Original Paper

Urologia

Received: September 16, 2014 Accepted after revision: October 7, 2014 Published online: January 29, 2015

Urol Int 2015;94:342–346 DOI: 10.1159/000368912

Internationalis

Is it Safe to Omit Baseline Bone Scan for Newly Diagnosed Prostate Cancer Patients? Yiwei Wang a Fangning Wan b, c Lei Xu a Naiqing Zhao d Zhibing Xu a Hang Wang a Guomin Wang a Dingwei Ye b, c Jianming Guo a   

 

 

 

 

 

 

 

 

a Department of Urology, Zhongshan Hospital, Fudan University, Shanghai, b Department of Urology, Fudan University Shanghai Cancer Center, Shanghai, c Department of Oncology, Fudan University Shanghai Medical College, Shanghai, and d School of Public Health, Fudan University, Shanghai, China  

 

 

 

Abstract Objectives: The aim of this study is to modify and validate a novel screening tool to determine the necessity of bone scans in Chinese PCa patients at the time of diagnosis. Methods: Five-hundred-and-one patients diagnosed with PCa between 2010 and 2013 at Zhongshan Hospital, Fudan University, were included in the study. All received bone scans using technetium 99m methylene diphosphonate (99mTcMDP) at the initial staging. Age, prostate-specific antigen (PSA) and alkaline phosphatase (ALP) at diagnosis, disease stage, and biopsy Gleason score were collected from all patients. Multivariate logistic regression analysis and discrimination analysis were performed. A validation analysis of this screening tool was performed by Shanghai Cancer Center, Fudan University. Results: Among the 501 patients, 84 (16.7%) of them had BM. The area under the ROC curve was 0.9006 (95% CI, 0.87–0.93). The sensitivity of the cut-off point was 94.1%, and the specificity was 58.3%. The validation

Y.W. and F.W. contributed equally to this work and should be considered co-first authors.

© 2015 S. Karger AG, Basel 0042–1138/15/0943–0342$39.50/0 E-Mail [email protected] www.karger.com/uin

analysis demonstrated an area under the ROC curve of 0.846 (95% CI, 0.805–0.887). Conclusions: Study results demonstrated that a baseline bone scan can be safely omitted for cT1-T3 PCa patients who have a PSA ≤39 ng/ml and an ALP ≤88 IU/l. This novel screening tool may help determine the necessity of including a bone scan at the time of initial diag© 2015 S. Karger AG, Basel nosis of PCa.

Introduction

The incidence and mortality of prostate cancer (PCa) are on an increasing trend in China [1–3]. Staging of the disease at diagnosis is currently a crucial factor for treatment selection. Bone metastasis (BM) is the most frequent site of metastasis for prostate cancer, and it has been correlated with reduced overall survival and quality of life among patients with PCa [4, 5]. A bone scan using technetium 99mTc methylene diphosphonate (99mTc-MDP) is routinely used to detect BM for PCa. However, nowadays more and more patients with prostate cancer are diagnosed prior to detectable overt metastasis due to prostate-

Jianming Guo, MD, PhD Department of Urology Zhongshan Hospital 180 Fenglin Rd., Shanghai 200032 (China) E-Mail guo.jianming @ zs-hospital.sh.cn Dingwei Ye, MD, PhD Department of Urology Fudan University Shanghai Cancer Center 270 Dong’an Rd., Shanghai 200032 (China) E-Mail dwyeli @ 163.com

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Key Words Alkaline phosphatase · Bone metastasis · Bone scan · Diagnosis · Prostate cancer

Materials This study used a database of 501 patients diagnosed with PCa, all of whom were histologically confirmed with adenocarcinoma, between January 2010 and January 2013 at Zhongshan Hospital, Fudan University. Age, laboratory parameters, including PSA, ALP, and LDH, disease stage according to the TNM 2002 staging system, and biopsy Gleason score were collected at the time of diagnosis. In addition, each patient received a bone scan using technetium 99mTc methylene diphosphonate (99mTc-MDP) regardless of baseline PCa characteristics. If the bone scan finding was equivocal, computed tomography (CT) or magnetic resonance imaging (MRI) was performed to confirm the diagnosis. Statistical analyses consisted of the following steps: First, the patients were categorized into two groups: bone metastases (BM) positive and BM negative. Age, PSA, ALP, and LDH level at diagnosis were described in mean, median, and range. Twosample t-test or Mann-Whitney test was used to compare age, PSA level, biopsy Gleason score, and clinical stage between the two patient cohorts. Second, the multivariate logistic regression model was used to generate a receiver operating characteristic (ROC) curve and to calculate area under curve (AUC). On the curve, the cut-off point was selected, followed by an analysis of discrimination expression. When D value (discrimination criterion) was ≥0, the result would be listed as ‘discriminated as BM’; whereas when D value was 100 ALP, IU/l Mean Median Range LDH, IU/l Mean Median Range Clinical stage, n (%) T1 T2 T3 T4 Gleason score, n (%) ≤6 3+4 4+3 8–10 Patients, n

Patients with p BM (n = 84) value 0.142

70.3 71 43–93

71.8 73 44–90 88

discriminated as BM discriminated as BM

0.00 2.47

≤39 ≤88 –0.46 >88 2.01

discriminated as no BM discriminated as BM

>39 ≤88 >88

1.77 4.24

discriminated as BM discriminated as BM

≤39 ≤88 >88

0.69 3.15

discriminated as BM discriminated as BM

>39 ≤88 >88

2.91 5.38

discriminated as BM discriminated as BM

≤39 ≤88 >88

2.46 4.92

discriminated as BM discriminated as BM

>39 ≤88 >88

4.69 7.15

discriminated as BM discriminated as BM

* D value stands for discrimination value.

Table 3 showed discrimination analysis among the patients grouped by individual variables. When D value (discrimination criterion) was ≥0, the result would be listed as ‘discriminated as BM’; whereas when D value was 10 ng/ml or Gleason score >8 or clinical stage >T3 [11]. National Comprehensive Cancer Network (NCCN) recommends that a bone scan is appropriate for the patients with (1) T1 disease who have a PSA of ≥20 ng/ml or a T2 disease who have a PSA of ≥10 ng/ml (2) Gleason score of ≥8 (3) symptomatic T3 to T4 patients [12]. Briganti et al. [10] suggested that baseline bone scans for staging might be restricted to patients with intermediate-risk (biopsy Gleason score ≤7, cT2/T3, and PSA >10) and high-risk [7] PCa (biopsy Gleason score 8–10). McArthur et al. stated that staging bone scans in newly diagnosed prostate cancer patients with a PSA level of 132.1 and for cT1-T3 patients having a Gleason score of ≥4 + 3 and PSA >44.5. The AUC of ROC was 0.87, lower than 0.90 of this study (p < 0.05). In the validation results, the area under the ROC was 0.846 (95% CI, 0.805–0.887) (fig. 2), which is larger than the AUC of Fudan CART model, Briganti’s CART model, SRE model, and ALP model [13, 14]. In this study, we optimized the screening model by incorporating ALP into the multiple logistic regression analysis. ALP was reported to be able to predict BM for PCa patients. Lorente et al. [15] and Wymenga et al. [16] found that the serum ALP level has a very good correlation with bone scan results. Elevated skeletal alkaline

Bone Metastasis in Prostate Cancer Patients

Urol Int 2015;94:342–346 DOI: 10.1159/000368912

Sensitivity

0.75

0.50

0.25

0 0

0.25

0.50

0.75

1.00

1 – Specificity

Fig. 2. ROC curve generated by Shanghai Cancer Center, fundan

university.

Table 4. Patient characteristics summarized by Shanghai Cancer

Center (n = 501) Patients without Patients with p value BM (n = 363) BM (n = 138) Mean age, years ALP, IU/l PSA, ng/ml Mean Median Range PSA, ng/ml, n (%) ≤10 10–20 20–50 50–100 >100 Clinical stage, n (%) T1 T2 T3 T4 Gleason score, n (%) ≤6 3+4 4+3 8–10 Patients, n (%)

67.4 68.3

69.0 290.2

40.1 17.1 1.1–469.4

548.1 129.4 1.14–6,060.0

95 (90.5) 115 (90.6) 81 (77.1) 40 (69.0) 32 (30.2)

10 (9.5) 12 (9.4) 24 (22.9) 18 (31.0) 74 (69.8)

68 (91.9) 247 (79.4) 32 (66.7) 16 (23.5)

6 (8.1) 64 (20.6) 16 (33.3) 52 (76.5)

115 (89.1) 74 (76.3) 60 (77.9) 111 (56.9) 363 (72.5)

14 (10.9) 23 (23.7) 17 (22.2) 84 (43.1) 138 (27.5)

0.045

Is it safe to omit baseline bone scan for newly diagnosed prostate cancer patients?

The aim of this study is to modify and validate a novel screening tool to determine the necessity of bone scans in Chinese PCa patients at the time of...
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