy:

• See Disease Characteristics

Surgery:

• See Disease Characteristics