John H. Marks, MD

Main Line Health

John H. Marks, MD

Chief, Division of Colorectal Surgery, Main Line Health

Director, Colorectal Center, Lankenau Medical Center

President, Multidisciplinary International Rectal Cancer Society


◽ Oncology - Colorectal Surgery

Bowel Obstruction; Colon Polyps; Colorectal Cancer; Crohn's Disease; Diverticulitis; Hemorrhoids; Incontinence; Irritable Bowel Syndrome (IBS); Motility Disorders; Ulcerative Colitis



Dr. Marks leads the global pursuit of improved treatment for colon and rectal cancers, and research to advance worldwide standards of care. He is an international instructor of laparoscopic, robotic, transanal and sphincter preserving procedures. Dr. Marks is one of the world’s most experienced colorectal surgeons, performing nearly 3,000 minimally invasive colorectal cancer surgeries, including more than 1,300 rectal cancer procedures.

Education & Fellowships

    ◽ Jefferson Medical College
    ◽ Internship: Thomas Jefferson University Hospital
    ◽ Residency: Thomas Jefferson University Hospital
    ◽ Fellowship: Thomas Jefferson University Hospital

Awards & Honors

    ◽ Top 10 Doctor - Metro Area (2014)
    ◽ Top 10 Doctor - State (2014)
    ◽ Patients' Choice Award (2015, 2016, 2017, 2018)