Tata Memorial breakthrough for bladder cancer: Study shows why radiation therapy after surgery reduces the risk of recurrence

What is bladder adjuvant radiotherapy?

It is a post-operative treatment used for patients with high-risk, muscle-invasive bladder cancer to reduce the risk of recurrence in the pelvic area. Modern, precise radiation techniques spare surrounding organs. So it is a safe way to ensure local control and improve survival chances after a radical cystectomy, which is a major surgical procedure to remove the bladder, surrounding pelvic lymph nodes, and, in men, the prostate and seminal vesicles. For women, it may include the uterus, cervix, fallopian tubes, ovaries and the anterior vaginal wall.

What’s the trial all about

The Bladder Adjuvant Radiotherapy (BART) trial is the largest randomised trial in the world to evaluate the role of radiation therapy after bladder cancer surgery. These findings position radiation therapy as an important treatment option for patients.

The trial enrolled more than 150 patients across four cancer centres in India between 2016 and 2024. Results showed a marked reduction in potentially painful local cancer recurrences among patients who received radiation after surgery, without an increase in side effects. Patients remain at very high risk of a pelvic relapse after surgery, even when they receive chemotherapy. These recurrences are devastating and very hard to treat, yet historically most research has not focussed on local control.

Smaller studies suggested a role for radiation, but there was no high-level, modern randomized evidence. Hence the trial.

What challenges did you face in conducting a randomised phase III study and how were they addressed?

The trial spanned several years and multiple centres across India. One major challenge was ensuring consistency in radiation planning and delivery across different centres. Data management and follow-up required close monitoring with electronic case report forms and regular site checks. These measures allowed researchers to maintain rigour and reliability across the study.

What are the most important takeaways for practising oncologists?

The key takeaway is that adjuvant pelvic radiotherapy after surgery can substantially improve pelvic control without causing toxicity. The second is that radiotherapy benefits high-risk patients. The third is that radiotherapy offers an immediately accessible and evidence-based way to improve outcomes compared to immunotherapy.

Radiation therapy is already widely accepted post-surgery for gynaecological cancers. Do you see radiation therapy evolving into a more personalized therapy approach for high-risk subgroups?

Gynaecologic oncology has shown us that with modern Intensity Modulated Radiation Therapy and image guidance are safe and effective for a complex anatomical region. If we apply those lessons in bladder cancer, adoption can be faster. Patients are often assumed to be destined for distant metastasis, when cancer cells spread from the original tumour to distant parts of the body, such as other organs or lymph nodes. So local treatments like radiotherapy have historically been ignored. However, our data shows these are precisely the patients who gain the most in pelvic control. This tells us radiotherapy should be part of a tailored strategy for the highest-risk groups. Over time, we can personalise this further.

We need to move past historical fears, today’s radiotherapy is safer, more precise and entirely feasible in routine practice. Be it disease-free survival, cancer-specific survival and overall survival, we saw a consistent 12–15% absolute improvement with radiotherapy. The next stage should be about integrating radiotherapy with immunotherapy.