Why does cancer come back stronger after chemo?
Cancer may sometimes come back after cancer drug treatment or radiotherapy. This can happen because the treatment didn't destroy all the cancer cells. Chemotherapy drugs kill cancer cells by attacking cells that are in the process of doubling to form 2 new cells.
Many of the commonly used cancer treatments, such as radiation or chemotherapy, kill tumor cells. But sometimes, after those cells have died and been cleared away, a tumor will respond by growing faster and more aggressively.
It can happen weeks, months, or even years after the original cancer was treated. It is not possible to know for sure if cancer will come back after your treatment ends. The chance of a cancer coming back depends on the type and stage of cancer you had.
No, it's not possible to guarantee that once you have completed cancer treatment the cancer will never come back.
Recurrent cancer may be more aggressive than the original cancer if it's already spread to other parts of the body, or if it's become resistant to chemotherapy. The sooner the cancer returns, the more serious it likely is.
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During the 3 decades, the proportion of survivors treated with chemotherapy alone increased from 18% in 1970-1979 to 54% in 1990-1999, and the life expectancy gap in this chemotherapy-alone group decreased from 11.0 years (95% UI, 9.0-13.1 years) to 6.0 years (95% UI, 4.5-7.6 years).
The cancers most often linked to chemo are myelodysplastic syndrome (MDS) and acute myelogenous leukemia (AML). Sometimes, MDS occurs first, then turns into AML. Acute lymphocytic leukemia (ALL) has also been linked to chemo. Chemo is known to be a greater risk factor than radiation therapy in causing leukemia.
A new study using mouse models adds to the evidence that chemotherapy can enhance cancer's spread beyond the primary tumor, showing how one chemo drug allows breast cancer cells to squeeze through and attach to blood vessel linings in the lungs.
Cancer survival rates by cancer type
The cancers with the lowest five-year survival estimates are mesothelioma (7.2%), pancreatic cancer (7.3%) and brain cancer (12.8%). The highest five-year survival estimates are seen in patients with testicular cancer (97%), melanoma of skin (92.3%) and prostate cancer (88%).
What percentage of cancer survivors get cancer again?
One to three percent of survivors develop a second cancer different from the originally treated cancer. The level of risk is small, and greater numbers of survivors are living longer due to improvements in treatment. However, even thinking about the possibility of having a second cancer can be stressful.
A return to normalcy is typical, but it takes a while – usually six months or so. “All who have done chemo do finally get back to normal,” Patricia said.

Second cancers are becoming more common since more people are living longer after their first cancer diagnosis than ever before. About 1 in every 6 people diagnosed with cancer has had a different type of cancer in the past.
If a cure is not possible, the goal of cancer treatment may be to control the disease. In these cases, chemo is used to shrink tumors and/or stop the cancer from growing and spreading. This can help the person with cancer feel better and live longer.
Remission can be partial or complete. In a complete remission, all signs and symptoms of cancer have disappeared. If you remain in complete remission for 5 years or more, some doctors may say that you are cured. Still, some cancer cells can remain in your body for many years after treatment.
- Worsening weakness and exhaustion.
- A need to sleep much of the time, often spending most of the day in bed or resting.
- Weight loss and muscle thinning or loss.
- Minimal or no appetite and difficulty eating or swallowing fluids.
- Decreased ability to talk and concentrate.
A cancer recurrence happens because, in spite of the best efforts to rid you of your cancer, some cells from your cancer remained. These cells can grow and may cause symptoms. These cells could be in the same place where your cancer first originated, or they could be in another part of your body.
Some cancers (whether common or rare) can also be aggressive, meaning they form, grow, or spread quickly. Despite the fact that there is no universally accepted definition of a rare cancer, a cancer is generally considered rare if: It starts in an unusual place in the body.
- acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML)
- certain breast cancers, such as inflammatory breast cancer (IBC) and triple-negative breast cancer (TNBC)
- large B-cell lymphoma.
- lung cancer.
- rare prostate cancers such as small-cell carcinomas or lymphomas.
It's not possible to predict how likely a cancer is to recur, but cancer is harder to treat and more likely to come back if it's: Fast growing. More advanced or widespread.
What cancer is common but often survivable?
Sr. No. (From most to least) | Type of cancer | Patients expected to survive five years after their diagnosis (percent) |
---|---|---|
1 | Prostate cancer | 99 |
2 | Thyroid cancer | 98 |
3 | Testicular cancer | 97 |
4 | Melanoma (Skin cancer) | 94 |
When treatment ends, you may expect life to return to the way it was before you were diagnosed with cancer. But it can take time to recover. You may have permanent scars on your body, or you may not be able to do some things you once did easily.
Therefore, chemotherapy alters the patient's perceptions of their HRQoL since there is a decrease in global health status/quality of life (QoL) and functional scales such as physical functioning, role functioning, emotional functioning, social functioning, body image, sexual function and sexual enjoyment.
During a course of treatment, you usually have around 4 to 8 cycles of treatment. A cycle is the time between one round of treatment until the start of the next. After each round of treatment you have a break, to allow your body to recover.
Many of the commonly used cancer treatments, such as radiation or chemotherapy, kill tumor cells. But sometimes, after those cells have died and been cleared away, a tumor will respond by growing faster and more aggressively. And scientists don't know why.
Stage 4 cancer is challenging to treat, but treatment options may help control the cancer and improve pain, other symptoms and quality of life. Systemic drug treatments, such as targeted therapy or chemotherapy, are common for stage 4 cancers.
Chemotherapy can cause fatigue, loss of appetite, nausea, bowel issues such as constipation or diarrhoea, hair loss, mouth sores, skin and nail problems. You may have trouble concentrating or remembering things. There can also be nerve and muscle effects and hearing changes. You will be at increased risk of infections.
A: Some people undergoing chemotherapy report that they feel more fatigue the further along they get in their regimen. Nerve damage can occur with chemotherapy, and this may get worse with each dose. Sometimes, treatment has to be stopped because of this.
Whether a person's cancer can be cured depends on the type and stage of the cancer, the type of treatment they can get, and other factors. Some cancers are more likely to be cured than others. But each cancer needs to be treated differently. There isn't one cure for cancer.
- Chronic lymphocytic leukaemia.
- Chronic myeloid leukaemia.
- Pleural mesothelioma.
- Secondary brain tumours.
- Secondary breast cancer.
- Secondary bone cancer.
- Secondary liver cancer.
- Secondary lung cancer.
Which type of cancer rarely spreads?
Basal cell carcinoma
These cancers usually develop on sun-exposed areas, especially the face, head, and neck. They tend to grow slowly. It's very rare for a basal cell cancer to spread to other parts of the body.
The number stages are: stage 0 – the cancer is where it started (in situ) and hasn't spread. stage 1 – the cancer is small and hasn't spread anywhere else. stage 2 – the cancer has grown, but hasn't spread.
One who remains alive and continues to function during and after overcoming a serious hardship or life-threatening disease. In cancer, a person is considered to be a survivor from the time of diagnosis until the end of life.
Beginning five years after diagnosis, those who had cancer in the 70s could expect to live 48.5 years, compared to 53.7 years among those diagnosed in the 80s and 57.1 years among people diagnosed in the 90s.
The cancers with the highest 5-year relative survival rates include melanoma, Hodgkin lymphoma, and breast, prostate, testicular, cervical, and thyroid cancer.
Cancer-related fatigue can last months or years after cancer diagnosis and treatment. People experiencing CRF describe it as feeling tired, weak, slow, and having no energy. With no means to relieve their symptoms, people with CRF report feeling depressed and helpless.
Cancer treatments, especially chemotherapy, can weaken your immune system. While chemotherapy doesn't permanently damage your immunity, it can take anywhere from weeks to months after cancer treatments are over for you to get a healthy immune response back.
After your last dose of chemotherapy, your white blood cell count will go down. It should start to go back to normal about a month after your last treatment. Your red blood cell count may also go down, but it should go back to normal around the same time.
A study from the American Cancer Society found that a year after being diagnosed, around 2/3 of people were concerned about their disease coming back. Some cancers come back only once, while others reappear two or three times. But some recurrent cancers might never go away or be cured.
- Unexplained weight loss.
- Fatigue.
- Fever.
- Pain.
- Skin changes.
- Change in bowl habits or bladder function.
- Sores that do not heal.
- Hoarseness or trouble swallowing.
What is the most common cause of death in cancer patients?
Widespread metastases are the primary cause of death from cancer.
Which cancer has the highest recurrence rate? Cancers with the highest recurrence rates include: Glioblastoma, the most common type of brain cancer, has a near 100 percent recurrence rate, according to a study published in the Journal of Neuro-Oncology.
Yet, oncologists do not routinely share prognoses. In a study of nearly 600 patients with advanced cancer, only 17.6% of the 71% who wanted to know their prognosis reported being told [2].
Other recent statistics on cancer survivorship : About 67% of cancer survivors have survived 5 or more years after diagnosis. About 18% of cancer survivors have survived 20 or more years after diagnosis. 64% of survivors are age 65 or older.
For many metastatic tumors, even if incurable, survival with chemotherapy and best treatment is now well over a year and frequently much more. Colorectal cancer survival often exceeds 24 months with 10% of patients surviving more than five years [10], [11].
Chemotherapy is the treatment of choice before most cancer surgeries, but new research shows that it could promote more aggressive tumors, The Telegraph reports.
Chemotherapy treatment will usually involve a number of chemotherapy doses (sometimes called cycles). The period of time beginning 7–12 days after you finish each chemotherapy dose—and possibly lasting up to one week—is when you have the fewest white blood cells in your body.
Weight changes, including unintended loss or gain. Skin changes, such as yellowing, darkening or redness of the skin, sores that won't heal, or changes to existing moles. Changes in bowel or bladder habits. Persistent cough or trouble breathing.
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