As cancer rates among young people soar, experts around the world are launching major studies in an attempt to discover what’s behind the rise.
But there’s another question about cancer that’s just as confusing: Why do some types of cancer keep coming back?
If five years have passed and there is no sign of cancer, patients are usually considered cured, as few see their disease return.
But with some forms of breast cancer, as many as a quarter of women will be diagnosed with the disease again, sometimes decades in the future.
Now medical experts around the world are looking for the reasons why.
Dr. Francisco Contreras, director and president of Oasis of Hope Hospital in Mexico, told DailyMail.com: ‘The thorn in the side of oncology is the recurrence of cancer after successful treatment.
‘This problem varies widely depending on the type and stage of the cancer, how aggressive the malignancy is and the type of therapy given.’
On average, breast cancer returns between three and 25 percent of the time. Experts believe that young, obese women are at greatest risk, as are women with more aggressive types
US data shows that deaths from breast cancer, the most common form of the disease in women, have steadily declined over time thanks to a range of new treatments, such as hormone therapies and drugs that help the immune system kill cancer cells ..
However, the Breast Cancer Research Foundation estimates that diagnoses in women under 50 have increased by two percent per year over the past five years.
Although these advances have proven very effective in destroying the disease, they have not stopped the disease from returning many years later.
Dr. Contreras noted that he recently saw a patient whose breast cancer returned 25 years after being declared cancer-free.
One possible reason, he suggests, for a small number of women could be the recent move to minimally invasive techniques for treating the disease, such as surgically removing a lump rather than the entire breast.
Although this may improve quality of life, the disease may return in the remaining tissues.
Another reason could have to do with hormones, namely the female sex hormone estrogen. About 80 percent of breast cancers are ER-positive, meaning cancer cells have receptors that allow estrogen to grow.
It is estimated that in about a quarter of patients with this condition, the cancer cells persist and then wake up years, even decades later.
In addition, one in five cases of breast cancer are genetically programmed to produce higher levels of the protein HER2, which has been shown to help breast cancer cells grow faster. These breast cancers are known as HER2 positive.
In ER-positive breast cancer, estrogen stimulates cell division in the breast, increasing the risk of cancer mutations in the DNA of the tissue.
Although most patients with this type of disease take hormone-suppressing medications after cancer treatment to compensate for this risk, some patients stop taking them too quickly and they are not always effective.
Most patients with HER2-positive breast cancer do not experience recurrence; The HER2 gene is known to mutate and cause cancer to return and spread.
There are also other types of breast cancer that have long been known to be particularly aggressive forms.
For example, triple-negative breast cancer (TNBC) is known to be growing rapidly, with research showing that up to 50 percent of patients experience recurrence and 37 percent die within five years of surgery.
TNBC, which accounts for 10 to 15 percent of all breast cancers, also has no estrogen or progesterone receptors or higher levels of HER2, meaning there are fewer options for targeted treatment.
Inflammatory breast cancer is only responsible for one to five percent of breast cancer cases. Unlike most forms of the disease, it does not cause a lump and usually occurs in women under 40 years of age.
Shannen Doherty (left) was first diagnosed with breast cancer in 2015 and went into remission in 2017. However, her cancer returned in 2020 and she is now in stage four. Olivia Newton-John (right) was first diagnosed with breast cancer in 1992. Nearly thirty years later, in 2021, she died from the disease.
Dr. Anne Peled, a breast cancer surgeon and co-director of Sutter Health Pacific Medical Center in San Francisco, told DailyMail.com: ‘Certain breast cancer types such as HER2-positive and triple negative breast cancers are more likely and more likely to return. recur in the first few years after diagnosis.
‘Although this makes it much more stressful to get through the first few years after treatment for our patients with this type of breast cancer, we like to celebrate with them if they get through these years cancer-free, because there is a risk that they will develop cancer again at some point in the future. is very low.’
However, she noted that while ER-positive and HER2-negative breast cancer is generally less likely to occur, the disease is more likely to return decades later.
It is also thought that women diagnosed with breast cancer before the age of 35 are at increased risk of recurrence because they are more likely to develop aggressive forms of the disease and be diagnosed at a later stage.
Dr. Jennifer Son, a breast surgeon at MedStar Georgetown University Hospital in Washington, DC, told DailyMail.com, “The younger a patient is, the greater the risk of recurrence because they have many more years to live.”
She also noted that obese women are, on average, 18 percent more likely to have a recurrence of breast cancer. This is because fat cells produce estrogen, which helps the growth of HER2-positive tumors.
It is also thought that in some cases the treatment makes tumors so small that they cannot be picked up on follow-up scans, allowing them to grow again.
Breast cancer recurrence can bring unique challenges, experts also warn.
Dr. For example, Son noted that “if patients have a recurrence and have already had a lumpectomy and radiation, they usually cannot have radiation again in the same breast.”
And secondary tumors can come back more aggressively, Dr. Contreras said, because they can become resistant to previously used treatments such as chemotherapy and radiation.
Secondary tumors can also spread to other areas, such as the lymph nodes, requiring more aggressive protocols.
However, thanks to targeted therapies, many women live for years – and even decades – with late-stage breast cancer.
Recent data from the Fred Hutch Cancer Center shows that 17 percent of women with breast cancer that has spread to other organs have been living with the disease for more than a decade.