Obese men with low risk prostate cancer have higher risk for unfavourable disease
Obesity is associated with greater risk for unfavourable pathological features in men with low risk prostate cancer who are eligible for active surveillance, according to a study. Obese men are likely to have transition zone cancer, which is related to unfavourable pathology findings in those with very low risk prostate cancer.
Researchers analysed the records of 890 patients with biopsy Gleason score 6 who underwent radical prostatectomy for prostate cancer via multiscore (12 or more) biopsy to examine the impact of obesity on unfavourable disease in men with low risk prostate cancer eligible for active surveillance and to confirm the underlying association with tumour location.
The definition of ‘unfavourable disease’ was a primary Gleason pattern ≥4 or pathological stage ≥T3. Researchers performed multivariate logistic regression analysis to identify factors tied to unfavourable disease and evaluated the association of unfavourable disease with anatomical location of the index tumour.
According to established body mass index (BMI) cutoff points for Asian men, a total of 216 (24.3 percent) men had a BMI of <23 kg/m2 (normal), 544 (61.1 percent) had a BMI or 23 to 27.5 kg/m2 (overweight) and 130 men (14.6 percent) had a BMI of ≥27.5 kg/m2 (obese).
Based on multivariate analysis, age, prostate volume and BMI were independently associated with unfavourable disease irrespective of the various active surveillance criteria used. Obese patients, compared with normal weight participants, had a higher risk of unfavourable disease for those fulfilling the John Hopkins Hospital criteria.
Across all criteria for active surveillance, transition zone cancer showed more frequent unfavourable disease than nontransition zone cancer (p<0.01 for all). For the John Hopkins Hospital criteria, the proportion of transition zone cancer was 4.2, 11.6 and 16.7 percent for normal weight, overweight and obesity, respectively (p=0.022).