Physician’s Profile
Profile image of Jonathan P. Knowles, MD

Jonathan P. Knowles, MD

Anal Cancer
Anal Fissures
Anal Fistula
Colon Cancer
Colon and Rectal Surgery
Inflammatory Bowel Disease (IBD)
Pelvic Floor Disorders
Rectal Cancer
Rectal Prolapse

Dr Jonathan Knowles is a surgical associate/advanced clinical fellow in Colorectal Surgery. He completed his medical training at University College London in 2000 and then trained in general and colorectal surgery. Since 2013 he worked as a colorectal surgeon at the Royal Free Hospital in London.

Dr Knowles has expertise in minimally invasive and open colorectal surgical procedures as well as in anorectal operations. This includes a wide spectrum of colorectal conditions including inflammatory bowel disease, colon and rectal cancer, diverticular disease and anorectal disorders.

Dr Knowles completed a Masters in Surgical Science and is a Fellow of the Royal College of Surgeons (2012).

At New York-Presbyterian/Columbia University, Dr Knowles works collaboratively with Dr Pokala Ravi Kiran obtaining additional exposure to complex and reoperative colorectal surgery.


A case series of anal melanoma including the results of treatment with imatinib in selected patients. Authors: J. Knowles*, A. C. Lynch, S. K. Warrier, M. Henderson, A. G. Heriot. Colorectal Disease 2 September 2016

Endothelin-1 stimulates colorectal cancer adjacent fibroblasts. Knowles J*, Taylor I, Winslet M, Abraham D, Loizidou M. Int. J. Cancer 2012: 130; 1264-1272

Mechanisms of endothelin 1-stimulated proliferation in colorectal cancer cell lines. K. Grant, J. Knowles, K. Dawas, G. Burnstock, I. Taylor, M. Loizidou. BJS 2007: 94; 1, 106-112

Title: Impact of an enhanced recovery after surgery (ERAS) pathway on colorectal surgery patients managed with perioperative Alvimopan. Accepted for eposter presentation ASCRS May 2022.

Title: Significant negative effect of previous abdominal surgery on outcomes after colorectal resection. Accepted for eposter presentation ASCRS May 2022.