Cochrane · systematic review · CD005004
Green tea (Camellia sinensis) for the prevention of cancer
Filippini, T, Malavolti, M, Borrelli, F, et al. · Cochrane Database of Systematic Reviews · 2020 · Cochrane Library
Gynaecological, Neuro-oncology and Orphan CancerAMSTAR 2: not assessed
SoF tableOnly the outcomes this review put in its Summary of Findings table are listed (the Cochrane Handbook caps them at about seven per comparison). Its other analyses are not shown here.
Questions
22
current version
GRADE rated
21
No studies
1
Included studies
NR
No studies 1 · 4.5%Ungraded 0 · 0%Very low 6 · 27.3%Low 15 · 68.2%Moderate 0 · 0%High 0 · 0%
Ungraded means an effect was reported without a GRADE rating; it is not a gap. No studies means the review found nothing to answer the question. The six categories are a display order, not a score.
Questions and results
Green tea extract supplementation compared with placebo for preventing cancer: experimental studies
Population: adults (aged at least 18 years)
| Outcome | Effect | Evidence | Status / GRADE |
|---|---|---|---|
Prostate cancer incidence Green tea extract supplementation vs placebo | RR 0.5 [0.18, 1.36] | 3 studies · 201 participants | Low |
Gynaecological cancer incidence Green tea extract supplementation vs placebo | RR 1.5 [0.41, 5.48] | 2 studies · 1157 participants | Low |
Non‐melanoma skin cancer incidence Green tea extract supplementation vs placebo | RR 1 [0.06, 15.92] | 1 study · 1075 participants | Low |
Quality of life Green tea extract supplementation vs placebo | no estimate extracted | NR | No studies |
Highest compared with lowest green tea exposure for preventing cancer: primary outcomes in nonexperimental studies
Population: adults (aged at least 18 years)
| Outcome | Effect | Evidence | Status / GRADE |
|---|---|---|---|
Any cancer incidence (3 studies) Highest vs lowest green tea exposure | RR 0.83 [0.65, 1.07] | 52479 participants | Low |
Any cancer mortality (8 studies) Highest vs lowest green tea exposure | RR 0.99 [0.91, 1.07] | 504366 participants | Low |
Highest compared with lowest green tea exposure for preventing cancer: individual cancer types in nonexperimental studies
Population: adults (aged at least 18 years)
| Outcome | Effect | Evidence | Status / GRADE |
|---|---|---|---|
Oral cancer risk (5 studies) Highest vs lowest green tea exposure | RR 0.71 | 55977 participants | Low |
Any gut cancer risk (7 studies) Highest vs lowest green tea exposure | RR 0.78 [0.59, 1.02] | 70299 participants | Low |
Oesophageal cancer risk (13 studies) Highest vs lowest green tea exposure | RR 0.81 [0.64, 1.04] | 74895 participants | Very low |
Stomach cancer risk (18 studies) Highest vs lowest green tea exposure | RR 0.86 [0.74, 1.01] | 438595 participants | Very low |
Liver cancer risk (6 studies) Highest vs lowest green tea exposure | RR 0.88 [0.68, 1.14] | 198885 participants | Low |
Pancreatic cancer risk (9 studies) Highest vs lowest green tea exposure | RR 0.88 [0.7, 1.1] | 326564 participants | Low |
Colorectal cancer risk (16 studies) Highest vs lowest green tea exposure | RR 0.84 [0.74, 0.96] | 610295 participants | Low |
Colon cancer risk (10 studies) Highest vs lowest green tea exposure | RR 0.89 [0.8, 0.98] | 389974 participants | Low |
Rectal cancer risk (9 studies) Highest vs lowest green tea exposure | RR 0.89 [0.75, 1.05] | 356851 participants | Low |
Lung cancer risk (17 studies) Highest vs lowest green tea exposure | RR 0.88 [0.76, 1.02] | 269565 participants | Very low |
Breast cancer risk (14 studies) Highest vs lowest green tea exposure | RR 0.88 [0.75, 1.02] | 250822 participants | Very low |
Gynaecological cancer risk (10 studies) Highest vs lowest green tea exposure | RR 0.69 [0.57, 0.83] | 66738 participants | Low |
Endometrial cancer risk (5 studies) Highest vs lowest green tea exposure | RR 0.77 [0.65, 0.91] | 60416 participants | Low |
Ovarian cancer risk (5 studies) Highest vs lowest green tea exposure | RR 0.64 [0.45, 0.9] | 6322 participants | Low |
Prostate cancer risk (13 studies) Highest vs lowest green tea exposure | RR 0.73 [0.56, 0.94] | 127239 participants | Very low |
Urinary tract cancer risk (7 studies) Highest vs lowest green tea exposure | RR 1.04 [0.79, 1.37] | 156039 participants | Very low |