Colorectal cancer
Radiation therapy

While a combination of radiation and chemotherapy may be useful for rectal cancer, for some people requiring treatment, chemoradiotherapy can increase acute treatment-related toxicity, and has not been shown to improve survival rates compared to radiotherapy alone, although it is associated with less local recurrence. The use of radiotherapy in colon cancer is not routine due to the sensitivity of the bowels to radiation. As with chemotherapy, radiotherapy can be used as a neoadjuvant for clinical stages T3 and T4 for rectal cancer. This results in downsizing or downstaging of the tumour, preparing it for surgical resection, and also decreases local recurrence rates. For locally advanced rectal cancer, neoadjuvant chemoradiotherapy has become the standard treatment. Additionally, when surgery is not possible radiation therapy has been suggested to be an effective treatment against CRC pulmonary metastases, which are developed by 10-15% of people with CRC.
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