Introduction
The complications of cancer and from cancer treatments are known to adversely affect a patient's quality of life (QoL). Various sequelae can occur with surgery, radiotherapy, and chemotherapy, which will negatively impact activities of daily living and overall QoL. These adverse effects may prompt the patient to withdraw from cancer treatments.1 Palliative care has an adjunctive role in oncology treatment, providing a holistic approach to the physical, emotional, and psychosocial wellbeing of cancer patients.2 The National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines in Oncology (NCCN Guidelines) defines palliative care as a comprehensive approach to health care that focuses on the patients, families, and caregivers, with aim to relieve the distressing symptoms and providing psychosocial and spiritual support to reflect the patient鈥檚 needs, values, beliefs, and cultural traditions.2
Homeopathic medicines have been used as complementary therapies to conventional treatments for oncologic palliative care to improve physical, psychosocial, and emotional wellbeing.3 Published research has shown that homeopathic medicines can offer clinical benefits when used as complementary therapies for palliative care of patients.3-5
The Science of Homeopathy
Homeopathy was established in the late 18th to early 19th century by a German physician named Samuel Hahnemann, who developed the system of medicine based on the notion of 鈥渓ike cures like.鈥 This principle was explained by the 鈥渓aw of similars鈥 and the 鈥渓aw of minimum dose鈥, which suggest that a substance that elicits specific symptoms in a healthy individual can, when administered in an extreme diluted form, treat those same or similar symptoms in a sick person. Homeopathic medicines are derived from natural sources such as plants, animals, or minerals. These raw materials are used to prepare the mother tincture, which then undergoes the potentization process involving serial dilutions with water and alcohol in defined ratios, followed by vigorous shaking (succussion), between each dilution step. The dilution and succussion methods are repeated until the desired potency is reached. According to homeopathic principles, the serial dilution and succussion steps are essential for activating the therapeutic properties of the medicine to stimulate the body鈥檚 intrinsic self-healing responses.6 Figure 1 illustrates the manufacturing and potentization process of homeopathic drug products.
Homeopathic dilutions are classified into three main types: Hahnemann鈥檚 Centesimal (C), Hahnemann's Decimal (X), and the Centesimal Korsakovian (CK) scale. While all three systems employ serial dilution and succussion steps, they differ in the solute: solvent ratio. The C potency uses a dilution factor of 100, while X potency utilizes a factor of 10. The process of dilution and succussion is repeated to increase the potency by one Centesimal each time. To produce high potency medicines, this sequence of serial dilutions and succussions is replicated until the desired potency is achieved. Therefore, a 30C dilution has a higher potency than a 6 C dilution.6,7
While potency is relevant to homeopathy, the accurate selection of homeopathic medicine according to the law of similars is of utmost importance.7 Additionally, individualized homeopathic choice relies on characteristic features, including the patient鈥檚 symptom sensations, factors that improve or worsen the symptoms (modalities), and concomitant symptoms (concurrent signs with the primary complaints).8
The Federal Food, Drug, and Cosmetic (FD&C) Act of 1938 classify homeopathic medicines as drugs.9 Homeopathic drug products (HDPs) are regulated as such by the United States (U.S.) Food and Drug Administration (FDA) and are subjected to requirements of the Homeopathic Pharmacopoeia of the United States (HPUS). HPUS serves as the official compendium, recognized by the FDA under the FD&C Act to set manufacturing standards and quality specifications for homeopathic medicines.10 In addition, HDPs must comply with the Federal Trade Commission (FTC) regulations on advertising requiring that all marketing claims be truthful and not misleading. The FTC enforces advertising responsibilities related to HDP labels that must contain the same components as allopathic medications (e.g. national drug code, therapeutic category, active ingredients, uses, warning, directions, and net contents), with the exception of the expiration date, which is optional. HDPs are also required to carry the FTC disclaimer to state that claims are based on traditional homeopathic practice and are not FDA evaluated.11-12
Homeopathic medicines are complementary to conventional treatments in managing certain acute and self-limiting conditions.13 They are marketed as single remedies or as multiple ingredient formulations sold as branded products (sometimes referred to as homeopathic complex products or regimens).6 The most common form of homeopathic medicines are pellets for sublingual administration. Other forms are available as oral liquids, topicals such as creams, ointments, or gels, and suppositories.14 Homeopathic dilutions are categorized into low, medium, or high potency, which are associated with the scope of symptom relief, ranging from localized to generalized, systemic effects.6-8
Table 1 summarizes the characteristics of symptom sensations, modalities, and concomitants (if present) for the common homeopathic medicines used in oncologic palliative care.8 Table 2 provides a summary of published homeopathy clinical trials evaluated for oncologic palliative care.15-25
Role of Homeopathy in Oncologic Palliative Care
Homeopathy for Palliative Care Following Oncologic Surgeries
Postsurgical complications may include infections, bleeding, pain and inflammation, seroma, and delayed healing. Seroma is a common post-operative complication characterized by the accumulation of serous fluid within the dead space at the surgical site. Its symptoms include swelling under the skin, tenderness and soreness to the touch, and possible fluid discharge from the site. Despite an emphasis on preventative measures, seroma formation persists and is primarily treated with fine needle aspirations or other approaches, which may increase risk for infection, limited mobility, and pain.26 Studies have demonstrated significant clinical benefits with Arnica montana when compared to placebo to reduce seroma formation and improve patient recovery outcomes following invasive procedures.15-16
Arnica montana鈥檚 action resembles the effects from trauma and muscular overexertion, which manifests as symptoms of bruising, achiness, and muscular pains. Symptoms associated Arnica are aggravated by the slightest touch, physical exertion, or movement, but improved with rest. By using the principle of 鈥渓ike cures like鈥, Arnica is indicated for trauma, contusion or bruising, muscle overexertion, sports-related injuries, and post-surgical recovery. In general, Arnica low potency ( less than 6C) products are used for localized trauma or bruising, while medium (6C or 9C) and high potencies (15C or 30C) are administered for generalized or extended pain. The dosing frequency can vary from two to six times daily, with more intense pain requiring more frequent dosing.8
In a randomized, double-blind, placebo-controlled trial, Sorrentino et al. investigated the impact of Arnica montana on post-operative blood loss and seroma production in women undergoing unilateral total mastectomy. The study randomized 53 patients to receive either Arnica or placebo. Both groups were monitored for post-operative drainage volumes over a 5-day follow-up period. While the overall difference in drainage volumes between groups did not reach statistical significance in the initial analysis (p=0.11), a regression analysis, which accounted for patient weight, treatment type, and fluid collected on the day of surgery, revealed a statistically significant reduction in total post-operative drainage volume for patients in the Arnica group (p=0.03). This result suggests that factors such as patient characteristics and surgical factors may have influenced the treatment鈥檚 effect. Additionally, the study found that drainage volumes on days 2 and 3 were statistically significantly lower in patients treated with Arnica (p=0.033) compared to those in placebo group (p=0.0223).15
Bellis perennis is another homeopathic medicine which exhibits similar actions to Arnica. It is indicated especially for trauma of the breast, including biopsy and lumpectomy.8 Arnica and Bellis combination has been studied in breast cancer patients undergoing surgery and reconstruction.16
Lotan et al. conducted a randomized, double-blind, placebo-controlled trial to evaluate the efficacy of homeopathic agents, Arnica montana and Bellis perennis, in reducing seroma formation following mastectomy and immediate breast reconstruction. The study randomized 55 patients (78 breasts) to receive either homeopathic medicines or placebo from the day of surgery until drain removal. The homeopathy treated group experienced 18% (2.4 days) reduction in drain removal time, averaging 11.1 days compared to 13.5 days in the placebo group, (p<0.05). The homeopathy treated patients also showed a trend towards lower opioid consumption post-operatively when compared to the placebo group (p<0.057). These study results suggest that Arnica montana with Bellis perennis may be beneficial in reducing seroma formation and decrease the need for opioid analgesics following mastectomy and breast reconstruction.16
Homeopathy for Palliative Care Following Radiotherapy
Another adverse effect occurring during cancer treatment is radiodermatitis. Radiodermatitis is a skin reaction to radiation exposure, which presents as erythema, dry or moist desquamation, ulcerations, or necrosis, affecting about 95% of cancer patients undergoing radiotherapy.27 Heightened skin sensitivity and fragility may be exacerbated in individuals undergoing concurrent chemotherapy which could further increase risk of radiodermatitis development.28 The Radiation Therapy Oncology Group (RTOG) classifies symptoms of acute dermatitis into 4 grade levels: Grade 1 (faint or dull erythema, dry desquamation), Grade 2 (bright or tender erythema, moist desquamation, moderate edema), Grade 3 (flowing, moist desquamation, running edema), and Grade 4 (ulceration, bleeding with or without necrosis).29 General recommendations for radiodermatitis include local skin hygiene and protection from sun exposure with sunscreen and proper clothing.27 Additional interventions may include certain topical corticosteroids such as betamethasone and mometasone, topical olive oil, polyurethane film, and low-level laser therapy.30
Calendula officinalis and Atropa belladonna are homeopathic medicines which have been evaluated for radiodermatitis in cancer patients receiving radiotherapy.17-19 Clinical evidence has shown Calendula to be beneficial for radiodermatitis.17-18 Calendula topical solution or ointment is typically prescribed as an antiseptic for healing wounds and skin ulcers, as well as an anti-inflammatory agent for insect bites or in contact with stinging agents. For wounds or skin ulcers, the affected area should be cleaned, followed by application with a thin layer of topical ointment and covered lightly. Calendula pellets in low dilution (4C or 5C) may be administered for the prolonged effect for healing wounds and skin ulcers.8
Pommier et al. evaluated the effects of Calendula officinalis in 254 breast cancer patients during radiotherapy. 17 The study randomized patients who underwent lumpectomy or mastectomy, to receive either Calendula (n=126) or trolamine (n=128) ointment twice daily or more until radiotherapy completion. Primary outcome of acute dermatitis RTOG grade 2 or higher was significantly lower in the Calendula group compared to the trolamine group, (41% vs. 63%, p<0.001). Calendula may be a beneficial alternative adjunctive treatment option for irradiated skin in breast cancer patients.17
Schneider et al. conducted a double-blinded, randomized controlled trial evaluating Calendula officinalis versus essential fatty acids (EFA) for the prevention and treatment of radiodermatitis in 51 head and neck cancer patients. 18 The primary endpoint was radiodermatitis development based on the RTOG criteria. A lower proportion of radiodermatitis grade 2 was observed in the Calendula group when compared to the EFA group (p=0.0120). The occurrence of radiodermatitis grades 1 and 2 were also lower in patients who received Calendula than EFA, 63.64% vs. 65.22% and 13.64% vs. 34.78%, respectively. Calendula delayed the development of radiodermatitis when compared to EFA, given that there was higher occurrence at the 15th to 20th radiotherapy session in the EFA group (71.42%), while most radiodermatitis was observed at the 20th session in the Calendula group (53.85%). These study results support Calendula officinalis as effective therapy in the prevention and treatment of skin toxicity in head and neck cancer patients receiving radiotherapy.18
Apis mellifica, Cantharis vesicatoria, and Atropa belladonna are homeopathic medicines that have also been used for sunburn or radiodermatitis due to their healing effects on skin burn and inflammation.8 Table 1 provides a summary of these homeopathic remedies. Apis manifests its effects similar to its honeybee source, which are stinging and burning pain sensations. Cantharis vesicatoria, like Apis, is also linked with intense burning skin that is worsened by touch.8
Belladona, also known as Atropa belladonna, is associated with the sensations of having dry mucous membranes, throbbing pains, congested and warm face, and cramping pains with a sudden onset and ending. It is indicated for inflammatory conditions such as first-degree burns, sunburns, and radiodermatitis.8 Despite their traditional use in homeopathy for skin burns and inflammation, limited clinical data has been reported for radiodermatitis.19
Balzarini et al. (2000) conducted a double-blind, randomized clinical trial to compare the efficacy of Belladonna versus placebo for the treatment of radiodermatitis in 66 breast cancer patients during radiotherapy and during recovery. 19 Although there were no statistically significant differences in the Index of Total Severity Scores (the sum of the scores of the 4 parameters of breast skin color, warmth, swelling, and pigmentation), there was a positive trend in efficacy of the homeopathic treated group. Investigators noted the small sample size could have affected the statistical significance; thus, further study with an adequately powered sample size may be needed to test the hypothesis.19
Homeopathy for the Management of Cancer Treatment-Induced Toxicities
Oral mucositis, or stomatitis, is characterized by the painful inflammation of the mucous membranes in the mouth. Stomatitis is a cancer therapy-induced complication affecting 40% of chemotherapy-treated patients, and up to 85% of patients undergoing stem cell transplantation experience oral mucositis. Management of stomatitis focuses on maintaining oral hygiene, using bland rinses, and avoiding general irritants. Severe cases may warrant the use of systemic analgesics or topical anesthetics.31 Although there are preventative and treatment options for stomatitis, they are limited by suboptimal efficacy.31 Homeopathic medicines have been evaluated for symptom improvements in patients with radiation 鈥 and chemotherapy 鈥 induced stomatitis.20-21
Oberbaum et al. performed a randomized, double-blind, placebo-controlled clinical trial to compare the effect of a homeopathic complex regimen (treatment group) to placebo on stomatitis in patients undergoing stem cell transplantation. 21 Thirty patients ranging in ages 3 to 25 were equally randomized to either the treatment or placebo, where the treatment group received the homeopathic complex mouth rinse five times daily starting from day 2 following transplantation. The difference in mean stomatitis scores was significantly less in the treatment group than placebo (10.4 vs. 24.3, p<0.01). The study results support the homeopathic complex regimen as a potential complementary medicine to reduce duration and severity of stomatitis in children undergoing stem cell transplantation. Further research is needed for patients who are at risk for chemotherapy-induced oral mucositis.21
Chemotherapy-induced nausea and vomiting (CINV) is another self-limiting sequelae of cancer therapy. Prevention and treatment of CINV depend on the emetogenic risk, combinations of 5-HT3 antagonists (e.g. ondansetron, granisetron), neurokininin-1 receptor antagonists (e.g. aprepitant), corticosteroids, and others may be tailored to acute, delayed, and breakthrough symptoms.32 Despite conventional anti-emetics to prevent or minimize CINV, patients may not completely avoid such adverse effects.32
Arsenicum album, a homeopathic medicine that is prepared from serial dilutions of arsenic trioxide, exerts its action to cause symptoms related to acute arsenic toxicity such as extreme fatigue, severe sensitivity to cold, and excessive burning sensation. Based on the principles of 鈥渓ike cures like鈥 and 鈥渕inimum dose鈥, Arsenicum is considered for conditions such as food poisoning, acute gastroenteritis, asthenia, weight loss, and reactive depression.8 Additionally, it has been included as part of palliative care for patients experiencing CINV.33Arsenicum was included in individualized homeopathic treatment protocols of studies focused on improving QoL.24
Nux vomica is derived from poison nuts, which act to cause symptom sensations of hypersensitivity to light, noise, smell, and coldness, in addition to confusion. Based on the 鈥渓aw of similars鈥, Nux is primarily used to treat behavioral disorders such as irritability, anger, addictive tendency, along with digestive conditions including heartburn and 鈥渉angover鈥 effects from excessive alcohol consumption.8Nux vomica has been evaluated as an individualized homeopathic medicine and as part of a multi-ingredient formulation (homeopathic complex product) for oncologic palliative care.22,24
P茅rol et. al conducted a randomized, multi-centered, double-blind, placebo-controlled clinical trial in non-metastatic breast cancer patients to explore the effects of a homeopathic complex product on CINV. 22 A total of 431 patients were assigned to receive the homeopathic complex (HC) or placebo (P) in addition to conventional emetic treatment (ondansetron 8mg and methylprednisolone 80mg) at the beginning of chemotherapy. There was no difference in the Functional Living Index (FLIE) nausea scores in the HC group vs. placebo (6.07 vs. 6.02, p=0.84) after the first chemotherapy session. Despite not finding statistical significance, lower rates of CINV were observed in the HC group when compared to the P group, indicating the need for further research to confirm potential benefit of the homeopathic complex for CINV in breast cancer patients.22
Gelsemium sempervirens and Ignatia amara are homeopathic medicines indicated for psychosocial and emotional disorders such as stress and sleep disturbance.8 Gelsemium is commonly used to alleviate behavioral disorders such as nervous apprehension, anxiousness, and sleeplessness due to anticipatory anxiety. Similar to Gelsemium, Ignatia is used for nervous apprehension, anxiety, sleeplessness, and stress-related conditions.8 Although these homeopathic medicines may be used as complementary therapies for patients experiencing behavioral disorders associated with cancer or cancer treatments, data from clinical trials is lacking.
Homeopathy on Quality of Life and Survival
Homeopathy is being used by cancer patients to support their QoL.5 There is evidence to suggest that homeopathic medicines individualized to patient symptoms have significantly improved QoL in cancer patients.24-25
Frass et al. conducted a randomized, double blind, placebo-controlled trial to evaluate the impact of individualized homeopathic treatments on QoL and survival outcomes in 150 patients with stage IV non-small cell lung cancer (NSCLC). Patients in the homeopathy and placebo groups received either individualized homeopathic medicines or identical placebos. Results from this study demonstrated significant improvements in QoL, functional status, and symptom burden at 9 and 18 weeks (p<0.001). Median survival in the homeopathy group reached 435 days, which was significantly longer compared to 257 days in the placebo group (p=0.01) and 228 days in the control group (p<0.001).24
Rostock et al (2011) conducted a prospective observational study which included two independent groups of cancer patients: 259 received individualized homeopathic treatment and 380 received conventional supportive care. The homeopathic treatment was individualized and tailored to the patients鈥 unique symptom profile, ensuring a personalized approach to care. QoL scores were assessed at baseline, 3 months, and 12 months. Significant improvements were reported in QoL of patients receiving individualized homeopathic treatment when compared to conventional supportive care at 3 and 12 months (p<0.001). Secondary outcomes of fatigue, pain, and nausea were also improved in the individualized homeopathy group.25
Evidence from clinical trials which demonstrated improved QoL in cancer patients treated with individualized homeopathic medicines adjunctively with conventional therapies supports their use in oncologic palliative care.23-25 However, there are also studies which have reported non-significant results with homeopathic medicines on cancer related symptoms and QoL.19,22
From a safety perspective, adverse effects of homeopathic agents have been evaluated in a systematic review to include 41 observational studies comparing homeopathy to control.34 The homeopathy groups were associated with less adverse effects than conventional medicines or other complementary therapies. Adverse effects from the homeopathy groups were classified as minor to moderate similar to the control groups according to the Common Terminology Criteria for Adverse Events (CTCAE).34
While some studies suggest that homeopathic medicines may offer potential benefits as complementary therapies in oncologic palliative care, including reducing pain, relieving treatment-related side effects, and improving QoL, the available data remains limited and heterogenous. Many existing clinical trials are characterized by small sample size, variable study methodologies, and inconsistent outcome measures, which limit the generalizability of the findings. To better understand the role of homeopathy in palliative cancer care, well-designed randomized controlled trials and systematic reviews are needed for the development of an evidence-based, complementary treatment approach to palliative care.
Implications for Practicing Pharmacists
The U.S. HDP market is projected to grow from $2.37 billion in 2023 to $6.8 billion by 2035, reflecting a compound annual growth rate of about 9% over the next decade.35
Since most homeopathic medicines are sold as over the counter (OTC) products in the U.S.9, pharmacists often serve as the first health care practitioners who patients seek for advice and product consultations. In a survey study by Millward et al., practicing pharmacists reported having limited knowledge about homeopathy, even though HDPs are readily accessible for direct-to-consumer purchase.36 In a survey conducted by Khader et al, faculty from U.S. pharmacy schools highlighted that pharmacists need to be knowledgeable about homeopathic products and capable of effectively communicating this information to patients.37
Pharmacists are trained to evaluate patients with self-limiting conditions and to determine whether self-care is appropriate or if referral for further medical evaluation is warranted. When patients choose alternative or complementary therapies, pharmacists should be prepared to identify situations where homeopathy is or is not appropriate for self-care. Patients should be educated that homeopathic medicines may be suitable as complementary therapies for oncologic palliative care, if desired, but they are not approved by the FDA to treat or cure cancer.
Like all medications, it is essential to educate patients on when to seek medical care and not to delay or replace required medical treatments. It is worth noting that HDPs are generally well tolerated, as demonstrated in controlled clinical trials and observational studies.34 However, patients should discontinue use or seek medical advice if they experience worsening symptoms, allergic reactions, (e.g. rash, hives, swelling of lips, tongue, throat or eyes, nausea, vomiting, diarrhea, or wheezing), or lack of improvement. Patients should avoid use if they have a known allergy to the source material of homeopathic medicine. Although most HDPs sold in the U.S. are highly diluted, patients should still inform their health care providers of all medications they are taking, including homeopathic medicines, so that any potential for drug interactions are properly evaluated.14
Patients should be instructed to follow administration directions provided on the product label. Oral pellets are administered sublingually by allowing them to dissolve under the tongue. Oral liquids should be taken by mouth using the measuring device provided with the HDP to ensure accurate dosing. Topical formulations are for external use only and should be applied to the affected area, avoiding opening wounds and the eyes or mouth.
In conjunction with the information from this article, pharmacists should rely on resources such as the Pharmacology and Homeopathic Materia Medica, Homeopathic Therapeutics: Frameworks and Protocols, and reputable online apps or platforms for the point-of-care HDP selection and patient consultations.8,33 It is important to advise patients to use HDPs that are monographed with the official HPUS, to encourage them to carefully read product labels, and to not stop or delay prescribed therapies without provider guidance.
Conclusion
Homeopathy is a complementary therapeutic approach based on the principles of 鈥渓ike cures like鈥 and 鈥渕inimum dose鈥. Homeopathic medicines such as Arnica and Calendula are used as adjunctive therapies to help manage acute or self-limiting cancer treatment-related symptoms. Pharmacists play an essential role in understanding the science of homeopathy to effectively educate patients seeking information on HDPs as complementary treatment options for oncologic palliative care.