Efficacy of episil in Japanese patients
The results of this study showed that episil is an effective device to relieve oral pain in Japanese patients with moderate to severe treatment-related OM, and its duration of action was determined to be long enough to support the patients’ oral intake. According to Hadjieva et al., who investigated the pain-relieving effect of episil in patients undergoing radiation therapy for head and neck cancer with OM, the mucositis pain score decreased rapidly 5 mins after application, and this effect appeared to last for eight hours. It has been reported that even though the adhesive film gradually peels off over time due to abrasion, its effect is not totally diminished by a single meal [14]. The present findings are consistent with these results.
To alleviate the pain of OM associated with cancer treatment, in clinical practice, systemic administration of analgesics (e.g. acetaminophen, NSAIDs, or opioids) is prescribed according to the severity of the mucositis. Similarly, it has become common practice to apply a local anesthetic, such as lidocaine, directly to the pain site to reduce pain [18].
However, there have been some challenges with the conventional methods for alleviating the pain associated with OM. Administration of systemic analgesics is good for controlling resting pain; however, it is less effective for contact pain or movement pain during eating and speaking. Moreover, the therapeutic effect following the intake of these analgesics can be delayed. In addition, systemic administration of analgesics has adverse effects, such as renal dysfunction, NSAID-induced gastric mucosal disorder, and constipation and nausea due to opioid use, which might negatively affect the performance of the cancer treatment itself [19,20]. The use of local anesthetics in patients with OM also has some problems. The effects of local anesthetics are immediate; however, their duration of action is not long, being approximately 20 to 30 mins. Occasionally, anesthetics become ineffective during meals, and oral pain may reappear. Patients have to use local anesthetics multiple times in a day. Additionally, local anesthetics block all nerve activities; hence, they paralyze all sensations in the mouth and do not just numb the oral pain. Unfortunately, this feeling is far from necessary, and even aspiration may be a concern because due to impairing the smooth swallowing reflex. In the present study, episil showed a strong pain-relieving effect within a short time, its effects were long-lasting, and frequent use was unnecessary. According to the product information leaflet, the thickness of the adhesive protective film formed by episil is approximately 0.5 to 6.5 μm, there is almost no sense of incongruity, and the taste is hardly affected. Furthermore, it can be used without concerns about systemic side effects or altering oral sensation. This study was not an actual comparison with other treatments, such as local anesthetics; however, the abovementioned points suggest that episil does not interfere with cancer treatment or adversely affect dietary QOL. This may be a clinical advantage compared to systemic analgesics or local anesthetics.
Episil has some major advantages as a pain relief formulation because, based on its mechanism of action, it does not elicit a pharmacological effect; rather, it simply offers physical wound protection. It is effective for breakthrough pain, such as contact pain during meals or talking, unlike systemic analgesics. Episil neither causes discomfort nor disturbs the pleasure of eating, and its effect is immediate and persistent. Although systemic side effects and drug-drug interactions were not investigated in this study, episil does not contain any medicinal components; therefore, it is thought that there should be less concern about its side effects due to systemic interactions with other drugs. Thus, episil may safer as a supportive therapy during cancer treatment than other treatments, such as opioids or NSAIDs.
In particular, episil may also be valuable in patients with mild OM who have not yet been treated aggressively. The active management of mild OM cases is sometimes difficult. Although the patients had a slight tingling sensation or discomfort in their mouth, making eating slightly more difficult, it was not as painful as when local anesthetics or systemic analgesics were used. Therefore, in many cases, only oral care and simple gargling or no treatment at all had been provided for mild OM patients. This suggests that episil could be a new formulation to facilitate eating and drinking without causing discomfort to such mild OM patients and contribute to improving their QOL during cancer treatment.
Effective use of episil
The use of episil itself is simple, and its use relies on the patient’s self-management. Therefore, some precautions or considerations may be required for safer and more effective use. First, it takes little time for patients to gain experience in the use of episil. In the present study, the protective effects of episil were observed 3–5 mins after its application. Thus, it seemed better to evaluate the effect after a while rather than immediately after application. Second, patients tended to apply more than the recommended quantities of episil into the oral cavity because it took some time for the effects of episil to manifest, and all patients wanted an immediate effect. However, excessive dosing may cause discomforts, such as nausea, vomiting, and even treatment interruption. Episil is designed to drip enough to cover the entire oral cavity in a single press. The recommended dose is 1–3 pump strokes, starting with 1 pump stroke and applying more as needed. However, if the patient feels uncomfortable, it is important to limit the drip to approximately three times, even if they feel the drip is inadequate. Based on the recommended dosing, the patient should start with one pump stroke and apply more if needed. Third, some patients felt slight soreness or discomfort when applying episil. However, this slight soreness due to episil’s stimulation was usually within the allowable range and transient in nature. If patients feel strong stimulation after the application of episil, it can be managed by having the patients gargle with local anesthetics, such as lidocaine, before using episil. Fourth, episil should not simply be squirted, but also spread over painful mucous membranes using the optimal amount. Severe OM causes extensive and deep pain. It was difficult for most of the patients who cannot move their tongues because of severe OM to spread episil properly in their mouth. In such cases, it was necessary to spread the liquid using a safe alternative method, such as using a finger. In addition, severe OM disturbs proper oral cleaning and gargling, which causes the patient’s mouth to become filled with viscous, dirty saliva and results in worse oral hygiene. The viscous saliva in the mouth clings to the mucous membranes and prevents episil from effectively forming a protective film. In these patients who cannot receive proper oral cleaning and gargling, episil may not work effectively, and the patients may feel discomfort. In fact, they may feel strong discomfort. Thus, it is desirable to start episil at the stage of mild to moderate OM, before the symptoms become severe. Using episil at the early stage of OM, before severe OM occurs, makes it easier for patients to experience its actual efficacy. This may facilitate the patients’ continuous usage of episil effectively even if OM becomes more severe. Finally, an unhealthy oral cavity may cause local infections, increase the grade of OM, exacerbate pain, and prolong the time to heal. During immunosuppression by chemotherapy, local infections with OM cause a high risk of spreading and systemic infections, which is one of the major concerns. To control the risk of infection in the oral cavity, professional dental care should be provided by dental hygienists and dentists, and appropriate self-care instruction should be given. In the present study, all patients were provided with adequate basic oral care by a dental care team, and no patients developed oral infections during the study period. To safely use episil, it is important that professional dental care be continued to provide oral care to patients with OM.
Although it was not a direct feeling during use, several patients reported that the pump of the container was difficult to push down firmly; therefore, it was difficult to dose/squirt the contents in their mouths. Patients with poor general conditions may have difficulty applying episil by themselves and may require the assistance of a healthcare professional, their family, or others.
The study has several limitations. The modest sample size makes it difficult to draw decisive conclusions. In addition, the questionnaire used in this study was prepared with reference to the Camurus test (HS-05-160). However, this test is not generally used in the clinical evaluation of OM. In assessing QOL in cancer patients, in particular, regarding the oral functions, a validated questionnaire on oral health, such as EORTC QLQ-OH15 may be more meaningful [21].
We did not aim to compare episil with other treatments in this study. Since the mechanism of action is completely different between episil and other treatments, a simple comparison may be difficult; however, it will be necessary to continue investigation, exploring the synergistic effect of combined use.
Despite these limitations, episil seems to be effective in Japanese patients suffering from OM pain. However, a future multi-institutional, collaborative study with a larger sample size is warranted to explore episil’s efficacy further.