Ultima Vez Modificado: 13 de marzo del 2005
Dear OncoLink "Ask The Experts,"
I am 25 years old and had a T1 cancerous polyp removed from my rectum in December. They are now recommending radiation therapy. I am wondering what the long-term effects of radiation therapy are and also whether or not it is really necessary.
Richard Whittington, MD, Associate Professor of Radiation Oncology at the University of Pennsylvania School of Medicine, responds:
This is a tough one. The short-term effects of radiation therapy are transient diarrhea, bladder irritability (frequency, urgency, having to get up at night to urinate), and irritation of the skin. The longer term effects in men and women are a little different. In men there is possible decreased fertility or sterility, with the risk depending on the radiation technique and the cancer location. Sperm banking is typically recommended if the individual is interested in having children. In a woman the risk of sterility is near 100%. With the long survival expected in a young individual, treatment with radiation could complicate the management of any future pelvic conditions, such as other polyps, prostate or bladder problems. Although there is very poor data to suggest that there is a marked increased risk, second tumors of the bladder, prostate or rectum may be slightly elevated. Other important considerations include:
1. What is the risk of the tumor returning?
This is generally determined by the size, grade and character of the tumor. The risk is higher for T1 lesions over 1 cm and very high if over 2cm. It is higher for poorly differentiated as opposed to well or moderately differentiated tumors. It is higher for tumors that arise in villous adenomas. It is higher when there is a colloid or anaplastic histology. Polypoid lesion with a negative stalk have a much lower risk than when the stalk is involved and is also lower than it is for sessile lesions.
2. If it returns, where will it return?
If the risk is low, as defined above, then the primary risk is local recurrence, but the high risk patients also have a higher risk of distant metastases which are usually incurable.
3. If it returns what do we do?
If it is superficial and local, another excision is possible, but a more invasive tumor may require a bowel resection. If it is a low lying lesion it is possible that the next procedure may be surgery with permanent colostomy, while if it is higher up and surgery is needed, then the rectum can be preserved.
4. What is the risk of other polyps/tumors developing?
These tumors are infrequent in this age group and raise the risk of a genetic predisposition to other polyps. Lynch syndrome is the most common. This is important because you have to plan comprehensive management at the beginning so you don't complicate the management of other polyps later on. It is also important because these are the tumors where the targeted therapies at the specific defective genes seem to be preventing the recurrences.
5. Are there any other conditions that could complicate the decision?
Inflammatory bowel disease or other local problems, diabetes, prior surgery will all raise the cost of radiation.