Chinese medicinal herbs for oesophageal cancer

Review question

Chinese herbal medicine is widely used as adjunct therapy to chemo- or radiotherapy in patients being treated for cancer of the oesophagus. As yet there is no evidence that Chinese herbal medicine is effective or not in this role.

Background

We performed a systematic review of the potential benefits of Chinese herbal medicine by comparing chemo- or radiotherapy for oesophageal cancer with and without concurrent herbal medicine. We searched the Cochrane Upper Gastrointestinal and Pancreatic Diseases Group Trials Register, the Cochrane Library, MEDLINE, EMBASE, Allied and Complementary Medicine Database (AMED), China National Knowledge Infrastructure (CNKI), VIP database, Wanfang database and the Chinese Cochrane Centre Controlled Trials Register up to 1 October, 2015. We also searched databases of ongoing trials, the Internet and reference lists.

Study characteristics

We identified nine randomised controlled trials (RCTs). All trials were conducted in China.

Key results

This updated review included nine trials involving 490 participants. When Chinese herbal medicine was used as adjunct therapy to chemo- or radiotherapy for oesophageal cancer, the results showed a positive effect on quality of life, increased tolerance of patients for adverse effects caused by radiotherapy or chemotherapy (e.g. radiation oesophagitis, gastrointestinal reactions and blood cell descent), but no effects on all-cause mortality, median survival times or time to progression.

Quality of the evidence

We judged the quality of evidence to be low to moderate due to risk of bias; the small number of people enrolled in these studies caused imprecision and inconsistent results. The nine included trials did not allow a subgroup analysis of different kinds of Chinese herbal medicine, the therapeutic purposes of which are different between each other; this might be another reason for imprecise results. High quality trials are required in the future.

Authors' conclusions: 

We currently find no evidence to determine whether TCM is an effective treatment for oesophageal cancer. The effect of TCM on short-term therapeutic effects is uncertain. TCM probably has positive effects on quality of life and on some adverse events caused by radiotherapy or chemotherapy in advanced oesophageal cancer patients undergoing radiotherapy or chemotherapy. The results of the review need to be interpreted cautiously owing to overall low quality evidence. Future trials should be large and correctly designed to detect important clinical effects and minimise risk of bias.

Read the full abstract...
Background: 

Oesophageal cancer is the seventh leading cause of cancer death worldwide. Traditional Chinese herbal medicine is sometimes used as an adjunct to radiotherapy or chemotherapy for this type of cancer. This review was first published in 2007 and updated in 2009; this 2016 update is the latest version of the review.

Objectives: 

To assess the efficacy and possible adverse effects of the addition of Chinese herbal medicine to treatment with radiotherapy or chemotherapy for oesophageal cancer.

Search strategy: 

We searched the Cochrane Upper Gastrointestinal and Pancreatic Diseases Group Trials Register, the Cochrane Library, MEDLINE, EMBASE, Allied and Complementary Medicine Database (AMED), China National Knowledge Infrastructure (CNKI), VIP database, Wanfang database and the Chinese Cochrane Centre Controlled Trials Register up to 1 October, 2015. We also searched databases of ongoing trials, the Internet and reference lists.

Selection criteria: 

Randomised controlled trials (RCTs) comparing the use of radiotherapy or chemotherapy with and without the addition of Chinese herbal medicine.

Data collection and analysis: 

At least two review authors independently extracted data and assessed trial quality.

Main results: 

We tried to contact the 142 study authors by telephone, and finally included nine studies with 490 participants. All included studies were conducted in China, and allocated advanced oesophageal cancer patients to radiotherapy or chemotherapy groups, with and without additional Chinese herbal medicine. Quality of life, short-term therapeutic effects, TCM symptoms and adverse events caused by radiotherapy or chemotherapy were reported in these studies. Overall, we considered the trials to be at unclear or high risk of bias.

The quality of life measure was conducted before and after the intervention; our analysis showed a beneficial effect, both in number of participants experiencing an improvement (risk ratio (RR) 2.20, 95% confidence interval (CI) 1.42 to 3.39; 5 RCTs, 233 participants, change of performance status score ≥ 10) and number of participants experiencing a deterioration (RR 0.41, 95% CI 0.27 to 0.62; 6 RCTs, 287 participants, change of performance status score ≤ 10). We judged this to have low quality evidence, downgrading quality of evidence for risk of bias and imprecision, and upgrading quality of evidence for the large effect.

For short-term therapeutic effects, the results suggest that traditional Chinese medicine (TCM) has a positive impact on improvement (complete response + partial response) (RR 1.17, 95% CI 1.02 to 1.35; 8 RCTs, 450 participants), moderate quality evidence and downgrading for risk of bias. There was no significant difference for progressive disease (RR 0.73, 95% CI 0.52 to 1.01; 8 RCTs, 450 participants), low quality evidence and downgrading for risk of bias and imprecision. Three studies assessed this outcome after four weeks or three months' follow-up, the remaining studies gave no detailed information for this outcome. TCM symptoms, which was similar to short-term therapeutic effects evaluated with TCM clinical criteria, was diagnosed in two studies of 88 people at the end of the intervention. The results suggest that TCM has a positive impact on both total effectiveness (RR 1.84, 95% CI 1.20 to 2.81) and ineffectiveness (RR 0.22, 95% CI 0.05 to 0.93); we judged the studies to have very low quality evidence, downgrading for risk of bias and imprecision.

Nine studies reported a series of adverse events caused by radiotherapy or chemotherapy at the end of the intervention, including mucositis, radiation oesophagitis, arrest of bone marrow, gastrointestinal reactions, renal and hepatic impairment, white blood cell descent, neurotoxicity, cardiac toxicity and anaemia. For those containing multiple studies, we conducted a pooled analysis. As a result, TCM showed a significant effect on radiation oesophagitis (RR 0.66, 95% CI 0.47 to 0.94; 2 RCTs, 90 participants), gastrointestinal reactions (RR 0.54, 95% CI 0.36 to 0.81; 4 RCTs, 268 participants) and white blood cell descent (RR 0.60, 95% CI 0.44 to 0.83; 4 RCTs, 224 participants). The quality of evidence was low or very low, downgrading for risk of bias and imprecision.

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