Hot chemo is the common name for a procedure called hyperthermic intraperitoneal chemotherapy, or HIPEC. During a major surgery to remove visible cancer from the abdomen, the surgeon bathes the abdominal cavity in chemotherapy drugs heated to about 106 to 109°F (41 to 43°C). The heat helps the drugs penetrate deeper into tissue and makes them more effective at killing microscopic cancer cells that surgery alone can’t catch. You may also hear it called a “chemo wash” or “hot chemo bath.”
How the Procedure Works
Hot chemo is always paired with a surgery called cytoreductive surgery, where the surgeon removes all visible tumors from the lining of the abdominal cavity (the peritoneum). This debulking step can be extensive, sometimes involving the removal of portions of organs where cancer has spread. The goal is to leave behind nothing the eye can see.
Once the visible cancer is removed, the surgical team connects a circuit of tubes and a heat exchanger to the open abdominal cavity. Chemotherapy fluid, warmed to the target temperature, is then circulated through the abdomen for 30 minutes to one hour depending on the type of cancer and the drugs being used. The heated fluid reaches surfaces and crevices throughout the abdomen, targeting cancer cells too small to see or remove surgically. After the timed perfusion, the fluid is drained and the surgeon closes the incision.
The core advantage of delivering chemo this way is concentration. The drugs reach the peritoneal surface at much higher doses than would be possible through an IV, while far less of the medication enters the bloodstream. This means a more powerful local effect with fewer of the systemic side effects people associate with traditional chemotherapy.
Which Cancers It Treats
Hot chemo targets cancers that have spread to the peritoneum, the thin membrane lining the inside of the abdomen. It is now the standard of care in the United States for two conditions: metastatic appendiceal cancer and peritoneal mesothelioma. It is also used for colorectal cancer that has spread to the peritoneum, though its role there is more established in Europe than in the U.S., where a key randomized trial failed to enroll enough patients and was closed.
For ovarian cancer, the picture is nuanced. A major study published in The Lancet Oncology found that adding HIPEC to surgery nearly doubled five-year overall survival in stage III ovarian cancer patients, from about 20% to 37%. Ten-year survival also improved. However, separate data showed that HIPEC combined with surgery did not improve outcomes over surgery alone in patients with platinum-sensitive recurrent ovarian cancer, so patient selection matters enormously.
More recently, the 2024 NCCN guidelines introduced HIPEC as an option for gastric cancer with limited peritoneal spread, though only at experienced centers and only after months of systemic therapy with stable or improved disease. This remains a tightly controlled recommendation.
Who Qualifies for Hot Chemo
Not everyone with peritoneal cancer is a candidate. Surgeons use a scoring system called the Peritoneal Cancer Index (PCI) to measure how widely cancer has spread across the abdomen. In one study, patients who underwent the procedure had a median PCI of about 5, while those excluded had a median score closer to 17. The difference in outcomes is stark: for colon cancer patients, a PCI under 10 was associated with five-year survival around 50%, while a PCI over 20 dropped that to zero.
The most common reason patients are excluded is extensive disease along the small bowel and its supporting tissue, which makes complete surgical removal impossible. Cancer growing into major blood vessels or other structures that can’t be safely resected is the second most common disqualifier. Age alone is not a strict cutoff. Older patients are evaluated on their overall fitness rather than automatically ruled out.
Risks and Complications
This is a major procedure, and the complication profile reflects that. Overall morbidity (the rate of significant complications) ranges from 30% to 70% across large studies, and perioperative mortality ranges from 0% to 18% depending on the center and patient population.
The most common serious complications involve the digestive tract. Small bowel perforations and leaks at surgical connection points are the most clinically significant, with severe gastrointestinal complications reported in 4.5% to 19% of patients. Other possible GI issues include abdominal abscesses, prolonged inability to tolerate food, and pancreatic or bile duct leaks.
Lung complications occur in roughly 10% to 16% of patients, with pneumonia specifically affecting 3% to 10%. Kidney problems are less common but possible, occurring in about 2% to 4% of cases, because some of the chemotherapy drugs used can stress the kidneys. These risks are part of why the procedure is performed only at specialized centers with teams experienced in both the surgery and the chemotherapy delivery.
Recovery Timeline
Plan for a long recovery. Most patients spend several days to two weeks in the hospital after the procedure. Total recovery to normal activity takes four to 12 weeks. The length depends on how extensive the surgery was, whether complications arise, and the patient’s baseline health. The early hospital days involve close monitoring for the complications described above, managing pain, and gradually reintroducing food as the digestive system wakes back up after being handled during surgery.
Chemotherapy Drugs Used
The specific drugs circulated during the procedure vary by cancer type and institutional preference. The most commonly used drug worldwide is mitomycin C, which is typically circulated for 60 to 90 minutes. Oxaliplatin is another frequent choice, favored by some teams because its protocol requires only 30 minutes of perfusion, though it carries a higher risk of postoperative bleeding. Cisplatin is sometimes used alone or combined with mitomycin C. Survival outcomes appear comparable between these options, so the choice often comes down to the treatment team’s experience and the specific clinical situation.