Melatonin offers a relatively safe option to support patients undergoing active treatment
In 8 randomized controlled trials, a control group receiving standard chemo/radiotherapy was compared to an intervention group receiving the same treatment with the addition of melatonin to find out if melatonin affects tumor remission, overall survival, and mitigation of treatment side effects.
Wang YM, Jin BZ, Ai F, et al. The efficacy and safety of melatonin in concurrent chemotherapy or radiotherapy for solid tumors: a meta-analysis of randomized controlled trials. Cancer Chemother Pharmacol. 2012 May;69(5):1213-1220.
A meta-analysis of 8 randomized controlled trials (RCTs). The incorporated studies were neither blinded nor placebo-controlled. All studies compared a control group receiving standard chemo/radiotherapy to an intervention group receiving the same treatment with the addition of melatonin. The standard treatment was chemotherapy in 6 of the trials, radiotherapy in 1 trial, and transarterial chemoembolization (TACE) in the remaining trial.
A combined total of 761 subjects from 8 different RCTs that studied various solid tumors.1-8 Seven of the studies were conducted in Italy, and 1 was conducted in China. Six of the Italian studies were led by the same researcher, P. Lissoni. Studies were performed between 1996 and 2007.
TABLE 1: Number of Total Subjects by Cancer type and Treatment Regimen
|Cancer Type||Treatment + Mlt||Treatment Alone|
|Lung|| || |
|Cisplatin + Etoposide||171||180|
|Breast|| || |
|GI|| || |
|5FU + Folinic acid||26||30|
|Head/Neck|| || |
|5FU + Cisplatin||13||14|
|HCC|| || |
|Glioblastoma|| || |
Note: The total number of subjects displayed does not equal 761 because 1 of the trials used a melatonin metabolite (5-MTT) arm in addition to melatonin, accounting for the 33 missing subjects.2
Study Medication and Dosage
Melatonin (20 mg orally) once daily at night, in combination with standard treatment.
Tumor remission, overall survival, and mitigation of treatment side effects.
Table 2: Meta-analysis Results
incl of 8
|Overall remission rate||8||32.6%||374||16.5%||387||1.95||<0.00001|
All 5 studies conducted by same lead investigator, P. Lissoni and used chemotherapy as standard treatment; did not include radiation therapy or TACE.
The short answer: Recommend 20 mg of melatonin, nightly, to your patients diagnosed with solid tumors to reduce side effects of chemotherapy and to improve survival/remission rates.
Melatonin, 20 mg nightly, offers a relatively safe option to support patients diagnosed with solid tumors, undergoing active treatment. This meta-analysis reviewed the safety and efficacy of melatonin in the setting of solid tumors only and should not be extrapolated to hematological cancers. Though the majority of available data (including small human samples, animal, and in vitro studies) assessing the safety and efficacy of melatonin in the setting of hematological cancers is positive, a few studies (1 animal and 2 in vitro) suggest the need for caution. A full discussion of this topic lies outside the scope of this article.
According to this review, melatonin was shown to be effective at increasing remission rate and offering a statistically significant improvement in 1-year survival rates among the study participants. Melatonin, 20 mg dosed nightly, also reduced the rates of chemotherapy-induced thrombocytopenia, neurotoxicity, and fatigue. As summarized in Table 2, more than half the pooled study subjects were patients with non-small cell lung cancer (NSCLC) who received the chemotherapy regimen cisplatin + etoposide (Cis/Eto).
The remaining subjects were divided across the other sites of solid tumors, including breast, GI, and head and neck. The inclusion of a small, isolated, radiotherapy study offers little strength to support the use of melatonin in this setting. The claim made by the authors in the title, “The efficacy and safety of melatonin in concurrent chemotherapy or radiotherapy…” overstates the weight of the radiotherapy evidence. The strongest evidence shown by this meta-analysis lies in the concurrent use of melatonin with Cis/Eto in patients diagnosed with NSCLC.
An oddity of this meta-analysis, and likely any meta-analysis done on the use of melatonin in the oncology setting, is the repetition of a single primary investigator across multiple studies.
An oddity of this meta-analysis, and likely any meta-analysis done on the use of melatonin in the oncology setting, is the repetition of a single primary investigator across multiple studies. To what extent this impacts the reproducibility, or generalizability, of the results is unknown. The results of a PubMed search on Paolo Lissoni reveal that he is involved in the authorship of 127 articles about melatonin. Conducting a meta-analysis without multiple studies by Lissoni would be very difficult. For example, a comparative meta-analysis by Seely, et al,9used broader inclusion criteria and included 21 trials, 18 of which involved Lissoni.
This meta-analysis only included RCTs; however, none of these trials was blinded or placebo-controlled. The lack of placebo control and blinding weakens the evidence presented. It may be argued that “placebo effect” may account, at least in part, for the benefits seen across the included trials. According to the American Cancer Society, 1 in 3 subjects taking a placebo may experience clinical benefit.10 That being stated, few conventional chemotherapy/radiotherapy trials are placebo controlled, and many are unblinded.11,12,13 Typically oncology trials compare 1 treatment regimen against a standard protocol to determine if the new therapy improves specific outcomes (eg, quality of life, progression free survival). FDA approval may be achieved with modest benefits in certain cancer settings (eg, metastatic disease), in part due to the paucity of available therapies for these patients.
Natural therapies should be assessed with a similar set of criteria in the oncology setting; for the same reasons, patients have few options. Because of its relatively low cost, excellent patient tolerability, and mild toxicity profile, melatonin should be considered in any integrative oncology plan for solid tumors. The results of Seely’s meta-analysis further support this conclusion and offer potentially broader applications. Additionally, melatonin plays an important role in the setting of breast cancer development and prognosis. Tina Kaczor’s article, “An Overview of Melatonin and Breast Cancer,” published by this journal in February 2010, provides an excellent synopsis of the information.14
For more research involving integrative oncology, click here.