A team of five city-based doctors and scientists have conceptualised a new staging system for cancer, based on the immune system, which they have named as the “iTNM system.”

Traditionally, doctors classify cancer stages based on the size of the tumour. But in an article published in Oral Oncology on August 4, 2019, the research team, led by Doctor Vishal Rao of the state’s anti-tobacco task force and head of oncology at HCG Hospitals, instead proposed using the immune system.

“The single greatest question that scientists have been grappling about cancer over the past few years is why the immune system does not react to cancer cells when it reacts violently to every other form of infection,” Dr Vishal said.

“The answer is that cancer cells are inherently a part of the body, but by using camouflage, move to mute the immune system quietly,” he added.

The authors of the study postulate that the existing method of looking at cancer stages by considering the size of the tumour is inherently flawed considering that some large, advanced-stage tumours can remain dormant for years while smaller-sized malignancies could progress rapidly and result in early deaths.

“Because a person’s cancer is currently being staged by the size of the tumour, you could, for example, when you classify a patient with stage 4 cancer, give that patient the impression that he or she may die soon. In reality, we often see stage 4 cancer patients living very long, but some early-stage cancer patients dying early due to the spreading,” Dr Vishal said.

He said the team was working with mathematicians and statisticians to develop a system of cancer stage measurement using the immune system.

“We have given ourselves a two-year deadline to develop this system,” he said.

The authors of the study added: “Several published studies have shown that the immune-classification has a prognostic value that may be superior to the existing TNM classification system.”

The Union for International Cancer Control’s existing TNM staging system, developed between 1942 and 1952, identifies stage solid tumours based on tumour (T), lymph node spread (N) and distant metastasis (M). The staging helps in planning treatment and assessing prognosis.