MRI to measure the effectiveness of neoadjuvant chemotherapy followed by chemoradiotherapy in rectal cancer

 

The treatment for rectal cancer depends on stage, location, presence of high-risk histology, perineural invasion, positive margins, and/or lymphovascular invasion. Physicians may recommend surgical procedures such as transanal local excision, transanal endoscopic microsurgery, polypectomy, or total mesorectal excision for stage II/III disease. Before surgical excision, patients frequently receive neoadjuvant chemotherapy and radiation therapy for locally advanced rectal cancer. Patients who have completed chemoradiation therapy could benefit from magnetic resonance imaging (MRI) to assess efficacy of chemoradiation on tumor shrinkage, ie, tumor regression grade, according to a study called MERCURY recently published online in the Journal of Clinical Oncology. Currently, MRI is not routinely ordered for the staging of rectal cancers before the administration of chemoradiation. These new data could spare patients from undergoing definitive surgery because the MRI allows doctors to measure the effectiveness of neoadjuvant treatment based on circumferential resection margin and to assess the risk for recurrence prior to surgery. The U.S. Preventive Services Task Force recommends annual fecal occult blood testing or periodic flexible sigmoidoscopy for persons older than 50 years.

 

Suggested reading:

1.      Patel UB, Taylor F, Blomqvist L, et al. Magnetic resonance imaging–detected tumor response for locally advanced rectal cancer predicts survival outcomes: MERCURY experience [published online ahead of print August 29, 2011]. J Clin Oncol.

2.      American Cancer Society. Cancer Facts and Figures 2010. Atlanta, GA: American Cancer Society; 2010.

3.      Kang H, O’Connell JB, Leonardi MJ, et al. Rare tumors of the colon and rectum: a national review. Int J Colorectal Dis. 2007;22:183-189.

4.      Balch GC, De Meo A, Guillem JG. Modern management of rectal cancer: a 2006 update. World J Gastroenterol. 2006;12:3186-3195.

5.      Winawer SJ, Fletcher RH, Miller L, et al. Colorectal cancer screening: clinical guidelines and rationale. Gastroenterology. 1997;112:594-642.

6.      U.S. Preventive Services Task Force. Screening for colorectal cancer. In: Guide to clinical preventive services: report of the U.S. Preventive Services Task Force. 2d ed. Baltimore, MD: Williams & Wilkins; 1996.

7.      Das P, Skibber JM, Rodriguez-Bigas MA, et al. Predictors of tumor response and downstaging in patients who receive preoperative chemoradiation for rectal cancer. Cancer. 2007;109:1750-1755.

8.      Lahaye MJ, Engelen SM, Nelemans PJ, et al. Imaging for predicting the risk factors – the circumferential resection margin and nodal disease – of local recurrence in rectal cancer: a meta-analysis. Semin Ultrasound CT MR. 2005;26:259-268.

9.      Compton CC, Greene FL. The staging of colorectal cancer: 2004 and beyond. CA Cancer J Clin. 2004;54:295-308.