Richard Whittington, MD
Last Modified: November 1, 2001
Dear OncoLink "Ask the Experts,"
My mother, who is 84 years old, was recently diagnosed with rectal cancer. The tumor is a flat malignancy that is attached to the back wall of her rectum. All test results show that the cancer has not spread, and is only isolated to the rectal wall. Her current surgeons see no alternative but to remove the tumor and perform a colostomy. The surgeon mentioned that the surgery was needed because the tumor had grown into the sphincter muscle.
In your opinion do you believe there is a viable alternative to this radical procedure? Possibly using radiation therapy...I believe I heard about using a radioactive isotope the size of a kernel of rice, which is inserted directly into the tumor. Or do you feel that another form of therapy could be used? Your input here would be greatly appreciated!
Richard Whittington, MD, Associate Professor of Radiation Oncology at the University of Pennsylvania School of Medicine, responds:
This is an unfortunate problem. Although we cannot comment on your mother's specific case, assuming that the staging information you have presented is correct and complete, the current literature reflects that the most common tumors of the rectum (adenocarcinomas) do not respond well to radiation alone.
The best that can be accomplished with modern radiation is to control about 25% of these tumors when surgery is omitted. Lower doses of radiation may be used with chemotherapy if the entire tumor can be locally excised (scooped out) with negative margins, and the cure rate is about 99%, with 90% avoiding a colostomy.
Unfortunately, when the tumor invades the sphincter muscle, the muscle usually doesn't work very well after the surgical excision. There is a less common tumor that occurs primarily in elderly women (which may be called an anal canal squamous cell tumor, basaloid squamous carcinoma of the rectum, transitional cell carcinoma of the rectum, or a cloacogenic carcinoma). This is exquisitely sensitive to the effects of radiation and chemotherapy. The control rate is about 90% with this treatment and it does not require a colostomy.
Surgery is possible and will control the tumor in the remaining patients and does require a colostomy, but still most people avoid it. It is also possible to do the surgery first which always requires a colostomy, and while this is an accepted treatment, most people still require radiation and chemotherapy afterwards and the results are the same as the radiation-chemo program. The NIH rejected a randomized trial of surgery first vs. radiation first as they felt it wasn't ethical to randomize 1/2 of the patients to a mandatory colostomy. Hopefully, your mother has a squamous/basaloid/transitional/cloacogenic carcinoma. Please speto her physician about the options.
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