3.1 ELABORACIÓN DEL FLUIDO
3.1.2 PROCESO DE ELABORACIÓN DEL FLUIDO DE PERFORACIÓN
Cases Referents All cases (N = 942) Aggressive PCaa (N = 647) Non-aggressive PCaa (N=295) All referents (N = 2062) N % N % N % N % Self-reported acne
ever had acneb 320 33.9 226 34.9 94 31.9 739 35.8
isolated facial acne 214 66.9 151 66.8 63 67.0 441 59.7 isolated corporal acne 12 3.8 9 4.0 3 3.2 33 4.5 generalized acne 94 29.4 66 29.2 28 29.8 248 33.6
not specified - - - - - 17 2.3
never had acne 621 65.9 421 65.1 200 67.8 1281 62.1
missing 1 0.1 0 - 1 0.3 42 2.0
a PCa with any of the following characteristics: T-stage ≥ T2c or N+ or M+ or Gleason score 8–10 or PSA > 20 ng/ml;
non-aggressive PCa: PCa with none of the aggressive characteristics
b Participants who initially answered “no” to the question whether they aver had acne, but did indicate a location where
acne was located, were recoded to “yes” for the question whether they ever had acne.
Abbreviations: PSA: prostate-specific antigen; PCa: prostate cancer Table 3. Association between acne and prostate cancer
All subjects Aggressiveb PCa Non-aggressiveb PCa
Referents N = 2020 Cases N = 941 ORa 95%CI Cases N = 647 OR 95%CI Cases N = 294 OR 95%CI Self-reported acne
Ever had acnec 739 320 0.95 (0.80-1.12) 226 0.97 (0.80-1.18) 94 0.90 (0.67-1.19)
Never acne 1281 621 1.00 421 1.00 200 1.00
a ORs were adjusted for age at the time of completion of the questionnaire and family history
b PCa with any of the following characteristics: T-stage ≥ T2c or N+ or M+ or Gleason score 8–10 or PSA > 20 ng/ml;
non-aggressive PCa: PCa with none of the aggressive characteristics
c Participants who answered “no” to the question whether they aver had acne, but did indicate where on the body the
acne was located, were recoded to “yes” for the question whether they ever had acne.
Chapter 7 Acne not associated with aggressive PC
DISCUSSION
In this large case-referent study, in which we evaluated self-reported acne for almost 1,000 PCa cases and more than 2,000 referents, we found no significant association between self-reported acne and PCa. We also did not find any association between acne and either aggressive or non-aggressive PCa. This went for both analyses when using pT≥T2c as a cut point for aggressive PCa, as suggested by d’Amico et al., as well as when replacing this criterion by pT≥T3 as used by Severi et al.12,16. These
results are in contradiction with the results of the study on P. acnes antibody titer and PCa, which found an association between titers at or above the median and PCa with an OR of 0.73, and an OR of even 0.59 for advanced PCa12.
Other studies that previously investigated the association between acne and PCa have yielded varying results. These results range from a negative association for facial acne scarring and PCa in a large Australian case-referent study (over 1,497 cases and 1,434 referents) to no significant differences for self-reported acne and PCa to a (non-significant) positive association between adulthood acne and prostate cancer mortality5,6,8. In our opinion, given the additional results from this investigation
in a large population, a history of acne cannot be used as a marker for PCa risk.
Potential biases in a case-referent design include recall bias. However, we have no reason to believe that men who have been diagnosed with PCa have a different recollection of acne occurrence as compared to healthy individuals. Differential misclassification is therefore not likely, but non-differ- ential misclassification may have led to some underestimation of the real strength of the association. Because of the nature of this study, selection bias is also unlikely to have played a role. The patients and referents were selected for this study regardless of past or current acne status and the questions on acne were part of a broader investigation into risk factors for PCa where an extensive risk factor questionnaire was taken along with blood samples for DNA. Confounding is by definition impossible because, naturally, we were not investigating any direct causal relationship between acne and PC. We were merely interested in the correlation between the two, as to evaluate whether acne might be a useful phenotype for screening purposes, independent of age and family history.
This study shows that the association between self-reported acne and (aggressive) PCa, if present at all, is too weak to be useful in clinical practice. Therefore, we conclude that acne is not suitable as a marker to identify men at low risk of aggressive PCa.
ACKNOWLEDGEMENTS
We thank the individuals who participated in this study and whose contribution made this work possi- ble. Principal investigators of the Nijmegen Biomedical Study are L.A.L.M. Kiemeney, M. den Heijer, A.L.M. Verbeek, D.W. Swinkels and B. Franke. Dr. Cremers was supported by contract number 202059 (ProMark) from the Seventh Framework Program of the European Union and by an Agiko stipend (number 92003573) of the Netherlands Organisation of Health Research and Development.
Acne not associated with aggressive PC
7
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