The digestive system is made up of a series of organs (oesophagus, stomach, liver, pancreas, colon-rectum, anus) that are part of or closely related to the alimentary canal. Its proper function is fundamentally important for the entire body.                         

Tumours of the gastrointestinal tract are common oncological illnesses, with a high incidence. In 2008, the number of new cases, on a global level, was estimated at being greater than 3,700,000, with an expected death rate of greater than 2,700,000.

Treatment of these tumours is complex and varies according to the site of emergence. A multidisciplinary team made up of an oncologist, surgeon, and radiation therapist chooses the best therapeutic path.

In gastrointestinal tumours, traditional radiation therapy with photons, with or without chemotherapy, can be used as neoadjuvant (before surgery), adjuvant (after surgery), or exclusive. 

In gastrointestinal illnesses, the ultimate goal of radiation therapy, i.e., irradiation at curative doses of the tumour tissue while saving the healthy surrounding tissue, is difficult to implement due to:

• the usually large treatment volumes which are required to cover regions at risk for tumour spread
• the presence of numerous healthy organs and tissues inside and near the target volume, which have a treatment tolerance threshold and may be affected by an excessive dose of radiation, manifesting toxic effects of various intensity (even fatal) in the short term (within six months of treatment) and long term (years after treatment).

Proton therapy may be indicated in this context as it allows the deposit of the necessary dose of radiation at the end of the proton beam path into the tissue, completely saving organs not in its path and with a lower release of the dose upon entry,  compared to traditional radiation therapy with photons.

The precision with which the dose of protons is deposited in the tissues is more conspicuous than photons of the density variations of the tissue that the proton beam crosses. The daily density variations (linked to the presence of gas and organ movement) that can be encountered in the irradiation of these tumours certainly make treatment with proton therapy complex.

The Trento Proton Therapy Centre currently treats liver and rectum and anus cancer.