RATIONALE: Diagnostic procedures, such as PET and CT scans, may improve the ability to detect the extent of locally advanced primary rectal cancer and may also help to measure a patient's response to treatment.

PURPOSE: This clinical trial is studying how well PET and CT scans detect residual or metastatic disease 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.

• Drug: chemotherapy
• Procedure: computed tomography
• Procedure: conventional surgery
• Procedure: neoadjuvant therapy
• Procedure: positron emission tomography
• Procedure: radionuclide imaging
• Radiation: fludeoxyglucose F 18
• Radiation: radiation therapy

• Nahas CS, Akhurst T, Yeung H, Riedel E, Markowitz AJ, Minsky BD, Paty PB, Weiser MR, Temple LK, Wong WD, Larson SM, Guillem JG. Positron emission tomography detection of distant metastatic or synchronous disease in patients with locally advanced rectal cancer receiving preoperative chemoradiation. Ann Surg Oncol. 2008 Mar;15(3):704-11. Epub 2007 Sep 20.
• Guillem JG, Puig-La Calle J Jr, Akhurst T, Tickoo S, Ruo L, Minsky BD, Gollub MJ, Klimstra DS, Mazumdar M, Paty PB, Macapinlac H, Yeung H, Saltz L, Finn RD, Erdi Y, Humm J, Cohen AM, Larson S. Prospective assessment of primary rectal cancer response to preoperative radiation and chemotherapy using 18-fluorodeoxyglucose positron emission tomography. Dis Colon Rectum. 2000 Jan;43(1):18-24.

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