Radiation therapy is a common and effective cancer treatment that utilizes high-energy rays, such as X-rays, gamma rays, or protons, to target and destroy cancer cells. This localized approach aims to deliver a precise dose of radiation to the tumor while minimizing exposure to surrounding healthy tissues. The fundamental mechanism involves damaging the DNA within cancer cells, which prevents them from growing and dividing, ultimately leading to their death and tumor shrinkage. This treatment can be used alone or in combination with other therapies like surgery or chemotherapy.
How Radiation Therapy Can Lead to Bleeding
Radiation therapy can cause bleeding, a side effect resulting from its effects on healthy tissues within the treated area. This primarily occurs through damage to small blood vessels like capillaries and venules. Radiation weakens vessel walls, making them fragile and susceptible to rupture. This direct injury can also alter vessel structure.
Beyond direct vascular damage, radiation also induces inflammation and changes in the surrounding tissues. This inflammation makes the tissues more permeable and fragile, increasing their vulnerability to injury and subsequent bleeding. Over time, particularly in chronic cases, radiation can lead to fibrosis, a process where normal tissue is replaced by scar-like tissue, and the development of abnormal, widened blood vessels called telangiectasias. These newly formed or altered vessels are often superficial and easily damaged, contributing to bleeding. The effects of radiation therapy are localized, meaning bleeding typically occurs only in the specific body region that received treatment.
Types and Timing of Bleeding
Radiation-induced bleeding can manifest at different times relative to treatment, broadly categorized as acute or late (chronic). Acute bleeding typically occurs during or shortly after radiation therapy, often within the first few weeks. This type of bleeding generally results from acute inflammation and direct tissue damage.
For instance, pelvic radiation may cause acute rectal bleeding due to proctitis, an inflammation of the rectum. Bladder inflammation (cystitis) can similarly lead to blood in the urine (hematuria) during or soon after treatment. In the head and neck region, mucositis, or inflammation of the mouth and throat lining, can cause sores or blood blisters.
Late or chronic bleeding can develop months or even years after radiation therapy has concluded. This delayed onset is attributed to long-term tissue changes, including fibrosis and the formation of fragile telangiectasias. Common examples include chronic rectal bleeding, often from telangiectasias in the bowel lining. Bladder bleeding (hemorrhagic cystitis) can also be a chronic complication, ranging from microscopic blood to severe bleeding with clots. Skin in the treated area might also develop visible, reddish-purple spider veins (telangiectasias) that can bleed if injured.
Addressing Radiation-Induced Bleeding
When radiation-induced bleeding occurs, it is important to report it to the oncology care team without delay. This allows medical professionals to assess the severity of the bleeding, determine its cause, and rule out other potential issues. Depending on the location and nature of the bleeding, doctors may perform a physical examination, conduct blood tests to check for anemia, or use imaging studies. Endoscopic procedures, such as a colonoscopy for rectal bleeding or a cystoscopy for bladder bleeding, can help visualize the affected area and identify the source of the bleeding.
Management strategies for radiation-induced bleeding vary based on its severity and location. For mild cases, conservative measures might be sufficient, including hydration, dietary adjustments for gastrointestinal bleeding, and the use of stool softeners. Medications such as tranexamic acid can be prescribed to help reduce bleeding, particularly from the bladder. Anti-inflammatory drugs or sucralfate enemas may also be used to soothe inflamed tissues and promote healing, especially in cases of rectal bleeding.
In more persistent or severe instances, procedural interventions may be necessary. Endoscopic techniques like argon plasma coagulation (APC) or laser therapy can be used to seal off bleeding vessels directly. Formalin application is another method used to chemically cauterize and seal fragile new blood vessels in the affected tissue. For severe bleeding, supportive care like blood transfusions may be required to address anemia, and surgery might be considered as a last resort. While radiation-induced bleeding can be concerning, many cases can be effectively managed with appropriate medical attention and interventions.