Dr. William Diehl, MD

Surgical Oncology  |  
Male  |  
Age 60
Insurances AcceptedSave
Dr. William Diehl, MD
Dr. Diehl is a board certified General Surgeon with special interest, training and expertise in Surgical Oncology and Breast Surgical Oncology. He trained at the prestigious Memorial Sloan-Kettering Cancer Center and is part of Summit Medical Group with admitting privileges at Morristown Medical Center and Saint Barnabas Medical Center. Dr. Diehl performs close to 750 surgical procedures a year, and, specific to breast cancer, treats approximately 150 new breast cancer patients

140 Park Ave Fl 3

Florham Park, NJ 07932

Contact Information

(973) 404-9980

Dr. William Diehl, MD

Dr. William Diehl, MD

Accepted insurance

  • Aetna
  • Amerihealth
  • Blue Cross Blue Shield
  • Cigna
  • Commercial Insurance Company
  • CoreSource
  • EmblemHealth
  • First Health (Coventry Health Care)
  • Government Employees Health Association (GEHA)
  • Guardian
  • HealthFirst
  • Highmark Blue Cross Blue Shield
  • Horizon Blue Cross Blue Shield of New Jersey
  • 8 More

*Please verify this information when scheduling an appointment.

Learn about Dr. Diehl

Be confident in your decisions by checking out your provider's top areas of care, education, patient reviews and more. Learn about finding the right doctor for you

Top Care Areas


See how frequently Dr. Diehl performs your care needs compared to other doctors.

Breast Diseases
very high
more than 95% of peers
more than 76% of peers
Stomach and Small Intestine Cancer
more than 76% of peers

Dr. Diehl's percentages are based on the rate of treatment compared to peers nationwide from insurance data. Learn more info about our data and this Top Care Areas component.

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Care Philosophy

This content was provided by Dr. Diehl "I firmly believe that the most effective doctors are those that treat patients, not diseases. Clearly understanding the disease of the patient is essential, but even diseases vary from patient to patient so I always teach the Surgical Residents that it's even more critical to know the patient than to know the disease. I strive to provide personalized services where I oversee all parts of patient care and am personally involved in all aspects. 

With a specialty in General Surgery and a further Sub-Specialty in Surgical Oncology and Breast Surgical Oncology from Memorial Sloan Kettering Cancer Center, I am able to provide advanced treatment options to patients derived from an extensive, broad base of surgical experience. Summit Medical Group is affiliated with the prestigious MD Anderson Cancer Center in Houston which is the leading cancer center in the world. This affiliation and access to all their treatment protocols and algorithms also allow me to provide the most advanced treatment options available anywhere in the world."


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  • Surgical Oncology
  • Breast Surgical Oncology
  • General Surgery

Board Certifications

  • General Surgery
    Accredited by: American Board of Surgery*

Conditions Treated

  • Abdominal Disorders
  • Abscess
  • Acute Leukemia
  • Acute Myeloid Leukemia
  • All Lymphoma
  • Anemia
  • Appendicitis
  • Autoimmune Diseases
  • Basal Cell Carcinoma
  • Benign Tumor
  • Bile Duct Cancer
  • Bladder Cancer
  • Bleeding Disorders
  • Blood Disorders
  • Bone Cancer
  • Bone Disorders
  • Brain Disorders
  • Breast Cancer
  • Breast Diseases
  • Breast Lump
  • Cancer
  • Central Nervous System Lymphoma
  • Cervical Cancer
  • Cholecystitis and Gallstones
  • Coagulation Disorders (incl. Hemophilia)
  • Colorectal Cancer
  • ENT Cancer
  • Gallbladder Cancer
  • Gallbladder and Biliary Tract Cancer
  • Gastrointestinal Diseases
  • Hernia
  • Hodgkin's Disease
  • Hypercoagulable State
  • Immune Thrombocytopenic Purpura (ITP)
  • Incisional Hernia
  • Inguinal Hernia
  • Kidney Cancer
  • Leukocytosis
  • Lipomas
  • Liver Cancer
  • Lymphoma, Large-Cell
  • Marginal Zone Lymphoma
  • Melanoma
  • Merkel Cell Carcinoma
  • Myeloma
  • Myeloproliferative Disorders
  • Non-Hodgkin's Lymphoma
  • Ovarian Cancer
  • Pancreatic Cancer
  • Pancytopenia
  • Primary Central Nervous System Lymphoma
  • Primary Hypercoagulable State (incl. Factor V Leiden Disease)
  • Prostate Cancer
  • Purpura
  • Retina Diseases
  • Secondary Malignancies
  • Skin Cancer
  • Small Intestine Cancer
  • Soft Tissue Sarcoma
  • Squamous Cell Carcinoma
  • Stomach Cancer
  • Stomach and Small Intestine Cancer
  • Throat Cancer (Nasopharyngeal)
  • Umbilical Hernia
  • Urinary Disorders
  • Uterine Cancer
  • Uterine Diseases
  • Ventral Hernia


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  • Appendectomy, Laparoscopic
  • Appendectomy, Open
  • Bile Duct Procedure
  • Biliary Drainage
  • Biopsy of Breast
  • Breast Surgical Procedure
  • Cholecystectomy With Robotic Assistance
  • Cholecystoenterostomy
  • Colectomy
  • Colectomy and Sigmoidectomy With Robotic Assistance
  • Colon and Rectal Surgery
  • Enterostomy (Laparoscopic or Open)
  • Excision of Bile Duct Tumor
  • Excision of Breast Tumor
  • Excision of Rectal Tumor
  • Excision of Skin Lesion
  • Excision of Stomach Tumor
  • Gallbladder Removal
  • Gallbladder Removal (Cholecystectomy), Laparoscopic
  • Gallbladder Removal (Cholecystectomy), Open
  • Gastrectomy
  • Gastrectomy With Robotic Assistance
  • Gastrotomy
  • Hepatectomy
  • Hernia Repair
  • Incisional Hernia Repair, Laparoscopic
  • Inguinal Hernia Repair, Laparoscopic
  • Inguinal Hernia Repair, Open
  • Laparoscopic Sigmoidectomy With Robotic Assistance
  • Laparoscopic Surgical Procedure
  • Laparotomy
  • Lymph Node Biopsy or Excision
  • Lymphadenectomy With Robotic Assistance
  • Mastectomy
  • Open Incisional and-or Ventral Hernia Repair
  • Pancreatectomy (incl. Pancreas Transplant and Whipple Procedure)
  • Plasmapheresis
  • Port Placements or Replacements
  • Splenectomy
  • Splenectomy and Splenorrhaphy
  • Stomach Surgery
  • Total Splenectomy With Robotic Assistance
  • Umbilical or Ventral Hernia Repair, Laparoscopic


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Background Check

0 Malpractice Claims

No malpractice history found for New Jersey.

0 Sanctions

No sanctions history found for the years that Healthgrades collects data.

0 Board Actions

No board actions found for the years that Healthgrades collects data.


  • Universidad Anahuac, Escuela De Medicina
    Medical School | Graduated 1981
  • Indiana University Med Center
    Residency Hospital | Completed 1982
  • Morristown Meml Hospital
    Residency Hospital | Completed 1986
  • Meml Sloan Kettering Canc C
    Fellowship Hospital | Completed 1988

Awards & Recognition

Awards & Honors
  • Healthgrades Honor Roll
Media & Publications

Dr. Diehl has no media or publications listed.

Languages Spoken

  • English
  • Spanish

Memberships & Professional Affiliations

Dr. Diehl does not have any memberships or affiliations listed. If you are Dr. Diehl and would like to add memberships or affiliations, please update your profile.

Dr. Diehl's Reviews

Likelihood of recommending Dr. Diehl to family and friends
based on 16 total reviews (6 with comments)
Dr. Diehl's Performance
  • Trustworthiness
  • Explains condition(s) well
  • Answers Questions
  • Time well spent
Office & Staff Performance
  • Scheduling
  • Office environment
  • Staff friendliness
  • Average wait time
    10 to 15 minutes
Patient Comments (6)
in Branchburg NJ |
I Didn’t think I would be posting again this year but i again needed a surgeon and of course I called Dr Diehl he is by far a great surgeon he has such compassion and understanding in treating the whole patient I can’t express enough the comfort I felt going into this second surgery knowing Dr Diehl would be caring for me thank you again for taking such good care of me! Sandra Willoughby
Great Meadows, NJ |
Dr. Diehl performed my breast biopsy. He was wonderful. He was considerate, extremely kind, knowledgeable; and I just knew I was in good hands. He did not rush me out of the office and answered all my questions. He personally called me with the results in three business days after the biopsy. Fortunately, my results were benign so I did not need further treatment except for a 6 month followup ultrasound. I would definately recommend Dr. Diehl to family and friends.
Morristown, NJ |
I recently had a breast biopsy done by Dr. Diehl after he was recommended to me by a few people I know and my OBGYN. Not only was he extremely knowledgeable about my situation, he was very kind and caring which is something you do not see most of the time. Very happy with my decision to use him and the final results.
in Basking Ridge, NJ |
Dr. Diehl initially diagnosed my breast cancer after performing a biopsy and ordering the pathology. His insistence on the most precise testing absolutely contributed to my positive outcome following chemo and a bilateral mastectomy. He is intellectually rigorous and extraordinarily kind-hearted. He is available at any time to answer questions and explain treatment options. When I was most upset and afraid in the days following my diagnosis, he brought me peace through his caring manner.
in Randolph, NJ |
He is a highly compassionate and skilled surgeon who immediately put me and husband at ease with his kind demeanor at the consult. We had met prior with 2 other "rockstar" area breast surgeons who shared a lack of urgency and left us feeling less than confident. Dr. Diehl looked at me as a person, not just body parts and urged me to proceed asap. My surgery revealed stage 2 DCIS, and we are so very glad we had his oncological background. He simply saved my life. Wonderful experience.
in Boonton, NJ |
Dr. Diehl performed a double mastectomy on my wife in 2014 for cancer. We were beyond scared to say the least. Dr. Diehl's calm demeanor and professionalism made us feel confident that my wife would get through this bout with cancer. The surgery went as planned without issue. My wife has been cancer free since because of Dr. Diehl. One word of caution, the Breast Reconstruction Surgeon that works or worked at the time with Dr. Diehl, was not in our insurance network. MAKE SURE YOURS IS!
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Now Accepting New Patients
Dr. Diehl accepts 22 insurance carriers
  • Aetna
    Aetna HMO
    Choice Plus POS II
  • Amerihealth
  • Blue Cross Blue Shield
    Blue Card PPO
  • Cigna
    Cigna HMO
    Cigna PPO
    Great West Healthcare-Cigna PPO
    Open Access Plus
  • Commercial Insurance Company
  • CoreSource
  • EmblemHealth
    Health Insurance Plan of Greater New York (HIP) PPO
  • First Health (Coventry Health Care)
    First Health (Coventry Health Care) PPO
  • Government Employees Health Association (GEHA)
  • Guardian
  • HealthFirst
  • Highmark Blue Cross Blue Shield
    Community Blue PPO
  • Horizon Blue Cross Blue Shield of New Jersey
    Direct Access
    Horizon Blue Cross Blue Shield HMO
    Horizon Blue Cross Blue Shield POS
    Horizon Blue Cross Blue Shield PPO
  • Humana
  • MagnaCare
    MagnaCare PPO
  • Medicaid
  • Meritain Health
  • MultiPlan
    MultiPlan PPO
    PHCS Network PPO
  • Oxford Health Plans
    Freedom Plan
  • QualCare
    QualCare HMO
    QualCare PPO
  • UnitedHealthCare
    Choice Plus POS
    Navigate HMO
    Navigate POS
    Options PPO
    United Healthcare

*Please verify this information when scheduling an appointment.

Hospitals where Dr. Diehl has admitting privileges

Morristown Medical Center
100 Madison Ave
Morristown, NJ 07960
View Hospital Profile
Saint Barnabas Medical Center
94 Old Short Hills Rd
Livingston, NJ 07039
View Hospital Profile

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