Obesity is now recognized as one of the leading preventable risk factors for cancer, contributing to the development of at least 13 cancer types. As obesity rates continue to rise worldwide, researchers are uncovering new ways excess body fat may influence cancer development.  Several factors can influence the risk, including the cancer type, sex, and fat distribution. 

In this article, we will discuss the potential mechanisms by which excess body weight may make you more likely to get cancer. We will also answer the most frequently asked questions. 

Obesity and Cancer Risk: Quick Facts

• Being overweight or obese is associated with a higher risk of 13 cancer types. These 13 cancers account for about 40% of all cancers diagnosed annually in the United States. 
• Researchers predict that obesity may soon surpass smoking as the top cause of cancer in the US [1].
• Excess body weight may drive cancer risk by increasing long-term inflammation and disrupting hormonal balance in the body. 
• Sustained weight loss may help lower cancer risk. 

What Is Obesity?

Being overweight or obese means your body weight is higher than what is considered normal for your height. In the U.S., a screening tool called the Body Mass Index (BMI) is used to determine whether a person is overweight or obese. 

An adult with a BMI between 25 and 29.9 is considered overweight. Likewise, obesity for an adult is when their BMI is 30 or higher. 

According to the Centers for Disease Control and Prevention (CDC), over 2 in 5 US adults are obese [2].

Being overweight or obese may increase your risk of getting many diseases, including [3]:

• Diabetes
• High blood pressure
• Diseases of the heart and blood vessels
• Stroke

Although BMI is widely used for screening, it does not directly measure body fat and may not accurately reflect health risk in every individual. 

What Are the Cancer Types Associated With Obesity?

Of more than 100 types of cancer, the following have direct links to overweight or obesity [2]:

1. Adenocarcinoma of the esophagus (cancer that starts in certain regions of the food pipe)
2. Breast (in women who no longer have monthly periods; postmenopausal)
3. Colon and rectum
4. Uterus
5. Gallbladder
6. Upper stomach
7. Kidneys
8. Liver
9. Ovaries
10. Pancreas
11. Thyroid
12. Meningioma (cancer that starts in the protective covering of the brain and spinal cord)
13. Multiple myeloma (cancer that forms in a certain type of white blood cell)

This is an active area of research, and scientists are investigating if obesity could drive the risk of other cancers. For example, a 2023 study involving over 2 million people and a 9-year follow-up found a link between 18 cancers and being obese/overweight [4].

Although obesity increases the risk of several cancers, it does not mean a person will develop cancer. Factors such as age, genetics, smoking status, alcohol use, physical activity, and environmental exposures also influence cancer risk. 

Obesity and Cancer Risk: What Are the Potential Mechanisms?

Researchers have suggested several mechanisms through which obesity may drive cancer risk.

Chronic Inflammation

Overweight or obese people often have chronic low-grade inflammation. While inflammation is protective, when it lingers for a longer period, it can create a “host environment” where cancer cells can grow and multiply. 

High Estrogen Levels

High estrogen levels due to excess production by fat cells may increase the risk of breast, endometrial, and ovarian cancer. 

High Levels of Insulin and Other Factors

Overweight or obese people usually have high levels of insulin and insulin-like growth factor-1 (IGF-1). Some cancer cells may use these growth factors to divide without limit. Elevated levels of insulin and IGF-1 may increase the risk of thyroid, breast, colon and rectum, prostate, ovarian, and endometrial cancers. 

Disruption of Hormones That Regulate Cell Growth

Many hormones regulate cell growth in human beings, including adipokines produced by fat tissue. Adipokines can stimulate or arrest cell growth, depending on the specific type. 

Obesity can disrupt the balance between these hormones, potentially increasing cancer risk. For example, levels of adiponectin (an adipokine that may limit cell growth) are low in people with obesity. 

Immune Suppression

Animal studies show that obesity can make T cells less powerful in their fight against cancer. For example, in a mouse study, researchers found that T cells in obese mice had problems entering the tumor. Even though some managed to get inside the tumor, they were unable to function [5].

Obesity and Cancer Risk: How Fat Distribution Might Affect the Risk

In some obesity-related cancers, the location of fat might be just as crucial as how much there is in the body. 

For example, in a 2025 study, researchers investigated the link between 12 obesity-related cancers and fat distribution in five different parts of the body:

1. Abdominal fat
2. Visceral fat (surrounding the organs inside the abdomen)
3. Fat on the buttocks and thighs
4. Liver fat 
5. Pancreas fat

They found the following [6]:

• Abdominal fat was linked to increased risk of endometrial cancer, liver cancer, and esophageal adenocarcinoma. 
• Fat on the buttocks and thighs was linked to a lower risk of breast cancer and a type of brain cancer (meningioma). 
• Higher visceral fat and liver fat increased the risk of liver cancer. 

Obesity and Cancer Risk: Does Gender Make a Difference?

Among obesity-associated cancers that occur in both men and women, cancer of the food pipe (esophageal adenocarcinoma) is nine times more likely to occur in men than in women in the U.S. [7].

Postmenopausal breast cancer is the most frequent obesity-related cancer among U.S. women. In U.S. men, the most frequent obesity-related cancer is colorectal cancer. 

Obesity and Cancer Risk: Frequently Asked Questions

Can losing excess weight reduce cancer risk?

Studies suggest that sustained weight loss, particularly losses of around 10% of body weight or more, may provide meaningful reductions in cancer-related risk factors [8].

What is 90% of cancer caused by?

Many cancers are influenced by environmental and lifestyle factors such as tobacco use, obesity, diet, alcohol consumption, infections, and UV exposure. Estimates vary, but researchers generally agree that a large proportion of cancers (up to 90%) may be preventable through risk-factor modification. [9].

Does obesity affect cancer survival?

Obesity appears to have a dual role in cancer survival. It is a risk factor for overall cancer-related deaths. However, some studies have observed better outcomes among patients with certain cancers who have obesity, a phenomenon known as the “obesity paradox.” Researchers continue to debate whether this reflects a true biological effect or limitations in how body composition is measured [10].

Can childhood obesity affect cancer risk in adulthood?

While the underlying mechanisms are poorly understood, childhood and adolescent obesity is strongly associated with blood cancer, breast cancer, and colorectal cancer [11].

Conclusion

Obesity is a complex condition that affects far more than body weight alone. Growing evidence suggests that excess body fat can influence cancer risk through chronic inflammation, hormonal changes, immune dysfunction, and metabolic disturbances. While obesity does not guarantee that a person will develop cancer, maintaining a healthy weight through diet, physical activity, and other lifestyle measures may help reduce risk. As researchers continue to uncover the links between obesity and cancer, preventing and treating obesity remains an important strategy for improving long-term health.

Lumakras (loo-ma-krass) is an oral targeted cancer medicine used to treat certain types of non-small cell lung cancer and colorectal cancer in adults. It is prescribed for patients whose tumors carry a specific genetic change, the KRAS G12C mutation. 

Lumakras was the first medicine developed to directly target the KRAS G12C mutation (a cancer-promoting gene) that was once considered “untreatable” due to its complex structure. This cancer drug made a remarkable breakthrough in cancer care, especially for cancer patients with the KRAS G12 mutation who previously had limited therapeutic options. 

The generic name for Lumakras is sotorasib, and it is available as an oral tablet as prescribed by your doctor. Read on to learn its uses, how it works, dosage, possible side effects, and safety measures.  

Lumakras (Sotorasib): Uses

The US Food and Drug Administration approved Lumakras in May 2021 to treat:

• Non-small cell lung cancer (NSCLC)
• Colorectal cancer (CRC)

Lumakras is only prescribed to adults under the following cases:

• When cancer has spread to other parts of the body or cannot be removed by surgery
• When a tumor has an abnormal KRAS G12C gene 
• When a patient has already tried other treatments (e.g., chemotherapy)

Before prescribing Lumakras, your healthcare provider will perform a biomarker test to ensure this drug is right for you.

Lumakras: Working Mechanism

Lumakras (sotorasib) specifically targets the cancer mutation (KRAS G12C) that drives tumor growth. Normally, the KRAS protein in your body acts like a molecular switch that tells cells when to grow and when to stop. 

However, when a mutation occurs in the KRAS protein, it gets stuck in an “ON” state, leading to continuous, uncontrolled cell growth and tumor formation (most commonly in NSCLC). 

Sotorasib, the active component in Lumakras, attaches to the KRAS G12C mutation and locks it in an inactive state, so it can’t send a signal to cancer cells to multiply, thus preventing the growth of tumor cells. 

Unlike traditional chemotherapy that kills both healthy and cancer cells, Lumakras works in a more selective way and only kills cancer cells with the KRAS G12C mutation. 

Lumakras: Drug Forms

Lumakras is available as an oral tablet in the following strengths: 

• 320 mg
• 240 mg
• 120 mg 

FDA Recommended Dosage

The FDA-approved dosage for patients with non-small cell lung cancer and metastatic colorectal cancer is 960 mg once a day. 

Depending on the Lumakras tablet strength you have, you may take:

• Three 320 mg tablets
• Four 240 mg tablets
• Eight 120 mg tablets. 

Your doctor will tell you exactly how many tablets to take each day to reach the total dose of 960 mg.

How It Is Taken

Lumakras tablet is taken orally, with or without food. You should swallow the tablets whole. Do not chew, crush, or split tablets.

If you have colorectal cancer, you’ll also receive a recommended dose of panitumumab intravenously (through a vein) after taking your first dose of Lumakras. 

If You Cannot Swallow Lumakras Tablets

If swallowing tablets is difficult, you can take Lumakras by mixing it with water:

• Put your dose in 120 ml (4 oz) of room-temperature, non-carbonated water (don’t crush or use other liquids). 
• Stir for about 3 minutes until the tablets break into small pieces (they won’t fully dissolve).
• Drink the mixture right away or within 2 hours.
• Do not chew any pieces.
• Rinse the glass with another 120 ml of water and drink it to get the full dose.
• If you missed a dose by more than 6 hours or vomit after taking a dose, do not take an extra dose; just continue with your next scheduled dose. 

Possible Side Effects

Lumakras can cause mild and serious side effects in patients with NSCLC and metastatic colorectal cancer. 

Common Side Effects

The most common side effects of Lumakras when used alone for NSCLC are:

• Diarrhea
• Musculoskeletal pain (pain in the muscle and bone)
• Nausea
• Tiredness
• Cough

The most common side effects of Lumakras when used in combination with panitumumab for CRC include:

• Rash
• Dry skin
• Diarrhea
• Stomatitis (mouth sores)
• Fatigue
• Muscle or bone pain 

Serious Side Effects

Serious side effects can rarely occur, which include:

• Liver problems (common signs include jaundice, bleeding or bruising, lack of appetite, weakness, dark urine, pain or aching in your stomach)
• Lung or breathing problems (common signs include new or worsening shortness of breath, cough, or fever). This could happen due to the inflammation in the lungs, which sometimes leads to death if not treated immediately.

Lumakras: Interaction with Other Drugs

You should not take stomach acid–reducing medicines such as Proton Pump Inhibitor (PPI) or H2 blockers at the same time as your scheduled Lumakras dose. This is because antacid medicines can affect how Lumakras works, and vice versa. 

If you cannot avoid taking antacid medicines, then administer Lumakras either 4 hours before or 10 hours after the antacid. 

Lumakras: Safety Measures

Before taking Lumakras, tell your healthcare provider if you:

• Have liver problems
• Have lung or breathing problems other than lung cancer
• Are allergic to sotorasib or any of the other ingredients of this medicine
• Are pregnant or plan to become pregnant. It is not known if Lumakras is safe for your unborn baby. 
• Are breastfeeding or plan to breastfeed. It is not safe to breastfeed while taking Lumakras. You may start breastfeeding 1 week after your last dose. 
• Are taking any prescription or non-prescription medicines, vitamins, and herbal supplements. Lumakras may affect the way other medicines work, and other medicines may affect how Lumakras works. 

Estimated Cost

Lumakras is currently available as a brand-name drug only, and no generic version is available yet. It can be quite expensive without insurance. Below are the estimated costs for different tablet strengths: 

• 120 mg tablets: $22,315.10 for 240 tablets
• 240 mg tablets: $22,315.10 for 120 tablets
• 320 mg tablets: $22,315.10 for 90 tablets

The cost of Lumakras can vary depending on the pharmacy, location, and insurance coverage. You may not pay the full price because insurance coverage, copay assistance, or pharmacy discount cards can help reduce the cost. Contact us if you are interested in exploring financial assistance opportunities or copay assistance for Lumakras.