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Madrid, 13 November 2019. Immunotherapy is already a treatment alternative for many kinds of cancer and has achieved major improvements in survival rates. And now it’s the turn of gastrointestinal cancer, which is also a candidate for this new therapy option, at least for some subtypes of gastrointestinal tumours. The news was confirmed by over a hundred health professionals who gathered recently in the auditorium of the MD Anderson España Foundation to hold the second International MD Anderson Cancer Center Conference on Gastrointestinal Oncology.

Doctor José María Viéitez, head of the Digestive Tumour Section of the MD Anderson Cancer Center Madrid’s Medical Oncology Department and one of the event’s coordinators, explains, “Five percent of patients with microsatellite instability could benefit from conventional immunotherapy, by which I mean PD-1 inhibitors or PD-L1 inhibitors”. For this subgroup, which includes tumours of the stomach, pancreas, small intestine and colon, it’s a very interesting new line of treatment, because timely detection of such tumours is crucial.

The problem is that there is a high percentage of patients for whom these immunotherapy treatments just don’t work. “PD-1 inhibitors and PD-L1 inhibitors act by stimulating the lymphocytes, so the tumour they’re trying to get to has to be infiltrated by lymphocytes in order for them to be effective”, says Doctor Viéitez. But neither the pancreas nor the colon have lymphocytic infiltration, and that complicates lymphocyte efficacy.

“In the case of the colon, the lymphocytes surround the tumour without infiltrating it. The pancreas, though, is what we call an immunological desert, because lymphocytes don’t even surround it”, Doctor Viéitez explains. He then goes on to say that studies are already under way whose initial results suggest that different immunotherapy strategies might be effective in this kind of tumour. These preliminary data will be discussed in the first session of the conference, which will be held this Wednesday afternoon.

Molecular biology, a growing voice in decision making

The importance of molecular biology occupies a great deal of the event’s agenda. There are discussion panels on how the treatment decision might be influenced by whether a patient has a native KRAS, for example. “Patients with metastatic colorectal cancer who have BRAF and RAS mutations have a poorer evolution and are more likely to have occult extrahepatic metastasis, so they don’t benefit as much from liver surgery”, says Doctor Viéitez.

However, in cases of metastatic colorectal cancer where only the liver is involved, local treatments with radiation therapy (radioembolization) and even a liver transplant might be options in addition to surgery. The conference will discuss this possibility. “This is a very controversial topic just now. A while back nobody even considered it, and now it’s being investigated in clinical trials, because it seems it may play a role in certain very specific cases”, noted Doctor Santiago González, head of the Surgical Oncology Department, medical director of MD Anderson Madrid and another of the conference organisers.

Participants will also discuss whether there are sufficient data to indicate that colon tumours on the right side, which usually have a worse prognosis than tumours on the left side, should be classified and treated differently. “Very probably they’re different kinds of tumours, and we must learn to tell them apart, just as we do now with the different subtypes of breast cancer”, asserts Doctor Viéitez.

A multidisciplinary focus that brings together two ways of seeing medicine

All these topics will be discussed by multidisciplinary panels made up of specialists in pathological anatomy, medical oncology, surgical oncology, radiation therapy oncology and radiology from MD Anderson Madrid, Houston, and other European centres. “Nowadays it’s impossible to even think of tackling cancer without a multidisciplinary approach, and that’s why we’ve tried not only to include speakers who are experts in different specialities, but also to organise case discussion sessions where we’ve invited a multidisciplinary panel of experts”, says Doctor González.

In addition, Doctor Miguel A. Rodríguez-Bigas, of the Surgical Oncology Department of MD Anderson Houston and another of the coordinators of this international gathering, has spoken of the presence of experts from both centres as a possible source of two-way benefits, and he has stressed the importance of the fact that the conference aims not only to educate, but also to foster relations between specialists in Madrid and Houston.

In Doctor Rodríguez-Bigas’ opinion, setting aside the time and the space to exchange ideas and experiences helps spark “possible future collaboration in more-basic research studies or in clinical trials that are already at more-advanced stages”, he says.