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Evidence Explorer · MS-N299 · Botanicals and nutraceuticals · Cancer control · Appraised 11 November 2026

A large randomized trial found that long-term epigallocatechin gallate (EGCG) extract did not significantly reduce Epstein–Barr virus DNA reactivation or cancer recurrence after radiotherapy for nasopharyngeal carcinoma.

Evidence at a glance

  • Evidence label: High-value negative randomized evidence; no demonstrated recurrence benefit
  • Benefit: No statistically significant reduction in EBV-DNA reactivation or clinical recurrence over three years.
  • Certainty: Moderate for no large benefit in the studied post-radiotherapy population; exact dose details were not verified from the accessible abstract.
  • Risk: Trial toxicity was described as minimal, but concentrated green-tea extracts can rarely cause clinically important liver injury and are not interchangeable with brewed tea.
  • Goal: Cancer control—viral reactivation and recurrence, not symptom relief.

What was studied

Population and design: 353 people with nasopharyngeal carcinoma who had a complete response after radiotherapy and negative plasma EBV DNA were enrolled; 327 were evaluable (161 EGCG, 166 placebo). Participants were assigned EGCG or placebo for three years. The study was registered as NCT01744587.

Results: The trial reported no significant between-group difference in plasma EBV-DNA reactivation or clinical recurrence. Minimal toxicity was reported. The accessible abstract did not provide the exact extract dose or absolute event counts, so those details are marked not verified here.

Interpretation: This is directly relevant human cancer-control evidence and is more informative than laboratory claims that green-tea catechins inhibit cancer cells. The randomized result was negative.

What this evidence cannot establish

The trial does not show that EGCG prevents nasopharyngeal-cancer recurrence, and EBV-DNA changes cannot be treated as a substitute for clinical outcomes.

It does not address other cancers, brewed green tea, shorter exposure, or different standardized extracts.

Safety and practical context

Concentrated green-tea extracts have been linked to rare acute liver injury. Stop-and-review symptoms include jaundice, dark urine, marked fatigue, nausea or right-upper-abdominal pain.

Caffeine content and medicine interactions vary by product. People receiving cancer treatment or with liver disease should review the exact product with their oncology and pharmacy teams.

Questions for the care team

  • What exact EGCG extract and dose were studied?
  • Could this product affect liver tests or interact with my medicines?
  • Is the proposed goal recurrence prevention, and does any randomized evidence support it?

Sources and identifiers

Funding and conflicts: The abstract reported no competing interests; funding details were not verified from full text.

Source access: Original reports, abstracts/full text where available, registries and authoritative safety sources checked 11 November 2026. The primary trial was appraised from its PubMed abstract; unsupported full-text details were omitted.

This educational evidence record is not a personal treatment recommendation. Symptom or toxicity findings do not establish tumor response, delayed recurrence or longer survival; laboratory and animal findings are not proof of clinical benefit.