From the Guidelines
The correct answer regarding preoperative radiotherapy for rectal adenocarcinoma is E: Reduce risk of local recurrence and improve outcomes in rectal cancer. Preoperative radiotherapy, also known as neoadjuvant radiotherapy, has become a standard approach in the management of locally advanced rectal cancer, as supported by the most recent guideline from 2024 1. It effectively reduces the risk of local recurrence by shrinking the tumor before surgery, which allows for better surgical margins and potentially more complete tumor removal. While preoperative radiotherapy does down-stage tumors, this occurs in approximately 60-70% of cases, not just 50%. Although it can increase some postoperative complications, particularly wound healing issues, the benefits generally outweigh these risks. Importantly, preoperative radiotherapy is actually more effective than postoperative radiation because it acts on better-oxygenated tissues before surgical disruption of blood supply, as shown in a study from 2018 1. The typical regimen involves either short-course radiotherapy (25 Gy in 5 fractions) or long-course chemoradiotherapy (45-50 Gy over 5-6 weeks with concurrent chemotherapy), with surgery following after an appropriate interval. Some key points to consider include:
- Preoperative radiotherapy reduces local recurrence risk and improves disease-free survival, as demonstrated in several studies, including those from 2010 1 and 2018 1.
- The choice between short-course radiotherapy and long-course chemoradiotherapy depends on various factors, including tumor stage and patient preferences, with both options being effective as shown in studies from 2017 1 and 2018 1.
- Total neoadjuvant therapy, which includes neoadjuvant chemotherapy and either short-course radiation or long-course CRT, has been proposed as a way to improve adherence, decrease the occurrence of distant metastases, and ultimately improve OS, as discussed in the 2024 guideline 1. Overall, preoperative radiotherapy is a crucial component of the multidisciplinary management of locally advanced rectal cancer, aiming to reduce local recurrence and improve outcomes.
From the Research
Preoperative Radiotherapy for Rectal Adenocarcinoma
- The use of preoperative radiotherapy in rectal adenocarcinoma has been shown to reduce the risk of local recurrence and improve overall survival rate 2.
- Preoperative radiotherapy can down-stage tumors, with one study showing that short-course preoperative radiotherapy followed by neoadjuvant chemotherapy achieved high rates of clinical and pathologic complete response 3.
- The addition of preoperative radiotherapy to surgery has been shown to improve local control and survival in patients with locally advanced rectal adenocarcinoma 4, 5.
- Preoperative external beam radiation therapy can achieve low local recurrence and excellent long-term survival rates in patients with adenocarcinoma of the rectum, with low morbidity and mortality 5.
- A study comparing short-course radiotherapy with a boost to chemoradiation found no significant difference in local recurrence rates between the two groups, but a lower rate of local recurrence was observed in elderly patients (>69 years) 6.
Effects on Postoperative Morbidity
- One study found that short-term preoperative radiotherapy does not increase the rate of postoperative complications and is a safe therapeutic adjunct for the treatment of locally advanced rectal cancer 2.
- Another study found that post-operative Clavien-Dindo Grade 3 complications within 30 days of surgery were identified in 30% of patients, with no Grade 4 or 5 adverse events 3.
Comparison to Postoperative Radiation
- The effectiveness of preoperative radiotherapy compared to postoperative radiation is still unclear, with some studies suggesting that preoperative radiotherapy may be more effective in reducing local recurrence and improving survival 4, 5.
Tumor Downstaging
- Preoperative radiotherapy can down-stage tumors in up to 50% of cases, although the exact percentage may vary depending on the specific treatment regimen and patient population 3, 6.