Primary radical therapy selection in high-risk non-metastatic prostate cancer

The role of chemotherapy and new targeted agents in the management of primary prostate cancer

While early treatment of primary prostate cancer is very effective, the incidence of primary prostate cancer continues to rise and therefore the detection of men with high-risk non-metastatic prostate cancer and their subsequent management is becoming increasingly important. There continues to be no molecularly-targeted or chemotherapeutic options with proven, statistically significant survival benefit in this setting. However, there are indications that further risk stratification using molecular features could potentially help distinguish indolent from aggressive prostate cancer, ultimately providing biological markers that could guide a more personalised approach to therapy selection.

Clinical management and research priorities for high-risk prostate cancer in the UK: Meeting report of a multidisciplinary panel in conjunction with the NCRI Prostate Cancer Clinical Studies Localised Subgroup

The management of high-risk prostate cancer has become increasingly sophisticated, with refinements in radical therapy and the inclusion of adjuvant local and systemic therapies. Despite this, high-risk prostate cancer continues to have significant treatment failure rates, with progression to metastasis, castrate resistance and ultimately disease-specific death. In an effort to discuss the challenges in this field, the UK National Clinical Research Institute’s Prostate Cancer Clinical Studies localised subgroup convened a multidisciplinary national meeting in the autumn of 2014. The remit of the meeting was to debate and reach a consensus on the key clinical and research challenges in high-risk prostate cancer and to identify themes that the UK would be best placed to pursue to help improve outcomes. This report presents the outcome of those discussions and the key recommendations for future research in this highly heterogeneous disease entity.

Molecular mechanisms underlying resistance to androgen deprivation therapy in prostate cancer

Prostate cancer (PCa) is the most widely diagnosed male cancer in the Western World and while low- and intermediate-risk PCa patients have a variety of treatment options, metastatic patients are limited to androgen deprivation therapy (ADT). This treatment paradigm has been in place for 75 years due to the unique role of androgens in promoting growth of prostatic epithelial cells via the transcription factor androgen receptor (AR) and downstream signaling pathways. Within 2 to 3 years of ADT, disease recurs-at which time, patients are considered to have castration-recurrent PCa (CR-PCa). A universal mechanism by which PCa becomes resistant to ADT has yet to be discovered. In this review article, we discuss underlying molecular mechanisms by which PCa evades ADT. Several major resistance pathways center on androgen signaling, including intratumoral and adrenal androgen production, AR-overexpression and amplification, expression of AR mutants, and constitutively-active AR splice variants. Other ADT resistance mechanisms, including activation of glucocorticoid receptor and impairment of DNA repair pathways are also discussed. New therapies have been approved for treatment of CR-PCa, but increase median survival by only 2-8 months. We discuss possible mechanisms of resistance to these new ADT agents. Finally, the practicality of the application of "precision oncology" to this continuing challenge of therapy resistance in metastatic or CR-PCa is examined. Empirical validation and clinical-based evidence are definitely needed to prove the superiority of "precision" treatment in providing a more targeted approach and curative therapies over the existing practices that are based on biological "cause-and-effect" relationship.

[Comparative oncologic and functional outcomes of prostate cancer surgery with other curative treatments]

OBJECTIVE

Review of the comparative results of different treatment strategies (surgery, radiotherapy, ultrasound, surveillance) of prostate cancer, in which the main goal is the local control and the second target is the tolerance of the side effects of those treatments.

MATERIALS AND METHODS

Review of literature using Medline databases selected based on scientific relevance. Clinical keys centered on the oncological and functional outcomes of comparative series between different curative treatments.

RESULTS

The numerous comparative series between surgery and other therapeutic modalities are essentially retrospective with significant methodological bias that is difficult to overcome in order to formulate the optimal thesis. However, there is a clear tendency toward surgery usually with young patients who have intermediate risk tumors without important comorbidity.

CONCLUSION

In the absence of randomized comparative series with significant power, the oncological and functional results of the radical prostatectomy with or without adjuvant treatment seem at least the same, in a selected population of patients, compared with the combination of radiotherapy-hormonotherapy in terms of survival, without biochemical recurrence, disease-specific survival and overall survival, for the aggressive tumors necessitating curative local treatments.

[Oncological outcomes of prostate cancer surgery]

OBJECTIVE

Review of the oncological results of the radical prostatectomy as initial treatment of prostate cancer, according to the surgical approach and the risk stratification using D'Amico risk groups.

MATERIALS AND METHODS

Review of literature using Medline databases and MedScience based on scientific relevance. Research focused on the oncological results of the radical prostatectomy in series and meta-analysis published since 10 years, taking into consideration the surgical approach if mentioned.

RESULTS

The characteristics of the operated tumor highly impact the local control authenticated by the pathologic stage and the rates of positive surgical margins (PSM), in addition to the survival and the biochemical recurrence. Surgical technique adapted according to the tumor treated, was a constant challenge to the urologist, who counter balance between the oncological control and the conservation of urinary and sexual function by conditioning the type of radical prostatectomy. Results of radical prostatectomy acceptable in terms of PSM and survival are not influenced by the surgical approach but by the degree of surgical experience.

CONCLUSION

Results of radical prostatectomy show the efficient local control of prostate cancer, taking into consideration the oncological rules and indications validated by multidisciplinary meetings, based on the national (CCAFU) and European oncological guidelines. Tendency is going toward considering radical prostatectomy indicated for patients with higher risk of disease progression, so integrating surgery in a multidisciplinary personalized approach.

Radiation resistance: Cancer stem cells (CSCs) and their enigmatic pro-survival signaling

Despite the fact that radiation therapy is a highly effective therapeutic approach, a small intratumoral cell subpopulation known as "cancer stem cells" (CSCs) is radiation-resistant and possesses specific molecular properties protecting it against radiation-induced damage. The exact mechanisms of this radioresistance are still not fully elucidated, but they relate to these cells' enhanced DNA repair capacities and their low intracellular ROS concentrations, resulting from their up-regulation of ROS scavengers. The low ROS content is accompanied by disturbances in cell cycle regulation, so it can be assumed that either CSCs are quiescent or dormant themselves, or that this cell population consists of at least two cell subpopulations: the normally and the slowly proliferating cells (quiescent or dormant cells). Slowly dividing CSCs show concomitant dysregulation of the signaling molecules mediating both cell cycle progression and maintenance of cell stemness. Despite a massive accumulation of data concerning the mechanisms underlying DNA damage response in CSCs, it represents a challenge to researchers in the era of personalized medicine to elucidate the role of intracellular ROS and of signaling pathways associated with the radiation resistance of these cells; there is a clear need to understand the molecular mechanisms helping CSCs to survive radiation exposure.