You may start to see changes in the tumor after a couple of weeks of treatment, although the timing can vary. Many patients notice that by around the halfway point of the treatment course, the visible part of the skin cancer is getting smaller, flatter, or less raised. For example, if it was a bump, it might be shrinking; if it was an ulcer, it might be filling in. Some small lesions might seemingly vanish even earlier. However, other times the tumor can be a bit masked by the treatment reaction – e.g., the area gets red and crusty, and you can’t easily distinguish cancer vs. inflammation. The ultrasound imaging done during IG-SRT is particularly helpful – it will show the tumor shrinking internally even before your eyes do. In fact, we often show patients on the screen how much smaller it’s gotten mid-way.
By the end of the treatment course, in most cases the tumor is effectively gone, but the area will likely still be somewhat red or scabbed. So even though the cancer cells are destroyed, you might not see “normal” skin immediately because the skin is still healing from radiation. Over the next few weeks after finishing, any residual scab or crust will fall off and reveal healed skin underneath. At that point, you typically see no sign of the tumor at all – just fresh skin that might be pinker than surrounding skin for a while.
Every patient and tumor is a little different. Some people with superficial BCCs see them fade away quite early in treatment; others with thicker nodules might see it shrink steadily but still have a remnant until near the end. Rest assured that the process is working continuously even if you can’t visually appreciate it day by day.
It’s similar to orthodontics: you don’t see teeth move daily, but over weeks they definitely shift. Likewise, over the weeks of IG-SRT the tumor is steadily being eroded. By the final sessions, oftentimes we’re treating mostly a red patch where the tumor used to be.
So in summary, expect visible shrinkage by mid-treatment, complete disappearance of the obvious tumor by end or shortly after, and then the healing of skin thereafter. We will be monitoring it, and believe me – seeing the tumor melt away is one of the rewarding aspects of this therapy for both doctor and patient. We often hear patients say, “I could see it getting smaller each week,” which is very reassuring to them.
