What is the role of Aloe vera (Sarısabır) in cancer treatment?

This article concerns a plant widely used in both alternative medicine and cosmetic products, known in Turkish as Sarısabır and called Aloe vera , and its role in cancer treatment.

What is Aloe vera?

Aloe vera, a cactus-like plant belonging to the lily family, has a long history in folk medicine. The clear, thick liquid inside its leaves has been used since ancient Egyptian times to treat skin problems. Oral and injectable forms have come to prominence during the last century. Studies have found topical Aloe vera effective, though not superior to standard treatments, for burns and abrasions, and oral Aloe vera for constipation. Recently, its anticancer properties have been the aspect most strongly promoted.

Some laboratory studies have shown inhibition of cancer cell proliferation and triggering of cell death. However, findings from the few clinical studieshavenotconfirmed these effects. Contrary to claims, the available evidence indicates that Aloe vera is also ineffective against radiotherapy -related skin problems, in terms of both prevention and treatment. In addition, the literature reports numerous, including fatal, side effects .

What is the history of Aloe vera?

Aloe vera, also known as Aloe barbadensis and Aloe capensis, is a long-lived, thick-leaved, cactus-like plant of the genus Aloe in the lily family. Although originating in South Africa, Aloe species also reached China and Southern European countries in the 17th century. Used in folk medicine for more than 2000 years, Aloe vera also occupies an important place in traditional medicine in contemporary cultures such as China, Japan and India. In America, it first gained popularity in the 1930s through studies suggesting effectiveness against burns caused by X-rays (radiotherapy).

Aloe's traditional medical use dates back to ancient Egypt, and it has been widely used for skin problems. Topical Aloe products are obtained from the thick, clear liquid released when the leaves are cut, and frequently appear in cosmetics and alternative medicine products. They are claimed to treat many skin and mucosal conditions, including wounds, burns, frostbite, dry skin, psoriasis, eczema (skin inflammation), genital herpes (genital cold sores), aphthous stomatitis (a disease characterized by mouth ulcers) and seborrheic dermatitis (oily eczema). However, studies have not produced sufficient evidence for these topical effects. Although some studies have yielded promising results, particularly for burns and abrasions, even they have not demonstrated superiority over standard treatments for these conditions.

Oral Aloe vera products include capsules obtained from Aloe leaves, dried latex and Aloe vera juice. They are used particularly for constipation because of their laxative (stool-softening) effects. However, the FDA (United States Food and Drug Administration) states that using Aloe as a stool softener is not safe . It even requested the removal of Aloe laxative products from all sales outlets in America in 2002. Beyond these uses, Aloe vera has frequently attracted attention in recent years through claims about its effects in cancer. Its topical form is particularly claimed to prevent and treat skin problems following radiotherapy. However, clinical studies do not support these claims.

What are the results of laboratory studies on Aloe vera's effects in cancer?

Laboratory studies have demonstrated certain properties of Aloe vera involving the immune systemregulation, inflammation (inflammatory response) prevention, antioxidant and anticancer activity. Aloe vera contains many active components; its immune-regulating properties have been attributed to Acemannan, and its anticancer properties to anthracene and anthraquinone components.

In a study published in 2014, Aloe emodin, an anthraquinone-type component in Aloe vera, was examined in cervical cancer cell lines, where it inhibited proliferation and increased sensitivity to radiotherapy. A laboratory study on liver cancer cell lines also found inhibition of cancer cell proliferation and triggering of cell death. A study of breast cancer cell lines likewise found suppressed proliferation, while another study on colorectal cancer cell lines found triggered cell death. Similarly, studies show that Aloe emodin inhibits cell growth in lung cancer, leukemia and neuroectodermal cancer (a group of nervous system tumors) cell lines. In one study, Aloin, another anthraquinone-type compound in Aloe, prevented colorectal cancer cell lines from forming new blood vessels for nourishment (angiogenesis).

What are the results of clinical studies on Aloe vera's effects in cancer?

Although the few clinical studies investigating Aloe vera's anticancer potential have produced some positive results, these are insufficient for clinical application. The effect most strongly promoted and advocated in cancer is preventing and treating skin problems caused by radiotherapy. Clinical studies have yielded inconsistent results and do not confirm this effect. In patients receiving postoperative adjuvant radiotherapy, a clinical study involving 225 breast cancer patients reported no significant benefit from Aloe vera for radiotherapy-related skin problems. A study combining two separate clinical studies also found no such effect. A review assessing seven clinical studies reached a similar result. In a study involving 57 head and neck cancer patients, Aloe vera delayed the onset and reduced the severity of radiotherapy-related skin problems, but did not prevent them or reduce their frequency.

In a study assessing Aloe vera alongside chemotherapy, patients with metastatic (spread to distant tissues) tumors were assessed: among 240 patients, some received chemotherapy alone and others chemotherapy combined with oral Aloe vera three times daily at 10 ml. Tumor regression and three-year survival rates were significantly higher in the Aloe group. Although a small epidemiological study found less lung cancer in regular oral Aloe users, the study was not sufficient to be considered promising.

A systematic review published in 2011 examined Aloe vera for preventing chemotherapy-related mouth sores. Despite some positive findings, researchers noted that the effect might be specific to a particular chemotherapy drug or cancer type, emphasizing the need for well-designed studies suitable for subgroup analyses. A preliminary study involving 20 patients with oral submucous fibrosis (thickening of the oral mucosa) found Aloe vera gel beneficial in reducing symptoms. Another study involving 58 head and neck cancer patients found no contribution of oral Aloe vera to symptom reduction or quality of life.

What are the possible side effects and risks of Aloe vera?

Although alternative medicine advocates claim it has no side effects, Aloe vera is an herbal treatment product with many reported adverse-effect cases. In four reported cases, injectable Aloe vera even caused death.

In a case reported in the literature, a 56-year-old woman with oral lichen planus (an inflammatory skin disease) refused corticosteroids, turned to alternative medicine and began drinking Aloe vera juice. Despite using it for 11 months, her lichen planus did not improve, and thyroid dysfunction (hypothyroidism) developed. Another case involving Aloe with chemotherapy developed severely low blood potassium (hypokalemia). A study published in 2010 reported three cases of toxic hepatitis (liver damage) associated with Aloe vera. Many other cases of Aloe-related toxic hepatitis have similarly been reported. There are also cases of delayed postoperative wound healing and Henoch-Schonlein purpura (a type of inflammation of blood vessel walls characterized by skin rashes).

Abdominal cramps, diarrhea and related disorders have also been reported with oral Aloe vera. Some preliminary studies reported blood sugar-lowering effects, warning diabetic patients using or considering Aloe vera about possible hypoglycemia (low blood sugar). The United States National Center for Complementary and Integrative Health also states that there is insufficient scientific evidence supporting Aloe vera for any health problem.

A study conducted in mice by the United States National Toxicology Program investigated the carcinogenic potential of oral Aloe vera. It showed that prolonged exposure to Aloe vera could be carcinogenic (cancer-causing). One study in mice showed that oral Aloe vera could trigger colon cancer; another showed that topical Aloe vera could increase the triggering of skin cancer by UV rays.

There is also evidence in the literature of Aloe vera drug interactions. A laboratory study showed that Aloe juice can block certain drug-metabolizing enzymes, affecting the concentrations of drugs metabolized by them. In a woman who lost approximately five liters of blood during surgery, an interaction between Sevoflurane (an inhaled anesthetic) and Aloe vera was held responsible.

So what should be done?

Aloe vera may offer certain benefits through its active components, but has not been shown superior to standard treatments for any health problem. Although claimed to be effective for many conditions, it has recently been promoted particularly for its effects in cancer. Its most strongly advocated effect in cancer patients is that its topical form prevents and treats radiotherapy-related skin problems. However, clinical studies indicate ineffectiveness in this regard. Oral and injectable forms have shown certain effects in laboratory studies, but these have not been confirmed clinically. Conversely, numerous side effects, including deaths, are reported in the literature. At present, it is therefore advisable to avoid these products until a clear benefit from Aloe vera and its active components is demonstrated and its safety profile established.