As with many types of cancer, acute lymphoblastic leukemia (ALL), also known as acute lymphocytic leukemia, can come back after successful treatment. This is known as a relapse.

Relapses can cause you to feel many of the symptoms you felt before you were first diagnosed. You might experience chills, easy bleeding, unexplained weight loss, and fatigue. This happens because the cancer cells have started multiplying in your bone marrow again.

If your ALL has relapsed, you’ll usually need more chemotherapy and possibly additional treatments as well.

The goal of ALL treatment is to eliminate cancer cells and lead to remission. About 92 percent of children under age 15 and 90 percent of adults with ALL will reach remission after treatment. However, cancer cells sometimes come back after remission. This is called a relapse.

The exact reasons for an ALL relapse are not always fully understood. A relapse might happen if the initial treatment did not remove all the cancer cells or if the cancer cells developed a resistance to the treatment. It might also occur if cancer cells spread undetected to a new area of the body.

Relapses are more likely in adults with ALL than children.

Any return of the ALL symptoms you had before remission could be a sign of a relapse. Symptoms to be aware of include:

Keep in mind that these symptoms are not always a sure sign that your ALL has relapsed. They might be caused by a standard virus or bacterial infection and not cancer.

However, it’s a good idea to let your primary care physician or cancer treatment team know if you have symptoms that are concerning to you.

To prepare for your visit, make a list detailing your symptoms. You can include information about:

  • when the symptoms first appeared
  • how severe your symptoms are
  • if your current symptoms are similar to the symptoms you had before your initial diagnosis

It can also help to include details about your previous treatments if you’re talking with a doctor who was not part of your initial cancer treatment.

The doctor will refer you for testing if they think it’s likely your symptoms are being caused by a relapse.

Although ALL itself is more common in children than in adults, ALL relapses are more common in adults than in children. In adults, the overall relapse rate is about 50 percent, while the relapse rate in children is about 10 percent. However, these rates are affected by multiple factors.

Relapse rates are higher in children who:

  • are younger than age 1
  • are older than age 9
  • had a high number of cancer cells in their bone marrow when they were first diagnosed
  • have certain genetic changes

Relapse rates are higher in adults who:

  • are older than age 50
  • had a high number of cancer cells in the bone marrow when they were first diagnosed
  • have certain genetic changes

The primary treatment for an ALL relapse is chemotherapy. This is called “reinduction chemotherapy” and is often more intensive than first-round chemotherapy.

Other treatments will depend on your:

  • age
  • overall health
  • prognosis, or outlook
  • how well you’re responding to the chemotherapy

Other treatment options might include:

  • Stem cell transplants. Stem cell transplants use stem cells to restore and replace bone marrow that was treated with chemotherapy and radiation. This option is generally offered to younger patients in overall good health.
  • Immunotherapy. Immunotherapy can help your immune system recognize and fight cancer cells. This includes newer immunotherapies such as CAR T-cell therapy, as well as more standard therapies such as blinatumomab or imatinib.
  • Supportive treatments. Treatments such as antibiotics, blood transfusions, and pain-relieving medications can help manage the symptoms of an ALL relapse.
  • Radiation therapy. Radiation therapy may help if you’re having symptoms caused by ALL that has spread to your brain or spinal cord.

There are multiple factors that affect your outlook with a relapse of ALL. Things that positively impact your outlook include:

  • being younger than age 20
  • having B-cell ALL
  • having been in remission for a longer period of time
  • having reached initial remission within 4 weeks

Things that can negatively impact your outlook include:

  • being older than age 50
  • having T-cell ALL
  • relapsing very soon after entering remission
  • taking longer than 4 weeks to reach an initial remission

Overall, children have a 5-year survival rate of 50 percent following a first relapse. Adults have a lower 5-year survival rate of 10 percent after relapse. However, new cancer treatments and therapies are continuously being researched and developed. The outlook for many cancers, even after a relapse, is likely to continue to improve over the next several years.

ALL is rare in adults, but it’s the most common type of leukemia diagnosed in children. It is considered to have relapsed when cancer cells are found in bone marrow after remission.

A relapse can cause symptoms that are very similar to those you had before you were first diagnosed. It’s a good idea to see a doctor if you think your ALL has relapsed.

A relapse is usually treated with chemotherapy. You might also receive a stem cell transplant or immunotherapy. Your outlook will depend on factors such as the type of ALL you have, your age, how long you were in remission, and how well you responded to initial treatment.