Mr Tim o'Brien MA DM FRCS (Urol) is a distinguished Consultant Urological Surgeon at Guy’s and St Thomas’ NHS Foundation Trust. He was honoured with the Golden Telescope by the British Association of Urological Surgeons, the highest accolade for a young consultant urologist in the UK.

Mr o'Brien has played a pivotal role in establishing the urology centre at Guy’s, significantly enhancing the assessment and treatment of urology patients. His contributions have garnered international recognition, and he continues to expand his clinical knowledge through research, board meetings, and clinical practice.

Specialising in kidney cancer, bladder cancer, and testis cancer, Mr o'Brien is renowned for handling complex kidney cancer surgeries, particularly those involving large, life-threatening tumours that invade the inferior vena cava or the heart. He has performed over 200 partial nephrectomies, preserving kidney function while removing cancer. His expertise in these techniques is sought after both nationally and across Europe.

At Guy’s, Mr o'Brien is the lead surgeon for retroperitoneal lymph node dissections in men with residual testis cancer post-chemotherapy. In 2012, he co-founded a multidisciplinary service for retroperitoneal fibrosis with Dr James Pattisson, aiming to advance the treatment of this challenging condition.

In the realm of bladder cancer, Mr o'Brien’s team has refined the technique of blue light cystoscopy (photodynamic assisted resection), enhancing the thoroughness of initial endoscopic bladder tumour surgeries. Their research on this technique has been widely published and recognised, earning a prestigious award from the European Association of Urology in 2011. Mr o'Brien was also invited to the FDA in Washington DC in 2010 to advocate for the technique’s approval in the United States.

In 2011, Mr o'Brien was elected Chairman of the Section of Oncology of the British Association of Urological Surgeons (BAUS) through a national ballot. In this role, he leads initiatives to improve urological cancer surgery across the UK.

Mr o'Brien’s areas of expertise include:

- Kidney cancer
- Bladder cancer
- Testis cancer
- Retroperitoneal fibrosis (RPF)
- Diagnostic urology
- Infection control
- Renal disease/failure
- Andrology
- Vasectomy (including reversal)

Appointed in 2011, Mr o'Brien continues to make significant strides in the field of urology, ensuring the highest standards of patient care and surgical excellence.