Vegetables, Fruit, and prostate Cancer.
Abstract
OBJECTIVES:
- To review all prospective studies which provided data about total fruits or vegetables, their subgroups, and specific types of vegetables and fruits, in relationship with prostate cancer risk, disease progression and mortality/survival.
- To define the amount of consumption found to be related with the described effects on cancer.
- To define possible effect modification by confounders.
DATA SOURCE: The Pubmed database was searched (No start date - Sep 11, 2009) for relevant articles using
the keywords "cancer, neoplasm, or neoplasms" combined with "vegetables, vegetable, fruit, or fruits" and a fair amount of other keywords.
The exact search term is described in the methods.
Prospective studies published in the English language were included. Reference lists were searched for additional articles.
RESULTS: 38 articles were found which provided information about 24 different cohorts.
Of these, 0 articles needed to be excluded because of language restrictions. And no articles were excluded because of any other reasons.
Results are described when any evidence for an association - as defined in the Methods - was found. In addition, data about total vegetables
or fruits, tomatoes, and soy is described.
- Total prostate cancer risk.
-Data about the relation with total vegetables was provided by 11 cohorts, including 26,599 cases. No evidence was found for an association.
-Data about the relation with total fruits was provided by 16 cohorts, including 27,557 cases. No evidence was found for an association.
-No evidence was found for an association with tomatoes (8 cohorts; 7,277 cases), tomato sauce (3 cohorts; 4,779 cases), and tomato juice (4 cohorts; 6,593 cases) or the combined effect of all 3 categories.
-Data about the relation with various soy foods was provided by 7 cohorts, including a total of 6,839 cases. No evidence was found for an association with total soy, tofu, and miso soup or the combined effect of all 3 categories.
-Data about the relation with citrus fruit was provided by 3 cohort, including a total of 4,705 cases. Citrus fruit possibly increases prostate cancer risk among white men.
-Data about the relation with legumes was provided by 4 cohorts, including a total of 5,179 cases. Legumes possibly protect against prostate cancer risk at the level of consumption of > 71 g/day. - Advanced stage/metastatic disease risk or disease progression.
-Data about the relation between total vegetables and advanced prostate cancer risk was provided by 5 cohorts, including 4,188 cases. Findings were inconsistent, but no evidence was found for an association.
-Data about the relation between total fruits and advanced prostate cancer risk was provided by 5 cohorts, including 4,618 cases. No evidence was found for an association.
-Data about tomatoes was provided by 3 cohorts (2,257 cases), and data about tomato sauce was provided by 2 cohorts (1,388 cases). Though dose response results were found, no (non)significant effects between tomato sauce and advanced stage prostate cancer risk were found in any cohort. Inclusion of data about cooked tomatoes and high grade disease in the model, strengthens the possibility of a dose response effect, but does not strenghten the evidence. No evidence was found for an association between tomatoes and/or tomato sauce and advanced prostate cancer risk.
-Data about the relation with soy was provided by 5 cohorts, including 1,944 cases. No evidence was found for an association. - Mortality risk.
-Data about the relation between total vegetables and prostate cancer mortality was provided by 4 cohorts, including 2,163 cases. Inconsistent findings were done, but no evidence was found for an association.
-Data about the relation between total vegetables and prostate cancer mortality was provided by 4 small cohorts, including 456 cases. No evidence was found for an association.
-No evidence was found for an association with tomatoes (2 cohorts; 298 cases), or tomato sauce (1 cohort; 312 cases).
-Data about the relation with soy was provided by 2 cohorts, including 345 cases. No evidence was found for an association. - Effect modification: Hardly any information is available about effect modification by possible confounders. No evidence was found for effect modification.
CONCLUSION: No evidence was found for an association between either total fruits or total vegetables and any examined end point: total cancer risk,
advanced cancer risk, and cancer mortality. In addition, no evidence was found for an association when advanced cancer and mortality are considered
as one single end point, or when advanced prostate cancer is stratified in disease stage and grade. No evidence was found for effect modification by confounders
of any of these associations.
No evidence was found for an association between tomatoes, tomato juice, or tomato sauce and total- or advanced prostate cancer risk or mortality. The evidence
did not change when all tomato categories were combined, or when advanced prostate cancer and mortality were grouped together.
No evidence was found for an association between any soy foods (total soy, tofu, miso soup, or a combination of these 3 items) and any cancer end point.
But when advanced cancer risk and cancer mortality are considered one end point, miso soup possibly increases risk. The level of consumption
for this effect could not be defined.
Citrus fruit possibly increases prostate cancer risk among white men. Legumes possibly protect against prostate cancer risk at daily consumption of > 71 g/day.
Total vegetables and prostate cancer.
Total prostate cancer risk: Data about total vegetables in relation to total prostate cancer risk was provided by 11 cohorts, including
a total of 26,599 cases.
A protective association was found in the second, but not first part of follow-up of "The Health Professionals Follow-up Study", including 436 cases (7).
But no information is available about the strenght or significance of the association, and no adjustments were made for possible confounders.
No other (non)significant associations were found.
Inclusion of intermediate levels of consumption:
A significantly increased risk was found in one cohort at the level of consumption of 140-193 g/day (Gonzalez A). No other (non)significant associations were
found at any level of consumption in any cohort.
Advanced stage prostate cancer risk: Data about total vegetables in relation to advanced prostate cancer risk was provided by 5 cohorts,
including a total of 4,188 cases.
A significant protective effect against extraprostatic prostate cancer was found in one cohort, including 29,361 men in which the amount of cases
is not defined (18). But a significantly increased risk of advanced prostate cancer was found in one larger cohort, including 288,109 men and 1,778 cancer cases (24).
No other associations were found.
Prostate cancer mortality: Data about total vegetables in relation to prostate cancer death was provided by 4 cohorts, including a total of 2,163 cases.
A signicantly increased risk of prostate cancer death was found in one cohort for low vs high consumption, but no specific amounts (servings/grams) of
consumption were defined (9). No other associations were found.
Conclusion: Few associations were found. No evidence was found for an association between total vegetables and total prostate cancer risk at any level of consumption.
Findings about the relation with advanced prostate cancer are contradictive, and no evidence was found for an association with advanced prostate cancer, or prostate
cancer death. In addition, no evidence was found for an association when advanced cancer and mortality are considered as one single end point, or when advanced prostate
cancer is stratified in disease stage and grade.
| Author | Cohort name | Cases | Relative Risk (RR) |
|---|---|---|---|
| 24) George SM (2008) | The NIH-AARP Diet and Health Study | 17,034 | RR = 0.97 (0.93-1.02; P = 0.106). |
| 23) Ambrosini GL (2008) | No cohort name | 97 | RR = 0.73 (0.38-1.40; P = 0.350). |
| 21) Gonzalez A (2009) | The VITAL Cohort | 761 | HR = 1.15 (0.93-1.42). |
| 18) Kirsh VA (2007) | The Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial | 1,338 | RR = 0.88 (0.71-1.08; P = 0.24). |
| 17) Stram DO (2006) | The Multiethnic Cohort Study | 3,922 | RR = 1.00 (0.91-1.15; P = 0.466). |
| 15) Key TJ (2004) | The EPIC Study | 1,104 | RR = 1.00 (0.81-1.22; P = 0.738). |
| 13) Tseng M (2004) | The NHEFS Cohort | 136 | No association. |
| 11) Chan JM (2000) | The ATBC Study | 184 | RR = 0.8 (0.5-1.3; P = 0.84). |
| 10) Schuurman AG (1998) | The Netherlands Cohort Study | 606 | RR = 0.80 (0.57-1.12; P = 0.51). |
| 7) Wu K (2004) | The Health Professionals Follow-up Study (1993-1998) | 436 | Cases consumed less vegetables (no data). |
| 7) Giovannucci E (1995) | The Health Professionals Follow-up Study (1986-1992) | 773 | RR = 1.04 (0.81-1.34; P = 0.68). |
| 2) Shibata A (1992) | The Leisure World Study | 208 | RR = 1.04 (0.74-1.46). |
| Total number of cases: | 26,599 |
| Author | Cohort name | Cases | End point | Relative Risk (RR) |
|---|---|---|---|---|
| 24) George SM (2008) | The NIH-AARP Diet and Health Study | 1,778 | Advanced prostate cancer | RR = 1.18 (1.01-1.38; P = 0.04). |
| 18) Kirsh VA (2007) | The Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial | Aggressive: 520. Extraprostatic: Not defined. | Aggressive or extraprostatic cancer | Aggressive cancer: RR = 0.81 (0.58-1.13; P = 0.27). Extraprostatic cancer: RR = 0.41 (0.22-0.74; P = 0.01). |
| 17) Stram DO (2006) | The Multiethnic Cohort Study | 1,345 | Nonlocalized and high grade disease | RR = 1.00 (0.90-1.10; P = 0.467). |
| 10) Schuurman AG (1998) | The Netherlands Cohort Study | 153 | Poorly- or undifferentiated prostate cancer | RR = 0.99 (0.94-1.05). |
| 7) Chan JM (2006) | The Health Professionals Follow-up Study | 392 | Prostate cancer progression | RR = 1.26 (0.85-1.87). |
| Total number of cases: | 4,188 |
| Author | Cohort name | Cases | Relative Risk (RR) |
|---|---|---|---|
| 22) Smit E (2007) | The Puerto Rico Heart Health Progeam | 167 | OR = 1.61 (0.68-3.83; P = 0.48). |
| 9) Rodriguez C (1997) | The Cancer Prevention Study | 1,748 | RR = 1.26 (1.07-1.48) for low vs high consumption. |
| 5) Hsing AW (1990) | The Lutheran Brotherhood Cohort Study | 149 | RR = 0.7 (0.4-1.2). |
| 1) Snowdon DA (1984) | The Adventist Health Study | 99 | No association. |
| Total number of cases: | 2,163 |
Total fruit and prostate cancer.
Total prostate cancer risk: Data about total fruits in relation to total prostate cancer risk was provided by 16 cohorts,
including a total of 27,557 cases.
A significant trend of an increased risk was found in one cohort, including 637 cases (10). No other (non)significant associations were found.
Inclusion of intermediate levels of consumption:
Significantly increased risks were found at the levels of consumption of 151 g/day (Chan JM), and 51-96 g/day (Gonzalez A). Though the trend was
significant, no (non)significant effects were found in one cohort (10; Schuurman AG).
No (non)significant protective effect was found at any level of consumption in any cohort.
Advanced stage prostate cancer risk: Data about advanced prostate cancer risk was provided by 6 publications about 5 cohorts,
including a total of 4,618 cases.
In "The Health Professional's Follow Up Study" (7), a significant protective effect was found against advanced prostate cancer risk (Giovannucci 1998), but no association
was found with prostate cancer progression in the same cohort (Chan 2006). No other associations were found.
Prostate cancer mortality: Data about total fruits in relation to prostate cancer death was provided by 4 small cohorts, including a total of 456 cases.
No associations were found.
Conclusion: Few associations were found with any end point. No evidence was found for an association between total fruits and total prostate cancer risk,
advanced prostate cancer risk, or prostate cancer mortality. In addition, no evidence was found for an association when advanced cancer and mortality are considered
as one single end point, or when advanced prostate cancer is stratified in disease stage and grade.
| Author | Cohort name | Cases | Relative Risk (RR) |
|---|---|---|---|
| 24) George SM (2008) | The NIH-AARP Diet and Health Study | 17,034 | RR = 1.01 (0.95-1.06; P = 0.766). |
| 23) Ambrosini GL (2008) | No cohort name | 97 | RR = 0.94 (0.46-1.89; P = 0.848). |
| 21) Gonzalez A (2007) | The VITAL Cohort | 763 | HR = 1.19 (0.96-1.47). |
| 19) Kurahashi N (2008) | The JPHC Study | 201 | No association (P = 0.97). |
| 18) Kirsh VA (2007) | The Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial | 1,338 | RR = 0.94 (0.77-1.15; P = 0.84). |
| 17) Stram DO (2006) | The Multiethnic Cohort Study | 3,922 | RR = 1.05 (0.94-1.16; P = 0.603). |
| 15) Key TJ (2004) | The EPIC Study | 1,104 | RR = 1.06 (0.84-1.34; P = 0.741). |
| 14) Allen NE (2004) | The Hiroshima/Nagasaki Life Span Study | 196 | RR = 1.20 (0.83-1.74; P = 0.40). |
| 13) Tseng M (2004) | The NHEFS Cohort | 136 | No association. |
| 11) Chan JM (2000) | The ATBC Study | 184 | RR = 1.3 (0.8-2.2; P = 0.13). |
| 10) Schuurman AG (1998) | The Netherlands Cohort Study | 637 | RR = 1.31 (0.96-1.79; P = 0.02). |
| 7) Wu K (2004) | The Health Professionals Follow-up Study (1993-1998) | 436 | No association. |
| 7) Giovannucci E (1995) | The Health Professionals Follow-up Study (1986-1992) | 773 | RR = 0.84 (0.59-1.84; P = 0.21). |
| 6) Le Marchand L (1994) | No cohort name | 198 | RR = 1.0 (0.7-1.6; P = 0.99). |
| 3) Severson RK (1989) | The Japan-Hawaii Study | 174 | RR = 1.57 (0.95-2.61). |
| 2) Shibata A (1992) | The Leisure World Study | 208 | RR = 1.04 (0.74-1.46). |
| 1) Mills PK (1989) | The Adventist Health Study | 156 | RR = 1.07 (0.72-1.58; P = 0.37). |
| Total number of cases: | 27,557 |
| Author | Cohort name | Cases | End point | Relative Risk (RR) |
|---|---|---|---|---|
| 24) George SM (2008) | The NIH-AARP Diet and Health Study | 1,778 | Advanced prostate cancer risk | RR = 0.98 (0.83-1.15; P = 0.91). |
| 18) Kirsh VA (2007) | The Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial | Aggressive: 520. Extraprostatic: Not defined. | Aggressive or extraprostatic cancer | Aggressive cancer: RR = 0.90 (0.65-1.25; P = 0.99). Extraprostatic cancer: RR = 1.05 (0.61-1.83; P = 0.92). |
| 17) Stram DO (2006) | The Multiethnic Cohort Study | 1,345 | Non-localized or high grade disease | RR = 1.01 (0.85-1.20; P = 0.769). |
| 10) Schuurman AG (1998) | The Netherlands Cohort Study | 160 | Poorly- or undifferentiated prostate cancer | RR = 1.02 (0.99-1.06). |
| 7) Chan JM (2006) | The Health Professionals Follow-up Study | 392 | Prostate cancer progression | RR = 0.90 (0.62-1.28). |
| 7) Giovannucci E (1998) | The Health Professionals Follow-up Study | 423 | Advanced prostate cancer risk | RR = 0.63 (0.43-0.93). |
| Total number of cases: | 4,618 |
| Author | Cohort name | Cases | Relative Risk (RR) |
|---|---|---|---|
| 22) Smit E (2007) | The Puerto Rico Heart Health Program | 167 | OR = 1.13 (0.45-2.79; P = 0.30). |
| 12) Appleby PN (2002) | The Health Food Shoppers Study | 41 | RR = 0.66 (0.34-1.29). |
| 5) Hsing AW (1990) | The Lutheran Brotherhood Cohort Study | 149 | RR = 0.9 (0.6-1.4). |
| 1) Snowdon DA (1984) | The Adventist Health Study | 99 | No association. |
| Total number of cases: | 456 |
Possible effect modification by confounders.
Data about possible effect modification is reviewed. Modifying effects on the relation between total fruits or total vegetables and
a) total prostate cancer risk, b) advanced prostate cancer risk, and c) prostate cancer death are discussed. All available data is discussed.
Total vegetables
- Total prostate cancer risk: No effect modification of age or country was found (15).
- Advanced prostate cancer risk: No effect modification of treatment groups and prognostic groups on prostate cancer progression was found (7).
An increased risk of advanced prostate cancer was found in one cohort, but this association was weaker in never-smokers (24). - Prostate cancer mortality: No data available.
Total fruits
- Total prostate cancer risk: No effect modification of age or country was found (15).
- Advanced prostate cancer risk: No effect modification of treatment groups and prognostic groups on prostate cancer progression was found (7).
- Prostate cancer mortality: No effect modification of smoking status was found (12).
Conclusion: Hardly any information is available about effect modification by possible confounders. No evidence was found for effect modification.