Cancer is a term that describes several malignant (dangerous, harmful) diseases that can affect just about every organ and system in the body. Malignant cells, or cancer cells, are abnormal cells that multiply uncontrollably. Unlike normal cells, which can stop multiplying and die off as they should,  cancer cells continue to multiply and can form tumors and growths. These can then invade adjacent tissues.

Cancerous cells can also break free from a tumor site and enter the bloodstream. Once they are in the bloodstream, the cells can travel to other parts of the body, spreading the disease to other organs. This process is metastasis.

Malignant diseases (cancers) are becoming increasingly survivable in the developing world. But they are still one of the leading causes of death in countries like the United States. The Centers for Disease Control and Prevention (CDC) reported 1,806,590 new cases of cancer reported in the U.S. in 2020 – the most recent year for which statistics are available.

Death can occur because of the actual tumors, such as when a tumor destroys the liver, or death can occur because of associated conditions, like sepsis. Having cancer and undergoing specific treatments, such as chemotherapy, can weaken the immune system, putting you at higher risk for developing an infection that could lead to sepsis.

Sepsis, which was often called blood poisoning, is the body’s life-threatening response to infection. Like strokes or heart attacks, sepsis is a medical emergency that requires rapid diagnosis and treatment.

Sepsis and septic shock can result from an infection anywhere in the body, such as pneumonia, influenza, or urinary tract infections. Worldwide, one-third of people who develop sepsis die. Many who survive are left with life-changing effects, such as post-traumatic stress disorder (PTSD), chronic pain and fatigue, organ dysfunction (organs don’t work properly), and/or amputations.

Sepsis risk with cancer

People with cancer are particularly susceptible to developing sepsis. Here are some statistics related to sepsis and cancer:


cancer patient

Why are people with malignancies at high risk?

There are several reasons why people with malignancies may be at higher risk of developing sepsis. These include:

  • Frequent hospital stays, which increases the risk of contracting a hospital-acquired infection
  • Surgeries, procedures that puncture the skin, insertion of urinary catheters, etc. Each time something is introduced into the body, the risk of infection goes up.
  • Depressed immune system because of treatment
  • Weakness due to malnutrition, illness, or frailty from age can increase the risk of developing an infection

What is cancer?

As described above, cancer is a disease that occurs when abnormal cells divide and invade body tissues. Oncologists determine the cancer diagnosis by where it starts. It is called by the primary site even if the cancer has spread.

Cancer can be solid, usually called tumors, but all tumors are not necessarily cancer. Benign tumors are masses that are not cancerous (remember: “B” for better). If it is cancerous, it is malignant.

Cancers of the blood or the lymph system are not solid cancers, so there are no tumors. Instead, the cancer cells circulate through the body through the blood and lymph fluid.

How do you get it?

Researchers don’t yet know precisely how or why malignancies start, but they know that certain events can trigger them or increase the likelihood of development. Many of these triggers can be related to some lifestyle factors, such as smoking (lung, mouth, and throat cancers) or getting too much sun exposure without skin protection (skin cancer). Others may be inadvertent, such as exposure to carcinogenic (cancer-causing) chemicals.

What are the symptoms?

Signs and symptoms of cancer depend on where the malignancy is. The signs may start as the malignant cells invade the organ or the disease spreads. For example, you may not notice possible signs of colon or bowel cancer until you:

  • Start losing weight
  • Experience either diarrhea or constipation more than usual for you
  • Become very fatigued
  • Experience nausea and vomiting
  • Stop eating because of lack of appetite

As you can see, the symptoms are similar to what could be for many other illnesses, so doctors may not automatically suspect a malignancy.

How do we treat cancer?

Each malignancy is different, and there are many differences among each type of cancer, as well.

The decision of how to treat each particular case rests on the doctor, your test results, and your overall state of health. Some tumors respond better to chemotherapy than radiotherapy; others are the other way around. Some tumors need radiotherapy to shrink them before chemotherapy or before surgery. In yet other cases, surgery is first, followed by treatment.

Several types of cancer, such as colon cancer and skin cancer, have a very high cure rate if detected early. The key is, though, early detection.

Can we prevent cancer?

You can lower the risk of some types of cancer by making some lifestyle changes. Of course, this is no guarantee that you will never get cancer. But a lower risk is better than a higher one.

Eating healthy foods, exercising, and minimizing stress in your life seem to be the key factors in trying to reduce your risks, as well screening regularly for common cancers. Screening is also essential if you have a family history or previous cancer.

Ask your doctor or healthcare provider what types of screening tests you should have and at what ages.

If you suspect sepsis, call 9-1-1 or go to a hospital and tell your medical professional, “I AM CONCERNED ABOUT SEPSIS.” 


You can learn more about infection prevention among people who are immunocompromised by clicking here.

Would you like to share your story about sepsis or read about others who have had sepsis? Please visit Faces of Sepsis, where you will find hundreds of stories from survivors and tributes to those who died from sepsis.

Suggested Citation: Sepsis Alliance. Sepsis and Cancer. 2023.

Updated January 3, 2023.

Read Personal Stories of Sepsis and Cancer

Natalie Zeleznikar


I was diagnosed with stage 1 breast cancer on my left side in 2015. (Sepsis and Cancer) I elected to have a double mastectomy as a friend had the same kind of cancer and chose a lumpectomy and three months later it went to other breast and she ended up with double mastectomy. I thought I was lucky to be stage 1, and really expected a six week recovery and didn’t worry. I was running an assisted living business as CEO and a few days before my scheduled return, friends came to see me. We had a glass of wine ... Read Full Story

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Patrick Dunne

Survivor, Tribute

Sepsis killed my lovely dad on March 3rd 2022. My heart is broken as this could have been avoided if only the doctor at the urgent care centre where we live had helped him more that day. My dad had prostate cancer but the cancer was very much at bay and his psaPSA levels were great, his oncologist was extremely happy with his cancer. (Sepsis and Cancer) But unfortunately at the start of the first lockdown my dad was catheterised due to not being able to pee properly. He was told he would need his prostate shaved to be able ... Read Full Story

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Pat Termini

Survivor, Tribute, Tribute

A couple of hours before my wife Pat passed away in the ICU at her hospital, I said to her “Honey, if you have to go, I will respect your wishes, I want you to do what is best for you.” 2 hours later she passed away peacefully. I do know that she is in a much better place now, free of pain. Pat was allergic to opioid medications, which includes most everything except Tylenol. The pain from sepsis she endured those last 2 weeks must have been excruciating. Pat was a fighter. She fought squamous cell cancer for 11+ ... Read Full Story

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Debra K.

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Hi, I’m Deb. Had a diagnosis of aggressive breast cancer, for the second time. After the surgery I was fine for two months. Then one morning I woke up with my right arm being sore. My elbow hurt and my wrist, and shoulder. I thought what was this? Haven’t I been through enough? My arm was dark pink, almost red. It was very warm to touch. I knew this was not good. (Sepsis and Cancer) Went to the ER. To my surprise they admitted me. After the blood tests I learned it was sepsis. How did I get myself involved ... Read Full Story

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Estelle Botha

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Our beautiful, talented 15-year-old ballerina girl passed away from sepsis while she was under chemotherapy treatment for Hodgkin’s lymphoma. (Sepsis and Cancer) At the time of her passing, we did not know the cause, and no-one used the word « sepsis » to help us make sense of the tragedy. Estelle had been telling her doctor that she was not feeling well and asking for a longer respite from chemotherapy sessions, but the doctor merely stated that chemo makes one feel unwell and that she must not skip chemo sessions. Four months into the treatment, Estelle was having a particularly difficult week, ... Read Full Story

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Cancer is a term that describes several malignant (dangerous, harmful) diseases that can affect just about every organ and system in the body. Malignant cells, or cancer cells, are abnormal cells that multiply in an uncontrolled fashion. Unlike normal cells, which can stop multiplying and die off as they should,  cancer cells continue to multiply and can form tumors and growths. These can then invade adjacent tissues.