CRD summary

This review assessed the safety and effectiveness of black cohosh in patients with cancer and concluded that its effectiveness was uncertain in menopausal women with breast cancer, but that it appeared to be safe. Despite possibly omitting relevant data, the authors' cautious conclusions are likely to be reliable.

Authors' objectives

To assess the safety and efficacy of black cohosh (Cimicifuga racemosa) in patients with cancer. This abstract will only cover the human studies.

Searching

The following databases were searched from inception to February 2007: MEDLINE, Science Citation Index Expanded, Expanded Academic ASAP, ProQuest Research Library, Plant Science, Biological Sciences, AMED, CINAHL and EMBASE; search terms were reported. Studies had to be published in English in peer-reviewed journals. Monograph databases and herbal and dietary supplement databases were searched for additional reference information and bibliographies (including BIOSIS Previews, Scopus, Natural Standards database, MICROMEDEX, Martindale and CAMline). Cochrane Database of Systematic Reviews, Cochrane Controlled Trials Register, ACP and DARE databases were also searched. Reference lists of review articles after 2002 were handsearched.

Study selection

Clinical trials or case studies that evaluated the use of black cohosh in patients with a current or previous diagnosis of cancer were eligible for inclusion. Review articles published from 2002 to March 2007 were also eligible.

In the included studies, most participants were menopausal women with breast cancer or a history of breast cancer. Black cohosh was most commonly given at a dose of 20mg. Comparator groups included placebo and tamoxifen. Hot flashes and adverse events were the main outcomes assessed.

The authors stated neither how the papers were selected for the review nor how many reviewers performed the selection.

Assessment of study quality

Clinical trials were quality assessed using the Jadad scale (maximum score of 5), which examines descriptions of blinding, randomisation and withdrawals. Two reviewers independently assessed study quality.

Data extraction

Two reviewers independently extracted data.

Methods of synthesis

Results were pooled in a narrative synthesis. Differences between studies were discussed and study details tabulated. Meta-analysis was not possible due to clinical heterogeneity.

Results of the review

Five clinical studies were included in the review (n=2,849): three randomised controlled trials (RCTs) (n=353); one non-randomised trial (n=23); and one retrospective case-control study (n=2,473). Jadad quality scores were 1, 2, 4 and 5 for the four trials.

Overall, the four trials that assessed the efficacy of black cohosh in the management of menopause in women diagnosed with breast cancer indicated that it may not have been effective for treating menopausal symptoms such as hot flashes. No significant adverse events were observed. Two open-label trials with poor Jadad scores reported significant reductions in hot flashes. The case-control study suggested potential benefit of black cohosh in treating breast cancer.

Authors' conclusions

The evidence for black cohosh to relieve hot flashes in menopausal women with breast cancer was inconclusive. The treatment appeared to be safe.

CRD commentary

The review addressed a clear question and was supported by appropriate inclusion criteria. Attempts to identify relevant studies were undertaken by searching electronic databases and checking references, although it appeared that no attempts were made to identify unpublished studies and this, coupled with the restriction of using only studies published in English, meant that relevant studies may have been omitted from the review. Suitable methods appeared to have been employed to minimise the risks of reviewer error and bias for the processes of data extraction and assessing study quality, although the authors did not report on the methods used to select studies for inclusion. Study quality was assessed and the assessment used when interpreting the results of the review. Sufficient study details were provided (although more numerical result details would have been useful) and an appropriate narrative synthesis of the data was undertaken. Despite the possibility that relevant studies were missed, the authors' conclusions were suitably cautious and likely to be reliable.

Implications of the review for practice and research

Practice: The authors did not state any implications for practice.

Research: The authors stated that more RCTs were needed to assess the effectiveness of black cohosh in treating hot flashes in menopausal cancer patients. Further research of black cohosh as a treatment for breast cancer and prostate cancer was also warranted. Future studies should accurately report plant identification, herbal product preparation, standardisations and the part of the plant used.

Funding

Not stated.

Bibliographic details

Walji R, Boon H, Guns E, Oneschuk D, Younus J. Black cohosh (Cimicifuga racemosa [L.] Nutt.): safety and efficacy for cancer patients Supportive Care in Cancer 2007; 15(8): 913-921. [PubMed: 17602247]

Original Paper URL

http://www.springerlink.com/content/u760031320441616/

Indexing Status

Subject indexing assigned by NLM

MeSH

Breast Neoplasms /drug therapy; Cimicifuga; Female; Gonadal Steroid Hormones; Humans; Male; Phytotherapy /contraindications; Prostatic Neoplasms /drug therapy; Treatment Outcome

AccessionNumber

12008102904

Database entry date

12/08/2009

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.