Active surveillance for prostate cancer: has the time finally come?

Conservative management of low-risk prostate cancer among young versus older men in the United States: Trends and outcomes from a novel national database

BACKGROUND

Management for men aged ≤55 years with low-risk prostate cancer (LRPC) is debated given quality-of-life implications with definitive treatment versus the potential missed opportunity for cure with conservative management. The objective of this study was to define rates of conservative management for LRPC and associated short-term outcomes in young versus older men in the United States.

METHODS

The nonpublic Surveillance, Epidemiology, and End Results Prostate with Active Surveillance/Watchful Waiting (AS/WW) Database identified 50,302 men who were diagnosed with LRPC from 2010 through 2015. AS/WW rates in the United States were stratified by age (≤55 vs ≥56 years). Prostate cancer-specific mortality and overall mortality were defined by initial management type (AS/WW vs definitive treatment [referent]) and age.

RESULTS

AS/WW utilization increased from 8.61% (2010) to 34.56% (2015) among men aged ≤55 years (P for trend <0.001) and from 15.99% to 43.81% among men aged ≥56 years (P for trend <.001). Among patients who had ≤2 positive biopsy cores, AS/WW rates increased from 12.90% to 48.78% for men aged ≤55 years and from 21.85% to 58.01% for men aged ≥56 years. Among patients who had ≥3 positive biopsy cores, AS/WW rates increased from 3.89% to 22.45% for men aged ≤55 years and from 10.05% to 28.49% for men aged ≥56 years (all P for trend <.001). Five-year prostate cancer-specific mortality rates were <0.30% across age and initial management type subgroups.

CONCLUSIONS

AS/WW rates quadrupled for patients aged ≤55 years from 2010 to 2015, with favorable short-term outcomes. These findings demonstrate the short-term safety and increasing acceptance of AS/WW for both younger and older patients. However, there are still higher absolute rates of AS/WW in older patients (P < .001), suggesting some national ambivalence toward AS/WW in younger patients.

Cigarette smoke modulates PC3 prostate cancer cell migration by altering adhesion molecules and the extracellular matrix

Prostate cancer (PCa) is the second leading cause of cancer-related mortality among American males. Studies suggest that cigarette smoking is associated with the progression of PCa; however, the molecular mechanisms underlying this process have not been extensively investigated. PCa progression is characterized by increased cell migration and alterations in extracellular matrix (ECM)- and cell adhesion molecule (CAM)-related gene expression. In the present study, the influence of cigarette smoke medium (SM) on cell migration and on the expression of ECM- and CAM-related genes in PC3 prostate adenocarcinoma cells was investigated. According to a wound-healing assay, SM treatment promoted PC3 cell migration. RNA expression levels from SM-treated and control cells were analyzed using a polymerase chain reaction (PCR) array. Of 84 genes analyzed, 27.38% (23/84) exhibited a ≥2-fold change in threshold cycle in PC3 cells following 0.5% SM treatment. Functional gene grouping analysis demonstrated that SM treatment modulated the RNA transcription of approximately 18.4% of CAMs and 33.93% of ECM-related genes. Quantitative PCR analysis showed that SM treatment led to a significant decrease in transcription levels of the following genes: Collagen 5 α-1(V), connective tissue growth factor, integrin β-2, kallmann syndrome 1, laminin α 3, matrix metallopeptidase 7 (MMP7), MMP13, secreted protein acidic cysteine-rich, thrombospondin-2 and versican; and that SM significantly increased the transcription levels of MMP2 and MMP12. Furthermore, MMP2 knockdown significantly reduced the migration of SM-treated PC3 cells. The present study provides novel insights into the association of cigarette smoking with PCa progression, via the alteration of ECM/CAM interactions.

Cigarette smoke induces nuclear translocation of heme oxygenase 1 (HO-1) in prostate cancer cells: nuclear HO-1 promotes vascular endothelial growth factor secretion

Prostate cancer is the second leading cause of male-cancer related death in the United States. Despite a number of evidence-based studies which strongly suggest an association between cigarette smoking and prostate cancer, the underlying biological mechanism is largely unknown. Heme oxygenase 1 (HO-1) has been implicated in maintaining cellular homeostasis, but also in tumor angiogenesis. Nuclear HO-1 protein expression has been observed in various types of tumors including prostate cancer. These studies, however, were reported as clinical and pathological observations, and failed to investigate nuclear HO-1 at the molecular level in cancer. The present study explores the relationship between cigarette smoke and nuclear HO-1-modulated promotion of vascular endothelial growth factor (VEGF) secretion. We have demonstrated that cigarette smoke medium (SM)-induced HO-1 mRNA expression and upregulated HO-1 protein levels in the prostate cancer cell lines DU145 and PC3. We also observed that SM significantly induced nuclear expression of HO-1, and enhanced secretion of VEGF in cells. Nuclear-directed expression of HO-1 activated the transcriptional activity of VEGF and promoted VEGF secretion in prostate cancer cells. This study provides new insights into the molecular mechanism by which cigarette smoke-induced nuclear translocation of HO-1 promotes VEGF secretion in prostate cancer cells. Nuclear HO-1 may, therefore, constitute an attractive therapeutic target to inhibit angiogenesis and the progression of prostate cancer.

Cetuximab in the treatment of squamous cell carcinoma of the head and neck

The majority of the head and neck cancers are squamous cell carcinomas, which commonly overexpress the EGF receptor (EGFR). Cetuximab is a chimeric monoclonal antibody that binds with high affinity to the extracellular domain of EGFR, and in addition induces antibody-dependent cellular cytoxicity. In a randomized Phase III trial in patients with locoregionally advanced squamous cell carcinoma of the head and neck, the addition of cetuximab to radiotherapy prolonged the median time of locoregional control from 14.9 to 24.4 months and increased the median overall survival from 29.3 to 49.0 months. In patients with platinum-refractory recurrent and/or metastatic disease, the objective response and disease-control rates in various studies ranged from 10 to 13% and from 46 to 56%, respectively. In the EXTREME trial, the addition of cetuximab to platinum/5-fluorouracil as first-line treatment of recurrent/metastatic squamous cell carcinoma of the head and neck not only led to significant improvements in survival, response rate and disease control, but also induced a better symptom control in comparison with that observed with platinum/5-fluorouracil alone.