Radiotherapy: What you might notice

Radiotherapy typically starts with a planning session (sometimes called simulation): a CT scan used to map the exact area to be treated. Small permanent skin marks or temporary marker dots may be used to line up the machine precisely each day.

Side effects from radiotherapy build up gradually, they are rarely noticeable after just one or two sessions. Most people feel little different in the first week regardless of treatment site.

By the middle of a course, cumulative effects become more noticeable, skin reactions in the treated area, fatigue, and site-specific effects (for example sore throat if the neck is treated, or bowel changes if the pelvis is treated).

Side effects are typically at their most noticeable in the final week of treatment and the week or two immediately after. This is expected, not a sign of a problem, since effects continue to build for a short time even after the last session.

Skin and site-specific effects typically continue to heal over the following weeks to months. Fatigue often lingers longer than people expect: sometimes for weeks after the physical effects have settled.