Current Clinical Trials

Stage I (old stage: Dukes A or Modified Astler-Coller A and B1) rectal cancer

Stage I tumors extend beneath the mucosa into the submucosa (T1) or into, but not through, the bowel muscle wall (T2). Because of its localized nature at presentation, stage I has a high cure rate.

Standard treatment options:

1. Wide surgical resection and anastomosis when an adequate low-anterior resection (LAR) can be performed with sufficient distal rectum to allow a conventional anastomosis or coloanal anastomosis.
2. Wide surgical resection with abdominoperineal resection (APR) for lesions too distal to permit LAR.
3. Local transanal or other resection [1,2] with or without perioperative external beam radiation therapy (EBRT) plus fluorouracil (5-FU).

There are three potential options for surgical resection in stage I rectal cancer: local excision, LAR, and APR. Local excision should be restricted to tumors confined to the rectal wall and that do not, on rectal ultrasound or magnetic resonance imaging, involve the full thickness of the rectum (i.e., not a T3 tumor). The ideal candidate for local excision has a T1 tumor with well-to-moderate differentiation that occupies less than one-third of the circumference of the bowel wall. Local excision should only be applied to very select patients with T2 tumors, as there is a higher risk of local and systemic failure.

For patients with T1 and T2 tumors, no randomized trials are available to compare local excision with or without postoperative chemoradiation to wide surgical resection (LAR and APR). Investigators with the Cancer and Leukemia Group B (CALGB) enrolled patients with T1 and T2 rectal adenocarcinomas that were within 10 cm of the dentate line and not more than 4 cm in diameter, and involving not more than 40% of the rectal circumference, onto a prospective protocol, CLB-8984. Patients with T1 tumors received no additional treatment following surgery, whereas patients with T2 tumors were treated with external beam radiation therapy (54 Gy of 30 fractions, 5 days/week) and 5-FU (500 mg/m² on days 1 through 2 and days 29 through 31 of radiation). At 48 months median follow-up, the 6-year failure-free survival and overall survival (OS) rates for patients with T1 tumors were 83% and 87%, respectively. For patients with T2 tumors, the 6-year failure-free survival and OS rates were 71% and 85%, respectively.[3]

Patients with tumors that are pathologically T1 may not need postoperative therapy. Patients with tumors that are T2 or greater have lymph node involvement about 20% of the time, and additional therapy should be considered, such as radiation and chemotherapy, or more standard surgical resection.[4] Patients with poor histologic features or positive margins after local excision should consider LAR or APR and postoperative treatment as dictated by full surgical staging.

Check for U.S. clinical trials from NCI's PDQ Cancer Clinical Trials Registry that are now accepting patients with stage I rectal cancer. The list of clinical trials can be further narrowed by location, drug, intervention, and other criteria.

General information about clinical trials is also available from the NCI Web site.

References

1. Bailey HR, Huval WV, Max E, et al.: Local excision of carcinoma of the rectum for cure. Surgery 111 (5): 555-61, 1992.  [PUBMED Abstract]
   
   
2. Benson R, Wong CS, Cummings BJ, et al.: Local excision and postoperative radiotherapy for distal rectal cancer. Int J Radiat Oncol Biol Phys 50 (5): 1309-16, 2001.  [PUBMED Abstract]
   
   
3. Steele GD Jr, Herndon JE, Bleday R, et al.: Sphincter-sparing treatment for distal rectal adenocarcinoma. Ann Surg Oncol 6 (5): 433-41, 1999 Jul-Aug.  [PUBMED Abstract]
   
   
4. Sitzler PJ, Seow-Choen F, Ho YH, et al.: Lymph node involvement and tumor depth in rectal cancers: an analysis of 805 patients. Dis Colon Rectum 40 (12): 1472-6, 1997.  [PUBMED Abstract]
   
   

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