William S Loui, MD

Medical Oncology

Accepting New Patients

Affiliated Provider

4.8 of 5 stars403 ratings, 49 reviews

Need help scheduling? Call 808-263-5022

Highlights

Age Groups Seen

Adult 21-65
Older Adult >65

Languages

English

Gender

Male

About William S Loui

About The Provider

William S. Loui, MD, FACP, is a board-certified physician specializing in oncology and hematology. He provides integrated cancer care at Adventist Health Castle, where he supervises overall patient cancer care and coordinates treatment with other specialists. He also sees patients for regular check-ups, ongoing treatment, and oversees chemotherapy, immunotherapy and hormone therapy.
Dr. Loui earned his medical degree from the John A. Burns School of Medicine at the University of Hawaii in Honolulu and undergraduate degree from Brown University in Providence, Rhode Island. He completed post-doctorate training at the Mayo Graduate School of Medicine in Rochester, Minnesota, including an internship and residency in internal medicine and a fellowship in hematology and oncology. Dr. Loui then completed a bone marrow transplantation fellowship at City of Hope National Medical Center in Duarte, California.
He is a fellow of the American College of Physicians (FACP) and certified by the American Board of Internal Medicine. Dr. Loui’s professional memberships include the American Society of Clinical Oncology, American Society of Hematology, American Medical Association, and Hawaii Society of Clinical Oncology.
His professional accomplishments are extensive. He was honored by the Susan B. Komen Race for the Cure for his work in health disparities and breast cancer. Dr. Loui has served on hospital leadership committees, nonprofit boards of directors, and in professional society leadership positions during his career. Notably, he has been a member of the Hawaii Chapter of American College of Physicians Executive Council for more than 10 years. He also is on the board of the American Cancer Society and a reviewer for the Society’s Cancer Journal and the American College of Physicians Annals of Internal Medicine.
During the past 20 years, Dr. Loui has given more than 100 lectures and presentations throughout the state and published his work in numerous peer-reviewed medical journals. He is an assistant clinical professor for the University of Hawaii’s Cancer Center and John A. Burns School of Medicine and an active volunteer for the Susan B. Komen Race for the Cure.
From his undergraduate days to today, Dr. Loui has been recognized for his work and achievements. Most recently he has been selected as a Top Doctor in Medical Oncology, Pacific Region by Castle Connolly for the past six years. He was recently honored to receive the University of Hawaii Cancer Center’s Silver Research Award.
Dr. Loui and his wife Sheree are the proud parents five children.

Provider Type

Physician

Video

Locations

Adventist Health Castle Cancer Care
- 642 Ulukahiki Street, Suite 300, Kailua, HI 96734
- Get Directions
- phone: 808-263-5022

Expertise

Education

University of Hawaii School of Medicine

Medical School

Mayo School of Medicine

Internship Program

Mayo School of Medicine

Residency Program

Mayo School of Medicine

Fellowship Program

Ratings & Reviews

4.8 out of 5

403 ratings, 49 reviews

The provider star rating is calculated using patient responses to the five care provider questions in our patient satisfaction survey. Below you can see the provider’s star rating and the number of his or her patients who have provided feedback.

Provider explained things clearly

Provider showed concern

Provider included you in decisions

Likelihood of recommending this provider

Provider discussed treatment options

Search reviews

Search Reviews

5 out of 5 stars
Reviewed on 9/11/2025
Dr. Loui is always very polite and always helpful. Explained my scan results and answered all my questions in detail so I can understand what is happening.
5 out of 5 stars
Reviewed on 8/26/2025
Dr. Loui always provides outstanding service. He is knowledgeable and thorough in providing care to me.
5 out of 5 stars
Reviewed on 8/25/2025
Dr. Loui was very attentive. Very good bedside manner.
5 out of 5 stars
Reviewed on 8/23/2025
Dr. Loui is excellent doctor
5 out of 5 stars
Reviewed on 8/15/2025
Maybe me feel comfortable
5 out of 5 stars
Reviewed on 8/14/2025
Very thoughtful
5 out of 5 stars
Reviewed on 8/14/2025
Always a positive visit!
5 out of 5 stars
Reviewed on 8/7/2025
Dr. William Loui came in about ten minutes upon arrival. The nurse checked me in and took my weight and blood pressure. Asked if there was any concerns to discuss with Dr. William Loui. There was none. Waited about three minutes and Dr. Loui came into the exam room. Very timely manner. Everything was finished in about 15 minutes.
5 out of 5 stars
Reviewed on 8/4/2025
Although he was also put on the spot to see me, he was very nice.Answered all my questions and we had a very nice visit
5 out of 5 stars
Reviewed on 7/29/2025
Care provider listens, and provides Options to compromise your needs
5 out of 5 stars
Reviewed on 7/24/2025
Dr. Loui is very personable and makes you feel at ease!
5 out of 5 stars
Reviewed on 7/15/2025
Dr. Loui took the time to explain everything in layman terms.
5 out of 5 stars
Reviewed on 6/24/2025
Dr. Loui is the best. He listens to my questions and provides me the response I need. Gentle and compassionate.
5 out of 5 stars
Reviewed on 6/21/2025
I like Dr. Loui very much. He's like a personal friend.
5 out of 5 stars
Reviewed on 6/19/2025
Good experience
5 out of 5 stars
Reviewed on 6/12/2025
Dr. Loui, great listener, always a delightful experience!
5 out of 5 stars
Reviewed on 6/11/2025
Very helpful info this appointmentAs usual too!
5 out of 5 stars
Reviewed on 5/30/2025
Excellent face-to-face followup visit with my oncologist.
5 out of 5 stars
Reviewed on 5/19/2025
I like how Dr. Loui treats me like a fellow human being rather than a dollar sign.
5 out of 5 stars
Reviewed on 5/14/2025
Dr Loui is very thorough and understanding.
5 out of 5 stars
Reviewed on 4/30/2025
Dr. Loui is very professional and has an excellent intuition for listening.
5 out of 5 stars
Reviewed on 4/18/2025
Doc Loui is awesome, always treats and services me as a person and not just a number.
5 out of 5 stars
Reviewed on 4/16/2025
Very focused on listening to what I have to share.
4 out of 5 stars
Reviewed on 4/11/2025
Dr. Loui is great, but we waited almost an hour to be seen
5 out of 5 stars
Reviewed on 4/8/2025
Dr. Loui is very thorough and I liked that he wanted to get to know me as a person before knowing me as a cancer patient
5 out of 5 stars
Reviewed on 3/14/2025
Great doctor.
5 out of 5 stars
Reviewed on 3/13/2025
The Dr took the time to get to know me personally as well as medically. He was very thorough and answered all my questions.
5 out of 5 stars
Reviewed on 3/7/2025
Dr Loui recognized the special concerns and fears that cancer patients, newly diagnosed and long term survivors, live with on a daily basis. He walks that path with myself and my wife. Very much mahalo.
4 out of 5 stars
Reviewed on 3/4/2025
I would recommend bit with a caveat that he runs late.
5 out of 5 stars
Reviewed on 2/26/2025
Dr Loui did a super job of listening to and responding to my concerns
4 out of 5 stars
Reviewed on 2/26/2025
My appointment was scheduled for 9am and I was not seen until 1030am. No explanation for the huge delay. That was unacceptable. I was aggravated because I had another appointment.
5 out of 5 stars
Reviewed on 2/14/2025
The last time a doctor knew anything about me personally was my Primary Care provider some 25 to 30 years ago. This doctor actually asked about me, not my issue or condition, but t'he non medical me.
5 out of 5 stars
Reviewed on 2/12/2025
Open and caring
5 out of 5 stars
Reviewed on 1/23/2025
Dr Loui is an extremely fine physician. I will stay with him as long as he will have me.
5 out of 5 stars
Reviewed on 12/25/2024
The whole experience with Dr. Loui was excellent. He asked how I was. Took my weight and blood pressure and temperature. Everything was good. Just needed Dr. Loui's approval for chemotherapy treatment.
5 out of 5 stars
Reviewed on 12/24/2024
I like Dr. LOUI very much.
3 out of 5 stars
Reviewed on 12/22/2024
doctor very good.
5 out of 5 stars
Reviewed on 12/20/2024
Very satisfied with my Doctor
4 out of 5 stars
Reviewed on 12/19/2024
Dr. Loui has always been on task and encouraging, patient & courteous. I have enjoyed my visits there and our vitual visits.
5 out of 5 stars
Reviewed on 12/4/2024
Thank to Dr. Loui who is always nice n caring,
5 out of 5 stars
Reviewed on 12/2/2024
I would 100% recommend this Dr
5 out of 5 stars
Reviewed on 12/1/2024
Dr. Loui always listens to my experience and is clear with his explanations and guidance.
5 out of 5 stars
Reviewed on 11/29/2024
He will go over any proposed treatment at an in-person appointment in a couple of weeks. I really appreciate meeting him face to face for this.
5 out of 5 stars
Reviewed on 11/22/2024
Already did a text on page 1 on how dr. LOUI was able to talk to me for the good news.
5 out of 5 stars
Reviewed on 11/22/2024
Although it was a long wait, Dr Loui did not rush my appointment and was thoughtful and caring in his care. He does not think any question is unimportant and provides clear resolutions to my concerns. I left the office confident in his decisions and recommendations for my future care plan.
5 out of 5 stars
Reviewed on 11/7/2024
Dr Loui Is happy to engage me in discussions about my treatments as well as addressing any concerns Iight have about current or future possible treatments. He always encouraged me to reach out for second opinions if I questioned a treatment plan and /or referenced me documentation so I could educate or research myself. It's much appreciated
5 out of 5 stars
Reviewed on 11/5/2024
Dr. Loui is very straight forward with the diagnosis and prognosis. He also gave me addition guidelines to maintain good health practices for my age.
5 out of 5 stars
Reviewed on 10/29/2024
Dr Loui was very attentive and addressed all questions and comments thoroughly.
5 out of 5 stars
Reviewed on 10/10/2024
I didn't have any concerns. Everything was alright. I would highly recommend Dr. William Loui to everyone that I know that needs any help.