Experts realized that cancers, even with different names, don’t have the same effect in every patient. Treatments, therefore, shouldn’t be the same
A cancer has a name, but also has a last name, a social security number, an address, a voter’s ID number, and even a military registration number. It may sound like a joke, but oncologists and pathologists have been discovering more and more that that’s no joke.
A lung cancer, for instance, does not affect the two people diagnosed with it in the same way – and that is why a specific treatment may work for one of them, and not the other.
Since 2018, after cancer genome study results were published (in which 35 thousand tumors were sequenced), specialists found out 3 million mutations which could happen with the disease).
One of them happens involving the fusion with NTRK genes, and predisposes some organisms to proliferate more quickly tumor cells.
“When that fusion happens, the activity for which that gene is responsible [in this case, cell division] is turned on the whole time. It is as if someone rang the doorbell and the button never stopped ringing. The fusion in the NTRK genes send a message to the tumor cell: you have to multiply yourself, and that happens in a disorderly fashion,” explains Isabela Werneck da Cunha, a pathologist at the D’Or chain in São Paulo and a lecturer at the Latin American Seminar for Journalists promoted by pharmaceutical company Bayer in Miami, Florida.
It just so happens that this fusion may indeed happen to some patients who have been diagnosed with cancer, as well as some who haven’t – even though it is the “same” cancer. Or even patients with different kinds of cancer (such as lung cancer and sarcoma) may present the same gene alteration and, therefore, benefit from the same treatment.
“Other tumors use other resources. The tumor cell is extremely smart. It seeks to find out how it can proliferate more quickly, and each tumor has its own mechanism,” completes the specialist.
So far, this alteration in the NTRK gene is known to happen more frequently in rare cancers, such as tumors in the salivary glands, and less frequently in more common types of cancer, such as those in the lungs, thyroid, and colon. On the whole, there are 17 types of cancer which can display this mutation, but the number may increase as genic studies advance.
Considering these different mechanisms adopted by cancers, new treatments tend to appear. This reinforces the idea that, in the future, the more personalized, unique, and specific the approach towards the disease, the better results may be obtained.
“It is clear that today, in 2019, there is no more room for a single treatment when we discuss medicine in general. In oncology, this is a paradigm. We are all different. We have to become aware that cancer can appear in each one of us, in our patients, in each organ, as a different tumor,” explains Gilberto Castro Junior, a clinical oncologist at the University of São Paulo’s Medical School (FMUSP) and at Sírio Libanês Hospital, who also attended the event.
Approved by the US regulating agency and their European equivalent, a new medication which proposes this personalized treatment is currently being analyzed by Brazil’s National Health Vigilance Agency (ANVISA).
Larotrectinib, whose commercial name is Vitrakvi, by Bayer, and Loxo Oncology, is a Tropomyosin-Receptor-Kinase A, B, and C, preventing the fusion of NTRK genes, therefore blocking the spread of cancer cells.
Still, with no date to begin to be commercialized in the country, the medication has shown good results in its clinical studies, according to Luz Cubillos Garzón, vice-president of Medical Affairs at the pharmaceutical division of Bayer laboratories for Latin America.
“75 percent of those who received the larotrectinib medication had good answers to the treatment, and in 22 percent of them there was a definite control on the disease. The medication can be ingested orally by patients, regardless of age and cancer type, and is indicated to adults and children,” explains the specialist.
Although it is estimated that the NTRK gene fusion happens between 0.5 and 1 percent of patients diagnosed with cancer, the medication is destined to people in which the disease is undergoing metastasis, and shouldn’t be used as a first approach in the treatment process. Before its recommendation, it is also necessary to confirm if the patient has the gene fusion through a DNA sequencing.
“This was one of the first drugs to be approved for a treatment which does not depend on the tumor type. The other one was entrectinib [by Roche pharmaceutical], which also acts on NTRK fusion,” points out pathologist Isabela Werneck.
*The reporter traveled to Miami (US) by invitation of Bayer pharmaceutical laboratories.