The use of multiple sessions – called fractionation – is a cornerstone of radiation therapy. Giving the radiation in many small doses (fractions) rather than one big dose helps maximize damage to cancer cells while allowing healthy cells to recover between treatments. Skin cancer cells, like many cancer cells, are more susceptible to incremental DNA damage over repeated exposures. By treating, say, 20 times, we cumulatively deliver a high total dose to the tumor, but any one treatment is low enough that normal skin can repair itself in the intervals. If we tried to give one or two very large doses, we’d risk causing a severe burn or ulcer in the skin. Instead, spreading it out provides a therapeutic balance – cancer cells accrue lethal damage, and healthy cells get time to heal after each mild insult. Additionally, cancer cells cycle in and out of phases of vulnerability; multiple treatments catch more of them at vulnerable moments. This approach is very standard in radiation oncology. The bottom line is that those numerous short sessions add up to effectively eradicate the tumor with minimal side effects, whereas a single massive dose would be unsafe. It’s important to attend all the sessions because each one is a building block toward the cure.
Category:
IG-SRT
