Table 3.

Clinical evaluations on the effects of phytosubstances/plant–based intervention on conventional treatments of PCa

Phytosubstance/plant-based supplement (dosage)	Study design	Year	Study participants (number)	Effects/results	Adverse events of phytosubstance	Major study limitations	Ref
Docetaxel, prednisone, and curcumin (6000 mg/day–12 curcumin capsules/day for 7 consecutive days)	Non-randomised, open-label, phase II trial	2016	Patients with progressing castration-resistant PC	High response rate, good tolerability, and patient acceptability (tumour objective response in 40% and a PSA response in 59% of men)	Well tolerated curcumin, without systemic toxic effects	Single-arm, non-randomised design of the study, the low number of patients	[22]
Docetaxel plus curcumin (6 g/day) or docetaxel plus placebo in first-line treatment for 7 consecutive days every 3 weeks	Double-blind, randomised, phase II study	2021	Patients with metastatic castration-resistant PCa (n = 50)	No effects of adding curcumin to treatment strategies in improving patient outcome and prognosis	Most common: anaemia, asthenia, diarrhoea, and alopecia. Nothing relevant was noted between the two groups of patients, except less lymphopenia and less hypocalcaemia in the experimental arm	Small sample size, titration of curcumin performed for only a few patients	[23]
Docetaxel every 21 days plus lycopene daily (30 mg/day)	Interventional Phase II clinical trial	2021	Metastatic castrate-resistant PCa patients (n = 13)	Favourable effects, synergistic activity of lycopene with docetaxel (downregulation of IGF-I signalling inhibition and decrease in the expression of survivin)	Not available	Small sample size	[21]
Soy isoflavones (200 mg/day) or placebo for 6 months, beginning with the first day of radiation therapy	Double-blind, placebo-controlled, randomised trial	2010	PC patients (n = 42)	Reduced urinary, sexual, and intestinal adverse effects of radiation therapy	Not available	A small number of subjects, study coordinators should assist patients with the administration of study questionnaires for better compliance	[26]
Ellagic acid (180 mg/day) throughout the chemo-therapy cycles and during the period between cycles	Clinical trial	2005	Hormone refractory PCa patients (n = 48) on standard chemo-therapy using vinorelbine and estramustine phosphate	Reduced toxicity induced by chemo-therapy (neutropenia)	Not available	Not available	[24]
Nanocurcumin (120 mg/day) or placebo 3 days before and during radiotherapy	Randomised, double-blind, placebo-controlled phase II trial	2019	PC patients (n = 64)	No effect on preventing and/or mitigating radiation-induced proctitis or in radiation-induced cystitis, duration of radiation toxicities, hematologic nadirs, and tumour response	Well tolerated, no drug-related severe adverse effects	Single-centre design (not representing the entire population), a small number of patients, underpowered trial to accept or reject the study hypothesis	[25]

Abbreviations: PCa, prostate cancer; g, gram; mg, milligram.