As part of his general surgical oncology practice, Mr Smith also treats rare or unusual presentations of common cancers, and other rare tumours that arise in the abdomen, soft tissue and retroperitoneum. There can be considerable crossover in treatment for neuroendocrine tumours, cystic tumours, and many benign neurogenic tumours in the retroperitoneum and abdomen, as well as rare tumours such as skin adenocarcinomas. Mr Smith treats these tumours via the multidisciplinary teams at the Royal Marsden.

Mr Smith is an expert in the management of retroperitoneal sarcoma. He manages these in the Royal Marsden Hospital as part of the sarcoma multidisciplinary team. The RMH Sarcoma Unit is one of the largest in the world, treating approximately 60 to 70 primary retroperitoneal sarcomas per year, and approximately 600-650 other new soft tissue sarcomas case.

Mr Smith is a member of the Transatlantic Retroperitoneal Sarcoma Working Group, which was established in 2013 to evaluate the evidence for management of retroperitoneal sarcoma and to try to develop a consensus on the approach to this challenging disease.

The primary method of control and a potential cure is surgery. The surgical approach needs to be individualised to each patient, but an extended (resection) is the current treatment paradigm, and this is a procedure which requires multivisceral resection of organs and is often performed as a team with another sarcoma expert surgeon, and occasionally other specialties such as vascular surgery and urology.

Mr Smith has an interest in pelvic rare tumours. He has expertise in perianal and ischial rectal fossa tumours, such as aggressive angiomyxoma, and also performs advanced pelvic surgery such as abdominal perineal resections, and exenterations when indicated, as the leader of a multidisciplinary team needed for these procedures.