The largest oncology congress in the world brought important advances that, in the opinion of doctors, will change the way in which some types of tumors are dealt with.
Every year, tens of thousands of doctors from around the world gather in Chicago, United States, to learn about the latest innovations in cancer diagnosis and treatment.
In 2022, the news presented at the Meeting of the American Society of Clinical Oncology made doctors and patients especially hopeful.
In the opinion of experts, the research published in this issue brings important advances that change the perspective of combating various types of tumors.
Understand below what the main advances announced now can mean for cancer treatment.
Breast cancer: drug benefits a much larger number of patients
The drug trastuzumab has been used in the treatment of breast cancer for decades.
However, despite the good results, it always had a limitation: it could only be prescribed to patients with tumors that express a gene called HER2 a lot, something checked by means of an exam.
But that has now changed: one of the great news of the 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 Brasília.
“After many years without great news, we have a new therapeutic option that increases the survival (longer life) of patients.”
According to Barroso, the new remedy works like a Trojan horse (that is, it appears to be 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 that are on the surface of cancer cells.
This has two main effects. The first one is to “call the attention” of the immune system, which starts to see cancer as a threat and triggers a series of actions to fight it.
The second is to allow deruxtecan (the second part of the drug) to “invade” the diseased cells. It is a potent chemotherapy drug that destroys the tumor from the inside out.
But the novelty goes beyond how it works: the new drug works well even in patients with tumors that express the HER2 gene less.
This means in practice that more people who can benefit from this remedy. Almost seven out of ten patients, estimates Barroso.
The drug, which is given into a vein every 21 days, is still pending approval from regulatory agencies for use in hospitals.
At first, 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 known as metastasis).
According to Barroso, it is likely that, over time, it will also become an option for tumors in early stages.
But Barroso regrets that the most modern treatments against cancer do not reach the public health network (SUS) in Brazil.
“Those who have a health insurance can even get the intravenous medications [aplicadas na veia]but the 80% of patients who depend on SUS do not have access”, he points out.
“There is a chasm between what is offered on public and private networks.”
Rectal cancer: drug with surprising results (even for doctors)
Imagine a drug that manages to make a disease disappear in all the patients in 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 area.
“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.
That’s exactly what happened in a trial of dostarlimab to treat cancer of the rectum (the final stretch of intestine). It is already used for other tumors, such as those affecting the endometrium (tissue that covers the uterus).
Dostarlimab belongs to the class of immunotherapies, which stimulate the immune system to attack the tumor.
The research involved 12 patients who were followed for six months. In the end, all of them no longer had any evidence of a tumor in the body.
This prevented them from having to go on to more aggressive treatments, such as surgery, radiotherapy or chemotherapy.
Although the result is impressive, some considerations need to be made.
The first has to do with follow-up time. “The six months of evaluation are a short period. It may be that the disease reappears a few years later”, analyzes Riechelmann.
Second, dostarlimab only works in a restricted group of patients who have tumors that have a feature described as “microsatellite instability.” It is estimated that about 1% of rectal cancer cases meet this criterion.
While the drug is not approved for the new use, research continues, even to find out how long patients actually live without this tumor.
“But the initial results were so good that it no longer makes sense to compare this immunotherapy with what was used before, such as chemo and radiotherapy,” says Riechelmann.
“It is a treatment that proved to be better and less toxic”, he concludes.
Colorectal cancer: exam avoids unnecessary chemotherapy
Generally, international oncology congresses bring advances related to new tools, diagnostic methods and, of course, medicines.
However, this year, a work on colorectal cancer (which affects parts of the large intestine) was highlighted precisely for following the opposite path: reducing the number of interventions to which the patient needs to undergo.
A group of researchers from Australian institutions evaluated a test that detects bits 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.
After recovery, however, the doctor is always in doubt whether any part of the tumor, even if microscopic, remains in the patient’s body. If there are leftovers, the disease can grow back and even spread throughout the body.
Just in case, many people undergo chemotherapy after surgery to eliminate any tumor cells that have gotten in the way.
This lowers the risk of relapses, but subjects patients to heavy therapy, which can have side effects.
That’s where the new test comes in: by detecting the bits of tumor DNA, it determines who really needs the second round of treatment.
“If the result of the liquid biopsy is positive, he goes to chemo. If it’s negative, he doesn’t need to”, summarizes oncologist Rodrigo Dienstmann, medical director of Oncoclínicas Precision Medicine, in São Paulo.
In the study that validated the technique, 455 volunteers were divided into two groups. The first 302 had the liquid biopsy right after the surgery. With the remaining 153, the doctor decided whether or not to go for chemo.
“In those who underwent liquid biopsy, 15% went to chemo afterwards. In the others, 28%”, informs Dienstmann.
“That is, it was possible to reduce the application of chemotherapy by half and obtain the same result of patient survival”, he compares.
“Liquid biopsy has revolutionary potential”, analyzes the doctor.
Pancreatic cancer: hope for successful treatment
Pancreatic adenocarcinoma is perhaps at the top of the list of tumors with the worst prognosis.
“This cancer has a very high mortality. About 90% of patients do not survive for five years, even when the diagnosis is early”, says doctor Paulo Hoff, president of Oncologia D’Or.
In the last ten years, changes in the treatment of this disease have been limited to the arrival of new chemotherapeutics ? advances related to more modern and less aggressive drugs, such as immunotherapics and monoclonal antibodies, did not benefit in the case of this disease that affects the pancreas.
But a new possibility has opened up: during this year’s American congress on oncology, the first tests were presented that use a method called CAR-T Cells against this type of cancer.
The therapeutic resource, already approved against some 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 they recognize and attack the tumor.
According to what was presented at the congress, CAR-T Cells were tested in a patient with pancreatic cancer in the United States. Initial results were positive.
“Although the use of this therapy against pancreatic adenocarcinoma is extremely interesting, it is not something that will be available in our clinics tomorrow”, ponders Hoff, who is a professor of Clinical Oncology at the University of São Paulo.
“There is a long way to go, but at least now we have hope that we can be on the right track.”
– Text originally published at https://www.bbc.com/portuguese/geral-61839292