Tumor Volume on PSMA PET as a Prognostic Biomarker in Prostate Cancer Patients Treated With Cabazitaxel

PURPOSE

The aim of this study was to evaluate the prognostic value of 68Ga-labeled prostate-specific membrane antigen (PSMA) PET/CT in metastatic castration-resistant prostate cancer patients receiving second-line chemotherapy with cabazitaxel.

METHODS

All patients with metastatic castration-resistant prostate cancer who underwent a PSMA PET/CT within 8 weeks before initiating the cabazitaxel treatment were retrospectively evaluated. The whole-body PSMA total tumor volume (PSMA-TV) was measured for each patient. Other factors such as prostate-specific antigen, hemoglobin, lactate dehydrogenase, and alkaline phosphatase were recorded. A log-rank cutoff finder was used to define the PSMA-TV optimal cutoff. Survival analyses were performed using Cox regression and Kaplan-Meier methods.

RESULTS

In total, 32 patients were included, receiving a median of 6 cycles of cabazitaxel (range, 2-10). After a median follow-up of 12 months, 28 patients presented disease progression, and 18 died. Baseline PSMA-TV presented a significant association with progression-free survival (PFS) and overall survival (OS; P = 0.035 and P = 0.002, respectively). Optimal PSMA-TV cutoffs were 515 mL for PFS and 473 mL for OS. Patients with low volume presented longer PFS and OS than those with high volume: median PFS, 21 versus 12 weeks, respectively (hazard ratio, 0.33; P = 0.017); and median OS, 24 versus 8.5 months, respectively (hazard ratio, 0.21; P = 0.002). On the multivariable analyses, PSMA-TV remained an independent predictor of OS (P = 0.016).

CONCLUSION

Our results show that total tumor volume measured on PSMA PET/CT is a prognostic biomarker in patients treated with cabazitaxel. High PSMA-TV before treatment initiation is associated with shorter PFS and OS.

Metastatic renal cell carcinoma to the pancreas and other sites-a multicenter retrospective study

Background

Metastatic renal cell carcinoma (mRCC) is a heterogenous disease with poor 5-year overall survival (OS) at 14%. Patients with mRCC to endocrine organs historically have prolonged OS. Pancreatic metastases are uncommon overall, with mRCC being the most common etiology of pancreatic metastases. In this study, we report the long-term outcomes of patients with mRCC to the pancreas in two separate cohorts.

Methods

We performed a multicenter, international retrospective cohort study of patients with mRCC to the pancreas at 15 academic centers. Cohort 1 included 91 patients with oligometastatic disease to the pancreas. Cohort 2 included 229 patients with multiples organ sites of metastases including the pancreas. The primary endpoint for Cohorts 1 and 2 was median OS from time of metastatic disease in the pancreas until death or last follow up.

Findings

In Cohort 1, the median OS (mOS) was 121 months with a median follow up time of 42 months. Patients who underwent surgical resection of oligometastatic disease had mOS of 100 months with a median follow-up time of 52.5 months. The mOS for patients treated with systemic therapy was not reached. In Cohort 2, the mOS was 90.77 months. Patients treated with first-line (1L) VEGFR therapy had mOS of 90.77 months; patients treated with IL immunotherapy (IO) had mOS of 92 months; patients on 1L combination VEGFR/IO had mOS of 74.9 months.

Interpretations

This is the largest retrospective cohort of mRCC involving the pancreas. We confirmed the previously reported long-term outcomes in patients with oligometastatic pancreas disease and demonstrated prolonged survival in patients with multiple RCC metastases that included the pancreas. In this retrospective study with heterogeneous population treated over 2 decades, mOS was similar when stratified by first-line therapy. Future research will be needed to determine whether mRCC patients with pancreatic metastases require a different initial treatment strategy.

Funding

Statistical analyses for this study were supported in part by the University of Colorado Cancer Center Support Grant from the NIH/NCI, P30CA046934-30.

Efficacy of Cabozantinib in Metastatic MiT Family Translocation Renal Cell Carcinomas

BACKGROUND

MiT family translocation renal cell carcinoma (TRCC) is a rare and aggressive subgroup of renal cell carcinoma harboring high expression of c-MET. While TRCC response rates to VEGF receptor tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors are limited, efficacy of cabozantinib (a VEGFR, MET, and AXL inhibitor) in this subgroup is unclear.

METHODS

We performed a multicenter, retrospective, international cohort study of patients with TRCC treated with cabozantinib. The main objectives were to estimate response rate according to RECIST 1.1 and to analyze progression-free survival (PFS) and overall survival (OS).

RESULTS

Fifty-two patients with metastatic TRCC treated in the participating centers and evaluable for response were included. Median age at metastatic diagnosis was 40 years (IQR 28.5-53). Patients' IMDC risk groups at diagnosis were favorable (9/52), intermediate (35/52), and poor (8/52). Eleven (21.2%) patients received cabozantinib as frontline therapy, 15 (28.8%) at second line, and 26 (50%) at third line and beyond. The proportion of patients who achieved an objective response was 17.3%, including 2 complete responses and 7 partial responses. For 26 (50%) patients, stable disease was the best response. With a median follow-up of 25.1 months (IQR 12.6-39), median PFS was 6.8 months (95%CI 4.6-16.3) and median OS was 18.3 months (95%CI 17.0-30.6). No difference of response was identified according to fusion transcript features.

CONCLUSION

This real-world study provides evidence of the activity of cabozantinib in TRCC, with more durable responses than those observed historically with other VEGFR-TKIs or ICIs.

Incidence of Germline Variants in Familial Bladder Cancer and Among Patients With Cancer Predisposition Syndromes

BACKGROUND

The familial aggregation of bladder cancers has been observed, but the incidence and association of familial bladder cancer with germline pathogenic and likely pathogenic (P/LP) variants is unknown.

PATIENTS AND METHODS

A retrospective analysis was conducted of patients with bladder cancer treated at the Dana-Farber Cancer Institute to identify those with a first-degree relative with bladder cancer. A second cohort of patients referred to DFCI for suspicion of a cancer predisposition syndrome was analyzed for candidate P/LP germline variants. Descriptive statistics were generated.

RESULTS

Among 885 patients with bladder cancer, 38 patients (4.3%) had a family history of bladder cancer in a first-degree relative. No significant association of age of diagnosis was observed between patients with and without a first-degree family history of bladder cancer (P = .3). In the second cohort, 27 of 80 (34%) patients with bladder cancer evaluated for cancer predisposition syndromes harbored a P/LP germline variant. P/LP variants were identified most commonly in the following genes: BRCA1 (n = 5), MSH2 (n = 5), MLH1 (n = 4), ATM (n = 3), and CHEK2 (n = 2). Of the 27 patients with identified germline P/LP variants, 20 (74%) had a family history of a tumor component syndrome in a first- or second-degree relative and 3 were subsequently diagnosed with another genetically-linked associated cancer.

CONCLUSION

Familial bladder cancer defined as bladder cancer in the proband and a first-degree relative, was present in 4.3% of patients with bladder cancer and was not associated with age of diagnosis. Additionally, among patients suspected to have a familial cancer syndrome, one-third harbored a germline P/LP variant. Further study of germline variants in patients with familial bladder cancer including somatic testing for loss of heterozygosity may provide insights regarding disease pathogenesis and inform therapy.

Prognostic significance and immune correlates of CD73 expression in renal cell carcinoma

Background

CD73–adenosine signaling in the tumor microenvironment is immunosuppressive and may be associated with aggressive renal cell carcinoma (RCC). We investigated the prognostic significance of CD73 protein expression in RCC leveraging nephrectomy samples. We also performed a complementary analysis using The Cancer Genome Atlas (TCGA) dataset to evaluate the correlation of CD73 (ecto-5′-nucleotidase (NT5E), CD39 (ectonucleoside triphosphate diphosphohydrolase 1 (ENTPD1)) and A2 adenosine receptor (A2AR; ADORA2A) transcript levels with markers of angiogenesis and antitumor immune response.

Methods

Patients with RCC with available archived nephrectomy samples were eligible for inclusion. Tumor CD73 protein expression was assessed by immunohistochemistry and quantified using a combined score (CS: % positive cells×intensity). Samples were categorized as CD73_negative (CS=0), CD73_low or CD73_high (< and ≥median CS, respectively). Multivariable Cox regression analysis compared disease-free survival (DFS) and overall survival (OS) between CD73 expression groups. In the TCGA dataset, samples were categorized as low, intermediate and high NT5E, ENTPD1 and ADORA2A gene expression groups. Gene expression signatures for infiltrating immune cells, angiogenesis, myeloid inflammation, and effector T-cell response were compared between NT5E, ENTPD1 and ADORA2A expression groups.

Results

Among the 138 patients eligible for inclusion, ‘any’ CD73 expression was observed in 30% of primary tumor samples. High CD73 expression was more frequent in patients with M1 RCC (29% vs 12% M0), grade 4 tumors (27% vs 13% grade 3 vs 15% grades 1 and 2), advanced T-stage (≥T3: 22% vs T2: 19% vs T1: 12%) and tumors with sarcomatoid histology (50% vs 12%). In the M0 cohort (n=107), patients with CD73_high tumor expression had significantly worse 5-year DFS (42%) and 10-year OS (22%) compared with those in the CD73_negative group (DFS: 75%, adjusted HR: 2.7, 95% CI 1.3 to 5.9, p=0.01; OS: 64%, adjusted HR: 2.6, 95% CI 1.2 to 5.8, p=0.02) independent of tumor stage and grade. In the TCGA analysis, high NT5E expression was associated with significantly worse 5-year OS (p=0.008). NT5E and ENTPD1 expression correlated with higher regulatory T cell (Treg) signature, while ADORA2A expression was associated with increased Treg and angiogenesis signatures.

Conclusions

High CD73 expression portends significantly worse survival outcomes independent of stage and grade. Our findings provide compelling support for targeting the immunosuppressive and proangiogenic CD73–adenosine pathway in RCC.

Treatments Outcomes in Histological Variants and Non-Urothelial Bladder Cancer: Results of a Multicenter Retrospective Study

Introduction

Less than one-third of bladder cancers are non-pure urothelial carcinoma [with variant histological (VH) or non-urothelial carcinoma (non-UC)] for which no treatment guidelines are available. We aim to evaluate the efficacy of systemic treatments in VH or non-UC bladder cancers.

Materials

Multicenter retrospective analysis of patients treated for advanced or metastatic VH or non-UC bladder cancers. Primary endpoint was overall response rate (ORR) according to treatment line, regimen and histology subtype. Secondary endpoints were progression-free survival (PFS) and overall survival (OS).

Results

Between 2005 and 2020, 46 patients from seven centers were included. The median age was 66 years (58.75; 74.75), 65.2% were male and 67.2% presented VH. At first line, the ORR for the entire population was 54.4% and median OS was 21.6 months (95% confidence interval [CI]: 14.2-38.6). The ORR of the 37 patients treated with chemotherapy at first line was 62.2% with median PFS and OS of 7.3 (95% CI: 4.5-8.6) and 21.6 months (95% CI: 14.2-35.7), respectively. Dose dense MVAC and platinum doublet chemotherapy had the highest ORR (71.4% and 65.2%). The 9 patients treated with immunotherapy at first line had an ORR of 22.2%, a median PFS of 3.3 months (95% CI:2.3-NR) and the median OS was not reached (95% CI:13.8-NR). Response to treatment varied depending on the histological sub-types and on the treatment type.

Conclusion

Chemotherapy and immunotherapy have shown to be effective in VH or non-UC cancers, a rare histological subtype for which we currently have very little data in the literature.

Safety and efficacy of restarting immune checkpoint inhibitors after clinically significant immune-related adverse events in metastatic renal cell carcinoma

BACKGROUND

Immune checkpoint inhibitors (ICI) induce a range of immune-related adverse events (irAEs) with various degrees of severity. While clinical experience with ICI retreatment following clinically significant irAEs is growing, the safety and efficacy are not yet well characterized.

METHODS

This multicenter retrospective study identified patients with metastatic renal cell carcinoma treated with ICI who had >1 week therapy interruption for irAEs. Patients were classified into retreatment and discontinuation cohorts based on whether or not they resumed an ICI. Toxicity and clinical outcomes were assessed descriptively.

RESULTS

Of 499 patients treated with ICIs, 80 developed irAEs warranting treatment interruption; 36 (45%) of whom were restarted on an ICI and 44 (55%) who permanently discontinued. Median time to initial irAE was similar between the retreatment and discontinuation cohorts (2.8 vs 2.7 months, p=0.59). The type and grade of irAEs were balanced across the cohorts; however, fewer retreatment patients required corticosteroids (55.6% vs 84.1%, p=0.007) and hospitalizations (33.3% vs 65.9%, p=0.007) for irAE management compared with discontinuation patients. Median treatment holiday before reinitiation was 0.9 months (0.2-31.6). After retreatment, 50% (n=18/36) experienced subsequent irAEs (12 new, 6 recurrent) with 7 (19%) grade 3 events and 13 drug interruptions. Median time to irAE recurrence after retreatment was 2.8 months (range: 0.3-13.8). Retreatment resulted in 6 (23.1%) additional responses in 26 patients whose disease had not previously responded. From first ICI initiation, median time to next therapy was 14.2 months (95% CI 8.2 to 18.9) and 9.0 months (5.3 to 25.8), and 2-year overall survival was 76% (95%CI 55% to 88%) and 66% (48% to 79%) in the retreatment and discontinuation groups, respectively.

CONCLUSIONS

Despite a considerable rate of irAE recurrence with retreatment after a prior clinically significant irAE, most irAEs were low grade and controllable. Prospective studies are warranted to confirm that retreatment enhances survival outcomes that justify the safety risks.