Response evaluation of bone metastasis in prostate cancer: Preliminary comparison of computerized bone scan index versus standardized clinical criteria.

OBJECTIVE: The correlation between the computer-assisted bone scan index (BSI) responses versus clinical response classification if bone metastases in prostate cancer patients are not clear. We compared changes in BSI with Prostate Cancer Working Group-3 (PCWG3) and MD Anderson (MDA) criteria. MATERIALS AND METHODS: Fifty-six consecutive patients with at least two bone scans (BS) within 12 months were included, who had BS before and after treatment with the same anticancer agent. RESULTS: Progressive disease (PD) by PCWG3 criteria was seen in 28% of the cases (median BSI increased by 1.69 units) versus non-PD in 72% (BSI change -0.13). MDAnderson showed PD in 34% (BSI increase 0.49), 45% stable disease (BSI change 0.00), and 20% partial responses (BSI decrease 1.44). Absolute BSI changes differed significantly among response categories by PCWG3 and MDA criteria (both P<0.0001). Response classification using dichotomized BSI data (>0/≤0 and >0.3/≤0.3 BSI units) showed a significant correlation with PCWG3 and MDA criteria (all P<0.001). Absolute BSI changes and dichotomized BSI correlated to prostate-specific antigen responses (both P<0.001) but not to clinical responses. CONCLUSION: Absolute changes in BSI and BSI response classification correlated significantly with standardized clinical response criteria for the assessment of treatment responses of skeletal metastases in prostate cancer.

Observer agreement of treatment responses on planar bone scintigraphy in prostate cancer patients: importance of the lesion assessment method.

PURPOSE: The aim of this study was to assess observer agreement on the evaluation of treatment responses of bone metastases by bone scintigraphy (BS) using different scoring methods in prostate cancer patients. PATIENTS AND METHODS: Sixty-three paired BS from 55 patients were included. BS was performed before and after more than 12 weeks of anticancer treatment. A panel of experienced nuclear medicine physicians from several institutions evaluated treatment response using three different methods: (a) standard clinical assessment, (b) MD Anderson criteria, and (c) Prostate Cancer Working Group 2 (PCWG-2) criteria. All methods were based on the evaluation of paired before-after bone scans. RESULTS: Readers were able to classify the presence of bone metastases at baseline with a high level of agreement [Cohen's κ=0.94, 95% confidence interval (CI) 0.82-1.00]. Observer agreement on bone response by PCWG-2 criteria showed considerable agreement (Cohen's κ=0.84, 95% CI: 0.69-0.99). Evaluation using standard clinical assessment and MD Anderson criteria showed moderate agreement (0.52, 95% CI: 0.36-0.69 and 0.64, 95% CI: 0.48-0.79, respectively). There was considerable variation among readers for regional lesion count on individual scans, with limits of agreement of -10 to 10 lesions or more for the majority of anatomical regions, including the thorax, spine, and pelvis. CONCLUSION: Observer agreement on treatment response by BS varied notably across methods. Optimal agreement was achieved by the PCWG-2 criteria. Variation in the classification of treatment response of bone metastases may have a significant impact on clinical decision-making, emphasizing the need for a uniform approach, including during clinical practice. Response assessment by lesion counting on repeated BS without access to previous scans cannot be recommended.

[Lactic acidosis in a 24-year-old woman with status asthmaticus].

A 24-year-old woman with asthma presented with symptoms of upper airway infection and tachypnoea and wheezes. She had a history of admissions to intensive care units (ICU) due to respiratory insufficiency. The initial lactate concentration was 2.1 mmol/l. The treatment consisted of inhaled and intravenous ß ² agonists. Hereafter, the lactate concentration rose to 9.8 mmol/l, and the patient was admitted to the ICU due to severe asthma exacerbation. The elevation of lactate concentration cleared after discontinuation of ß ² agonist therapy. Although lactic acidosis is a rare side effect to ß ² agonist treatment, it is important to recog-nize it when present.