We determine the cancer is gone through a combination of clinical examination, imaging, and the statistical cure rates. At the end of the treatment course, the treated site is carefully examined – by that time, there should be no visible or palpable sign of the tumor remaining. If there was a lump, it should no longer be felt. If it was an ulcer, it should have closed up, leaving just healing skin. We also utilize the ultrasound imaging as a verification tool: the ultrasound can be used in the final week or at the end to scan the area and confirm that there’s no detectable tumor mass or thickness under the skin. Essentially, we’re looking to see that the previously seen tumor on ultrasound has resolved – typically, it will show just normal tissue now. This real-time imaging is a unique advantage; it’s like getting confirmation that nothing abnormal remains, very much like Mohs surgery confirms by microscope that all cancer is out.
Beyond that, we rely on follow-up observations. We know IG-SRT has over a 99% cure rate from large studies, so if a patient completes the full regimen, the expectation is that the cancer is cured. We schedule a follow-up visit (commonly about 6-8 weeks after completion) to check the area. At that visit, the skin has mostly healed so we can inspect it clearly – we expect to see normal, healthy skin. If something looks off (like a persistent nodule or sore), we would investigate further, possibly with a biopsy. But that scenario is rare. In most cases, the site looks scar-free and cancer-free.
We also continue to monitor the site at regular skin exam appointments over the next year(s). If at any point there is a suspicion of recurrence (like a bump reappearing in that spot), we’d biopsy it. However, given the high success rate and the imaging confirmation, we usually have confidence that the cancer is gone. Many patients enjoy actually watching the tumor shrink away during treatment – it gives them assurance.
In summary, we know the cancer is gone when: (a) the tumor has visibly and palpably disappeared, (b) the ultrasound shows no remaining lesion, and (c) time passes with no evidence of recurrence. It’s a bit different from surgery where you get a pathology report saying “margins clear” – here we get a visual/imaging “all clear.” And because research tells us that if anything were left behind it would usually regrow within the first year or two, and that’s very uncommon, we trust the treatment process as definitive. If you ever want extra reassurance, some centers will do a post-treatment biopsy of the area (though that’s not routine if all looks well). But honestly, with the ability to directly see it gone and the literature backing it, that’s typically sufficient proof of cure for both doctor and patient.
