Cancer is one of the great challenges of contemporary medicine. In the United States, lifetime risk statistics from the American Cancer Society indicate that one in three women and one in two men will be diagnosed with some type of cancer. Faced with this panorama, scientific research has managed to develop treatments that are changing the survival chances of some patients, even when they face tumors in advanced stages.
One of these advances is immunotherapy, a strategy that, instead of directly attacking cancer cells, seeks to enable the body’s own immune system to recognize and combat them.
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This was explained by Stephen Liu, director of the Department of Oncology and Hematology at MedStar Georgetown University Hospital, classified by the publication US News & World Report as the Washington DC metropolitan area’s number one medical center for cancer treatment.
Oncologist Stephen Liu. Photo:MedStar Georgetown
During a presentation held this Tuesday, the specialist explained that the immune system has mechanisms to regulate its activity. When an infection is under control, the body activates signals that function as switches to prevent the defenses from continuing to attack the body disproportionately.
The problem appears when cancer cells learn to use those same mechanisms to protect themselves.
Liu explained that some tumors can express proteins like PD-1 and take advantage of these regulatory mechanisms to prevent the immune system from identifying them as a threat. In other words, cancer manages to send a signal that tells the body’s defenses that they should not attack it.
Immunotherapy seeks to interrupt that process. Through medications that bind to certain proteins and prevent them from fulfilling their function, the tumor is prevented from blocking the immune response. In this way, the defense system can recognize cancer cells and fight them.
The specialist clarified that these medications do not directly destroy cancer. Its function is to remove from the tumor the mechanisms it uses to protect itself and allow the body to do the work of fighting it.
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A patient with lung cancer who has been alive for 13 years
To illustrate the impact of these advances, Liu presented the case of one of his patients, a 66-year-old man diagnosed with stage 4 lung cancer, who had developed metastases to the liver.
In the images shown during the presentation, a large mass was initially observed in the right lung. The patient had come to the clinic with significant weight loss and pain. After receiving the treatment, the images showed how the tumor began to shrink until it practically disappeared.
Immunotherapy today is used against about 20 types of cancer. Photo:iStock
The patient received one of these drugs as part of a clinical trial that began in September 2013, precisely Liu’s first month working at Georgetown.
Thirteen years later, the man is still alive and has not needed cancer treatment for approximately a decade.
The case is especially significant considering that, when diagnosed, the survival of patients with stage 4 lung cancer was approximately 11 months.
For the specialist, this story represents the potential of a therapeutic strategy that has changed the treatment possibilities for patients with advanced diseases.
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A therapy that is already used against 20 types of cancer
Liu noted that there are currently 11 immunotherapy drugs approved by the United States Food and Drug Administration (FDA), initially developed to treat melanoma, but whose use has expanded to about 20 types of cancer.
Among them he mentioned lung, colon and breast cancer, as well as other tumors. These therapies are used in both early and advanced stages of the disease.
The oncologist highlighted that the medications currently available represent just the beginning of a new generation of treatments. Researchers are working on the development of new molecules and antibodies designed from scratch in laboratories, with the hope of achieving more effective therapies.
One in three Americans will develop some type of cancer. Photo:iStock
However, he warned that progress in the fight against cancer does not depend exclusively on developing better drugs.
Local treatments, such as surgeries and radiotherapy, also need to be improved. In this last field, he explained, more precise techniques are being developed that allow radiation to be concentrated in the areas that need treatment and reduce the effects on other tissues.
In addition, he pointed out that in certain cases immunotherapy can begin before surgery, because this strategy can increase the chances of response to treatment.
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Prevention, another front in the fight against cancer
The specialist insisted that one of the objectives of oncological research should be to ensure that more people can be cured, but also to prevent them from developing the disease.
To do this, he considered it essential to better understand the causes of different types of cancer. In the case of lung cancer, he indicated that more research is still needed and regretted that the resources allocated to studying its prevention are limited.
As an example of the advances that preventive research can achieve, he mentioned the vaccine against the human papillomavirus (HPV), related to the prevention of cervical cancer.
Liu highlighted that this vaccine was developed at Georgetown by researchers from the institution and that it has currently contributed to cervical cancer being close to disappearing in some countries.
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Immunotherapy is changing the fight against tumors. Photo:iStock
Their hope is that similar advances can be made for other tumors, including lung cancer. In fact, he mentioned that there is research underway to develop vaccines against this disease, although he acknowledged that there is still a lot of work to do to understand its causes and mechanisms.
The specialist’s central message is that cancer, although it continues to be a common and complex disease, no longer faces the same therapeutic possibilities as a decade ago.
EDWIN CAICEDO
Environment and Health Journalist
@CaicedoUcros
