HIPEC, or hyperthermic intraperitoneal chemotherapy, is a treatment for advanced cancers that have spread to the peritoneum. It involves delivering heated chemotherapy directly into the peritoneal cavity during cytoreductive surgery to remove any visible tumors. HIPEC aims to treat any remaining microscopic disease. Heating the chemotherapy to 41-42°C allows it to penetrate deeper tissues and more effectively kill cancer cells compared to normal intraperitoneal or intravenous chemotherapy alone. While HIPEC is effective, it is also associated with increased risks of complications due to the combined effects of surgery, chemotherapy, and localized hyperthermia.
1. Hyperthermic Intraperitoneal Chemotherapy
Known by the shorter and much easier to remember acronym HIPEC, it actually constitutes one
half of a two-part surgery in which it is combined with cytoreductive surgery. This treatment is
used for patients who have an advanced tumour which is isolated in the peritoneal or the belly
region.
Initially, when there is a disease spreading in the peritoneum, doctors used to opt for
conventional treatment procedures such as a cytoreductive surgery and then give chemotherapy
through an IV line. But, doctors know that if chemotherapy is given through the vein, it will
reach the blood and the organs, but will not reach the peritoneal cavity in sufficient
concentration. This is because, the depth and penetration of this chemo to kill the cancer cells Is
only 5 mm. In order to overcome that, some form of chemotherapy is given into the tummy or
the peritoneum, which is called intraperitoneal chemotherapy. It was found that if the chemo was
2. given at normal body temperature of about 37°C, the efficacy wasn’t very high. Various research
studies found that if chemotherapy was combined with
high temperature in the range of 41-42°C, which is called Hyperthermia, the efficacy of the
chemo doubled or even tripled, and the depth of penetration also increased manifold. As a
result, Hyperthermic Intraperitoneal Chemotherapy (HIPEC) is more effective in killing the
cancer cells which are spread in the tummy region. This technique needs a specialized, dedicated
team, HIPEC machine and trained doctors and is done immediately after the cytoreductive
surgery.
How does HIPEC work?
It is a known phenomenon that if the chemotherapy bakes the cancer cells which have spread
into small nodules in the tummy, then it is penetrating up to 1 cm, and not just 5 mm. So the
cancer cells are on sustained burying of a thin layer of chemo fluid and are killed. In the case of
hyperthermia, where the body temperature of the chemo fluid is increased to 41-42°C , it kills the
DNA, RNA and lysosomes and destroys the cancer cells. Once they are destroyed, the chemo
can penetrate deep inside and kill the remaining cancer cells. So, along with the macroscopic or
the visible cancer cells, microscopic ones not visible to the doctor’s eye are also taken care of by
HIPEC technique.
Techniques of HIPEC delivery
It has a narrow therapeutic temperature range of 41 – 43° C. If the temperature is less
than 41°C, it is not beneficial, while excess of 43°C results in complications.HIPEC
consists of three components:
The circulating speed of the fluid that circulates in the tummy with chemo should be at
least 1litre/minute.
The pressure should be around 14-15 Pa.
To ensure such precise parameters, conventional heart-lung or other machines are of no use. A
dedicated HIPEC machine is essential which can measure and maintain the flow rate, the
temperature in all the quadrants of the tummy and the volume. The procedure lasts for 90
minutes.
3. What are the drug regimens in use for HIPEC?
There is a selection criteria for the drugs needed for intraperitoneal chemo:
Heat Sustainability: It should not be destroyed by high temperatures.
It should be capable of reaching maintaining high levels of concentration in the tummy or
the peritoneal cavity.
It is specific to the type of cancer. For example, in cases of carcinoma ovary, usually a
drug called cisplatin is prescribed, while for colon or rectal cancers oxaliplatin is used.
While these are the most common drugs used in HIPEC, there are many other drugs
which are used in extraordinary circumstances.
Role of HIPEC in Advanced Ovarian and Colorectal Cancer
In India, most of the ovarian cancer patients visit a doctor when they are in Stage 3C, and
colorectal cancer patients too usually seek medical opinion when it is quite late and the disease is
in its advanced stage. If a person has Stage 4 colorectal cancer with peritoneal spread,
conventional treatments will not be able to cure him/her. In addition to systemic chemo, if
cytoreductive surgery along with HIPEC is done on a patient who has responded well to chemo
and where the cancer has not spread outside the tummy, the chances of curing him/her is more
than 60-75% with a five to ten year life span which is a tremendous improvement in colorectal
cancer. HIPEC and cytoreductive surgery is the only ray of hope for those affected with
advanced stage 4 ovarian cancer or recurrent cancer.
What are the complications after HIPEC?
It is important to note that HIPEC is tough on the body. It is experiencing the compounding
effects of a major surgery, addition of chemo and an increase in temperature. The effects of
fever, i.e., increase in metabolic rate, sweating, weakness, high heart rate and low urine output
are experienced on a magnified scale. For the first one or two weeks after the HIPEC procedure,
the patients are prone to bacterial, fungal and/or viral infections due to decreased immunity and
need constant monitoring. The intestine takes some days to recover, so adequate nutrition
4. including protein and albumin through the parenteral route. The doctors must perform hourly
mobilizations so the patients don’t develop venous
thrombosis or lung infection. In general, the complication rate is about two fold more than
normal surgery, but highly manageable.
Advantages of HIPEC
Notwithstanding the possible complications of HIPEC, it still has several distinct advantages It is
found that in peritoneal surface cancers like those affecting the stomach, ovaries, colon etc., if
only surgery is done, the time taken for curing ranges from 24-36 months for a patient. If
cytoreductive surgery is carried out and intravenous chemo is given, the cure rate drops to about
32 months. Now, if along with this surgery, HIPEC procedure is carried out with the help of a
dedicated machine, the patients can be cured within a couple of months. They have more than
50-60% chance of living beyond five to ten years with an excellent quality of life. Therefore,
incorporating the HIPEC technique gives a fresh lease of hope to tackle this malignant disease
for which there would otherwise be no cure is available. HIPEC is the only option for peritoneal
surface malignancies.
It reduces the side effects of chemotherapy.
It improves the efficacy of chemotherapy absorption and increases the susceptibility of
cancer cells.
It helps in concentrating the chemotherapy within the tummy.