Five major advances in anal and rectal cancer treatment with radiotherapy

(Press-News.org) Vienna, Austria – Rectal cancer is a type of bowel cancer that develops in the last several centimetres of the large intestine, just before the anus. It’s one of the most common cancers in Europe, with over 125,000 people diagnosed annually*. Treatment traditionally involves surgery to remove the tumour—a major operation that can permanently affect sexual function, continence, and quality of life.

 

While radiotherapy and chemotherapy are already used to shrink tumours before surgery, there is growing momentum behind treatment strategies that avoid surgery in patients, where the tumour has disappeared after radiotherapy and chemotherapy. Such so-call “organ preservation strategies” aim to preserve the rectum, and thereby maintain a better quality of life for cancer patients—especially for early-stage and locally advanced cases.

 

In contrast, anal cancer affects the lowest few centimetres of the bowel. It is a rare disease and is diagnosed in around 14,000 people in Europe annually. Anal cancer is more sensitive to radiotherapy, and previous clinical trials have shown that a combination of radiotherapy and chemotherapy can replace the need for major surgery and a permanent colostomy. However, the current standard approach results in high rates of short and long-term side effects.

 

Now, five pivotal studies presented at ESTRO 2025, the annual congress of the European Society for Radiotherapy and Oncology, showcase how radiotherapy is reshaping this landscape. From reduced-dose treatments to cutting-edge combinations with immunotherapy and chemotherapy, these innovations offer safer, more effective, and organ-preserving alternatives to traditional surgery.

 

 

Shorter, Lower-Dose Radiotherapy for is a highly effective treatment for Early-Stage Anal Cancer
  The ACT4 PLATO trial (1), led by Professor David Sebag-Montefiore, has demonstrated that a reduced-dose, shorter-course highly focused radiotherapy technique (IMRT) offers excellent tumour control with fewer side effects for early-stage anal cancer. The randomised phase II trial, conducted across 28 UK sites, showed similar efficacy and late toxicity levels using a reduced-dose IMRT regimen over 4.5 weeks and standard-dose IMRT over 5.5 weeks.

“Our results support moving toward shorter, more personalised radiotherapy,” said Professor Sebag-Montefiore. “This approach reduces the treatment burden for both patients and healthcare systems.”
 

Read the press release on the ACT4 PLATO trial  

2. Radiotherapy alone and Radiotherapy combined with Chemotherapy both Enable Patients to avoid surgery for Rectal Cancer 

The STAR-TREC study (2) has shown that organ-preserving strategies are feasible for patients treated with radiotherapy alone as well as for patients treated with radiotherapy and chemotherapy. Among 344 patients at 37 international sites, 80% of those treated with chemoradiotherapy and 61% of those treated with radiotherapy alone could be spared surgery at one year. 
 

“Avoiding surgery helps preserve bowel function and quality of life,” said Prof Dr Corrie Marijnen, of the Netherlands Cancer Institute. “This study shows that radiotherapy-based strategies (whether alone with more intensive treatment course, or combined with chemotherapy) can be a viable alternative for many patients.” 
 

Read the press release on the STAR-TREC trial
   

3. Immunotherapy-Radiotherapy Combo Eliminates Cancer in Two-Third of Patients in UK Trial

PRIME-RT, a trial conducted across the UK, found that 67% of evaluable patients receiving a short-course of radiotherapy, meaning only 5 outpatient sessions (no overnight stay) of radiotherapy, combined with immunotherapy had a complete response, meaning no signs of cancer remained.
 

“By combining immunotherapy with radiotherapy, we are seeing higher response rates than expected, especially with short-course radiotherapy," said Professor Campbell Roxburgh, from the University of Glasgow, UK.
 

Read the press release on the PRIME-RT trial

 

4. Combining Radiotherapy with Immunotherapy and Chemotherapy for Better Organ Preservation

Similarly, in the STELLAR II trial from China, immunotherapy added to short-course radiotherapy and chemotherapy increased complete disappearance of the tumour to 45.5%,

compared to 25% with standard treatment.

 

“By combining immunotherapy with short-course radiotherapy and chemotherapy, we may be able to improve survival rates and, crucially, help more patients avoid invasive

surgery and its long-term effects,” said Professor Jing Jin, from the National Cancer Centre, China.

 

Read the press releases on the STELLAR II trial
  5.    Short-Course Radiotherapy with Chemotherapy Boosts Long-Term Survival

The phase III STELLAR trial tracked 591 patients in China with locally advanced rectal cancer over five years. It found that short-course radiotherapy followed by chemotherapy improved survival by 8.4% compared to standard long-course chemoradiotherapy—with no negative impact on anorectal function or quality of life.


"This could be a game-changer for patients, offering a faster, equally safe, and potentially more effective option," said Dr Jing Jin from the National Cancer Centre in China.
 

Read the press releases on the phase III STELLAR trial  

A New Paradigm in Rectal Cancer Treatment

 

Together, these five studies demonstrate the transformative potential of radiotherapy as a curative and organ-preserving treatment. As new data emerges, personalised radiotherapy strategies are offering patients safer, effective alternatives to surgery.

 

“These breakthroughs represent a major step forward,” said Professor Guckenberger. “By leveraging advanced radiotherapy strategies, we are not only improving survival rates but also prioritising quality of life for patients worldwide.”

 

With these findings set to influence global clinical guidelines, the future of rectal cancer treatment is moving decisively toward combined radiotherapy-driven, organ-preserving solutions.

 

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References

 

Abstract n° E25-3665: “PLATO ACT 4: Long term results of an RCT evaluating reduced dose and standard dose chemoradiotherapy in early-stage anal cancer”, presented in the Joint Green Journal - The Lancet Oncology: Top Clinical Trials session, on Sunday 4 May at 11:40 hrs (CEST), Plenary Hall. Abstract n° E25-1489: “STAR-TREC (NCT02945566): A randomised phase II/III trial of CRT versus 5x5 Gy SCRT for organ preservation in early/intermediate risk rectal cancer”, presented in the Joint Green Journal - The Lancet Oncology: Top Clinical Trials session, on Sunday 4 May at 11:49 hrs (CEST), Plenary Hall. Abstract n° E25-1116: “PRIME-RT:  Durvalumab (MEDI 4736) with extended neoadjuvant regimens in locally advanced rectal cancer: a randomised phase II trial”, presented in the Joint Green Journal - The Lancet Oncology: Top Clinical Trials session, on Sunday 4 May at 12.06 hrs (CEST), Plenary Hall. Abstract no E25-837: “Preoperative Short-course Radiotherapy Followed by Chemotherapy and PD-1 Inhibitor for Locally Advanced Rectal Cancer: Phase II Results of STELLAR II”, presented in the Joint Green Journal - The Lancet Oncology: Top Clinical Trials session, on Sunday 4 May at 12.24 hrs (CEST), Plenary Hall. Abstract no E25-2250: “Short-term radiotherapy plus chemotherapy for locally advanced rectal cancer: 5-year outcomes of the phase III clinical trial”, presented in the Joint Green Journal - The Lancet Oncology: Top Clinical Trials session, on Sunday 4 May at 12.15 hrs (CEST), Plenary Hall.  

Note: When obtaining outside comment, journalists are requested to ensure that their contacts are aware of the embargo on this release.

 

 

About ESTRO 2025

ESTRO 2025 brings together around 7,000 participants from over 80 countries, showcasing the latest research in clinical radiation oncology, radiobiology, medical physics, technology, and brachytherapy. Leading doctors and scientists from around the world present groundbreaking findings, according to the theme of the conference “Transformative innovation through collaboration”.

 

ESTRO 2025 is the annual congress of the European Society for Radiotherapy and Oncology (ESTRO), an organisation dedicated to advancing cancer treatment through radiotherapy and multimodal approaches. ESTRO promotes education, science, and research and advocates for universal access to radiotherapy. With nearly 10,000 members worldwide, it supports radiation oncology professionals and the broader oncology community in their daily practice.

 

For further information, embargoed press materials, or to arrange interviews with the researchers, please contact the ESTRO press office.
 

ESTRO Press Office
Cécile Hardon-Villard
chardon@estro.org
Mobile : +33 679 43 16 01

 

* Source: International Agency for Research on Cancer (IARC), GLOBOCAN 2020. https://gco.iarc.fr/

 

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