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- André Biernath – @andre_biernath
- BBC News Brazil
Each year, tens of thousands of physicians from around the world gather in Chicago, USA, to learn about the latest innovations in cancer diagnosis and treatment.
In 2022, the information presented at the meeting of the American Society of Clinical Oncology made doctors and patients feel particularly optimistic.
According to experts, the research published this year brings important advances that change the perspective of the fight against various types of tumors.
Here’s what major breakthroughs announced may mean for cancer treatment.
Breast cancer: the drug benefits many more patients
The drug trastuzumab has been used in the treatment of breast cancer for decades.
However, despite the good results, it always had a limit: it could only be prescribed to patients with tumors that highly expressed a gene called HER2, which is verified by a test.
But that has now changed: one of the big news from Congress was the results of the study on the drug trastuzumab deruxtecan.
“We are witnessing the arrival of a revolutionary drug,” says oncologist Romualdo Barroso, research coordinator at Hospital Sírio-Libanês in Brasilia.
“After many years of no major news, we have a new treatment option that increases survival (longer life) for patients.”
According to Barroso, the new remedy works like a Trojan horse (meaning it looks like one thing, but works like another).
Trastuzumab is a monoclonal antibody, a type of drug that can be used to both prevent and treat disease. In the case of breast cancer, it binds to receptors on the surface of cancer cells.
This has two main effects. The first is to “get the attention” of the immune system, which begins to see the cancer as a threat and initiates a series of actions to fight it.
The second is to allow deruxtecan (the second part of the drug) to “invade” diseased cells. It is a powerful chemotherapy drug that destroys the tumor from the inside.
But the novelty goes beyond how it works: the new drug works well even in patients with tumors that express less of the HER2 gene.
This means in practice that more people can benefit from this remedy. Almost seven out of ten patients, estimates Barroso.
The drug, which is given into a vein every 21 days, still awaits regulatory approval for use in hospitals.
Initially, it can be used as a second line of treatment, that is, when the first options have failed and the disease has spread to other parts of the body (a process called metastasis).
According to Barroso, it is likely that over time it will also become an option for early-stage tumors.
Rectal cancer: drug with surprising results (even for doctors)
Imagine a drug that manages to make a disease disappear in all the patients of the study carried out to analyze whether it works or not.
Naturally, such a positive result draws the attention of those who are not specialists in the field.
“But even for us doctors, it’s very surprising,” says oncologist Rachel Riechelmann, director of the department of clinical oncology at AC Camargo Cancer Center in São Paulo.
This is exactly what happened in a trial of dostarlimab to treat cancer of the rectum (the last part of the intestine). It is already used for other tumors, such as those that affect the endometrium (tissue that lines the uterus).
Dostarlimab belongs to the class of immunotherapies, which stimulate the immune system to attack the tumor.
The study involved 12 patients who were followed for six months. In the end, all of them no longer had any evidence of a tumor in their bodies.
This saved them from having to switch to more aggressive treatments, such as surgery, radiotherapy or chemotherapy.
Although the result is impressive, some considerations should be made.
The first has to do with time tracking. “The six months of evaluation is a short period. It is possible that the disease reappears a few years later”, analyzes Riechelmann.
Second, dostarlimab only works in a limited group of patients who have tumors with a feature described as “microsatellite instability.” It is estimated that about 1% of rectal cancer cases meet this criteria.
Although the drug is not approved for the new use, research is still ongoing to find out how long patients actually live without this tumor.
“But the first results were so good that it no longer makes sense to compare this immunotherapy with what was used before, such as chemotherapy and radiotherapy,” says Riechelmann.
“It is a treatment that has proven to be better and less toxic,” he concludes.
Colorectal Cancer: Screening Avoids Unnecessary Chemo
Generally, international oncology congresses bring advances related to new tools, diagnostic methods and, of course, drugs.
However, this year the work on colorectal cancer (which affects parts of the large intestine) was raised precisely because it had followed the opposite path: reducing the number of interventions that the patient must undergo.
A group of researchers from Australian institutions has evaluated a test that detects fragments of tumor DNA that appear in the bloodstream. The method is known as “liquid biopsy.”
But what does this have to do with colorectal cancer? Patients diagnosed with this disease usually undergo surgery to remove the affected part of the intestine.
However, after healing, the doctor always wonders if there is still a microscopic part of the tumor in the patient’s body. If it remains, the disease can grow back and even spread throughout the body.
Just in case, many people undergo chemotherapy after surgery to kill tumor cells that got in the way.
This reduces the risk of relapse, but subjects patients to intense therapy, which can have side effects.
This is where the new test comes in: by detecting the pieces of DNA from the tumor, it determines who really needs the second round of treatment.
“If the result of the liquid biopsy is positive, he goes to chemotherapy. If it’s negative, you don’t need it”, sums up oncologist Rodrigo Dienstmann, medical director of Precision Medicine Oncoclinics, in São Paulo.
In the study that validated the technique, 455 volunteers were divided into two groups. The first 302 had the liquid biopsy immediately after surgery. With the remaining 153, the doctor decided whether or not to go for chemotherapy.
“Among those who had a liquid biopsy, 15% went on to chemotherapy afterwards. Among the others, 28%”, reports Dienstmann.
“That is, it was possible to reduce the application of chemotherapy by half and obtain the same result in patient survival,” he compares.
“The liquid biopsy has a revolutionary potential”, analyzes the doctor.
Pancreatic cancer: hope for successful treatment
Pancreatic adenocarcinoma may top the list of tumors with the worst prognosis.
“This cancer has a very high mortality. Around 90% of patients do not survive five years, even when diagnosed early”, explains Dr. Paulo Hoff, president of Oncologia D’Or.
In the last ten years, the evolution of the treatment of this disease has been limited to the arrival of new chemotherapies; the progress linked to more modern and less aggressive drugs, such as immunotherapies and monoclonal antibodies, has not benefited in this case. this disease that affects the pancreas.
But a new possibility has been opened: at this year’s American Congress of Oncology, the first tests with a method called CAR-T cells against this type of cancer were presented.
The therapeutic resource, already approved against certain blood tumors (such as lymphomas, leukemias and multiple myeloma), consists of extracting the patient’s own immune cells, modifying them in the laboratory and reintroducing them into the body, so that it recognizes and attacks the tumour.
As presented at the conference, CAR-T cells were tested in a patient with pancreatic cancer in the United States. The first results were positive.
“Although the use of this therapy against pancreatic adenocarcinoma is extremely interesting, it is not something that will be available tomorrow in our clinics,” reflects Hoff, professor of clinical oncology at the University of São Paulo.
“There is still a long way to go, but at least now we have hope that we can be on the right track.”