Chemotherapy is one of the most aggressive and toxic treatments available for cancer patients, but the treatment can usually be avoided if the disease is detected at an early stage. A study published in the New England Journal of Medicine on August 25 revealed that some patients can safely avoid chemotherapy depending on their genetic composition.
The investigation called “Microarray in Node-Negative and 1 to 3 Positive Lymph Node Disease May Avoid Chemotherapy (MINDACT)” was executed in Portugal by Drs. Fatima Cardoso, Laura vant’Veer, Ph.D. Jan Bogaerts, M.D. Emiel Rutgers and Martine Piccart, along with an entire team of specialists in oncology and genetics.
The background
In early stage breast cancer, doctors perform surgery to extract the harmful nodes and sometimes this is enough to prevent the recurrence of the disease. However, physicians recommend patients to undergo chemotherapy due to high risks of relapse affecting patients.
The mystery has always been on the level of risk of each patient. In the past, most oncologists considered factors such as tumor size and patient age, but this information is not as accurate as expected to determine the risk of recurrence of cancer.
The study executed by the MINDACT Investigators aimed to evaluate the actual risk of each patient to discriminate more who should receive chemotherapy and who might skip such treatment.
The investigators considered the MammaPrint, or the 70-gene signature test, as one of the most accurate tests to predict the clinical outcome in breast cancer. They tried to demonstrate that implementing this test in breast cancer patients could help scientists achieve standard clinical criteria in selecting patients for chemotherapy.
Scientific methods behind the investigation
Around 6,600 women with early-stage breast cancer were involved in the study. The team used the MammaPrint to determine their genomic risk and their clinical risk. According to their combined results, the patients received or not chemotherapy. In about 1,500 cases, which represented 23 percent of the total subjects, the results were discordant, and patients were high-risk in their clinical profile and low-risk in their genomic profiles.
This group was the one considered critical for the investigation since the goal was to assess the survival rate among patients who did not receive chemotherapy with a high-risk clinical result but a low-risk genomic profile, to understand the role of the patient’s genomic features.
Study results and other theories
Half of women that fitted this profile received chemotherapy while the other half did not. Investigators checked their evolution for five years. The rate of survival in the group that did not receive chemotherapy was 94,7 percent.
The difference between patients who received chemo and those who did not was only 1,5 percent. Distant metastasis was also reported surprisingly low in those patients who skipped chemotherapy.
The major finding of this study goes to women who get high-risk results in clinical features but a low-risk profile in their genomic results in the MammaPrint test.
This discordant pattern is quite typical, almost 50 percent of women with breast cancer fit this description and are these women who may safely skip chemotherapy since their genes provide them a stronger capacity to avoid recurrence of cancer, not requiring the aggressive treatment.
However, to some doctors, the existing difference proves that chemotherapy is still getting better results that not being exposed to the treatment. Receiving chemotherapy or not is a decision that only the doctor and the patient can take.
The investigator’s goal is to provide more evidence and nourish the oncology field to provide doctors a better background and basis to make informed and accurate decisions.
The investigation process is not over yet
Most doctors recognize that other genomic tests may provide significant information to physicians, but research focused on discovering what kind of information can we extract from those tests is needed to allow doctors adapt and use them.
This study is the result of a high collaborative team of investigators from all over the world, conducting an investigation that aims to change oncology practices into a more advanced stage where doctors take better advantages of available technology. The American Association for Cancer Research shared the investigation, funded by the European Commission, in their annual conference.