Fig. 13

Pre-treatment and post-chemoradiotherapy T2-weighted MR images of 74-year-old male patient with a distal tumour primarily staged as cT1-2 (upper row; a = pre-treatment, b = post-treatment, arrowheads indicating intact bowel wall around the tumour), and another 62 year old male patient with a more advanced cT4b tumour invading the dorsal bladder wall (bottom row, c = pre-treatment, d = post-treatment, arrows indicating invasion of the bladder). In both cases the tumour has decreased in size and become largely hypointense after CRT, indicating a fibrotic transformation (white arrowheads in b, white arrows in d). If and to what extent viable residual tumour is present within the fibrosis is difficult to discern. The upper patient proved to be a complete responder (ycT0, followed by watch-and-wait with no signs of tumour regrowth for > 2 years). The bottom patient underwent resection showing a ypT3 tumour remnant at histopathology. The fibrosis invading and retracting the bladder wall (white arrows in d) did not contain any vital residual tumour cells