Hypofractionated Radiotherapy in Rectal Cancer – Efficacy and Outcomes

Radiotherapy has long been used as an effective cancer treatment. Conventional long-course radiotherapy (LRT) protocols have produced successful results, particularly in locally advanced cancers. However, hypofractionated radiotherapy (HRT) is attracting attention for advantages such as shorter treatment duration and fewer hospital visits. This article examines hypofractionated radiotherapy in rectal cancer , covering its efficacy, safety, and adverse effects in detail.

What Is Hypofractionated Radiotherapy?

Hypofractionated radiotherapy delivers higher doses in fewer fractions. It aims to shorten the overall treatment duration without compromising efficacy. These protocols are becoming increasingly common across different cancers.

Studies of Hypofractionated Radiotherapy's Efficacy in Rectal Cancer

The main studies examining hypofractionated radiotherapy in rectal cancer and their details are outlined below:

Study 1: "Efficacy of Hypofractionated Preoperative Chemoradiotherapy in Rectal Cancer"

A prospective clinical study was published in Oncology Letters in May 2023. It included 76 patients with the following clinical stage distribution:

• Stage I: 5 patients (6.6%),
• Stage II: 29 patients (38.2%),
• Stage III: 36 patients (47.4%),
• Stage IVA: 6 patients (7.9%).

Treatment: Hypofractionated radiotherapy (33-35 Gy in 10 fractions) was given with oral capecitabine.

Surgery: Performed 4-8 weeks after radiotherapy.

Results:

• Pathological Complete Response (pCR): Complete response in 11.8% of patients.
• Disease-Free Survival: 5-year rate: 76.5%.
• Overall Survival: 5-year rate: 90.6%.
• Tumor and Lymph Node Downstaging: Tumor downstaging was observed in 36.8% of patients and lymph node downstaging in 32.9%.
• Sphincter Preservation Rate: 71.9% in distal tumors; 100% in proximal tumors.
• Adverse Effects: Severe (Grade 3) toxicity was reported in only 5.3%.

Study 2: "Stockholm III Trial"

Features of the randomized controlled trial published in Lancet Oncology in 2011:

• Population: 385 patients.
• Treatment Arms:
  1. Hypofractionated radiotherapy (5x5 Gy) and surgery within 1 week.
  2. Hypofractionated radiotherapy (5x5 Gy) and surgery within 4-8 weeks.
  3. Long-course radiotherapy (2 Gy/fx, 25 fx in total) and surgery within 4-8 weeks.

Results:

• Overall Survival: 73% with hypofractionated radiotherapy; 65% with long-course radiotherapy.
• Disease-Free Survival: 53% with hypofractionated radiotherapy; 52% with long-course radiotherapy.
• Adverse Effects:
  • Less acute toxicity (46.5% vs. 59.8%).
  • No difference in late adverse effects.

Study 3: Bujko et al.

Summary of the study published in the British Journal of Surgery in 2006:

• Design: Randomized controlled trial.
• Population: 515 patients.
• Treatment Arms:
  1. Hypofractionated radiotherapy (5x5 Gy) and surgery.
  2. Conventional radiotherapy (1.8 Gy/fx, 28 fx in total) and surgery.

Results:

• Overall Survival: 73% with hypofractionated radiotherapy, 65% with conventional radiotherapy.
• Disease-Free Survival: Similar in both groups (53% vs. 52%).
• Adverse Effects: Less acute diarrhea with hypofractionated radiotherapy (14% vs. 27%).

Comparison with Conventional Radiotherapy

Conventional long-course radiotherapy (LRT) generally delivers a total dose of 50-54 Gy in 25-28 fractions and may take 5-6 weeks. Hypofractionated radiotherapy substantially shortens this period while offering similar efficacy.

Key Differences:

• Treatment duration: 5-6 weeks for LRT, 1-2 weeks for HRT.
• Adverse effects: Both approaches have similar safety profiles.
• Patient comfort: HRT offers an advantage because of its shorter duration.

Which Patients Is It Suitable For?

Hypofractionated radiotherapy is a suitable option in the following settings:

1. Patients with Locally Advanced Disease: To reduce tumor size before surgery.
2. Patients with Metastatic Disease: To shorten treatment and accelerate the transition to systemic therapy.
3. Older Patients and Those in Poor General Health: A short treatment course may be ideal for these groups.

The Future of Hypofractionated Radiotherapy

Hypofractionated radiotherapy offers promise in rectal cancer for both efficacy and patient comfort. However, further studies are needed to support the data on long-term outcomes and adverse effects.

Recommendations for Clinical Practice:

1. Personalized Treatment: Patient characteristics should inform treatment planning.
2. A Multidisciplinary Approach: The surgeon, oncologist, and radiation oncologist should work together.
3. Long-Term Follow-Up: Late toxicity risks should be monitored.

Conclusion

Hypofractionated radiotherapy is considered a revolutionary option for rectal cancer treatment. Its shorter duration and low toxicity rates make it a strong alternative to conventional radiotherapy. In light of current data, more studies are needed before extending this approach to broader patient groups and integrating it into routine clinical practice.

This treatment approach aims to improve quality of life and the treatment process for patients with rectal cancer.