Effect of Sulforaphane on Prostate CAncer PrEvention
Condition: Prostate Cancer
MeSH terms: Prostatic Neoplasms
Study type: Interventional

Summary: 
      The biology of prostate cancer is associated with changes in genes and metabolites within
      prostate tissue. There is robust evidence to suggest that a diet rich in broccoli can prevent
      or retard the development of prostate cancer by influencing these changes. This is likely to
      be due to a natural chemical that is obtained in these vegetables known as sulforaphane.

      In this study, we are seeking to provide further evidence that a diet rich in broccoli may
      prevent prostate cancer from developing, and to understand how this may happen. We propose to
      undertake a human intervention study to test the hypothesis that a broccoli-rich diet can
      alter the metabolism and gene expression within prostate tissue of men under active
      surveillance in a manner that would reduce the probability of the emergence and progression
      of aggressive cancerous clones. Participants recruited onto this study will be randomly
      allocated to one of three dietary groups in which they will be required to consume one
      portion per week of a broccoli soup delivering a different concentration of sulforaphane.
      This will be part of their normal diet for one year.

      Blood, urine and prostate biopsy tissue will be obtained before and after a 12 month
      intervention period. Prostate biopsies will be obtained either though transperineal template
      biopsies, a technique accepted as best clinical practice because it provides better sampling
      of the prostate, or transrectal ultrasound guided biopsy which is currently the standard of
      care for obtaining biopsies.

      This study has been funded by Biotechnology and Biological Sciences Research Council (BBSRC)
      and Prostate Cancer foundation (PCF).
    

Detailed description: 
      The study is a randomised double-blinded dietary intervention study. The study population
      will consist of smoking and non-smoking men aged between 18 and 80 years old. Participants
      recruited into this study will be randomly placed into one of three dietary groups in which
      they will be required to consume one portion of broccoli soup per week, delivering a
      different level of glucoraphanin (sulforaphane precursor), as part of their normal diet for
      one year. The three types of soup will contain (i)standard broccoli,
      (ii)glucoraphanin-enriched broccoli (Beneforte®), or (iii)Beneforte extra. Beneforte and
      Beneforte extra broccoli are especially cultivated to deliver high sulforaphane levels after
      consumption. All the three broccoli varieties have the same appearance and flavour thus
      enabling a blinded human intervention study to be undertaken. Broccoli soups will be
      manufactured by a food company that supplies soups to the leading supermarket retailers in
      the United Kingdom. In order to assess the habitual diet of the participants, they will be
      asked to keep three 7-day diet diaries, one pre-intervention, after 6-months and another one
      week before the end of their intervention. Considering the effect of exercise on whole body
      metabolism we will also obtain information on the physical activity of study participants.
      They will be asked to complete a validated physical activity questionnaire together with the
      diet diary (i.e before starting the study diet then at 6 and 12 months). Twenty six
      participants will be recruited to each of the broccoli groups. The participants will be
      characterised as having a low or intermediate risk of developing prostate cancer and will be
      undergoing active surveillance. A number of physiological tests will be performed on the
      participants before they start the dietary intervention (baseline) and after their 12 months
      on the intervention. The study will involve collection of prostate biopsies, blood and urine
      samples at baseline and after a 12 month dietary intervention. Prostate biopsies will be
      obtained through transperineal template biopsy (TPB) where possible or standard transrectal
      ultrasound scan guided biopsy (TRUS biopsy). TPB is a clinical procedure carried out under a
      general or regional anaesthetic which gives more detailed information about the position,
      amount and aggressiveness of the cancer within the prostate than other standard techniques.
      However, patients who do not wish to undergo TPB can alternatively choose the standard TRUS
      biopsy.

      At the end of the trial participants will be asked to give written consent if they wish to
      continue the diet for a further 12 months. Consenting patients will thereafter be required to
      eat one portion of broccoli soup per week for 12-months. We will not ask participants to
      attend extra hospital visits for the purpose of the study or give additional biological
      samples; instead we will capture clinical data related to their follow up of prostate cancer.

      It is anticipated that the dropout rate for this study will be approximately 25% due to the
      clinical progression of prostate cancer within the 12-month study period. In the event of
      clinical progression the volunteer will discontinue the intervention, receive advice from the
      urologist in charge and in case of prostatectomy will be asked to donate part of their
      prostate gland for research purposes.
    

Intervention name(s): Standard broccoli soup; Beneforte broccoli soup; Beneforte extra broccoli soup
Intervention type(s): Dietary Supplement; Dietary Supplement; Dietary Supplement
Intervention description(s): Volunteers will be required to consume one portion of broccoli soup per week as part of their normal diet for one year.; Volunteers will be required to consume one portion per week of a soup containing glucoraphanin-enriched broccoli (Beneforte®) as part of their normal diet for one year.; Volunteers will be in which they will be required to consume one portion per week of a soup containing an other variety of glucoraphanin-enriched broccoli (Beneforte extra) as part of their normal diet for one year.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Prevention
Keywords: prostate cancer prevention; diet; global gene expression; metabolic changes