Hyperbaric Oxygen Therapy (HBOT): How It Works for Cancer, Healing, and Beyond

Introduction: Breathing Under Pressure

Imagine breathing pure oxygen at twice the atmospheric pressure of sea level. At first glance, it sounds extreme — even dangerous. But hyperbaric oxygen therapy (HBOT) has been used safely in medicine for over a century, and the science behind it is both elegant and profound. By dramatically increasing the amount of oxygen dissolved in the blood and tissues, HBOT triggers a cascade of biological responses that promote healing, fight infection, reduce inflammation, support the immune system, and — increasingly — create conditions hostile to cancer.

HBOT is one of the most versatile therapeutic tools in medicine, with FDA-approved indications ranging from decompression sickness in divers to diabetic foot wounds, radiation injuries, and carbon monoxide poisoning. Beyond these established uses, a growing body of research is exploring HBOT's potential in cancer care, traumatic brain injury, stroke recovery, long COVID, anti-aging, and neurological conditions.

In this comprehensive post, we explore the physics and physiology of HBOT, its FDA-approved medical applications, its emerging role in cancer treatment, its benefits for a wide range of other conditions, and practical guidance on accessing and using HBOT safely.

The Physics of HBOT: Henry's Law and the Oxygen Advantage

To understand how HBOT works, we need to start with a fundamental principle of physics: Henry's Law, which states that the amount of a gas dissolved in a liquid is proportional to the partial pressure of that gas above the liquid.

Under normal atmospheric conditions (1 atmosphere, or 1 ATA), the oxygen we breathe is carried in the blood primarily by hemoglobin in red blood cells. Hemoglobin is approximately 97–99% saturated with oxygen under normal conditions, meaning there is very little additional capacity to carry more oxygen via hemoglobin.

However, a small amount of oxygen is also dissolved directly in the plasma (the liquid component of blood). Under normal conditions, this dissolved oxygen is minimal — approximately 0.3 mL of oxygen per 100 mL of blood.

HBOT changes this equation dramatically. By placing a patient in a pressurized chamber breathing 100% pure oxygen at 2–3 ATA (two to three times normal atmospheric pressure), two things happen simultaneously:

1. Increased partial pressure of oxygen: The partial pressure of oxygen in the lungs increases dramatically — from approximately 160 mmHg at sea level to 1,520 mmHg at 2 ATA breathing 100% oxygen.
2. Massively increased dissolved oxygen: Per Henry's Law, this dramatically increases the amount of oxygen dissolved directly in the plasma. At 3 ATA breathing 100% oxygen, dissolved plasma oxygen increases to approximately 6 mL per 100 mL of blood — enough to sustain life even without hemoglobin.

This dissolved oxygen is the key to HBOT's therapeutic power. Unlike hemoglobin-bound oxygen, dissolved oxygen can penetrate into tissues that are poorly perfused, hypoxic (oxygen-deprived), or where red blood cells cannot reach due to swelling, inflammation, or damaged blood vessels. It reaches every corner of the body — including the interior of tumors, the depths of chronic wounds, and the ischemic penumbra surrounding strokes.

The Physiology of HBOT: What Happens in the Body

The dramatically elevated tissue oxygen levels achieved during HBOT trigger a remarkable cascade of biological responses:

1. Hyperoxic Vasoconstriction

High oxygen levels cause blood vessels to constrict (vasoconstriction) — a seemingly paradoxical response that is actually therapeutically beneficial in many contexts. This vasoconstriction reduces edema (swelling) by decreasing fluid leakage from blood vessels, which is particularly valuable in traumatic brain injury, crush injuries, and post-surgical swelling.

2. Neovascularization and Angiogenesis

Paradoxically, while HBOT causes acute vasoconstriction during treatment, the repeated cycles of high oxygen followed by return to normal oxygen levels stimulate the growth of new blood vessels (angiogenesis) in hypoxic tissues. This is mediated through upregulation of vascular endothelial growth factor (VEGF) and other angiogenic factors during the post-treatment period. This neovascularization is the primary mechanism by which HBOT heals chronic wounds and radiation-damaged tissue.

3. Stem Cell Mobilization

One of the most remarkable discoveries in HBOT research is its ability to mobilize stem cells from the bone marrow into the circulation. A landmark study by Thom et al. published in the American Journal of Physiology (2006) found that a series of HBOT sessions increased circulating stem cells (CD34+ progenitor cells) by approximately 800% compared to baseline. These mobilized stem cells can home to sites of injury and contribute to tissue repair and regeneration.

4. Anti-Inflammatory Effects

HBOT has potent anti-inflammatory effects through multiple mechanisms:

• Suppression of NF-κB, the master regulator of inflammatory gene expression
• Reduction of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6)
• Inhibition of neutrophil adhesion to blood vessel walls, reducing inflammatory cell infiltration into tissues
• Reduction of oxidative stress through upregulation of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase)

5. Antimicrobial Effects

High tissue oxygen levels are directly toxic to anaerobic bacteria (bacteria that cannot survive in the presence of oxygen) and enhance the killing ability of immune cells (neutrophils and macrophages) against both aerobic and anaerobic pathogens. HBOT also enhances the effectiveness of certain antibiotics, particularly aminoglycosides, which require oxygen for their bactericidal activity.

6. Mitochondrial Stimulation

HBOT stimulates mitochondrial function and biogenesis in normal cells, enhancing their capacity for oxidative phosphorylation and ATP production. This is the basis of HBOT's benefits in neurological conditions, fatigue, and anti-aging applications. Importantly, this mitochondrial stimulation in normal cells contrasts with HBOT's effects on cancer cells, which have dysfunctional mitochondria and respond very differently to hyperoxia.

7. Epigenetic Effects

Emerging research has revealed that HBOT has significant epigenetic effects, altering gene expression patterns through changes in DNA methylation and histone modification. A 2020 study published in Aging by Hachmo et al. found that a protocol of 60 HBOT sessions significantly increased telomere length and reduced senescent cell burden in healthy aging adults — findings with profound implications for anti-aging medicine.

FDA-Approved Medical Indications for HBOT

HBOT has 14 FDA-approved indications, representing conditions where the evidence for benefit is well-established:

1. Decompression sickness ("the bends"): The original and most established indication. Nitrogen bubbles formed during rapid ascent from depth are reabsorbed under HBOT pressure.
2. Arterial gas embolism: Air bubbles in the arterial circulation, often from diving accidents or medical procedures.
3. Carbon monoxide poisoning: HBOT dramatically accelerates the elimination of carbon monoxide from hemoglobin and reduces neurological damage.
4. Clostridial myonecrosis (gas gangrene): HBOT is directly toxic to the anaerobic bacteria causing gas gangrene and reduces toxin production.
5. Crush injuries and acute traumatic ischemia: HBOT reduces swelling, preserves tissue viability, and promotes healing in severe crush injuries.
6. Enhancement of healing in selected problem wounds: Particularly diabetic foot ulcers and other chronic wounds that have failed to heal with standard treatment.
7. Exceptional blood loss anemia: When transfusion is not possible (e.g., due to religious beliefs), HBOT can sustain life by maximizing dissolved plasma oxygen.
8. Intracranial abscess: HBOT enhances antibiotic effectiveness and directly inhibits anaerobic bacteria in brain abscesses.
9. Necrotizing soft tissue infections: Rapidly spreading, life-threatening infections of the skin and soft tissue.
10. Osteomyelitis (refractory): Chronic bone infections that have not responded to antibiotics and surgery.
11. Delayed radiation injury (soft tissue and bony): One of the most important indications for cancer patients — HBOT heals radiation-damaged tissue that has failed to heal with conventional treatment.
12. Compromised skin grafts and flaps: HBOT improves the survival of skin grafts and surgical flaps by enhancing oxygen delivery to ischemic tissue.
13. Thermal burns: HBOT reduces edema, enhances immune function, and promotes healing in severe burns.
14. Idiopathic sudden sensorineural hearing loss: HBOT has been shown to improve hearing recovery when administered early.

HBOT and Cancer: A Complex and Evolving Relationship

The relationship between HBOT and cancer is one of the most nuanced and actively researched areas in integrative oncology. For decades, oncologists were cautious about HBOT in cancer patients, based on the theoretical concern that increasing oxygen delivery might stimulate tumor growth through angiogenesis. This concern has been substantially revised by modern research, which reveals a far more complex and largely favorable picture.

The Tumor Hypoxia Problem

To understand HBOT's role in cancer, we must first understand tumor hypoxia — one of the most important and underappreciated features of solid tumors.

As tumors grow beyond a few millimeters, they outgrow their blood supply and develop regions of severe oxygen deprivation (hypoxia). Paradoxically, this hypoxia — which one might expect to kill cancer cells — actually makes them more aggressive, more treatment-resistant, and more metastatic. Here's why:

• HIF-1α activation: Hypoxia activates hypoxia-inducible factor 1-alpha (HIF-1α), a transcription factor that drives expression of genes promoting angiogenesis (VEGF), glycolysis (GLUT1, HK2), survival (BCL-2), invasion (MMP2, MMP9), and metastasis. HIF-1α is one of the most important drivers of cancer progression and treatment resistance.
• Chemotherapy resistance: Many chemotherapy drugs require oxygen to generate the free radicals that kill cancer cells. Hypoxic tumor regions are therefore inherently resistant to many chemotherapy agents.
• Radiation resistance: Radiation kills cancer cells primarily through oxygen-dependent free radical generation. Hypoxic tumor cells are 2–3 times more resistant to radiation than well-oxygenated cells — a phenomenon called the oxygen enhancement ratio (OER). Hypoxic tumor regions are the primary sites of radiation treatment failure.
• Immune evasion: Hypoxia suppresses anti-tumor immune responses by impairing T cell function and promoting immunosuppressive cell populations in the tumor microenvironment.
• Metabolic reprogramming: Hypoxia reinforces the Warburg Effect, driving cancer cells further toward glycolytic metabolism and away from the oxidative phosphorylation that normal cells use.

How HBOT Addresses Tumor Hypoxia

By dramatically increasing dissolved plasma oxygen, HBOT can penetrate hypoxic tumor regions that are inaccessible to red blood cells and re-oxygenate them. This re-oxygenation has several important anti-cancer consequences:

• HIF-1α suppression: Increased oxygen levels suppress HIF-1α activity, reducing the expression of genes that drive cancer progression, angiogenesis, and treatment resistance.
• Chemotherapy sensitization: Re-oxygenating hypoxic tumor regions restores their sensitivity to oxygen-dependent chemotherapy drugs.
• Radiation sensitization: This is the most well-established anti-cancer application of HBOT. Multiple clinical studies have shown that HBOT administered before or during radiation therapy significantly improves tumor control rates by overcoming the oxygen enhancement ratio in hypoxic tumor regions. A Cochrane systematic review of HBOT combined with radiation therapy found significant improvements in local tumor control for head and neck cancers and cervical cancers.
• Immune restoration: Re-oxygenating the tumor microenvironment restores T cell function and reduces immunosuppressive cell populations, potentially enhancing anti-tumor immune responses.

HBOT and the Metabolic Theory of Cancer

Dr. Thomas Seyfried's metabolic theory of cancer provides a compelling framework for understanding HBOT's anti-cancer potential. If cancer is fundamentally a disease of mitochondrial dysfunction and metabolic reprogramming — with cancer cells dependent on glycolysis and unable to efficiently use oxidative phosphorylation — then flooding the tumor microenvironment with oxygen creates a metabolic crisis for cancer cells.

Normal cells with healthy mitochondria can efficiently use the increased oxygen delivered by HBOT, enhancing their energy production and resilience. Cancer cells with dysfunctional mitochondria cannot efficiently use this oxygen — and the increased oxidative stress generated by hyperoxia may be selectively toxic to them.

Seyfried and colleagues have proposed and studied the "Press-Pulse" therapeutic strategy for cancer, which combines metabolic therapies that reduce glucose availability (the "press" — ketogenic diet, caloric restriction, 2-DG) with acute metabolic stressors (the "pulse" — including HBOT) to create a synergistic metabolic assault on cancer cells. In this framework, HBOT serves as a metabolic pulse that generates oxidative stress selectively in cancer cells while normal cells are protected by their intact antioxidant defenses and mitochondrial function.

Preclinical studies of the Press-Pulse strategy combining ketogenic diet with HBOT have shown significant tumor growth inhibition and improved survival in mouse models of glioblastoma and other cancers, with the combination producing greater effects than either intervention alone.

HBOT and Radiation Injury: A Critical Application for Cancer Survivors

One of the most important and well-established applications of HBOT in cancer care is the treatment of delayed radiation injury — tissue damage that develops months to years after radiation therapy. Radiation damages blood vessels in the treated area, leading to progressive tissue hypoxia, fibrosis, and impaired healing. This can manifest as:

• Osteoradionecrosis (radiation-induced bone death, particularly of the jaw)
• Radiation proctitis (damage to the rectum after pelvic radiation)
• Radiation cystitis (damage to the bladder after pelvic radiation)
• Soft tissue radionecrosis
• Radiation-induced brain necrosis
• Lymphedema

HBOT is FDA-approved for delayed radiation injury and has a strong evidence base for this indication. By delivering oxygen to hypoxic, radiation-damaged tissue and stimulating neovascularization, HBOT can heal wounds that have failed to respond to all other treatments and prevent the need for major reconstructive surgery. For cancer survivors suffering from radiation complications, HBOT can be genuinely life-changing.

HBOT and Chemotherapy Side Effects

Beyond radiation injury, HBOT has shown promise for managing several chemotherapy-related complications:

• Chemotherapy-induced peripheral neuropathy (CIPN): HBOT's ability to enhance oxygen delivery to peripheral nerves and stimulate nerve regeneration may help reduce CIPN symptoms.
• Cancer-related fatigue: By enhancing mitochondrial function and reducing systemic inflammation, HBOT may address the biological drivers of cancer-related fatigue.
• Cognitive impairment ("chemo brain"): Emerging research suggests HBOT may improve cognitive function in cancer survivors experiencing treatment-related cognitive impairment, through enhanced cerebral oxygenation and neuroplasticity.
• Wound healing after surgery: HBOT accelerates healing of surgical wounds, which can be impaired in cancer patients due to malnutrition, immunosuppression, and prior radiation.

HBOT for Other Medical Conditions

Traumatic Brain Injury (TBI) and Concussion

TBI and concussion result in areas of brain tissue that are damaged but potentially salvageable — the "ischemic penumbra" — where cells are alive but not functioning due to inadequate oxygen delivery. HBOT can deliver oxygen to these areas, potentially rescuing neurons that would otherwise die.

Multiple studies, including research from the Israeli Defense Forces and several US military research programs, have shown that HBOT improves cognitive function, reduces post-concussion symptoms, and promotes neurological recovery in TBI patients. A 2013 study published in PLOS ONE found that HBOT significantly improved cognitive function and quality of life in veterans with chronic TBI and post-concussion syndrome.

Stroke Recovery

Similar to TBI, stroke creates an ischemic penumbra of potentially salvageable brain tissue surrounding the core infarct. HBOT can deliver oxygen to this penumbra, potentially rescuing neurons and improving neurological recovery. Research has shown benefits in both acute stroke (when administered within hours) and chronic stroke (improving function even years after the event).

A 2013 randomized controlled trial published in PLOS ONE by Efrati et al. found that HBOT significantly improved neurological function in chronic stroke patients, with improvements in motor function, cognitive performance, and quality of life — even in patients who had plateaued in their recovery years earlier.

Autism Spectrum Disorder (ASD)

Several studies have explored HBOT in autism, based on evidence of cerebral hypoperfusion (reduced blood flow to the brain) and neuroinflammation in some children with ASD. A 2009 randomized controlled trial published in BMC Pediatrics found that HBOT improved several behavioral measures in children with autism, including social interaction, eye contact, and sensory awareness. The evidence remains preliminary but is generating significant interest.

Long COVID and Post-Viral Syndromes

Long COVID — persistent symptoms following SARS-CoV-2 infection — has emerged as a major public health challenge. Symptoms including fatigue, cognitive impairment ("brain fog"), breathlessness, and exercise intolerance share features with other post-viral syndromes and may involve mitochondrial dysfunction, neuroinflammation, and microclotting.

A landmark 2022 randomized controlled trial published in Nature Communications by Zilberman-Itskovich et al. found that 40 sessions of HBOT significantly improved cognitive function, fatigue, sleep quality, and quality of life in long COVID patients compared to sham treatment. Brain imaging showed increased cerebral blood flow and neuroplasticity in HBOT-treated patients. This study generated significant excitement and positioned HBOT as one of the most promising treatments for long COVID.

Diabetic Wounds and Peripheral Vascular Disease

Diabetic foot ulcers are a leading cause of lower limb amputation worldwide. They result from a combination of peripheral neuropathy, impaired circulation, and immune dysfunction that prevents normal wound healing. HBOT is FDA-approved for this indication and has a strong evidence base, with multiple studies showing significantly improved wound healing rates and reduced amputation rates in diabetic patients with non-healing foot ulcers.

Anti-Aging and Longevity

The 2020 study by Hachmo et al. in Aging mentioned earlier deserves special attention. This randomized controlled trial found that 60 sessions of HBOT in healthy aging adults produced:

• Significant lengthening of telomeres (the protective caps on chromosomes that shorten with aging) — an average increase of 20% in telomere length
• Significant reduction in senescent cells ("zombie cells" that accumulate with aging and drive inflammation and tissue dysfunction) — a 37% reduction in senescent T cells
• Improved cognitive function, particularly attention and processing speed

These findings — if replicated — would represent the first demonstration that a non-pharmacological intervention can reverse cellular aging markers in humans. They have generated enormous interest in HBOT as an anti-aging therapy.

Fibromyalgia and Chronic Pain

Fibromyalgia is characterized by widespread pain, fatigue, and cognitive impairment. Research has suggested that fibromyalgia may involve neuroinflammation and abnormal pain processing in the brain. A 2015 randomized controlled trial published in PLOS ONE by Efrati et al. found that HBOT significantly reduced pain, improved quality of life, and produced measurable changes in brain activity patterns in fibromyalgia patients.

Lyme Disease and Chronic Infections

HBOT's antimicrobial properties — direct toxicity to anaerobic organisms and enhancement of immune cell killing — have led to its use in chronic Lyme disease and other chronic infections. While the evidence base is less robust than for other indications, many patients report significant symptom improvement, and the biological rationale is sound.

Post-Surgical Recovery

HBOT accelerates wound healing, reduces infection risk, and enhances tissue regeneration after surgery. It is used by some elite athletes and high-performance individuals to accelerate recovery from surgery and injury.

Soft-Shell vs. Hard-Shell Chambers: Understanding the Difference

HBOT chambers come in two main types, and understanding the difference is important for patients considering this therapy:

Hard-Shell (Monoplace and Multiplace) Chambers

Hard-shell chambers are rigid, pressurized vessels that can achieve pressures of 2–3 ATA or higher while delivering 100% pure oxygen. These are the chambers used in hospitals, wound care centers, and dedicated HBOT clinics for FDA-approved medical indications. They are the gold standard for therapeutic HBOT and are required for most of the medical applications discussed in this post.

• Monoplace chambers: Accommodate one patient lying down; the entire chamber is pressurized with oxygen.
• Multiplace chambers: Accommodate multiple patients simultaneously; patients breathe oxygen through masks while the chamber is pressurized with air.

Mild Hyperbaric Chambers (Soft-Shell)

Soft-shell or "mild" hyperbaric chambers are inflatable chambers that typically achieve pressures of 1.3–1.5 ATA while delivering air or supplemental oxygen. They are widely available for home use and at wellness centers.

Important distinctions:

• Mild chambers cannot achieve the pressures required for most FDA-approved medical indications.
• At 1.3–1.5 ATA, the increase in dissolved oxygen is modest compared to hard-shell chambers at 2–3 ATA.
• However, mild HBOT may still provide meaningful benefits for wellness applications, recovery, and some of the emerging indications discussed above.
• Mild chambers are significantly less expensive and more accessible than hard-shell chambers.
• For serious medical conditions including cancer, radiation injury, and wound healing, hard-shell chambers at therapeutic pressures are strongly preferred.

A Typical HBOT Session: What to Expect

For patients considering HBOT, understanding what a session involves can reduce anxiety and improve compliance:

• Duration: Typically 60–90 minutes per session, including pressurization and depressurization time.
• Pressure: For medical indications, typically 2.0–2.4 ATA; for some conditions (decompression sickness, gas embolism), up to 3.0 ATA.
• Oxygen: 100% pure oxygen breathed through a mask or hood (in multiplace chambers) or filling the entire chamber (in monoplace chambers).
• Sensations: Patients typically feel pressure in their ears during pressurization (similar to descending in an airplane), which can be relieved by swallowing, yawning, or the Valsalva maneuver. The chamber is comfortable and patients can read, watch videos, or sleep during treatment.
• Number of sessions: Varies by indication. Wound healing and radiation injury typically require 20–40 sessions. Cancer adjunct protocols may involve 20–60 sessions. Anti-aging protocols in research have used 60 sessions.
• Frequency: Typically once daily, 5 days per week.

Safety Considerations and Contraindications

HBOT has an excellent safety profile when administered appropriately, but there are important considerations:

• Oxygen toxicity: Breathing high-pressure oxygen for extended periods can cause pulmonary oxygen toxicity (lung damage) or CNS oxygen toxicity (seizures). These risks are managed through careful pressure and duration protocols and are rare at standard therapeutic pressures.
• Ear and sinus barotrauma: Pressure changes can cause ear pain or sinus discomfort, particularly in patients with upper respiratory infections or Eustachian tube dysfunction. This is the most common side effect and is usually mild.
• Claustrophobia: Some patients experience anxiety in the enclosed chamber. Mild sedation or anxiolytics can be used if needed.
• Fire risk: Pure oxygen is highly flammable. Strict protocols prohibit flammable materials in the chamber.
• Contraindications: Untreated pneumothorax (collapsed lung) is an absolute contraindication. Relative contraindications include certain medications (bleomycin, doxorubicin, cisplatin — which may have enhanced toxicity under hyperoxic conditions), active viral infections, and uncontrolled seizure disorders.
• Cancer-specific caution: While the evidence increasingly supports HBOT's safety in cancer patients, the theoretical concern about stimulating tumor angiogenesis has not been entirely dismissed. HBOT should be used in cancer patients under the guidance of an oncologist familiar with the current evidence.

Integrating HBOT into a Comprehensive Cancer Care Plan

At Holistic Healing LLC, we view HBOT as a powerful component of a comprehensive, multi-layered approach to cancer care. It works synergistically with:

• Ketogenic diet and metabolic therapy: The Press-Pulse strategy combines dietary glucose restriction (press) with HBOT (pulse) to create a synergistic metabolic assault on cancer cells. Seyfried's research suggests this combination is particularly powerful.
• IV vitamin C: Both HBOT and IV vitamin C generate selective oxidative stress in cancer cells while protecting normal cells. Their combination may be synergistic.
• Red light therapy: Both therapies target mitochondrial function — HBOT by increasing oxygen availability, red light therapy by enhancing cytochrome c oxidase activity. Together they may provide complementary mitochondrial support.
• Radiation therapy: HBOT administered before radiation sessions can significantly improve tumor control by overcoming radiation resistance in hypoxic tumor regions.
• Immunotherapy: HBOT's ability to re-oxygenate the tumor microenvironment and restore T cell function may enhance the effectiveness of checkpoint inhibitor immunotherapy.
• Repurposed drugs: Ivermectin, fenbendazole, metformin, and other metabolic agents complement HBOT's metabolic disruption of cancer cells.

Conclusion: Breathing New Life into Healing

Hyperbaric oxygen therapy is one of medicine's most versatile and underutilized therapeutic tools. From its established role in wound healing, radiation injury, and decompression sickness to its emerging applications in cancer care, traumatic brain injury, long COVID, and anti-aging, HBOT's ability to harness the healing power of oxygen under pressure is generating growing scientific and clinical interest.

For cancer patients, HBOT offers a multi-faceted contribution: sensitizing tumors to radiation and chemotherapy, suppressing HIF-1α and the hypoxia-driven pathways that make cancer more aggressive, creating metabolic stress in cancer cells through the Press-Pulse strategy, healing radiation-induced tissue damage, and supporting immune function. These benefits, combined with HBOT's excellent safety profile and its synergy with other integrative cancer therapies, make it a compelling addition to a comprehensive cancer care plan.

At Holistic Healing LLC, we encourage anyone interested in HBOT to seek out a qualified provider — ideally one with experience in both conventional HBOT indications and integrative oncology — who can evaluate your individual situation and design an appropriate protocol.

Sometimes, the most powerful medicine is the simplest: oxygen, delivered with precision and intention.

Disclaimer

This blog post is for informational and educational purposes only and does not constitute medical advice, diagnosis, or treatment. Always consult with a qualified and licensed healthcare professional before starting HBOT or any new therapy, especially during cancer treatment. Some HBOT applications discussed in this post are investigational and not FDA-approved for those specific indications.