SINGAPORE - A targeted method of administering chemotherapy drugs to patients with colon, gastric and ovarian cancers could potentially bring hope to those who are in the late stages of their ailment.
The Pressurised Intraperitoneal Aerosol Chemotherapy (Pipac) method distributes drugs in aerosol form - through a device called a port - directly into the abdomen via a catheter.
The technique, which has fewer side effects compared with conventional chemotherapy, has been successfully introduced at the National University Hospital (NUH) and National University Cancer Institute, Singapore (NCIS).
Professor Jimmy So, head and senior consultant with NUH's division of general surgery (upper gastrointestinal surgery), has been using the method with Dr Yong Wei Peng since December 2016.
The latter is a senior consultant with the department of haematology-oncology at NCIS.
A total of 49 Pipac procedures have been administered to 31 patients so far, with the majority afflicted with gastric or colorectal cancer.
Around 60 per cent of patients saw their tumours shrink in size. But for many, the cancer had already spread to other organs, and they were unresponsive to the treatment, especially since they were in the late or final stages of the disease, noted Prof So.
There were two cases of mild pancreatitis among the patients but no deaths.
Prof So said at the advanced stage, the cancer often spreads to the peritoneal cavity, which is a space within the abdomen that contains organs such as the stomach and liver.
This tends to produce excess fluid in the abdomen, causing significant bloating and intestinal obstruction, which can be extremely uncomfortable for the patient.
The Pipac method sees the chemotherapy solution converted into fine aerosol droplets
before they are distributed more evenly in the peritoneum cavity and more deeply into the cancer cells.
"Smaller amounts of the chemotherapy drug can be administered since it directly targets the affected area, which means that very little of it will be absorbed into the bloodstream, thus reducing the side effects," said Prof So.
On average, around 3,000 new patients are diagnosed with the three cancers each year, with around 30 per cent showing spread to the peritoneal cavity.
The three cancers are among the leading causes of cancer-related deaths in Singapore.
The Pipac method is performed as a short and minimally invasive keyhole procedure.
The chemotherapy is administered as fine air droplets by a micro-pump into the peritoneal cavity under gentle pressure for around 30 minutes.
The procedure is done under general anaesthesia, with continuous real-time video monitoring within the abdomen.
Ideally, the patients should undergo at least three rounds of treatment to see effective results, said Dr Yong.
"Pipac is well-tolerated and tumour regression was observed in patients receiving at least two Pipac procedures.
"The encouraging result has led to the development of Pipac with immunotherapy in a new study," he added.
NUH is currently leading a new international clinical trial which combines the Pipac treatment with immunotherapy for stomach cancer patients who have had the ailment spread to their peritoneum.
Prof So hopes that the trial could soon be extended to patients who are at an earlier stage of cancer so that the treatment could be more effective for them.
He noted that some international trials - which involved patients with early stage cancers - had seen a clinical response rate of up to 80 or 90 per cent.
Currently, NUH is the main training centre for Pipac procedures in Asia, transferring the skills to more than 140 clinicians from 28 countries around the world.