GIST Specialist for Santa Monica, CA
A gastrointestinal stromal tumor is rare enough that most surgeons see one or two in a career. Joshua Ellenhorn, MD, FACS has built a practice around them. His operating room is twenty minutes inland from Ocean Avenue, at Cedars-Sinai.
- Clinical Professor of Surgery, Cedars-Sinai Medical Center
- Fellow of the American College of Surgeons
- Published surgical videos of his own laparoscopic and robotic GIST resections
- Works alongside your existing Westside oncologist
What a Gastrointestinal Stromal Tumor Is
GIST begin in the interstitial cells of Cajal, a network of pacemaker cells buried in the wall of the digestive tract that sets the rhythm of the contractions moving food along. They are not stomach cancer and not lymphoma. They are a sarcoma, and they behave differently from both.
Because those cells sit within the wall rather than on the inner surface, a GIST tends to grow outward into the abdomen. It can become surprisingly large before it produces a single symptom, and it can hide from a camera passed down the throat because there is nothing to see on the lining above it.
The stomach accounts for roughly sixty percent of cases and the small intestine another thirty. Nearly all carry a mutation in KIT or, less often, PDGFRA, which locks a growth signal permanently on. That same mutation is the reason a pill can work against this cancer when it does nothing for most sarcomas.
How it usually announces itself
- Iron deficiency anemia on routine bloodwork, with no visible bleeding anywhere
- Dark, tarry stools or, less often, vomited blood
- A dull ache or sense of pressure that patients struggle to localise
- Filling up after a few mouthfuls, or bloating that does not settle
- Nausea and vomiting once a tumor starts to obstruct the bowel
- A mass the patient or a physician can feel through the abdominal wall
A large share are found by accident, on imaging ordered for something unrelated.
Getting the Diagnosis Right the First Time
Most GIST surface on a CT scan, a PET/CT, or an upper endoscopy. Sometimes the appearance is characteristic enough that the diagnosis is not in serious doubt and tissue adds nothing before an operation.
Small bowel tumors are the awkward ones. They sit beyond the reach of a standard endoscope, which is why a Santa Monica patient being worked up for unexplained anemia can go through a normal upper endoscopy and a normal colonoscopy and still have a GIST. Cross sectional imaging, and occasionally capsule study or enteroscopy, is what finds them.
When tissue is needed, endoscopic ultrasound lets the deeper layers of the wall be sampled without tearing the capsule. Rupture matters: it can seed tumor cells across the abdominal cavity and change the whole trajectory of the disease. That risk is a large part of why the decision to biopsy belongs with someone who does this often.
Mutation testing on the specimen is not a box to tick. KIT driven, PDGFRA driven, and wild type tumors respond to different drugs at different doses, and the answer can change whether medication should come before the operation or after it.
Why Santa Monica Patients Travel Inland for This
The Westside has no shortage of excellent hospitals. Providence Saint John's and UCLA Santa Monica both do fine general surgery. The issue is not competence, it is frequency. GIST makes up about one percent of gastrointestinal cancers, so even a busy general surgeon may operate on a handful across an entire career.
The decisions that determine your outcome are precisely the ones that reward repetition. Can this gastric tumor come out as a wedge, or does it need a formal resection? Can the capsule survive a laparoscopic approach, or will it tear? Should imatinib run for a few months first to shrink a tumor sitting awkwardly against the duodenum? Is this liver spot worth resecting or is it better controlled with a drug?
None of those have a protocol answer. They are judgment, and judgment is built from cases. Getting them right the first time is what keeps you from needing a second, larger operation later.
The Three Paths, and How One Is Chosen
Size, site, mitotic rate, mutation status, and whether disease has spread all feed into the plan. So does what matters to you.
Active Surveillance
A small gastric GIST with a low mitotic rate can often be watched with periodic imaging instead of removed. Hearing that surgery is not needed yet is a legitimate result of a specialist visit, and it is a conclusion a surgeon who sees these regularly is more comfortable reaching.
Blocking the Signal
Imatinib, sunitinib, and regorafenib were designed to shut down the abnormal KIT and PDGFRA signalling that drives GIST growth. They shrink tumors before surgery, lower recurrence risk after it, and hold metastatic disease in check. They rarely finish the job alone.
Complete Resection
Surgery is what cures a GIST. The aim is removal with an intact capsule and clear margins, laparoscopically or robotically where the anatomy allows, open where it does not. Small bowel tumors usually mean removing a short segment of intestine and rejoining it in the same sitting.
His Own Operations, on Video
Very few surgeons publish recordings of their GIST work. These are real resections narrated by the surgeon who performed them, which is a more useful answer than any claim about experience.
Laparoscopic Resection of a Gastric GIST
A stomach GIST removed through small incisions with the capsule kept whole.
Gastric GIST Resection: A Simplified Approach
A technique refined across many cases to shorten both the operation and the recovery.
Robotic Resection of a Duodenal GIST
Duodenal GIST is one of the least forgiving locations. Robotic assistance allows removal while sparing the pancreas and bile duct.
Ask Before You Consent
Whether you keep most of your stomach, or a short segment of bowel instead of a long one, often comes down to technique rather than tumor biology. Have your scans read by someone who does this weekly before you agree to an operation.
The Paperwork Behind the Recommendation
Two board certifications, a teaching appointment at Cedars-Sinai, and membership of the societies that write the guidelines for this disease.
- American Board of Surgery, certified in General Surgery
- American Board of Surgery, certified in Colorectal Surgery
- California State Medical License
- Florida State Medical License
Joshua Ellenhorn, MD, FACS
Dr. Ellenhorn is a surgical oncologist and Clinical Professor of Surgery at Cedars-Sinai Medical Center, and a collaborative member of the Samuel Oschin Comprehensive Cancer Institute. He is regarded as one of the leading GIST surgeons in the country.
The practice is narrow by design. Rather than covering the breadth of general surgery, he concentrates on complex abdominal cancers and on gastrointestinal stromal tumors in particular. That focus is what makes the level of technical detail in his published operative videos possible, and it is why oncologists across Los Angeles and out of state refer these cases specifically to him.
He is board certified by the American Board of Surgery in both General Surgery and Colorectal Surgery, a Fellow of the American College of Surgeons, and a member of the Society of Surgical Oncology and the American Society of Clinical Oncology. He practises as part of the Surgery Group of Los Angeles.
What Patients Say
Reviews left by patients treated by Dr. Ellenhorn at the Surgery Group of Los Angeles.
★★★★★The staff at the Surgery Group of Los Angeles are wonderful. They are kind, very attentive, the office is clean and I did not have to wait long at all. I cannot say enough great things about Dr. Ellenhorn. He is an excellent surgeon who is highly skilled and very knowledgeable. I cannot thank him enough for all he has done for my family and I.
Erika Frank
★★★★★Very kind stuff, great service. Dr Joshua Ellenhorn is a very calm doctor who takes time with his patient.
Anita Lukacevic
From Santa Monica to a Plan
Send the Records Ahead
Call (310) 356-3792 or book online. Forward your CT or PET imaging, any endoscopy report, and the pathology with mutation testing if it has been done. Sending it in advance means the appointment starts with answers instead of admin.
A Direct Reading
Dr. Ellenhorn reviews the imaging and pathology himself and tells you what the size, site, and mitotic index actually mean for your risk. If the honest recommendation is surveillance rather than an operation, you will hear that.
Surgery, Then Handover
Minimally invasive resections are often same day or one night. You leave with a defined surveillance schedule, and your Santa Monica oncologist gets the operative report and pathology directly if targeted therapy is part of the plan.
Twenty Minutes Inland
From downtown Santa Monica or Ocean Avenue, the I-10 east to La Cienega and north through the mid city is the usual route. When the freeway is backed up, Olympic Boulevard or Santa Monica Boulevard run straight east and often move better in the late afternoon. Coming from north of Montana Avenue, San Vicente to Wilshire then east is the cleaner line.
The office sits in the medical plaza next to Cedars-Sinai Medical Center, which means imaging, pathology, and the operating rooms are in one building rather than scattered across three appointments in three places. Expect twenty to twenty five minutes from 90401 through 90405 outside of rush hour.
Patients coming from further afield, including Arizona and Nevada, can have imaging and pathology reviewed remotely before committing to the trip.
8635 W 3rd St, Suite 880W
Los Angeles, CA 90048
Monday to Saturday, 11:00am to 8:00pm
Closed Sunday
Frequently Asked Questions
How long is the drive from Santa Monica to your office?
I already have an oncologist on the Westside. Do I have to switch?
A scan found a mass in my small intestine. Could it be a GIST?
Why did my GIST cause anemia rather than pain?
What is a mitotic index and why does everyone keep mentioning it?
Is a biopsy risky if the tumor could rupture?
How long is recovery from a laparoscopic GIST resection?
Will I need a colostomy or ileostomy?
Does insurance cover a second opinion on a GIST?
Have a GIST Diagnosis? Get It Read Properly.
If a scan or an unexplained anemia workup in Santa Monica has turned up a gastrointestinal stromal tumor, have it assessed by a surgeon who treats this tumor as a specialty before any decision is made.
