Tumors share a striking biological resemblance to wounds stuck mid-repair. In 1986, pathologist Harold Dvorak proposed that tumors are essentially “wounds that do not heal,” co-opting the body’s normal tissue-repair machinery to build the supportive environment they need to grow and survive.1PubMed. Tumors: wounds that do not heal. Similarities between tumor stroma generation and wound healing Decades of research have since confirmed and expanded that idea, revealing just how deeply cancer relies on wound-healing signals that never shut off. But the phrase “a cancer wound that never heals” also describes a painful clinical reality: malignant fungating wounds, where tumors break through the skin and create open sores that resist closure. Both meanings matter, and understanding the connection between them changes how you think about cancer biology and cancer care.
How Normal Wound Healing Gets Hijacked
When you cut yourself, your body launches a carefully staged response. First comes inflammation: immune cells flood the area, cleaning out debris and bacteria. Then a rebuilding phase kicks in, where new blood vessels sprout, connective tissue fills the gap, and specialized cells called fibroblasts lay down a temporary scaffold. Finally, the process winds down. The scaffold matures, extra blood vessels get pruned back, and the inflammatory signals quiet. The wound closes, the scar forms, and repair is done.
In cancer, the rebuilding phase never reaches that final shutdown. Tumor cells send out the same chemical signals your body uses during tissue repair, recruiting fibroblasts, growing new blood vessels, and suppressing the immune response. But because the tumor keeps proliferating, the “stop” signal never arrives. The supportive tissue around the tumor, called the stroma, ends up resembling the granulation tissue of a wound in its proliferative phase, complete with fibroblasts that have transformed into their wound-repair form. In a healing wound, that granulation tissue eventually resolves. In cancer, it persists indefinitely, feeding the tumor’s growth.2Frontiers in Immunology. Wound healing: insights into autoimmunity, ageing, and cancer ecosystems through inflammation and IL-6 modulation Work over the past few decades has reinforced this view and placed it on increasingly firm molecular footing.3PubMed Central. Tumors: wounds that do not heal-redux
The Blood Vessel Problem
One of the clearest parallels between wound healing and cancer is the growth of new blood vessels, a process called angiogenesis. In a normal wound, vessels sprout in an orderly sequence. Growth-stimulating molecules like VEGF get released first, followed by stabilizing factors, and finally by inhibitors that tell the process to stop. The timing depends on how tightly each molecule clings to components in the surrounding tissue matrix; those with the weakest grip get released earliest, and strong-binding inhibitors arrive last to put on the brakes.4PLOS ONE. Normal Wound Healing and Tumor Angiogenesis as a Game of Competitive Inhibition
Tumors flood their edges with so many growth stimulators that the inhibitors cannot keep up. The result is an overabundance of new vessel formation without proper stabilization, producing a chaotic, leaky, poorly organized vascular network. Modeling work has shown that high levels of the signaling molecule Jagged can push blood vessel cells into an abnormal hybrid state, creating the kind of tortuous, poorly perfused vessels that are a hallmark of solid tumors.5PubMed Central. Jagged mediates differences in normal and tumor angiogenesis by affecting tip-stalk fate decision Those chaotic vessels are one reason tumors develop oxygen-starved zones at their cores, which in turn drive still more distress signals and more aggressive behavior.
A Scaffold That Feeds the Fire
Normal wound healing lays down a temporary scaffold of fibrin and fibronectin, a kind of biological mesh that gives new tissue a framework to grow on. In tumors, this provisional matrix never gets properly cleared away. Tumor cells keep the clotting cascade activated, leading to persistent fibrin deposits. The enzyme that would normally break down fibrin gets blocked, and factors that promote clotting stay elevated.6JCI Insight. The fibrotic tumor stroma – Section: Provisional matrix deposition in cancer: priming for fibrosis
This matters for more than structural reasons. The lingering fibrin directly stimulates fibroblasts to multiply, produce extra connective tissue, and transform into a contractile, wound-repair form. It also draws in immune cells and biases them toward states that dampen immune surveillance rather than fighting the tumor. The dense, fibrotic stroma that results is not just a bystander; it actively protects the tumor from the immune system and from drugs trying to reach it. The stroma found in many solid tumors is, in fact, pathologically very similar to what you see in fibrotic diseases.7PubMed. Integrins in wound healing, fibrosis and tumor stroma: High potential targets for therapeutics and drug delivery
How Cancer Disarms the Immune Response
Your immune system is designed to both attack threats and protect your own tissues from collateral damage. Wound healing requires the protective side: you do not want your immune cells to keep destroying tissue when they should be helping rebuild it. Tumors exploit this by creating an environment rich in immunosuppressive signals, convincing the body that what is happening is a repair job, not an invasion.
One group of cells that illustrates this are myeloid-derived suppressor cells, or MDSCs. Under normal conditions, these immature immune cells get released during tissue damage and inflammation to prevent the immune response from spiraling out of control. They help maintain tolerance and support tissue repair. In cancer, though, they accumulate around the tumor in large numbers and suppress the very immune cells that could attack it.8PubMed Central. Myeloid-derived suppressor cells (MDSC): When good intentions go awry The tumor is, in effect, wrapping itself in the immune system’s own peacekeeping forces.
The pro-inflammatory signals that tumors co-opt from wound healing also help sustain populations of cancer stem cells, a subset of tumor cells thought to drive growth, resist treatment, and seed new tumors. Inflammatory molecules and developmental pathways that normally orchestrate tissue repair can, when chronically activated in a tumor’s microenvironment, support the survival and self-renewal of these cells.9PubMed Central. Wound healing and cancer stem cells: inflammation as a driver of treatment resistance in breast cancer Tumors hijack the proliferative and remodeling programs of wound healing and turn them into a continuous, immunosuppressive environment that enables growth and immune evasion.10Frontiers in Immunology. Tumors vs. Chronic Wounds: An Immune Cell’s Perspective
When Real Wounds Become Cancer
The wound-cancer connection runs in both directions. Not only do tumors behave like wounds, but actual chronic wounds can give rise to cancer. Malignant tumors develop more often at sites of chronic injury, and sustained inflammation is one of the most significant risk factors for malignant disease.11Nature Reviews Molecular Cell Biology. Cancer as an overhealing wound: an old hypothesis revisited
The clearest example is Marjolin’s ulcer, a rare but aggressive skin cancer that arises in scar tissue, chronic ulcers, or areas of long-standing inflammation. It most commonly takes the form of squamous cell carcinoma and is estimated to occur in roughly one to two percent of burn scars.12PubMed Central. Marjolin’s ulcer in chronic wounds – review of available literature The transformation typically takes decades, with an average latency of about 30 to 35 years from the original injury.13PubMed Central. From perineal burn scar to Marjolin ulcer: A case report of malignant transformation
The mechanism makes intuitive sense once you understand the wound-healing parallel. A chronic wound that never fully resolves keeps pumping out growth factors, inflammatory signals, and tissue-remodeling enzymes year after year. The cells in and around the wound are constantly dividing. Eventually, one of those dividing cells accumulates enough genetic damage to become cancerous. The chronic wound has, in essence, been running a decades-long experiment in uncontrolled cell turnover, and cancer is the unfortunate result. Proper wound care and early surgical management of burns are key preventive measures, but in settings where healthcare access is limited, neglected wounds can linger for the years necessary for transformation to occur.
Regeneration, Wound Healing, and Cancer Risk
The relationship between the body’s ability to regenerate tissue and its vulnerability to cancer is genuinely complicated. Cells with high regenerative capacity are often the very cells that become the source of cancer, because they divide frequently and maintain the molecular machinery for growth. At the same time, imperfect regeneration in the form of scarring or fibrotic wound healing can create tissue conditions that favor cancer development. Some researchers have proposed that variation in regenerative capacity across species and across different tissues in the same organism creates trade-offs that significantly alter cancer risk.14Annual Reviews. Relationships Between Regeneration, Wound Healing, and Cancer The idea is not that regeneration is good and wound healing is bad, or vice versa. Rather, any process that involves intense cell division and tissue remodeling carries inherent cancer risk, and how a given organism manages that risk varies widely.
Malignant Fungating Wounds
For some patients, the metaphor of cancer as a wound that never heals becomes literal. Malignant fungating wounds develop when a tumor grows through the skin, either from a primary cancer arising in or near the skin, from a deeper tumor invading upward, or from metastatic cells seeding the skin surface.15PubMed Central. Management of malignant cutaneous wounds in oncologic patients The name “fungating” comes from their appearance: they can present as crater-like ulcers or as raised, cauliflower-shaped nodules that spread outward.
Breast cancer is the most common underlying diagnosis, accounting for roughly half of malignant fungating wounds in one prospective study.16Journal of Pain and Symptom Management. Symptoms Associated with Malignant Wounds: A Prospective Case Series At a large tertiary cancer center, breast cancer and squamous cell carcinoma of the skin were the top two tumor types leading to these wounds, followed by vulvar carcinoma.17PubMed Central. Radiotherapy in the treatment of malignant fungating wounds: clinical practice, response rates, and outcome from a tertiary cancer center But any cancer that is near or spreads to the skin can produce one.
The Symptom Burden of Living with a Malignant Wound
Malignant fungating wounds carry a heavy and often underappreciated symptom load. In one prospective case series, about two-thirds of these wounds were associated with at least one significant symptom, and more than a fifth were associated with two or more. Pain was the most common, affecting roughly a third of wounds, followed by the physical bulk of the wound itself, distress over its appearance, wound fluid leakage, and odor.16Journal of Pain and Symptom Management. Symptoms Associated with Malignant Wounds: A Prospective Case Series Wounds in the perineal and genital area tended to produce the highest number of symptoms per wound.
Odor deserves special mention because of its outsized social and emotional impact. Necrotic tissue in the wound bed creates an environment where anaerobic bacteria thrive, producing volatile compounds that are impossible to ignore. The smell can permeate clothing, rooms, and relationships. For many patients, it is the single most distressing symptom, driving isolation far more than pain does.
Managing Symptoms When Cure Is Not the Goal
Because malignant fungating wounds often appear in advanced cancer, treatment priorities shift from healing the wound to controlling its symptoms. The wound will not close while the underlying cancer persists, so the focus becomes comfort and quality of life.
For odor, topical metronidazole gel is the most studied intervention. A phase III trial found that applying a 0.75% metronidazole gel eliminated detectable anaerobic bacteria in most treated wounds within two weeks.18PubMed Central. Safe and effective deodorization of malodorous fungating tumors using topical metronidazole 0.75 % gel (GK567): a multicenter, open-label, phase III study (RDT.07.SRE.27013) A systematic review confirmed that metronidazole and silver-based treatments showed improved odor outcomes, though the evidence base remains small and there is no standardized way to measure wound odor across studies.19Journal of Tissue Viability. Systematic review of topical interventions for the management of odour in patients with chronic or malignant fungating wounds
Bleeding is managed with topical agents including calcium alginate dressings, adrenaline-soaked gauze, silver nitrate sticks, and surgical hemostats applied directly to the wound surface. A systematic review of topical bleeding management for breast cancer wounds found no reports of significant adverse effects across the range of treatments used.20Journal of Pain and Symptom Management. Topical Management of Bleeding From Malignant Wounds Caused by Breast Cancer: A Systematic Review Nonadherent dressings help prevent re-injury during dressing changes, which can themselves be a significant source of pain and anxiety.
The Psychological Weight on Patients
A wound that is visibly cancerous changes how patients see themselves and how they move through the world. In qualitative research, women with malignant fungating wounds described the experience as living in a body that felt unbounded, out of their control. Symptoms like odor and excessive leakage were sources of deep embarrassment that restricted their social lives and eroded their sense of identity.21European Journal of Oncology Nursing. Malignant fungating wounds – The meaning of living in an unbounded body
The numbers back this up. A study comparing cancer patients with and without malignant wounds found that those with wounds were significantly more likely to report reduced feelings of being at peace, with about 41% scoring poorly on that measure compared to about 31% of patients without wounds. Psychological distress was also linked to pain severity and how often dressings needed changing.22Palliative & Supportive Care. Psychological symptom burden associated with malignant wounds: Secondary analysis of a prospective cohort study In another study, quality-of-life scores for patients with these wounds were the lowest recorded, with age, odor, pain, and psychological distress together accounting for the vast majority of the variation in quality of life.23PubMed. Symptom burden and quality of life in patients with malignant fungating wounds
Caregiver Burden
The impact extends well beyond the patient. Caregivers describe the visibility of the cancer as one of the most shocking aspects of the experience. The wound becomes the center of daily life for both patient and caregiver, consuming time and emotional energy as they try to control odor, manage leakage, and change dressings. In qualitative interviews, caregivers reported managing the wound entirely on their own, without help or guidance from healthcare professionals, and the isolation was a major burden.24PubMed. Caring for a loved one with a malignant fungating wound Research on informal caregivers and wound management more broadly confirms that the physical and psychological toll of wound care falls heavily on family members.25PubMed. Informal carers and wound management: an integrative literature review
The isolation caregivers describe is partly structural: malignant wound management is not a topic that gets much attention in standard caregiver education, and many clinicians outside specialized palliative care or wound care teams have limited experience with it. The result is that families often improvise with whatever dressings and strategies they can find, sometimes going through the messy trial and error of odor control with no professional support at all.
Breaking Through the Tumor’s Protective Shell
Understanding tumors as wounds that never heal has opened up new therapeutic angles. If the tumor’s fibrotic stroma acts as both a shield and a growth support, then disrupting that stroma could make existing treatments work better. One promising direction involves using nanocarriers loaded with collagenase, an enzyme that breaks down the dense collagen in the tumor’s matrix. By degrading this barrier locally, researchers have shown they can reduce the internal pressure within tumors and improve how deeply drugs can penetrate the tissue.26PubMed Central. Collagenase-mediated extracellular matrix targeting for enhanced drug penetration and therapeutic efficacy in nanoscale delivery systems for cancer therapy Delivering the enzyme via a nanocarrier rather than systemically also avoids the collateral damage that would come from dissolving collagen throughout the body.
The stroma-targeting approach reflects a broader shift in how researchers think about treating solid tumors. For decades, cancer therapy focused almost exclusively on killing the tumor cells themselves. The wound-healing framework suggests that the environment around the tumor, the fibrotic scaffold, the leaky blood vessels, the immunosuppressive signals, is not just background. It is infrastructure the tumor cannot live without. Dismantling that infrastructure, rather than simply poisoning the tumor cells, may prove to be one of the more effective ways to make cancers vulnerable.