Colonoscopy clinicians in Torrance, California

CMS lists 40 clinicians with a primary specialty of Gastroenterology, Internal Medicine, Family Practice, or General Practice who have billed Medicare for at least one colonoscopy and practice in Torrance, California (details below).

Colonoscopy volume

Clinician	Colonoscopies billed	Percentile rank
James Sattler, MD	248	93%
David Kim, MD	240	93%
Jerome Cohen, MD	208	89%
Tonny Lee, MD	181	86%
Karl Fukunaga, MD	174	85%
Gloria Sze, MD	161	82%
Waleed Shindy, MD	147	79%
Oren Zaidel, MD	146	79%
Daniel Cho, MD	143	78%
Robert Webman, MD	130	74%
Minh Nguyen, MD	119	71%
John Kasher, MD	115	69%
Robert Mecum, MD	106	66%
David Chung, MD	103	65%
Timothy Tran, MD	98	63%
Chirag Patel, MD	97	63%
Azam Riyaz, MD	96	62%
James Kao, MD	88	59%
Chun Hsu, MD	84	57%
Wei-Chung Chen, MD	82	56%
Shahina Hakim, MD	82	56%
John Zeroogian, MD	81	55%
Thai Ha, MD	78	54%
Daniel Shue, MD	76	53%
Adrienne Lenhart, MD	72	51%
Alexander Nguyen, MD	70	50%
Didi Mwengela, MD	69	49%
Sonya Dasharathy, MD	62	46%
Bao Sean Nguyen, MD	53	41%
Melissa Munsell, MD	48	38%
Ellie Chen, MD	46	36%
Nazir Khaja, MD	44	35%
Jennifer Kolb, MD	31	27%
Nimah Ather, MD	25	23%
Sutha Sachar, MD	19	19%
Kelsey Collins, MD	18	18%
Kenneth Holt, MD	12	14%
Fouzia Oza, MD	11	13%
Viktor Eysselein, MD	1-10	13% or below
Marcil Mamita, MD	1-10	13% or below

Sorted by the number of colonoscopies billed to Medicare, highest first, not by quality or skill. CMS suppresses counts between 1 and 10 to protect patient privacy and publishes the range instead.

Understanding CMS Data

CMS's "Colonoscopy" category combines specific billing codes for colonoscopy to calculate the number of times each clinician billed Medicare for a "Colonoscopy." These include screening colonoscopy, diagnostic colonoscopy, and colonoscopy with biopsy or polyp removal. CMS's list also includes flexible sigmoidoscopy and laparoscopic appendectomy, so a clinician's count may include those procedures. CMS counts one procedure per patient per day, so a colonoscopy that included both a biopsy and a polyp removal counts once. CMS reports only procedures that clinicians billed to Original Medicare and Medicare Advantage. Therefore, CMS's procedure volume data does not include procedures that clinicians may have performed on patients who have other health care coverage (e.g., commercial insurance, self-pay, or the VA). Billing variation and coding errors can also affect CMS's data. Therefore, the number of procedures that CMS reports for a clinician may be higher or lower than the actual number of colonoscopies a clinician performed during the reporting period. Lastly, only clinicians with a primary specialty of Gastroenterology, Internal Medicine, Family Practice, or General Practice (as reported to Medicare) are presented.

Source: Centers for Medicare & Medicaid Services (August 18, 2026 release).