A 52-year-old man comes to the physician because of weight loss and constipation for the past 3 months. He has no abdominal pain, vomiting, or black stools. He has smoked 1 pack of cigarettes daily for 20 years.
His vital signs are within normal limits. Examination shows no abnormalities. Test of the stool for occult blood is positive.
Laboratory results are as follows:

He undergoes a colonoscopy that shows a nonobstructive mass in the rectum 10 cm from the anal verge. Biopsy during colonoscopy shows moderately differentiated adenocarcinoma. MR imaging shows tumor invading through the muscularis propria into perirectal tissues. CT scan of the chest, abdomen, and pelvis shows no lymph node enlargement or evidence of metastatic disease.
Which of the following is the most appropriate treatment for this patient?

Question

A 52-year-old man comes to the physician because of weight loss and constipation for the past 3 months.  He has no abdominal pain, vomiting, or black stools.  He has smoked 1 pack of cigarettes daily for 20 years.
His vital signs are within normal limits.  Examination shows no abnormalities.  Test of the stool for occult blood is positive.
Laboratory results are as follows:

He undergoes a colonoscopy that shows a nonobstructive mass in the rectum 10 cm from the anal verge.  Biopsy during colonoscopy shows moderately differentiated adenocarcinoma.  MR imaging shows tumor invading through the muscularis propria into perirectal tissues.  CT scan of the chest, abdomen, and pelvis  shows no lymph node enlargement or evidence of metastatic disease.
Which of the following is the most appropriate treatment for this patient?

Quizplus · Accepted Answer

Colorectal cancers are the 4^th most frequently diagnosed cancers in the United States. This patient has a T3 tumor, in which the tumor invades through muscularis propria. The standard of care for patients with T3/T4 tumor, with or without regional lymph node involvement, is preoperative chemoradiotherapy followed by curative surgical resection, followed by further chemotherapy. Chemotherapy during radiation therapy (to radiosensitize the tissue), followed by surgery and postoperative chemotherapy, is associated with improved cure rates in these patients. ^th There are important differences in the treatment of rectal versus colon cancer. Sphincter preservation is an important consideration as it obviates the need for a permanent colostomy. Due to its pelvic location, local failure in rectal cancer is associated with higher morbidity and worse outcome. Neoadjuvant therapy causes significant down-staging of the primary tumor before resection and is associated with higher rates of sphincter preservation and local control. The flow chart shows the sequence of treatment in locally advanced (T3/T4) rectal cancer. 11ec193a_96cc_bb51_853d_03f1cf14f204_MD0002_00 Educational objective: Neoadjuvant concurrent chemoradiotherapy is the standard of care in locally advanced (T3/T4) rectal cancer. Neoadjuvant therapy causes significant down-staging of the primary tumor before resection and is associated with higher rates of sphincter preservation and local control. __________ References: Preoperative versus postoperative chemoradiotherapy for rectal cancer. (http://www.ncbi.nlm.nih.gov/pubmed/15496622) Preoperative multimodality therapy improves disease-free survival in patients with carcinoma of the rectum: NSABP R-03. (http://www.ncbi.nlm.nih.gov/pubmed/19770376)

A 52-Year-Old Man Comes to the Physician Because of Weight