Survival Outlook Can Improve Over Time After CRS/HIPEC
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Liang XL, Su YD, Li XB, Fu YB, Ma R, Yang R, Wu HL, Cui YR, Li Y. Prognostic Factors of Long-Term Survival and Conditional Survival Analysis in MPM Patients Treated with CRS+HIPEC: A Retrospective Study of Two Centers. Ann Surg Oncol. 2025 Apr;32(4):2912-2922. doi: 10.1245/s10434-024-16485-1. Epub 2024 Nov 13. PMID: 39538101.
Malignant peritoneal mesothelioma is a rare cancer of the abdominal lining. Because it is uncommon, survival estimates are often based on limited data and may not reflect how a patient’s outlook changes after successfully reaching important milestones following treatment.
A study published in Annals of Surgical Oncology examined long-term and “conditional” survival among patients with malignant peritoneal mesothelioma who underwent cytoreductive surgery with hyperthermic intraperitoneal chemotherapy, commonly called CRS/HIPEC.
The Key Study Question
Which factors are associated with long-term survival after CRS/HIPEC, and how does a patient’s survival outlook change as more time passes after surgery?
Understanding Conditional Survival
Traditional survival statistics are calculated from the time of diagnosis or treatment. Conditional survival provides a changing estimate based on how long a person has already survived.
For example, the outlook for someone who is four years beyond surgery may be different from the outlook estimated immediately after treatment. Conditional survival recognizes that prognosis is not necessarily fixed and may become more favorable as patients reach additional milestones.
The Big Picture
Researchers retrospectively reviewed information from 212 patients with malignant peritoneal mesothelioma treated with CRS/HIPEC at two medical centers.
For the detailed comparison of factors associated with survival, the researchers evaluated:
53 patients who survived at least 48 months
37 patients who survived 16 months or less
They examined patient health, tumor characteristics, surgical factors, postoperative complications and long-term outcomes.
What the Researchers Found
The study found that the estimated probability of surviving an additional five years increased as patients lived longer following CRS/HIPEC.
The five-year conditional survival estimate was:
27% at the time of surgery
84% among patients who had already survived four years
The survival curve also began to level off approximately five years after surgery. The researchers suggested that some patients who remain disease-free or stable for this length of time may experience durable long-term survival.
Several factors were associated with reaching long-term survival:
A Peritoneal Cancer Index of 20 or lower
Requiring fewer red blood cell transfusions during surgery
Avoiding serious postoperative complications
The Peritoneal Cancer Index, or PCI, measures how extensively tumors have spread throughout the abdominal cavity. A lower PCI generally represents a lower volume of disease.
The association with blood transfusions may reflect the complexity of the operation, the amount of blood lost or the extent of disease rather than the transfusion itself. These factors are not necessarily within a patient’s control.
Why This Matters for Patients
Survival statistics given at diagnosis can feel permanent, but this research demonstrates why prognosis should be viewed as something that may change over time.
For patients who continue to recover and survive following CRS/HIPEC, earlier estimates may become less representative of their current outlook. Reaching another year after treatment provides new information that can make future survival estimates more favorable.
The findings also reinforce the importance of careful patient selection, experienced multidisciplinary care and strategies to reduce serious surgical complications. Patients considering CRS/HIPEC should be evaluated by specialists familiar with both peritoneal mesothelioma and complex peritoneal surgery.
Important Study Limitations
This was a retrospective study, meaning researchers reviewed previously collected medical records rather than conducting a prospective clinical trial. All patients had been selected to undergo CRS/HIPEC, so the findings do not apply automatically to every person with peritoneal mesothelioma.
The study also did not compare CRS/HIPEC with other treatments. It therefore cannot prove that the procedure caused the reported survival outcomes.
The long-term and short-term survival comparison focused on patients at opposite ends of the survival range and did not include everyone in between. Results from two centers may also differ from those achieved in other healthcare settings.
Most importantly, conditional survival describes patterns across a group of patients. It cannot predict exactly what will happen to an individual.
The Bottom Line
For selected patients with malignant peritoneal mesothelioma treated with CRS/HIPEC, survival outlook may improve as more time passes after surgery. In this study, patients who had already survived several years had a substantially more favorable estimate of surviving additional years.
These findings offer a hopeful and important message: the prognosis provided at the beginning of treatment may not tell the whole story. Each milestone reached can provide new information about the road ahead.
