Development and validation of a novel risk model in newly diagnosed de novo bone metastatic prostate cancer (M1b): a retrospective study

Abstract

Background Previous studies suggested that bone metastasis has a significant effect on the time of progression to metastatic castration-resistant prostate cancer (CRPC) for newly diagnosed de novo bone metastatic hormone-sensitive prostate cancer (mHSPC). Nevertheless, the effect of different bone metastasis sites was not fully evaluated. This study aimed to develop and validate a novel bone metastatic risk model. Methods We enrolled 122 patients who were newly diagnosed with de novo bone metastatic prostate cancer following primary androgen deprivation based therapy at our institution from January 2008 to June 2021. The metastatic bone sites were classified into six sites: skull; cervical, thoracic, and lumbar vertebrae; chest (ribs and sternum); pelvis; upper limbs; and lower limbs. We calculated the bone metastatic score (BMS) for each site: 0 points were assigned for non-metastasis and 1 point was assigned for metastasis. The X-tile was adopted to acquire optimal cutoff points of BMS. We defined high-risk group (HRG) as BMS ≥ 3 and low-risk group (LRG) as BMS < 3. The new bone risk stratification was validated by calculating the area under the receiver operating characteristic curve (AUC). Subsequently, the relevant clinical prognostic variables were added to construct a predictive nomogram for predicting CRPC. Results The median patient age was 73 years. Most patients had Gleason score ≤8 (93 cases, 76.2%). The median follow-up duration was 11.5 months (range: 2–92 months). Eighty-six patients progressed to CRPC during the follow-up. The most common bone metastatic site was the pelvis (90.2%). The median BMS was 4. Seventy-six patients had HRG, while forty-six had LRG. The 1-, 2-, and 3-year AUCs for H/LRG were 0.620, 0.754, and 0.793, respectively. The HRG was associated with earlier time to CRPC. A nomogram based on four parameters (Gleason score, H/LRG, prostate-specific antigen [PSA] nadir, and time to PSA nadir) was developed to predict CRPC. Internal validation using bootstrapping demonstrated good accuracy for predicting the CRPC (C-index: 0.727). The calibration analysis demonstrated that the model performed well. Conclusion We established a novel H/LRG risk model for newly diagnosed de novo bone metastatic prostate cancer, which provided evidence to support clinical decision-making.

Sternum Metastases: From Case-Identifying Strategy to Multidisciplinary Management

“…Alternatively, a bone metastatic score was calculated based on a prediction model in patients with newly diagnosed metastatic prostatic cancer following androgen deprivation therapy as the first -line treatment (N = 122 men; median age of 73; median follow-up duration of 11.5 months). The most frequent skeletal site of disease spreading was the pelvis at 92%, while 83% of them had chest involvement (sternum and ribs) with a hazard ratio (HR) of 2.093; 95% CI: 1.272–3.444, p = 0.004 [ 22 ].…”

“…Zhang 2023 [22] N = 122 patients with bone metastatic prostate cancer after first-line therapy with androgen deprivation treatment 83% of them had chest wall involvement (sternum + ribs); HR = 2.093; 95% CI: 1.272-3.444, p = 0.004.…”

“…Overall, we identified 14 studies (of more than 1 subject/article) [ 18 , 20 , 21 , 22 , 24 , 51 , 53 , 64 , 66 , 70 , 72 , 73 , 74 , 75 ] and 34 single case reports [ 14 , 15 , 16 , 17 , 19 , 23 , 25 , 26 , 38 , 41 , 42 , 43 , 47 , 52 , 55 , 56 , 59 , 60 , 62 , 68 , 71 , 76 , 77 , 78 , 89 , 98 , 99 , 100 , 101 , 102 ] within our methods with respect to sternal metastases (n = 48 papers) ( Table 5 ).…”

“…A narrative review allows a more flexible approach since the study design, the studied population, and the assessments/therapies were inhomogeneous. The 14 studies we mentioned may be classified into one of three groups: studies that addressed the incidence of bone metastases (including the sternum) amid different primary cancers, such as prostate cancer (N = 122 with bone metastases, 83% of them with chest wall metastases), head and neck cancers (N = 3620, 0.8% with bone metastases, and 10.34% of this subgroup with sternum involvement), and glioblastoma (N = 92 with bone metastases, 37% of them with non-vertebral metastases, including the sternum); assessments-based cohorts, namely, one on breast cancer (N = 410; accuracy and sensitivity of PET/CT vs. bone scintigraphy is superior with concern to sternum spreading) and another on bone metastases of unknown origin (N = 83, including a subgroup with sternum metastases; some features of PET/CT help with differentiation from multiple myeloma); and the third category is represented by cohorts with various therapeutic approaches, such as palliative arterial embolization (N = 10), thymic neuroendocrine neoplasia-associated management (1/5 subject detected with sternum metastases), survival rates for subjects with sternum metastases vs. non-sternum chest wall involvement (N = 87), oligo-metastatic (sternal) breast cancer (N = 4; in two other studies, N = 10 and N = 2, respectively), oligo-metastatic head and neck cancer (N = 81), applications of conformal radiotherapy (N = 24,215, including an analysis on sternum spreading), and EBRT followed by MR-HIFU (N = 6) [ 18 , 20 , 21 , 22 , 24 , 51 , 53 , 64 , 66 , 70 , 72 , 73 , 74 , 75 ].…”

“…Another unusual case was an 80-year-old female with metastatic hepatocellular carcinoma requiring a radical sternum and ribs dissection and further chest wall reconstruction using titanium plates and an acellular dermal matrix [26] (Table 1). [20,22,24].…”