A chemo bath, formally known as HIPEC (hyperthermic intraperitoneal chemotherapy), is a procedure where heated chemotherapy is poured directly into the abdominal cavity during surgery. After a surgeon removes all visible tumors from the abdomen, the chemotherapy solution, warmed to about 107°F (42°C), is circulated throughout the area for roughly 90 minutes to kill any remaining microscopic cancer cells. The technique is most commonly used for cancers that have spread to the lining of the abdomen, a surface called the peritoneum.
How a Chemo Bath Works
The procedure combines two steps performed in a single operation. First, a surgeon performs what’s called cytoreductive surgery, carefully cutting away every visible tumor from the abdominal lining, organs, and surrounding tissue. This debulking phase can take several hours depending on how far the cancer has spread.
Once the surgeon is satisfied that no visible disease remains, the chemotherapy solution is introduced. Thin tubes are placed into the open abdominal cavity, and a pump circulates the heated liquid so it reaches every surface inside. The heat serves two purposes: it helps the chemotherapy drugs penetrate deeper into tissue, and it damages cancer cells directly, since cancer cells are more vulnerable to heat than healthy cells. The solution bathes the entire abdominal cavity for 60 to 120 minutes before being drained. Then the surgeon closes the incision.
Delivering chemo this way allows drug concentrations in the abdomen to be far higher than what’s possible through an IV. Studies have shown that local drug exposure can be 20 to 1,000 times greater than with standard intravenous chemotherapy, while the rest of the body absorbs significantly less. That means fewer of the systemic side effects people typically associate with chemo, like severe nausea and hair loss, though those can still occur to some degree.
Cancers Treated With HIPEC
HIPEC is used primarily for cancers that spread along the peritoneal surface rather than through the bloodstream to distant organs like the lungs or brain. The most common candidates include:
- Appendix cancer with a condition called pseudomyxoma peritonei, where mucus-producing tumors coat the abdominal lining
- Colorectal cancer that has spread to the peritoneum
- Ovarian cancer, particularly advanced-stage cases
- Mesothelioma of the peritoneum, a rare cancer of the abdominal lining
- Gastric cancer with peritoneal involvement
Not everyone with these cancers qualifies. The best outcomes happen when the cancer is limited to the abdominal lining and hasn’t spread to distant sites. Patients also need to be healthy enough to tolerate what is a lengthy, physically demanding surgery. Surgeons use scoring systems during the operation to assess how extensively cancer has spread across the peritoneum, and if the disease is too widespread to remove completely, proceeding with HIPEC may not provide benefit.
What the Patient Experiences
The entire operation typically lasts anywhere from 6 to 18 hours, depending on the extent of tumor removal needed before the chemo bath begins. You’ll be under general anesthesia for the full procedure and won’t feel any of it.
Recovery is significant. Most patients spend 10 to 14 days in the hospital afterward, and the first several days are usually spent in an intensive care unit. The combination of extensive surgery and chemotherapy exposure means your body has a lot of healing to do simultaneously. Expect to have drainage tubes, a urinary catheter, and IV lines for nutrition and pain management in the days following the procedure. Many patients can’t eat solid food for the first week or so as the digestive system recovers from being handled during surgery.
Full recovery at home generally takes 2 to 3 months, though some people take longer. Fatigue is the most persistent complaint. Gradually returning to normal activities over weeks is typical, with light walking encouraged early and more strenuous activity added as healing allows.
Potential Risks and Side Effects
Because HIPEC involves both major surgery and chemotherapy, the complication rate is higher than for either alone. Roughly 30 to 40 percent of patients experience some form of complication, though many are manageable. The most common issues include infections, fluid collections in the abdomen, slow return of bowel function, and blood clots. More serious complications like bowel leaks from surgical connections or kidney problems from chemotherapy exposure occur less frequently but can require additional procedures.
Systemic chemotherapy side effects are generally milder than with IV chemo because less drug reaches the bloodstream. Some patients still experience temporary drops in blood cell counts, which can increase infection risk in the weeks after surgery. Hair loss is uncommon but possible depending on the specific drugs used in the bath.
How Effective Is HIPEC
Outcomes vary substantially by cancer type. For appendix cancers with pseudomyxoma peritonei, HIPEC combined with complete tumor removal has produced 10-year survival rates above 60 percent in experienced centers. This is a cancer that previously had no effective treatment.
For colorectal cancer that has spread to the peritoneum, adding HIPEC to surgical debulking has shown median survival improvements, with some studies reporting median survival in the range of 2 to 4 years compared to roughly 12 to 16 months with systemic chemotherapy alone. Results for ovarian cancer have also been encouraging. A landmark Dutch trial found that adding HIPEC to interval surgery for stage III ovarian cancer extended median survival by nearly 12 months compared to surgery without the chemo bath.
The completeness of tumor removal matters more than almost any other factor. When surgeons can remove all visible disease before circulating the heated chemo, outcomes improve dramatically. If significant tumor is left behind, the chemo bath alone is unlikely to control the cancer.
Where HIPEC Is Performed
HIPEC is a highly specialized procedure that requires a surgical team experienced in both complex abdominal operations and peritoneal surface cancers. It’s offered at major cancer centers and select academic hospitals, not at every community hospital. Surgical volume matters: centers that perform more of these procedures tend to have lower complication rates and better outcomes. If you or someone you know is being considered for HIPEC, seeking out a center that performs at least 12 to 20 cases per year is a reasonable benchmark for adequate experience.
The procedure has grown steadily more common over the past two decades. What was once considered experimental for most indications is now part of standard treatment guidelines for select peritoneal cancers, particularly appendiceal and colorectal cancers with limited peritoneal spread.