Urology Department, Mansoura University, Mansoura, Egypt.
Prostate Cancer Prostatic Dis. 2010 Jun;13(2):186-90. doi: 10.1038/pcan.2009.53. Epub 2009 Dec 22.
To clinically apply the inverse PSA-body mass index (BMI) correlation and enhance PSA sensitivity in obese cases, a new formula is warranted. An innovated BMI-PSA equation is designed. PSA-BMI adjusted formula (named Hekal's equation): measured total PSA (ng ml(-1)) multiplied by age (years) and divided by BMI of the patient. The formula is applied over a randomly chosen 1000 cases of different PSA, BMI, age and trans-rectal ultrasound biopsy results, the yield of new PSA is correlated with pathology and age-specific PSA adjustment values. Among the 988 cases with complete data, obesity (BMI: 30-35 kg m(-2)) in 236 cases (23.8%) and 79 cases (7.9%) have BMI>35 kg m(-2). Mean PSA was 5.8 ng ml(-1) (s.d.+/-8.4 ng ml(-1)). Cases stratified based on their age (every 10 years). The new equation was applied. Obesity is detected in 33.5 and 43.6% of fifth and sixth decade of life respectively (P=0.02), with low measured PSA values (2.1, 3.8 ng ml(-1), respectively). By such PSA measurement biopsy may be omitted, missing 53.3% of malignant cases. In contrast, PSA adjusted were 4 and 9.3 ng ml(-1) within the same group of patients. With such values, the decision of a biopsy could not be missed for the targeted groups. Specificity and sensitivity of adjusted PSA values at cutoff point 4 ng ml(-1) was 41.7 and 70%, respectively. Based on our results, the new PSA-BMI adjusted formula is reproducible, easy applied formula. With such a formula the higher sensitivity of PSA in obese patients could be achieved. The misleading low PSA in obese cases in the fifth and sixth decade will be corrected.
为了将反 PSA-体重指数（BMI）相关性应用于临床并提高肥胖患者的 PSA 敏感性，需要一个新的公式。设计了一个创新的 BMI-PSA 方程。PSA-BMI 调整公式（命名为 Hekal 方程）：测量的总 PSA（ng/ml）乘以年龄（岁），再除以患者的 BMI。该公式适用于随机选择的 1000 例不同 PSA、BMI、年龄和经直肠超声活检结果，新 PSA 的检出率与病理学和年龄特异性 PSA 调整值相关。在 988 例完整数据中，236 例（23.8%）和 79 例（7.9%）肥胖（BMI：30-35kg/m2），BMI>35kg/m2。平均 PSA 为 5.8ng/ml（标准差+/-8.4ng/ml）。根据年龄分层（每 10 年）。应用新方程。第五和第六个十年分别发现肥胖率为 33.5%和 43.6%（P=0.02），PSA 值较低（分别为 2.1、3.8ng/ml）。通过这种 PSA 测量，活检可能被省略，漏诊了 53.3%的恶性病例。相比之下，同一组患者的 PSA 调整值为 4 和 9.3ng/ml。有了这些值，就不会错过针对目标人群进行活检的决定。在截断点 4ng/ml 时，调整后的 PSA 值的特异性和敏感性分别为 41.7%和 70%。根据我们的结果，新的 PSA-BMI 调整公式是可复制的、易于应用的公式。通过这种公式，可以提高肥胖患者 PSA 的敏感性。第五和第六个十年肥胖患者 PSA 较低的误导性问题将得到纠正。
