Despite the advent of newer drugs like targeted therapy and immunotherapy, conventional chemotherapy continues to remain a mainstay of cancer treatment. But chemotherapy is not a disease specific drug, that it, it doesn’t work only on cancer cells. One of the ways chemotherapy works is by attacking rapidly growing cells – and since cancer cells are among the most rapidly growing cells in a person with cancer, chemotherapy preferentially kills those cells. Unfortunately, chemotherapy can also harm other healthy cells in the body – therefore it requires a careful balance of the right dose at the right interval to maximize chemotherapy’s effects on cancer cells and simultaneously minimize its effect on healthy cells.
Most of the time, chemotherapy is given intravenously or orally (“systemic chemotherapy”) – which means that the chemotherapy drug circulates all over the body. If chemotherapy could be delivered directly to the site of cancer without allowing it to go other parts of the body, we could give much higher (and therefore more effective) doses of the treatment, at the same time reducing the side-effects of chemotherapy.
A unique group of cancers which lends itself to this hypothesis is Peritoneal surface malignancy (PSM). The peritoneum is the thin inner lining of the abdominal cavity which extends onto and covers the abdominal organs. Certain cancers, notably cancers of the ovary, appendix and colorectal cancers tend to shed cancer cells into the abdominal cavity which then deposit on the surface of the abdominal wall and the abdominal organs – the surface covered by peritoneum. Treatment of peritoneal surface cancers has historically been challenging. While grossly visible disease can be removed by meticulous surgery (cytoreductive surgery or CRS), it is harder to treat microscopic and invisible disease. Conventional chemotherapy is not very effective in these cases, because of poor concentrations of systemic chemotherapy in the peritoneum. Would instilling chemotherapy directly onto the peritoneal surface help?
This was the premise on which medical research into HIPEC began. HIPEC stands for Hyperthermic Intraperitoneal Chemotherapy. Heating the chemotherapy (hyperthermia) helps increase the chemotherapy penetration into cancer cells as well as to enhance the effects of chemotherapy.
Typically, the surgical process starts with cytoreduction, where all visible cancer is completely removed – often an extensive surgical procedure in itself. Next the abdominal cavity is prepared to receive a pre-calculated dose of appropriate chemotherapy. The chemotherapy is delivered into the abdominal cavity by a special HIPEC machine which allows us to monitor the inflow and outflow temperatures of the chemotherapy infusion. The chemotherapy flows into and drains out of the abdomen via a system of tubes, at a set rate of flow with temperature transducers placed within the abdominal cavity that let us know if the temperature is exactly what is required (normally 41 to 43 degrees Celsius).
With increasing medical evidence of the efficacy of CRS and HIPEC for certain cancers, its usage is slowly increasing. Selection criteria are stringent – it does not benefit everyone, and many people are not medically fit enough to withstand it. Also, it is useful only when the cytoreductive part has been done completely or near completely. In addition, the toxicity (side effects) could be significant, with prolonged hospital stays and delayed recovery in some patients. Nnevertheless, it has been shown to significantly increase survival rates in many carefully selected patients.
For optimal outcomes, these procedures are best done in a high-volume center with close surgical teamwork. Teamwork also allows us to ensure each part of the surgery is done by the person most suited to that particular part. Consultants, registrars and surgical residents all play their own crucial role. Not to mention an experienced anesthesia team, and operating room technicians familiar with the HIPEC machine, and dedicated theatre nurses. The picture above shows the HIPEC machine in the background with our surgical resident and registrar carefully setting up the process to ensure it is done “just right”!
Gurunatha Rao says:
Dr. Sir,
It is this quality of continuous medical advancement technology absorption in your daily medical practise which impresses me most.
This article gives such a complicated research findings in understandable language to even a layman like me.
Am proud that I had the opportunity to have undergone chemotherapy treatment under your guidance and consequently living well after 15 years of colorectal surgery.
Million thanks Dr Sir.
Gurunath