Prostate Cancer in 2021: Novelties in Prognostic and Therapeutic Biomarker Evaluation

The 2021 novelties in prognostic and therapeutic tissue markers in patients with prostate cancer (PCa) can be subdivided into two major groups. The first group is related to prognostic markers based on morphological and immunohistochemical evaluations. The novelties in this group can then be subdivided into two subgroups, one involving morphologic evaluation only, i.e., PCa grading, and the other involving both morphologic and immunohistochemical evaluations, i.e., aggressive variant PCa (AVPCa). Grading concerns androgen-dependent PCa, while AVPCa represents a late phase in its natural history, when it becomes androgen-independent. The novelties of the other major group are related to molecular markers predicting significant disease or response to therapy. This group mainly includes novelties in the molecular evaluation of PCa in tissue material and liquid biopsies.

Prostate epithelial genes define therapy-relevant prostate cancer molecular subtype

Background and objectives Transcriptomic landscape of prostate cancer (PCa) shows multidimensional variability, potentially arising from the cell-of-origin, reflected in serum markers, and most importantly related to drug sensitivities. For example, Aggressive Variant Prostate Cancer (AVPC) presents low PSA per tumor burden, and characterized by de novo resistance to androgen receptor signaling inhibitors (ARIs). Understanding PCa transcriptomic complexity can provide biological insight and therapeutic guidance. However, unsupervised clustering analysis is hindered by potential confounding factors such as stromal contamination and stress-related material degradation. Materials and methods To focus on prostate epithelial cell-relevant heterogeneity, we defined 1,629 genes expressed by prostate epithelial cells by analyzing publicly available bulk and single- cell RNA sequencing data. Consensus clustering and CIBERSORT deconvolution were used for class discovery and proportion estimate analysis. The Cancer Genome Atlas Prostate Adenocarcinoma dataset served as a training set. The resulting clusters were analyzed in association with clinical, pathologic, and genomic characteristics and impact on survival. Serum markers PSA and PAP was analyzed to predict response to docetaxel chemotherapy in metastatic setting. Results We identified two luminal subtypes and two aggressive variant subtypes of PCa: luminal A (Adipogenic/AR-active/PSA-high) (30.0%); luminal S (Secretory/PAP-high) (26.0%); AVPC-I (Immune-infiltrative) (14.7%), AVPC-M (Myc-active) (4.2%), and mixed (25.0%). AVPC-I and AVPC-M subtypes predicted to be resistant to ARI and have low PSA per tumor burden. Luminal A and AVPC-M predicted to be resistant to docetaxel and have high PSA/PAP Ratio. Metastatic PCa patients with high PSA/PAP ratio (>20) had significantly shorter progression-free survival than those with low ratio (≤20) following docetaxel chemotherapy. Conclusion We propose four prostate adenocarcinoma subtypes with distinct transcriptomic, genomic, and pathologic characteristics. PSA/PAP ratio in advanced cancer may aid in determining which patients would benefit from maximized androgen receptor inhibition or early use of antimicrotubule agents.

Lymphoepithelial carcinoma of the larynx: An unusual response to EXTREME regimen therapy. A new option for treatment?

Lymphoepithelial Carcinoma (LEC), an aggressive variant of Squamous Cell Carcinoma (SCC), is an undifferentiated carcinoma with an intermixed reactive lymphoplasmacytic infiltrate. Most cases of LEC occur in the nasopharynx, while it rarely involves other sites. LEC of larynx and hypopharynx is an extremely rare and aggressive neoplasm, characterized by a high propensity to loco-regional dissemination and a poor prognosis; it represents the 0,2% of all tumours of the larynx. Since it is such a rare tumor, the current literature provides only recommendations and there are no treatment guidelines available. A 70-year-old man with laryngeal LEC and both distant and nodal metastases was treated with chemotherapy, following EXTREME regimen therapy. It was classified as a cT3 N3b M1 glottic cancer (Stage IVC, AJCC 8th Ed.), stage IVC. As the response on metastases was unexpectedly encouraging, surgical treatment on T could be performed. Patient underwent to total laryngectomy and bilateral neck dissection. To date, eight months after surgery, the patient is disease free. The unusual clinical course is reported.

Efficacy of the PD-L1 inhibitor avelumab in neuroendocrine or aggressive variant prostate cancer: Results from a phase II, single-arm study.

89 Background: Men with metastatic neuroendocrine/small cell and aggressive variant prostate cancer (NEPC/AVPC) have poor outcomes despite platinum and taxane chemotherapy. These tumors share common features with small cell lung cancer, including higher tumor mutational burden and genomic alterations, and thus may be responsive to immunotherapy. Methods: We conducted a single arm, 2-stage phase II investigator-sponsored trial, (PICK-NEPC, NCT03179410) with the PD-L1 inhibitor avelumab in patients with NEPC/AVPC. NEPC/AVPC was defined either by histologic criteria (neuroendocrine or small cell features) by central pathology review or by aggressive variant clinical criteria (prior progression on abiraterone or enzalutamide with liver metastasis, bulky radiographic progression and low PSA, or high serum LDH). Prior chemotherapy or hormonal therapy was allowed. Avelumab 10 mg/kg IV every 2 weeks was administered until progression or unacceptable toxicity with ongoing ADT. The primary endpoint was overall response rate (ORR) defined by modified PCWG3 and iRECIST criteria. Results: We consented 19 men with AVPC/NEPC, and 15 initiated treatment with avelumab. The median age was 71 (range 51-85), and 27% had neuroendocrine or small cell histology, while 73% met AVPC clinical criteria with adenocarcinoma histology. Men had received a median of two prior systemic therapies (range 1-3) including carboplatin (27%), docetaxel (73%), enzalutamide (67%), and abiraterone (47%). Median PSA was 54 ng/mL (range 0-393) and 73% had liver metastasis. The ORR by iRECIST was 6.7% (95% CI 0-32%) with 1 CR, 0 PRs, 3 (20%) with stable disease, and 11 (73%) with progressive disease. The patient with a CR had NEPC with a CNS metastasis that was found to be MSI-high/TMB-high due to a somatic MSH2 alteration; he finished 12 months of avelumab and maintains a durable CR and undetectable PSA 6 months after completing all therapy including ADT. Median radiographic progression free survival was 1.8 months (95% CI 1.6-2.0 mo) and median time on therapy was 56 days (range 28-356). Median overall survival was 7.4 mo (85% CI 2.8-12.5 mo). Two grade 3 adverse events (abdominal pain due to hepatic disease progression versus immune hepatitis and pericarditis), and one grade 4 (immune hepatitis) adverse event were attributed to avelumab with no grade 5 adverse events. Grade 1 or 2 infusion-related reactions were experienced by 9 (60%). Conclusions: PD-L1 inhibition with avelumab demonstrated limited clinical efficacy in men with metastatic NEPC/AVPC other than in those with MSI-high disease. Further research is needed into mechanisms of immune evasion in NEPC/AVPC to develop novel immunotherapies. Clinical trial information: NCT03179410.