BENGALURU: Peritoneal carcinomatosis (PC) is form of cancer affecting the peritoneum, a thin membrane surrounding our abdominal organs. In India , the most common cancers causing PC arise from ovary, colorectal, stomach and appendicular cancers. The prognosis of such patients is very poor. If untreated, they usually do not survive beyond six months. Traditionally, they were deemed incurable and were managed with palliative chemotheraphy and palliative surgery or symptomatic care.
With the better understanding of the disease (PC) and its pathology it is now understood that PC is a locoregional disease limited only to peritoneal cavity. This has led to the evolution of newer modes of delivering chemotheraphy within the peritoneal cavity combined with aggressive surgery. Intraperitoneal chemotheraphy is one such form of delivering chemotheraphy which has shown better survival and outcomes, specially in PC from ovarian and stomach cancer. Cytoreductive surgery (CRS) with HIPEC (Heated intraperitoneal chemotheraphy) has evolved as new ray of hope for patients diagnosed with PC.
It works on the principle that all the visible macroscopic cancerous deposits within the peritoneal cavity are removed with cytoreductive surgery, followed by heated intraperitoneal chemotheraphy. It has shown promising results and improved survival in patients with PC but the morbidity and mortality associated with the procedure has limited its adoption. Patients with PC who cannot be operated on are left with the option of going through cycles of chemotheraphy. To overcome these challenges a newer and novel method of delivering chemotheraphy was developed.
PIPAC (Pressurized intraperitoneal aerosol chemotheraphy) is a novel technique for delivering normothermic chemotheraphy into the abdominal cavity in the form of aerosol under pressure. Applying an aerosol in the peritonenal cavity allows a homogenous distribution of the chemotherapeutic agent within the abdomen. Furthermore , an artificial pressure gradient is generated that overcomes tumoral interstitial fluid presure, an obstacle in cancer theraphy.
This results in a higher local drug concentration compared to conventional chemotharaphy. At the same time the plasma concentration of the drug remains low so that side-effects and organ toxicity are minimal. Upon initial diagnosis of advanced cancer, virtually all patints want to continue to live and to live well. At this moment of despair, PIPAC comes in as a silver lining.
The technique has allowed us to get nearly 30% to 50 % better responses and disease control compared to conventional treatments. The very essence of medicine involves both curing and caring. With PIPAC physicians can offer patients the care and support they look for. However, it has to borne in mind that PIPAC is still being done in a clinical trial setup but is showing better outcomes.
There are innumerable studies going on all over the world to compare PIPAC with the existing standard of care which is palliative chemotherapy. As clinicians, our duty is to put this new body of knowledge into the right context and give the best of cure to our patients. (The author is Chairman and HOD Surgical Oncology - Manipal Comprehensive Cancer Center, Manipal Hospitals Bengaluru. With inputs from Dr Ashwin Rajagopal, Dr Rohit Kumar, Surgical Oncology, Manipal Hospitals)