Why Cancer Returns: 8 Root Causes Most Treatments Overlook

May 19, 2026 BelieveBig Blog, Podcast

Cancer treatment can feel like crossing a finish line. You’ve done the chemo, radiation, or surgery, and you’re told you’re “cancer-free.” But for many, a lingering question remains: “Why does cancer return?”
Some estimates suggest recurrence rates can be alarmingly high. And according to integrative oncologist Dr.

Michael Karlfeldt, the answer lies in something many conventional approaches overlook: Cancer is not just a tumor, it’s a reflection of the body’s internal environment. If we only focus on shrinking the tumor and ignore what caused it, the conditions that allowed cancer to grow may still be present.

Let’s explore 8 key root causes of cancer recurrence, and what you can do to support long-term healing.

1. Treating the Tumor Instead of the Whole Body
Many treatments focus on eliminating the tumor itself. But Dr. Karlfeldt explains:
• The tumor is often a symptom, not the root problem
• Cancer develops from a systemic imbalance in the body
If the internal environment doesn’t change, cancer can return, because the conditions that allowed it to grow are still there.
Key takeaway: Healing requires addressing the whole body, not just the tumor.

2. Weakened Immune System After Treatment
Conventional treatments can save lives, but they can also:
• Deplete the immune system
• Increase toxic burden
• Leave the body vulnerable
Without a strong immune system, the body struggles to:
• Detect abnormal cells
• Eliminate lingering cancer cells
Healing doesn’t stop after treatment, it begins there.

3. Cancer Stem Cells Left Behind
One of the most overlooked factors in recurrence is cancer stem cells.
These cells:
• Can survive chemo and radiation
• Lie dormant in the body
• Can later trigger new tumor growth
In some cases, treatments may even activate these cells.
Why this matters: Even if the tumor shrinks, the root drivers may still remain.

4. Chronic Infections and Hidden Pathogens
Dr. Karlfeldt highlights a growing connection between cancer and infections such as:
• Mold and fungus
• Parasites
• Lyme-related bacteria (Borrelia, Bartonella, Babesia)
• Viruses like Epstein-Barr
These infections:
• Stress the immune system
• Create inflammation
• Distract the body from targeting cancer cells
A healthy immune system can’t fight everything at once.

5. Toxic Overload from the Environment
We are constantly exposed to toxins, from:
• Plastics
• Heavy metals (mercury, aluminum, lead)
• Chemicals in food, water, and products
These toxins can:
• Suppress immune function
• Disrupt hormones
• Create an inflammatory environment where cancer can thrive
Even small daily exposures add up over time.

6. Unresolved Stress and Trauma
One of the most powerful (and often ignored) contributors is chronic stress and trauma.
Stress can:
• Suppress the immune system
• Block detoxification
• Prevent the body from repairing itself
Dr. Karlfeldt describes cancer as:
“A cell shifting into survival mode.”
Living in constant stress keeps the body stuck in that same survival state.

7. Poor Detoxification and Internal Imbalance
After treatment, the body often carries:
• Residual chemotherapy toxins
• Heavy metals
• Inflammatory compounds
Without proper detoxification, these can:
• Damage cells
• Promote inflammation
• Increase recurrence risk
Supporting detox pathways is essential for long-term healing.

8. Lifestyle, Diet, and Environment
Healing also depends on daily choices:
• Nutrient-dense, low-inflammatory foods
• Reducing toxin exposure
• Healthy relationships and emotional support
• Strong spiritual connection
Dr. Karlfeldt emphasizes:
Healing requires looking at what’s around you, on you, and in you.

A Faith-Centered Perspective on Healing
For many, healing is not just physical, it’s spiritual.
Peace, prayer, and trust in God can:
• Reduce stress
• Support the body’s healing state
• Bring hope in uncertain seasons
As shared in the episode, even simple declarations of faith can create profound shifts in the body and mind.

Final Thoughts: Healing Beyond Survival
Being declared “cancer-free” is a milestone, but it’s not the end of the journey.
It’s an invitation to:
• Restore the body
• Strengthen the immune system
• Address root causes
• Create a healing environment

🎧 Listen to the Full Episode

To hear this powerful conversation and gain deeper insight into preventing cancer recurrence, listen to Episode #116 of the Believe Big Podcast.

💛 Support the Believe Big Mission

If this message encouraged you, consider supporting Believe Big.
Your donation helps:
• Fund life-changing research (like mistletoe therapy trials)
• Provide resources to patients
• Bring hope and healing to those navigating cancer

Together, we can help more people not just survive, but truly heal.

Resources Mentioned