What are the effects of preoperative radiotherapy on rectal adenocarcinoma?

From the Guidelines

The correct answer regarding preoperative radiotherapy for rectal adenocarcinoma is D: Reduce risk of local recurrence and improve outcomes in rectal cancer. Preoperative radiotherapy has been consistently shown to decrease local recurrence rates by approximately 50-60% compared to surgery alone, as seen in studies such as the one published in the Journal of Clinical Oncology in 2024 1. While preoperative radiotherapy does effectively downstage tumors, this occurs in approximately 60-70% of cases, not just 50% as suggested in option C. Regarding survival benefits (option A), preoperative radiotherapy has not consistently demonstrated significant overall survival advantages in all patient populations, though it may benefit specific subgroups. Option B is partially correct as preoperative radiotherapy can increase some aspects of postoperative morbidity, particularly wound healing complications and bowel dysfunction, but this is not its primary characteristic. Some key points to consider include:

• The main value of preoperative radiotherapy lies in its ability to shrink tumors before surgery, increase the likelihood of achieving negative resection margins, preserve sphincter function in low-lying tumors, and significantly reduce local recurrence rates, which collectively improve outcomes for rectal cancer patients.
• The use of preoperative radiotherapy, either as short-course preoperative radiotherapy (SCPRT) or chemoradiation, aims to reduce local recurrence, as noted in the Annals of Oncology in 2017 1.
• Recent guidelines, such as those from the Journal of Clinical Oncology in 2024 1, support the use of preoperative radiotherapy in the management of locally advanced rectal cancer, emphasizing its role in reducing local recurrence and potentially improving outcomes.
• The choice between SCPRT and chemoradiation depends on various factors, including the stage and location of the tumor, as well as the patient's overall health and preferences, as discussed in the Journal of the National Comprehensive Cancer Network in 2018 1. Overall, the evidence supports the use of preoperative radiotherapy as a valuable component of rectal cancer treatment, primarily for its ability to reduce local recurrence and improve patient outcomes, as highlighted in the most recent and highest quality studies, such as the one published in the Journal of Clinical Oncology in 2024 1.

From the Research

Preoperative Radiotherapy for Rectal Adenocarcinoma

• The use of preoperative radiotherapy in rectal adenocarcinoma has been studied extensively, with evidence suggesting its benefits in reducing local recurrence and improving survival rates 2, 3, 4.
• Preoperative radiotherapy can down-stage tumors, making them more manageable for surgical removal, with some studies indicating down-staging in up to 50% of cases 5.
• However, preoperative radiotherapy may also increase the risk of postoperative morbidity, including complications such as venous thromboembolism, femoral neck and pelvic fractures, intestinal obstruction, and postoperative fistulas 3.
• The timing of surgery after preoperative radiotherapy is crucial, with delayed surgery potentially negatively impacting survival rates 6.
• The addition of chemotherapy to preoperative radiotherapy may enhance down-staging and improve the likelihood of sphincter preservation 4, 5.
• Different radiation therapy regimens, such as short-course radiation therapy followed by consolidation neoadjuvant chemotherapy, have shown promising results in terms of feasibility and early oncologic outcomes 5.

Specific Options

• Option A (Improves survival): Supported by studies such as the Swedish Rectal Cancer Trial, which demonstrated that preoperative radiotherapy improves overall survival rate 2.
• Option B (Increases postoperative morbidity): Supported by studies such as the Stockholm I and II Trials, which found an increased risk of postoperative morbidity and mortality with preoperative radiotherapy 3.
• Option C (Down-stages tumour in up to 50% of cases): While down-staging is a recognized benefit of preoperative radiotherapy, the exact percentage of cases that experience down-staging is not consistently reported across studies.
• Option D (Reduce risk of local recurrence and improve outcomes in rectal cancer): Supported by multiple studies, including those cited above, which demonstrate the efficacy of preoperative radiotherapy in reducing local recurrence and improving outcomes in rectal cancer 2, 3, 4.