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John H. Marks, MD

Main Line Health

John H. Marks, MD

Chief, Division of Colorectal Surgery, Main Line Health


◽ 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).

    Colorectal Center at Lankenau Medical Center, Main Line Health

    • First and only hospital in eastern Pennsylvania, New Jersey and Delaware to be accredited by the National Accreditation Program for Rectal Cancer (NAPRC) from the American College of Surgeons

    • At the forefront of minimally invasive laparoscopic and robotic-assisted surgery, including the single-port robot, to optimize cancer patient outcomes and quality of life

    • Patients experience reduced recovery time and discomfort, minimal to no surgical incision, and sphincter preservation to retain normal bowel function and avoid colostomy bags
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