Short-Term Pain Relief from Electroacupuncture and Electroceutical Stimulation at ST36 and SP9 in Cancer Patients: A Retrospective Case Series
Article information
Abstract
Background:
Electroacupuncture (EA) and electroceutical stimulation (EC) have shown promise for pain management, although clinical evidence in cancer patients is limited.
Methods:
This retrospective case series analyzed cancer patients hospitalized at Daejeon Korean Medicine Hospital between January 1 and March 31, 2025 who had received a session of EA or EC at ST36 and SP9. Pain severity was assessed using the Numeric Rating Scale (NRS) at baseline, immediately after, and 15 minutes posttreatment. Changes were analyzed using repeated measures ANOVA with Bonferroni-corrected post hoc tests.
Results:
Nine female cancer patients were included. Overall NRS scores declined over time, with a significant reduction from baseline to 15 minutes (p=.047). Pain reduction was more evident in patients with chemotherapy-induced or non-cancer-related musculoskeletal pain, whereas no significant change was observed in those with cancer-related pain.
Conclusions:
EA or EC at ST36 and SP9 may offer immediate pain relief in cancer patients with chemotherapy-induced or other musculoskeletal pain. Further studies to confirm efficacy and clarify indications are warranted.
I. Introduction
Pain is one of the most prevalent and distressing symptoms experienced by individuals with cancer, significantly compromising quality of life and interfering with daily functioning1. A recent meta-analysis reported that pain prevalence among cancer patients reaches 66.4% in those with advanced or terminal disease, 55.0% during anticancer treatment, and 39.3% even after curative therapy2. Furthermore, nearly half of cancer survivors (47%) report persistent chronic pain, either as a sequela of prior treatments-including chemotherapy, radiotherapy, or surgery-or due to comorbid conditions unrelated to cancer3.
Pharmacologic approaches, particularly non-steroidal anti-inflammatory drugs (NSAIDs) and opioids, remain central to cancer pain management. However, their effectiveness is often limited. Approximately 40% of patients report inadequate pain relief or experience adverse effects-including sedation, constipation, and the risk of dependency-that restrict ongoing treatment4. These limitations have prompted growing interest in complementary and integrative therapies, such as acupuncture, for supportive symptom management in oncology settings5,6.
Among these approaches, electroacupuncture (EA), which combines traditional acupuncture with low-frequency electrical stimulation, has shown promise in modulating nociceptive signaling by activating endogenous opioids, regulating neurotransmitters, and reducing inflammation7,8. More recently, electroceutical (EC) devices, which are noninvasive, patch-type devices designed to deliver transcutaneous electrical stimulation, have emerged as needle-free alternatives that offer broader accessibility and better patient acceptability9,10. Acupoints such as ST36 and SP9 are commonly targeted in both EA and EC interventions due to their analgesic properties, likely mediated through multiple mechanisms including modulation of inflammatory pathways, activation of endogenous opioids, and local adenosine release11-15.
Despite their increasing clinical use, evidence regarding the immediate analgesic effects of EA and EC remains limited, particularly in cancer populations. Regarding the growing use of EA and EC at the ST36 and SP9 acupoints in our clinic, this study aimed to retrospectively evaluate their short-term analgesic effects in hospitalized cancer patients. Additionally, we sought to assess whether treatment responses differ by pain etiology and to compare the observed effects between EA and EC modalities.
II. Methods
1. Study design
This retrospective observational case series was conducted at Daejeon Korean Medicine Hospital, Daejeon University. Medical records of cancer patients hospitalized between January 1 and March 30, 2025, were reviewed. The study period was intentionally limited to coincide with the recent introduction of EA and EC at ST36 and SP9 for cancer pain management, ensuring consistent documentation and standardized treatment protocols. The study was approved by the Institutional Review Board (DJDSKH-25-E-03-1), and written informed consent was obtained from all participants.
2. Inclusion criteria
Patients were eligible for inclusion if they met the following criteria: (1) a confirmed diagnosis of cancer; (2) documented pain with clearly defined etiology (e.g., musculoskeletal, neuropathic, visceral, or cancer-related); (3) received a session of EA or EC stimulation at bilateral ST36 and SP9; (4) pain intensity assessed using the Numeric Rating Scale (NRS) at predefined time points.
3. Data extraction
The following variables were extracted from the medical records: (1) patient ID, age, and sex; (2) primary cancer site and current disease status; (3) pain location, presumed etiology, and analgesic use; (4) type of intervention (EA or EC) and parameters; (5) Pain scores measured by NRS at baseline, immediately post-treatment (0 min), and at 15 minutes post-treatment.
4. Pain classification
Pain was categorized into three etiological groups: (1) cancer-related pain - pain due to tumor invasion or metastasis; (2) cancer therapy-related pain - pain induced by anticancer treatment (e.g. chemotherapy, surgery, or radiation); (3) Other pain - pain unrelated to cancer or its treatment, such as degenerative joint disease, frozen shoulder, or hernia.
5. Intervention
All patients received a single session of either EA or EC stimulation applied bilaterally to two standardized acupoints: ST36 (足三里) and SP9 (陰陵泉) (Fig. 1A). The duration of stimulation was fixed at 15 minutes for both modalities.
Intervention modalities and individual pain responses.
(A) Schematic illustration of treatment modality and acupoint locations for each case. All patients received a single session of electroacupuncture (EA) or electroceutical (EC) stimulation at bilateral ST36 and SP9. (B) Individual Numeric Rating Scale (NRS) scores recorded at baseline, immediately after treatment, and 15 minutes post-treatment.
EA was performed using 0.25×30 mm sterile disposable needles (Dongbang Healthcare Products, Seoul, Korea) inserted at each acupoint. Electrical stimulation was delivered using an EA device (STN-330, StraTek, Anyang, Korea) set to a frequency of 2 Hz. The intensity was gradually increased until the patient reported a clear but comfortable perception of stimulation, ensuring subjective awareness without discomfort.
EC stimulation was administered using a patch-type electrical stimulator (WE-3000, MEDIWE, Osan, Korea) combined with 0.18×1.3 mm sterile disposable needles (Dongbang Healthcare Products, Seoul, Korea) applied to the same bilateral acupoints. Needles were inserted into the acupoints, after which a device patch was placed over them to deliver an electric current through the needles. Stimulation intensity was adjusted from level 1 to 5 based on each patient’s report of perception.
6. Statistical analysis
Descriptive statistics (mean±standard deviation) were calculated for NRS scores at each time point. Shapiro-Wilk tests were used to assess the normality of data distributions. Repeated measures analysis of variance (ANOVA) was conducted to evaluate changes in pain intensity over time (baseline, immediately post-treatment, and 15 minutes post-treatment). Mauchly’s test was performed to assess the assumption of sphericity. Bonferroni- adjusted post-hoc comparisons were applied to determine which specific time points differed significantly. Due to the small sample size and limited statistical power, subgroup analyses by pain type and intervention type (EA vs. EC) were descriptive only. All analyses were performed using R (version 4.3.2).
III. Results
1. Patient Characteristics
A total of nine patients with cancer were included, with a median age of 65 years (range, 48-81 years). The primary cancer sites were the bladder (n=1), ovary (n=1), lung (n=1), pancreas (n=1), kidney (n=2), breast (n=1), and thyroid (n=2). Disease status varied from no evidence of disease (NED) to recurrent or metastatic conditions.
Pain etiologies were categorized as follows: cancer-related pain (n=2), chemotherapy-related pain (n=2), and other non-cancer-related pain (n=5), including degenerative arthritis, compression fracture, frozen shoulder, and hernia. Three patients were on analgesics ranging from acetaminophen to oxycodone. Of the nine cases, four received EA and five received EC. No adverse effects were observed in any of the patients. Detailed case information is presented in Table 1.
Patient Characteristics and Changes in Pain Scores (NRS)
2. Changes in Pain Severity
Individual changes in NRS scores across the three time points (before, 0 min, and 15 min) are presented in Figure 1B. Overall, the mean NRS score decreased from 5.9±2.0 at baseline to 4.9±2.6 immediately after treatment, and further 4.6±2.5 at 15 minutes post-treatment, demonstrating a statistically significant reduction in pain over time (p=.004), particularly between baseline and 15 minutes (p=.047) (Fig. 2A). Detailed statistical results are presented in Table 2.
Changes in pain severity over time.
(A) Overall trend in pain scores across time points (baseline, immediately post-treatment, and 15 minutes post-treatment). Mean values with standard deviations are presented. (B) Stratified analysis by pain etiology : cancer-related pain, chemotherapy-related pain, and other pain. (C) Stratified analysis by intervention type : EA vs EC. EA : electroacupuncture, EC : electroceutical, NRS : Numeric Rating Scale, ns : not significant.
Statistical results of normality, ANOVA, and post-hoc analyses
3. Subgroup Analysis by Pain Etiology and Intervention Type
Subgroup analyses by pain etiology and intervention type were performed, with results reported descriptively due to the limited sample size. Among patients with cancer-related pain (n=2), no meaningful change in NRS was observed. Both cases involved stage IV disease with ongoing opioid use. In the chemotherapy-related pain group (n=2), both patients showed reduction in NRS scores. Among those with other types of pain (n=5), 4 out of 5 patients showed reductions in NRS scores (Table 1, Fig. 2B).
Among the four patients treated with EA, two showed NRS reductions: one with chemotherapy-related pain and one with hernia-related pain. The remaining two, who had cancer-related pain, showed no response. Among the five patients treated with EC, four showed clinically meaningful reductions in NRS scores. Most patients with musculoskeletal and degenerative pain who received EC reported reductions in pain severity (Table 1, Fig. 2C).
IV. Discussion
This retrospective case series of 9 cancer patients evaluated the short-term effects of electroacupuncture (EA) and electroceutical (EC) stimulation at bilateral ST36 and SP9 on pain intensity. On average, NRS scores showed a decreasing trend over time, with a statistically significant reduction between baseline and 15 minutes post-treatment. These effects were particularly evident in cases of musculoskeletal pain, whether related to chemotherapy or unrelated to cancer and its treatment. Both EA and EC appeared to provide short-term analgesic benefits.
Cancer patients frequently experience pain from a variety of sources—not only from cancer itself or its treatment, but also from chronic musculoskeletal conditions, which are both common and clinically significant. In this context, complementary therapies, including EA, have been increasingly explored to improve pain management and overall quality of life. For example, a recent randomized trial evaluated the effects of EA on chronic musculoskeletal pain in 360 cancer survivors16. In this study, EA on acupoints including ST36 and SP9 (varied by individual pain location or general symptoms) produced greater reduction in pain severity compared to usual care. Several animal studies have also reported analgesic effect of EA on ST or SP9. For instance, EA on ST36 has been shown to alleviate paclitaxel-induced mechanical allodynia in rat models while sham EA did not produce this effect11. A study with rheumatoid arthritis-induced rat models reported that EA on both ST36 and SP9 showed decrease in nitric oxide synthase-positive neurons at each site, with more pronounced effects when both acupoints were used in combination17.
Several mechanisms have been proposed to explain the analgesic effects of EA at ST36 and SP9. Central mechanisms include modulation of TRPV1-related pathways, inhibition of sympathetic sprouting in the dorsal root ganglion, and suppression of neurogenic inflammation via the ERK and TLR4 pathways12,14. Another potential mechanism involves the local release of adenosine, acting through adenosine A1 receptors, which has been shown to exert analgesic effects18. A clinical study reported that acupuncture at ST36 significantly increased adenosine levels, whereas stimulation at a non-acupoint located 2 cm lateral to ST36 did not produce this effect19. Interestingly, the study also found that acupuncture at ST36 without needle rotation failed to increase adenosine levels, which may imply that adequate stimulation, such as that delivered by EA or EC, may be essential for achieving effective analgesia.
In contrast, cancer-related pain did not respond meaningfully to electrostimulation in this study. Both patients in this subgroup had stage IV disease and were on opioid analgesics. The lack of response in this subgroup may be attributed to opioid-induced hyperalgesia, neuroplastic changes, or the complex pathophysiology involving visceral infiltration and central sensitization, which are often refractory to localized interventions20. These findings underscore the need for differentiated treatment strategies tailored to the etiology of cancer pain.
Given the small sample size and observational design, this study was not intended to compare the efficacy of EA and EC. Although descriptively better outcomes were observed in the EC group, these findings may be incidental and should not be overinterpreted. Nevertheless, the patch-type EC device offers advantages such as noninvasiveness, ease of application, and greater patient acceptability, which is particularly relevant in oncology settings involving immunocompromised or patients with needle aversion, or those unable to tolerate prolonged procedures.
Several limitations must be considered. First, the sample size was small (n=9) and comprised only female patients, which limits generalizability. Second, the retrospective design and absence of a control group preclude causal inferences. In addition, the stimulation intensity could not be standardized across patients due to the retrospective nature of the study. Third, pain classification was based on clinician notes rather than standardized diagnostic criteria, introducing potential misclassification bias. Moreover, only immediate post-treatment outcomes were assessed, and follow-up data were excluded due to overlapping interventions such as medication adjustments, herbal therapy, and additional acupuncture, which may have confounded pain trajectories.
Despite these limitations, this study provides preliminary support for the feasibility and short-term utility of EA and EC as adjunctive interventions for pain in cancer patients, especially for musculoskeletal and chemotherapy-related pain. Future studies should employ randomized controlled designs with larger, more diverse populations and standardized intervention protocols. Additionally, comparisons across different acupoint combinations and stimulation intensity would help identify optimal treatment parameters and further elucidate underlying mechanisms.
V. Conclusion
This retrospective case series suggests that EA and EC stimulation targeting ST36 and SP9 may offer immediate pain relief in selected cancer patients, particularly those with musculoskeletal or treatment-related pain. In contrast, patients with advanced cancer-related pain did not demonstrate short-term improvements, highlighting the complex nature of this pain subtype. While these preliminary findings support the feasibility of EA and EC as adjunctive therapies, further rigorous studies are needed to confirm efficacy, identify optimal candidates, and establish their role in integrative pain management for cancer patients.
Acknowledgments
No funding to declare.
Conflict of Interest
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.