Penn Medicine Provider
Medical Oncology
William J. Chapin, MD, MSCE
5.0
(215)
Accepting new patients
Sees patients age 18 and up
Abramson Cancer Center Perelman 2nd Floor West
Make an appointmentCall 215-615-5858

About me

  • Assistant Professor of Medicine (Hematology-Oncology) at the Hospital of the University of Pennsylvania

Education and training

  • Medical School: University of Chicago
  • Residency: Hospital of the University of Pennsylvania
  • Fellowship: Hospital of the University of Pennsylvania

What my patients think about me

Average Rating
5.0

215 reviews

Comments are submitted by patients and reflect their views and opinions. The comments are not endorsed by and do not necessarily reflect the views of Penn Medicine.

May 2025
5.0
5.0
we get. in and we out on time. thank you
May 2025
5.0
5.0
i trust his assessment.
May 2025
5.0
5.0
explain clearly about the disease and the path forward.
May 2025
5.0
5.0
i am very happy with the care provided by dr. chapin.

Insurance accepted

My Locations

Penn Medicine hospital privileges

  • Hospital of the University of Pennsylvania: Has privileges to treat patients in the hospital.
Dr. Chapin is a Penn Medicine physician.

Qualifications and experience

My research

Swami N, Hwang WT, O’Hara MH, Chapin WJ. Real-world evaluation of a “hyperselection” predictive biomarker for anti-EGFR therapy benefit in patients with RAS/RAF wild-type, MMRp/MSS mCRC , J Clin Oncol, 43(16): 2025

Nishwant Swami, Wei-Ting Hwang, Ronac Mamtani, Mark O'Hara, William Chapin Real-world survival comparison of second-line treatment strategies for patients with RAS/RAF wild-type, right-sided metastatic colorectal cancer. , Journal of Clinical Oncology, 43(4_suppl): 2025,73

Margalit O, Stemmer A, Chapin WJ, Schacham-Shmueli E, Kopetz S, Andre T, Overman MJ, Pietrantonio F, Boursi B Duration of Immunotherapy in dMMR/MSI-H Metastatic Colorectal Cancer Patients , European Journal of Cancer, 212: 2024,114336

Chapin WJ, Hwang W, Mamtani R, O’Hara MH Real-world uptake and effectiveness of triplet versus doublet chemotherapy with bevacizumab in patients with metastatic colorectal cancer in the United States , ESMO Gastrointestinal Oncology, 5: 2024,100087

Chapin WJ, Hwang W, Mamtani R, O’Hara MH Low- vs High-Dose 5-FU in Triplet Chemotherapy Plus Bevacizumab for Patients With Colorectal Cancer , JAMA Netw Open, 7(7): 2024,e2424855

Rathore S, Reiss KA, Teitelbaum UR, Chapin WJ Exploring the association of smoking status with clinical outcomes in patients with mPDAC treated on a clinical trial of maintenance niraparib plus immune checkpoint blockade. , American Society of Clinical Oncology Annual Meeting, Chicago, IL. , 42(suppl 16): 2024,Abstract e16302

William Joseph Chapin, Wei-Ting Hwang, Ronac Mamtani, and Mark H. O'Hara Real-world comparison of low- versus high-dose continuous 5FU infusion in patients receiving triplet chemotherapy plus bevacizumab for newly diagnosed metastatic colorectal cancer (mCRC). , Journal of Clinical Oncology , 42(3_suppl): 2024,62-62

William Joseph Chapin, Wei-Ting Hwang, Ronac Mamtani, Mark H O'Hara Real-world comparison of triplet-versus doublet-chemotherapy with bevacizumab in patients with newly diagnosed metastatic colorectal cancer (mCRC). , The American Society of Clinical Oncology Annual meeting, Chicago, IL., 41(16_suppl): 2023,3574-3574

William Joseph Chapin, Parul Agarwal, Lisa DiCicco, Rayleigh Palmer, Nadia Cenou, Alexander Chan Chi Huang, Thomas Benjamin Karasic Phase II trial of XmAb20717 (vudalimab) in patients with advanced biliary tract cancers. , American Society of Clinical Oncology Annual Meeting, Chicago, IL., 41(16_suppl): 2023,TPS4184-TPS4184

Alese OB, Wu C, Chapin WJ, Ulanja MB, Zheng-Lin B, Amankwah M, Eads J. Update on Emerging Therapies for Advanced Colorectal Cancer , Am Soc Clin Oncol Educ Book, 43: 2023,e389574.