Effectiveness and Safety of Acupuncture for Nausea and Vomiting in Cancer Patients: A Systematic Review and Meta-Analysis

Acupuncture represents one of the most studied complementary therapies for the relief of nausea and vomiting in oncology patients, a problem that affects more than 80% of people undergoing cancer treatments. These symptoms are not only uncomfortable but can lead to serious complications such as dehydration, malnutrition, and even cause patients to discontinue treatment. Although effective antiemetic medications exist, they do not always fully control symptoms and can cause unwanted side effects, creating a need for safe and effective complementary approaches.

This systematic review and meta-analysis sought to comprehensively evaluate the efficacy and safety of acupuncture in the control of nausea and vomiting in cancer patients undergoing different types of treatment. The investigators conducted an extensive search across three medical databases and two clinical trial registries, analyzing studies published through December 2024. Only randomized controlled trials comparing needle acupuncture (including manual acupuncture, electroacupuncture, and auricular acupuncture) with control groups — either sham acupuncture or usual care — were included. The methodology followed rigorous international standards, with two independent investigators evaluating each study to minimize bias and ensure the quality of the analysis.

The results revealed important and clinically relevant findings. Seventeen studies were included in the review, totaling 2,036 patients, and twelve of these provided sufficient data for the quantitative meta-analysis. Acupuncture did not show significant effects on nausea or vomiting in the acute phase, which occurs within the first 24 hours after cancer treatment. However, it proved effective in controlling delayed vomiting, which appears more than 24 hours after treatment.

This finding is particularly valuable because delayed vomiting is often more difficult to control with conventional medications and tends to persist for several days, causing prolonged suffering to patients. Subgroup analysis revealed that the benefits of acupuncture become more evident when treatment is maintained for at least five consecutive days.

Regarding the acupuncture points used, the study identified a specific combination of sites that were most frequently employed in the trials. Point PC-6, located on the wrist, was the most used, appearing in fifteen of the seventeen studies analyzed. This point is traditionally known for its efficacy in controlling nausea and already has solid scientific support. The second most common point was ST-36, located on the leg, followed by other points such as CV-12 (abdomen), LI-4 (hand), LR-3 (foot), and ST-25 (lateral abdomen).

This combination of points acts on different body systems, modulating both the nervous system and gastrointestinal functions, which may explain its efficacy in controlling symptoms.

From a safety standpoint, the results were reassuring for patients and clinicians. No serious adverse events related to acupuncture were reported in any of the studies analyzed. The side effects observed were classified as mild to moderate, including primarily small localized bleeding at the needle insertion sites, mild pain during application, and occasionally small bruises. These findings are especially important given that oncology patients frequently have compromised immune systems and may be using multiple medications — situations that could theoretically increase the risk of complications.

The clinical implications of these findings are significant for both patients and clinicians. For patients, especially those who experience persistent delayed vomiting despite the use of antiemetic medications, acupuncture represents an additional safe and potentially effective therapeutic option. The treatment can be integrated into conventional oncology care protocols without interfering with other treatments or medications. For clinicians, the results suggest that acupuncture should be considered as part of a multimodal approach to symptom control, especially when implemented for at least five consecutive days and using the point combination identified as most effective.

It is important to acknowledge the limitations of this study, which provide important directions for future research. Most of the analyzed studies focused on nausea and vomiting caused by chemotherapy, with less attention to symptoms related to radiotherapy, surgery, or other aspects of oncology treatment. In addition, many studies used acupuncture in combination with antiemetic medications, making it difficult to determine exactly how much of the observed benefit can be attributed specifically to acupuncture. Treatment protocols also varied considerably among studies, including differences in the number of sessions, treatment duration, and specific techniques used, which may have influenced the overall results.

In conclusion, this review provides solid evidence that acupuncture is a safe and effective complementary therapy for the control of delayed vomiting in oncology patients, although its efficacy for acute symptoms remains uncertain. The benefits appear to be more pronounced when treatment is maintained for longer periods, suggesting that acupuncture may exert cumulative effects over time. For patients and families considering this therapeutic option, the results indicate that acupuncture may offer significant additional relief when integrated into conventional care, with minimal risk of side effects. Future research should focus on the development of standardized treatment protocols and on exploring its efficacy across different types of cancer and treatment modalities, to maximize the benefits of this ancient therapeutic practice in the context of modern oncology.