The potential effects of traditional Chinese medicine on the outcomes after breast cancer surgery: a large population-based study

Abstract

Background

Detailed evidence concerning the impact of traditional Chinese medicine (TCM) on clinical outcomes for breast cancer patients in Taiwan is not yet fully available. Our research sought to examine the association between TCM integration and postoperative outcomes among women undergoing mastectomies.

Methods

Utilizing a large insurance database, we identified a cohort of adult women who underwent breast cancer surgery during the 2010–2019 period. We compared sociodemographic profiles and comorbidities between TCM users and non-users. Multiple logistic regression models were employed to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for both mortality and postoperative complications.

Results

Among 91,298 eligible patients, the one-year preoperative prevalence of TCM utilization was 39.8%. Compared to the control group, TCM users demonstrated a significantly lower likelihood of postoperative stroke (OR 0.76, 95% CI 0.62–0.93) and a reduced requirement for intensive care (OR 0.74, 95% CI 0.59–0.91). Notably, a cumulative exposure of more than four TCM consultations within the year preceding surgery was specifically linked to a decreased risk of stroke (OR 0.76, 95% CI 0.61–0.95).

Conclusion

TCM utilization is prevalent among the Taiwanese breast cancer population prior to surgery. Our findings suggest that preoperative TCM use is correlated with improved post-mastectomy outcomes, particularly regarding stroke prevention and reduced intensive care needs. Nevertheless, these observational benefits warrant further confirmation through prospective and large-scale clinical investigations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-026-05257-x.

Background

Breast cancer has emerged as the most prevalent malignancy among women globally, with 2020 estimates indicating more than 2.3 million new diagnoses annually [1, 2]. Recent longitudinal data from the United States show a steady rise (0.5% annually) in incidence from 2010 to 2019, a trend primarily attributed to the growing detection of hormone receptor-positive and localized tumors [2]. Beyond genetic predispositions such as nucleotide polymorphisms and family history, various lifestyle factors including alcohol intake, tobacco use, and body mass index are established contributors to disease risk [3]. Clinical management strategies for patients involve a personalized combination of surgical intervention, chemotherapy, and advanced biological or endocrine therapies. The selection of these treatment modalities is fundamentally guided by the specific stage of the disease and the presence of any metastatic progression [4].

Historical data indicates that more than a quarter of the elderly population in the United States utilized complementary and alternative medicine as early as 2002 [5]. Traditional Chinese medicine (TCM) represents a significant category within this framework. Patients with cancer frequently turn to TCM to manage a wide range of distressing symptoms, including sleep disturbances, chronic fatigue, vertigo, and gastrointestinal issues, as well as psychological burdens like anxiety and depression [6]. The integration of TCM with conventional Western oncology has been recognized as a beneficial strategy. This multidisciplinary approach aims not only to enhance the overall quality of life and alleviate treatment-related side effects but also to positively influence clinical indicators such as tumor markers [6]. Extensive research continues to explore how these combined modalities can optimize patient outcomes and symptomatic relief in the breast cancer population [7].

Earlier literature suggests that roughly 9% to 20% of breast cancer patients utilize complementary therapies as a supplementary medical resource [8, 9]. In Taiwan, specifically, historical data from 2007 indicated that over one-third of the breast cancer population integrated TCM into their care [10]. While certain studies have pointed toward the therapeutic advantages of herbal medicine and acupuncture regarding clinical outcomes and survival [11, 12], there remains a lack of detailed evidence focusing on the perioperative period for these patients. Therefore, we executed a large-scale retrospective cohort analysis using nationwide data. Our primary objective was to assess surgical outcomes and mortality among breast cancer patients who had received TCM interventions during the 12-month period preceding their operation.

Methods

Data source

By formal request to the Ministry of Health and Welfare, we utilized Taiwan’s public health insurance records, which encompass nearly the entire national population. This large database centralizes comprehensive clinical data, including outpatient and inpatient records, diagnostic history, and medical costs. While the technical specifics of this repository have been detailed in earlier literature, our study adhered to strict data security protocols; participant identities were fully anonymized and pseudonymized before the analysis. Ethical oversight was provided by the Taipei Medical University Institutional Review Board (TMU-JIRB-201710033; TMU-JIRB-201902053; TMU-JIRB-201905042), which granted a waiver for individual consent due to the retrospective nature of the de-identified data.

Study design

We identified eligible subjects from the nationwide beneficiary pool that included individuals aged 18 years or older who received a primary breast cancer diagnosis between 2010 and 2019 and subsequently underwent a mastectomy. We ensured diagnostic accuracy by cross-validating cases with the official cancer registry data, resulting in a final cohort of 91,298 incident breast cancer patients who underwent mastectomies. Our primary exposure variable was defined as the utilization of TCM during the 12 months prior to surgery. This study aimed to compare baseline characteristics (sociodemographics, comorbidities, tumor specifics) and assess the comparative risks of complications and mortality post-mastectomy between those who did and did not use TCM.

Criteria and definition

Breast cancer cases were identified through a combination of the national cancer registry and clinical diagnoses. To ensure the inclusion of only incident cases, individuals with a documented history of breast cancer in the preceding 24 months were excluded. We also adjusted for a range of comorbidities such as metabolic, cardiovascular, and respiratory diseases by comparing physician-documented diagnoses against International Classification of Diseases (ICD) protocols. Comprehensive details regarding the ICD-9, ICD-10, and administrative codes for these comorbidities, as well as records of inpatient and emergency department utilization, are documented in Table S1.

In this analysis, low-income status was identified by a patient’s exemption from medical copayments as regulated by the government’s healthcare hierarchy. We categorized TCM utilization as any clinical encounter involving acupuncture, Chinese herbal products, or manual therapy recorded within the national insurance claims. Specifically, patients were designated as TCM users if they had sought these treatments during the 12-month period preceding their breast cancer surgery.

We employed SAS version 9.2 to execute the statistical framework for this study. Initially, baseline characteristics (included continuous data and categorical data) were compared across cohorts using chi-square and t-tests as appropriate. We then applied multivariate analysis to derive adjusted odds ratios (ORs) and 95% confidence intervals (CIs), aiming to assess how TCM integration influenced the risk of death and surgical complications (including, but not limited to, acute renal failure, pulmonary embolism, and postoperative hemorrhage). Differences were considered statistically meaningful if the p-value was under 0.05.

Results

Between 1 Jan 2010 and 31 Dec 2019 (Table 1), the one-year prevalence of TCM use was 39.8% before breast cancer surgery among 91,298 women in Taiwan. A greater proportion of younger patients than older patients used TCM (43.3% vs. 20.3%, p < 0.0001). Patients who were hospitalized twice (40.5% vs. 37.6%, p = 0.0009) or had three visits for emergency care (45% vs. 38.3%, p < 0.0001) had higher proportions of TCM use than did those who were not hospitalized or received emergency care. Breast cancer patients with medical conditions such as diabetes (64.1% vs. 36.0%, p < 0.0001), hypertension (61.7% vs. 38.3%, p < 0.0001), hyperlipidemia (56.5% vs. 43.4%, p < 0.0001), mental disorders (52.4% vs. 47.6%, p < 0.0001), ischemic heart disease (56.9% vs. 43.2%, p < 0.0001), liver cirrhosis (57.0% vs. 43.0%, p = 0.0256), and renal dialysis (78.9% vs. 21.1%, p < 0.0001) had a lower prevalence of TCM use before breast cancer surgery than people without these comorbidities. On the other hand, a greater prevalence of TCM use was found among patients with COPD than among patients without COPD (50.2% vs. 49.8%, p < 0.0001).

Table 1.

Baseline characteristics of female breast surgery patients with and without TCM

	No TCM (N = 54965)		TCM (N = 36333)		p-value
	n	(%)	N	(%)
Age, years					< 0.0001
18–29	2480	(58.2)	1783	(41.8)
30–39	6004	(56.8)	4575	(43.2)
40–49	16,235	(57.9)	11,796	(42.1)
50–59	16,741	(60.3)	11,040	(39.7)
60–69	8686	(63.2)	5051	(36.8)
70–79	3698	(67.2)	1802	(32.8)
≥ 80	1121	(79.7)	286	(20.3)
Low income					0.0972
No	54,028	(60.2)	35,660	(39.8)
Yes	937	(58.2)	673	(41.8)
Volume of hospital					0.0029
Low	10,190	(60.7)	6590	(39.3)
Moderate	17,404	(59.4)	11,893	(40.6)
High	27,371	(60.5)	17,850	(39.5)
Number of hospitalizations					0.0009
0	37,223	(60.1)	24,662	(39.9)
1	10,657	(59.7)	7184	(40.3)
2	2841	(59.5)	1931	(40.5)
≥ 3	4244	(62.4)	2556	(37.6)
Number of emergency visits					< 0.0001
0	40,174	(61.7)	24,904	(38.3)
1	9259	(57.1)	6960	(42.9)
2	3071	(55.5)	2458	(44.5)
≥ 3	2461	(55.0)	2011	(45.0)
Medical conditions
COPD	806	(49.8)	813	(50.2)	< 0.0001
Mental disorders	7237	(52.4)	6585	(47.6)	< 0.0001
Hyperlipidemia	2827	(56.5)	2176	(43.5)	< 0.0001
Ischemic heart disease	2138	(56.8)	1623	(43.2)	< 0.0001
Liver cirrhosis	669	(57.0)	504	(43.0)	0.0256
Heart failure	361	(61.0)	231	(39.0)	0.6988
Hypertension	9976	(61.7)	6198	(38.3)	< 0.0001
Diabetes	4952	(64.0)	2780	(36.0)	< 0.0001
Renal dialysis	400	(78.9)	107	(21.1)	< 0.0001

TCM Traditional Chinese medicine

Compared with patients who did not use TCM (Table 2), patients who used TCM had lower risks of stroke (OR 0.76, 95% CI 0.62–0.93) and shorter ICU stays (OR 0.74, 95% CI 0.59–0.91) after breast cancer surgery. Medical expenditure (1459 ± 781 vs. 1507 ± 955 US dollars, p < 0.0001) and length of hospital stay (3.9 ± 3.4 vs. 4.1 ± 4.0 days, p < 0.0001) were also lower among patients who used TCM than among those who did not use TCM. In the further analysis (Table 3), the adjusted ORs for more than 4 visits of TCM use associated with reduced postoperative stroke was 0.76 (95% CI 0.61–0.95). However, the use of the five most frequently prescribed TCM herbal formulas (included Si Jun Zi Tang, Tao Hong Si Wu Tang, Wu Ling San, Bun Jong Yih Chih Tang, and Xiao Chai Hu Tang) were not associated with reduced postoperative stroke (Table 4).

Table 2.

Adverse outcomes in female breast surgery patients with and without traditional Chinese medicine

	No TCM (N = 54965)		TCM (N = 36333)		Risk of outcomes
	Events	%	Events	%	OR	(95% CI)a
30-day in-hospital mortality	21	0.04	8	0.02	0.70	(0.30–1.61)
Postoperative complications
Pulmonary embolism	9	0.02	13	0.04	2.33	(0.99–5.50)
Acute myocardial infarction	11	0.02	3	0.01	0.53	(0.15–1.90)
Acute renal failure	12	0.02	13	0.04	2.03	(0.90–4.55)
Pneumonia	181	0.3	100	0.3	0.91	(0.71–1.17)
Septicemia	1372	2.5	822	2.3	0.94	(0.86–1.03)
Stroke	349	0.6	140	0.4	0.76	(0.62–0.93)
Postoperative bleeding	516	0.9	358	1.0	1.07	(0.93–1.23)
Deep wound infection	167	0.3	114	0.3	1.00	(0.79–1.27)
Intensive care	302	0.6	123	0.3	0.74	(0.59–0.91)
Medical expenditure, US dollarsb	1507 ± 955		1459 ± 781		p < 0.0001
Length of hospital stay, daysb	4.1 ± 4.0		3.9 ± 3.4		p < 0.0001

CI Confidence interval, OR Odds ratio, TCM Traditional Chinese medicine

^aAdjusted for all covariates listed in Table 1

^bMean±SD

Table 3.

Risk of postoperative stroke in association with use frequency of TCM before breast cancer surgery

		Postoperative stroke
Number of TCM visits	n	Events	Incidence, %	OR	(95% CI)a
0	58,499	289	0.49	1.00	(reference)
1	554	2	0.36	0.73	(0.18–2.95)
2	572	4	0.70	1.53	(0.56–4.18)
3	616	5	0.81	1.68	(0.68–4.15)
≥ 4	37,752	118	0.31	0.76	(0.61–0.95)

CI Confidence interval, OR Odds ratio, TCM Traditional Chinese medicine

^aAdjusted for all covariates listed in Table 1

Table 4.

Risk of postoperative stroke in association with use frequency of TCM in patients before breast cancer surgery

		Postoperative stroke
	n	Events	Incidence, %	OR	(95% CI)a
No TCM	58,499	289	0.49	1.00	(reference)
Patients with TCM who used
Si Jun Zi Tang	384	0	0.00	-	-
Tao Hong Si Wu Tang	998	0	0.00	-	-
Wu Ling San	1423	7	0.49	1.13	(0.53–2.42)
Bun Jong Yih Chih Tang	1781	8	0.45	1.21	(0.59–2.47)
Xiao Chai Hu Tang	3477	10	0.29	0.80	(0.42–1.52)

CI Confidence interval, OR Odds ratio, TCM Traditional Chinese medicine

^aAdjusted for all covariates listed in Table 1

Discussion

Between 2010 and 2019, we observed that 39.8% of patients utilized TCM in the year before their breast cancer surgery. Preoperative TCM use was associated with lower risks of postoperative stroke and intensive care. This protective effect against stroke was most evident in individuals who had attended more than four TCM consultations. While the five most common herbal formulas did not show a statistically significant association with stroke reduction individually, it is worth noting that no stroke incidents occurred among patients treated with either Si Jun Zi Tang or Tao Hong Si Wu Tang.

The utilization of TCM observed in our study surpassed the 35.6% prevalence rate documented among breast cancer patients in 2007 [10]. This upward trend suggests a growing tendency for individuals to seek complementary medical perspectives following a cancer diagnosis or during the perioperative period. In Taiwan, TCM is formally integrated into the National Health Insurance system rather than being viewed solely as an adjunct therapy. Modalities such as Tai Chi, acupuncture, and Tuina have demonstrated efficacy in supporting oncological care [13, 14]. Given that a breast cancer diagnosis often triggers significant psychological distress and sleep disturbances, many patients pursue these therapies to improve their overall quality of life [15]. Furthermore, influenced by increased access to digital health information and higher educational backgrounds, a notable segment of the patient population now utilizes complementary and alternative medicine as a secondary therapeutic strategy [8, 9].

Our analysis revealed that pre-existing conditions, including chronic obstructive pulmonary disease, ischemic heart disease, and metabolic disorders, significantly influenced the likelihood of seeking TCM among breast cancer patients [16–20]. Given their established impact on surgical prognosis, these comorbidities were treated as covariates and adjusted within our multivariate regression framework. The integration of TCM may be driven by its documented clinical benefits for these specific conditions. For instance, acupuncture has demonstrated efficacy in blood pressure regulation and the clinical management of hypertension [21, 22]. Previous investigations have confirmed its capacity to lower apolipoprotein B and triglyceride levels while also potentially reducing the secondary risks of diabetes and stroke [23]. Similarly, red yeast rice is frequently prescribed as a cost-effective and reliable intervention for lipid modulation [24–26]. Such evidence suggests that patients with cardiovascular or metabolic issues may actively pursue TCM as a complementary strategy to optimize their health status prior to surgery.

Clinical evidence suggests that acupuncture interventions lead to notable improvements in depression symptoms compared to standard care protocols [27]. Furthermore, research indicates that acupuncture may offer neuroprotective benefits, such as a decreased incidence of dementia among patients recovering from non-hemorrhagic stroke [28]. Based on these observations, it is plausible that the therapeutic potential of TCM for psychological well-being contributes to its higher adoption among breast cancer patients with pre-existing mental health conditions. Our analysis also extended to patients with chronic obstructive pulmonary disease to determine if similar patterns of increased TCM utilization existed within this specific subpopulation. Integrating traditional herbal therapies has been shown to offer protective benefits for individuals with chronic obstructive pulmonary disease, specifically by lowering death rates and preventing the sudden worsening of respiratory symptoms [29].

While certain herbal interventions have demonstrated potential in slowing the transition from pre-diabetic states to clinical diabetes [24, 30], our findings indicate that individuals with established diabetes or those undergoing renal dialysis are less frequent users of TCM. This disparity may stem from a strong reliance on conventional biochemical therapies among diabetic patients, who may have limited exposure to TCM alternatives. For those requiring renal dialysis, the intensive nature of their treatment schedule likely curtails their ability to seek supplementary TCM consultations. Furthermore, these patients may be discouraged from integrating TCM into their regimen by Western medical practitioners who prioritize standardized dialysis protocols. Similarly, patients managing type 1 diabetes with insulin therapy might exhibit lower inclination toward complementary treatments due to the complexity and necessity of their primary medical requirements.

Research indicates that integrating TCM with standard oncological protocols can enhance the well-being of individuals with breast cancer more effectively than conventional care alone [31]. While long-term causality remains a subject for ongoing study, initial evidence suggests that short-term TCM intervention following a diagnosis correlates with more favorable survival rates over a five-year period [32]. Furthermore, the synergistic use of TCM and chemotherapy has demonstrated clinical advantages by optimizing immune responses and minimizing treatment-related toxicity [33]. Laboratory models further support these findings, showing that certain herbal adjuncts may increase the anti-tumor potency of agents such as doxorubicin while simultaneously reducing their systemic side effects [34]. Despite meta-analyses suggesting lower mortality among TCM users, the inherent variability in clinical methodologies across different studies necessitates a cautious interpretation of these overall benefits [35]. Our current analysis did not specifically examine the influence of the most common herbal prescriptions on post-surgical stroke risk, and therefore, the potential advantages of TCM in post-operative recovery must be confirmed through more rigorous and large-scale prospective trials.

Cumulative evidence suggests that TCM, particularly through herbal remedies and acupuncture, plays a protective role in mitigating cerebrovascular risks [25, 36, 37]. Research involving stroke cohorts has demonstrated that supplemental TCM treatment can lead to fewer adverse outcomes and a decreased reliance on acute medical services like hospitalization and emergency care [38, 39]. Furthermore, the clinical benefits of acupuncture extend to lowering the incidence of various post-stroke complications, ranging from respiratory infections and urinary tract issues to neurological and cardiac events such as dementia and myocardial infarction [40–43]. Large-scale population studies have also highlighted acupuncture’s capacity to prevent stroke recurrence [44]. These established clinical insights provide a robust theoretical framework for our observation that TCM users exhibited a lower risk of stroke following breast cancer surgery.

Existing evidence highlights the therapeutic potential of TCM herbal interventions in lowering the risk of metabolic and neurological complications, such as diabetes and epilepsy, among stroke survivors [45, 46]. Specific herbal prescriptions have demonstrated physiological benefits by enhancing circulatory flow, suppressing inflammatory pathways, and preventing programmed cell death in neural tissues [47, 48]. Furthermore, supplemental TCM has been shown to improve clinical outcomes related to cardiac function and survival rates in the breast cancer population [11, 12]. Based on these established mechanisms, we hypothesize that preoperative TCM integration contributes to the observed reduction in stroke risk and intensive care requirements following mastectomy. These prior insights provide a plausible biological foundation for the favorable outcomes observed in our study.

Several constraints in our research warrant consideration. Primarily, the reliance on retrospective claims data meant we did not have access to granular clinical details such as diagnostic imaging results, laboratory markers, or specific cancer staging. Consequently, the precise severity of the malignancy could not be accounted for in our models. Additionally, our data only captured services reimbursed by the insurance system in Taiwan, meaning that any out-of-pocket folk therapies or non-registered treatments were excluded from the analysis. The inherent variability in treatment protocols among different TCM practitioners also poses a challenge to identifying the specific efficacy of individual acupuncture points. Lastly, despite our comprehensive adjustment for multiple variables in the regression analysis, the possibility of residual confounding persists due to the cross-sectional nature of the data.

To summarize, our findings indicate that integrating TCM during the year preceding breast cancer surgery is correlated with lower risks of postoperative stroke and a reduced requirement for intensive care. Nevertheless, these observed benefits warrant further verification through prospective and large-scale clinical investigations. Based on these results, we suggest that both Western medical practitioners and public health administrators should be mindful of TCM’s role in the comprehensive care of patients with breast cancer.

Abbreviations

OR

Odds ratio

CAM

Complementary and alternative medicine

TCM

Traditional Chinese medicine

CI

Confidence interval

ICD-9-CM

International code of diseases, ninth edition, clinical modification

Authors’ contributions

All authors contributed to collected the data of participants and clinical grading. CT Chen drafted the manuscript. CC Liao analyzed the data. CT Chen and CC Liao conceived the idea and corrected the manuscript. All authors read and approved the final manuscript. CH Hsu has equal contribution with the corresponding author.

Funding

This study was supported in part by the National Science and Technology Council, Taiwan (NSTC112-2314-B-038-141; NSTC113-2629-B-532-001; NSTC111-2320-B-532-001-MY3).

Data availability

The data underlying this study is from the Health and Welfare Data Science Center. Interested researchers can obtain the data through formal application to the Health and Welfare Data Science Center, Department of Statistics, Ministry of Health and Welfare, Taiwan (https://dep.mohw.gov.tw/DOS/cp-5119-59201-113.html) and contact the agency with email (stpeicih@mohw.gov.tw). Under the regulations from the Health and Welfare Data Science Center, we have made the formal application (included application documents, study proposals, and ethics approval of the institutional review board) of the current insurance data from in 2019. The authors of the present study had no special access privileges in accessing the data which other interested researchers would not have.

Declarations

Ethics approval and consent to participate

This research was conducted in accordance with international guidelines and the ethical standards outlined in the Declaration of Helsinki. As these reimbursement claims were used in this study, the electronic database was decoded with patient identifications scrambled for further academic access for research to protect privacy. Although the Ministry of Health and Welfare exempt such uses from informed consent, because patient identifications are decoded and scrambled. This study was approved by the institutional review board of Taipei Medical University (TMU-JIRB-201710033; TMU-JIRB-201902053; TMU-JIRB-201905042).

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.