Short course RT vs Long course CRT for Rectal Cancer: which to choose?

Rectal carcinomas are divided into early, intermediate and locally advanced stage. The early rectal carcinoma has a low risk on local recurrence after TME surgery and is defined as limited growth in or thru the rectal wall: clinically T1-T3b, which has no threatened mesorectal fascia, no suspected lymph nodes and no metastasis. The intermediate rectal carcinoma is defined as a clinically T3c-d with no evidence of lymph node metastasis, or a T1-3 with metastasis in up to 3 regional perirectal lymph nodes, with no threatening of the mesorectal fascia. For patients with an intermediate rectal carcinoma, the benefit of neoadjuvant radiotherapy lies in reducing the risk of local recurrence. Neoadjuvant radiotherapy with 5x5Grey , with short interval until surgery, has become the standard from the TME study. The absolute risk reduction in this group is approximately 12% over 10 years. A negative effect of neoadjuvant radiotherapy is an increased risk of perineal complications after abdominoperineal resection. Also there are reduced functional outcomes after neoadjuvant radiotherapy with TME surgery: more faecal incontinence, a higher defecation frequency and more sexual function disorders such as erectile dysfunction and vaginal dryness compared to treatment with TME surgery alone. Locally advanced rectal carcinoma is defined as a tumor with a high risk of local recurrence after surgical treatment. This includes T4, involved mesorectal fascia, N2 features or extramesorectal pathological nodes. Almost all available literature recommends neoadjuvant chemoradiation followed by resection in locally advanced rectal carcinoma to reduce the tumor volume before resection and increase the number of R0 resections and reduce the number of locoregional recurrences after resection. A negative effect is a significant amount of acute toxicity, such as radiation proctitis, diarrhea and irradiated skin effects. There is also an effect on functional outcomes after treatment with chronic diarrhea and urinary complaints.