comparing treatment centers for peritoneal meso - what metrics actually matter

The questions you're asking are exactly the right ones, and the fact that one center couldn't give you a volume number without a handoff is actually meaningful data about how they communicate with patients.

On the case volume issue, the 2022 paper you found is likely referencing work that's consistent with what Sugarbaker and colleagues have published over the years showing a volume-outcome relationship for cytoreductive surgery with HIPEC. But you're right to be skeptical of how centers count cases. "Peritoneal surface malignancy" programs often lump colorectal, ovarian, appendiceal, and meso together. When I advise patients on this, the number that matters is meso-specific HIPEC cases per year, not the broader category. Anything under 10 mesothelioma-specific cases annually and I'd want to understand why they're presenting themselves as a referral center.

The case selection problem you identified is real and honestly underappreciated. A center reporting 40% five-year survival in a population that skewed toward epithelioid histology (cell type) and low peritoneal cancer index (a scoring system that measures how far disease has spread in the abdomen) is not the same as 40% in an unselected population. Ask them directly what their median PCI was in their reported cohort. If they can answer that without hesitation, that tells you something.

For complication rates, the Clavien-Dindo classification system is the standard way serious programs report surgical complications. If a center can tell you their rate of grade 3 or higher complications using that system, they're tracking outcomes rigorously. I've seen centers quote complication rates under 10% that turn out to be counting only events requiring reoperation, not things like prolonged ICU stays. The definition matters enormously.

Your oncologist's advice about asking for the specific surgeon's numbers rather than the program's aggregate is solid. One thing worth asking is whether the surgeon you'd actually be operated on by has done at least 50 HIPEC procedures personally, and whether they trained with a high-volume program. The Peritoneal Surface Oncology Group International has a list of training programs that carry some weight.

Please talk to your own oncologist about any of this before making decisions, especially the volume thresholds since your specific situation matters more than any general benchmark.

The volume question you're wrestling with is real and the inconsistency you're getting is actually pretty common. The 2022 study you found is likely the Sugarbaker group's analysis out of Washington, and the 20-case threshold for peritoneal meso specifically is a reasonable benchmark, but you're right to be skeptical when centers start bundling all abdominal cases together. That's a meaningful difference.

The metric that actually changed how I advise patients on this is completeness of cytoreduction score, specifically what percentage of a center's patients achieve CC-0 or CC-1 (meaning no visible residual tumor or residual nodules under 2.5mm after surgery). A center can quote you a 5-year survival rate all day but if they're not achieving CC-0 in the majority of their meso cases, the comparison is essentially meaningless. I'd ask for that number directly.

On the complication question, ask specifically about grade 3 or higher adverse events using the Clavien-Dindo classification. That's a standardized scale so you can actually compare across centers. If they don't know what you're referring to, that tells you something.

The handoff you experienced when asking about surgeon-specific case volume is worth noting. At a high-volume center like the one at Brigham and Women's or the PCI program in Pittsburgh, that question gets answered without hesitation because the surgeons are tracking it themselves.

And honestly, your oncologist should be helping you get these numbers, not just telling you what to ask. Please do loop them in on what you're finding, they may be able to make direct calls to programs they have relationships with.

The 2022 study you found is the Sugarbaker data, and the volume threshold question is actually something I followed pretty closely when it came out. The 20 case per year minimum for meso specifically is still the most cited benchmark, but you're right to be skeptical about how centers count. When I was advising a patient in early 2023 who eventually went to a center in Pittsburgh, we spent about three weeks just trying to get apples-to-apples numbers before we could compare anything meaningful.

Here's what actually cuts through the noise. Ask them specifically: how many HIPEC procedures for malignant peritoneal mesothelioma did your team complete in the last 24 months. Not abdominal cancers broadly. Not cytoreduction generally. That specific disease, that specific procedure. A good center will have someone who can answer that without transferring you twice.

The survival rate comparison problem you identified is real and honestly undersold. Centers that do higher volume tend to have more complete cytoreduction (CC-0 or CC-1 resection, meaning no visible remaining tumor or only tiny deposits) and that single variable predicts outcomes more than almost anything else in the literature. So you can ask them directly: what percentage of your peritoneal meso patients achieve CC-0 at the time of surgery. If they can't tell you, that's information too.

Complication rates are reported so inconsistently across centers that I usually tell people to ask about grade 3 or higher complications using the Clavien-Dindo classification (that's a standardized scoring system for surgical complications). That at least forces them to give you a number that means something.

The handoff you experienced at that one center actually is a reasonable signal. Not definitive, but at high-volume specialized programs, the patient coordinators typically handle these questions regularly.

Please do loop in your own oncologist on whatever you find, because case selection and your specific staging matter enormously for interpreting any of this.

What you're doing here is genuinely hard, and the frustration of getting inconsistent answers from three different centers is real. That kind of confusion can make you feel like you're doing something wrong when you're actually doing everything right.

The volume question is one I've seen trip up a lot of families. When we were helping a patient work through this back in 2021, we eventually learned to ask specifically "how many cytoreductive surgeries with HIPEC did your team perform for peritoneal mesothelioma patients in the last 12 months" and write down exactly what they say. If they hedge or reframe the question back to you, that itself is information. The center that wouldn't give a number at all... I'd keep that in mind.

On the survival stats piece, you're right to be skeptical. Case mix matters enormously. A center treating mostly epithelioid type in earlier stage patients will show better numbers than one taking on complex recurrences. You can ask them directly what percentage of their HIPEC patients had an epithelioid histology and what the median PCI score was for their last 50 cases. Not every coordinator can answer that on the spot, but a high-volume center should be able to get you that from their database within a week or so.

The 2022 study you found is solid. The 20-case annual threshold for peritoneal meso specifically has held up in the literature pretty consistently.

If you're finding this research process is also wearing on you emotionally, which honestly would make complete sense given everything, talking with an oncology social worker could help. For something this persistent, professional counseling is worth pursuing alongside all of this.