Treatment-related neuroendocrine prostate cancer managed with partial stereotactic ablative radiotherapy (P-SABR) for long-term survival: a case series

Understanding the molecular regulators of neuroendocrine prostate cancer

Worldwide, prostate cancer (PCa) remains a leading cause of death in men. Histologically, the majority of PCa cases are classified as adenocarcinomas, which are mainly composed of androgen receptor-positive luminal cells. PCa is initially driven by the androgen receptor axis, where androgen-mediated activation of the receptor is one of the primary culprits for disease progression. Therefore, in advanced stage PCa, patients are generally treated with androgen deprivation therapies alone or in combination with androgen receptor pathway inhibitors. However, after an initial decrease, the cancer recurs for majority patients. At this stage, cancer is known as castration-resistant prostate cancer (CRPC). Majority of CRPC tumors still depend on androgen receptor axis for its progression to metastasis. However, in around 20-30% of cases, CRPC progresses via an androgen receptor-independent pathway and is often presented as neuroendocrine cancer (NE). This NE phenotype is highly aggressive with poor overall survival as compared to CRPC adenocarcinoma. NE cancers are resistant to standard taxane chemotherapies, which are often used to treat metastatic disease. Pathologically and morphologically, NE cancers are highly diverse and often co-exist with adenocarcinoma. Due to the lack of proper biomarkers, it is often difficult to make an early diagnosis of this lethal disease. Moreover, increased tumor heterogeneity and admixtures of adeno and NE subtypes in the same tumor make early detection of NE tumors very difficult. With the advancement of our knowledge and sequencing technology, we are now able to better understand the molecular mediators of this transformation pathway. This current study will give an update on how various molecular regulators are involved in these lineage transformation processes and what challenges we are still facing to detect and treat this cancer.

Quadruplet Therapy in De Novo High-Volume Mixed Neuroendocrine Prostate Cancer Using 177Lu-PSMA: A Case Report

ABSTRACT

We present a case of de novo high-volume metastatic prostate cancer with high PSMA expression, partially PSMA-negative, using quadruplet therapy (PROMISE ver. 2 miTNM; miT4N2M1aM1b(dmi) PRIMARY score: 5, PSMA-expression score: 0-3). Because of our patient's partial PSMA negativity and after a multidisciplinary tumor board discussion, we decided to use a modified protocol involving doublet hormonal therapy along with 177Lu-PSMA and radiation therapy to address the PSMA-negative disease. The patient responded well to this treatment, but recurrence was ultimately inevitable. This case represents a typical example of mixed neuroendocrine prostate carcinoma and highlights its resistant phenotype in response to quadruplet therapy.