An Analysis of Patients Treated with Stereotactic Body Radiotherapy for Metastatic Urinary Tract Tumors to Identify Predictors of Response

PURPOSE/OBJECTIVE(S)

To identify selection criteria linked to outcomes in patients treated with stereotactic body radiotherapy (SBRT) for metastatic tumors of the urinary tract (UT).

MATERIALS/METHODS

Single institution retrospective analysis of SBRT treated patients for oligometastatic/progressive UT tumors from 2006-2022. Charts were queried for M1 status at diagnosis or during disease course, treatment details (surgery, SBRT, systemic therapy), metabolic status (diabetes [DM], BMI) and outcomes. A linear quadratic formula was used to calculate the biologically effective dose (BED) using an α/β of 10 for tumor. Descriptive statistics portrayed the cohort, and analyses were done at patient and site level. Time-to-event analyses, including overall survival (OS) and progression-free survival (PFS) from SBRT, were assessed by the Kaplan-Meier method. Cox regression was used for univariable (UVA) and multivariable analyses (MVA) to identify predictors of outcomes.

RESULTS

A total of 35 patients were treated at 44 metastatic sites, including: bone (25%), node (36.4%), lung (20.5%), soft tissue (13.6%) and liver (4.5%). Most were male (74.3%) with a median age of 70 (range: 51-89), without DM (60%) having a median BMI of 29.8, and ECOG <2 (97.1%) at time of SBRT. Six (17.1%) patients were M1 at diagnosis. Of the 29 non-M1 patients, 86.2% received definitive local therapy (LT), 58.6% had at least T3/N+ disease, 75.8% received systemic therapy with a median of 2 agents (range: 1-6) prior to SBRT. Sixteen (45.7%) received immunotherapy (IO) with most receiving this before (75%) and after (56.2%) SBRT. Six patients had positive PD-L1 status (n = 10). The median RT dose, fractionation and BED was 40 Gy (range: 14-46), 5 fractions, and 72 (range: 28-132), respectively. At a median follow-up of 34.8, the median OS was 18.4 m (range: 9.3-27.4) with a 2-year OS of 35.9%. At patient level, 62.8% recurred after SBRT. The median PFS after SBRT was 5.3 m (range: 1.8-8.7) with a 2-yr PFS of 29.3%. Patient-level PFS was improved with LT (6.7 vs 1.4 m; p = 0.001) and DM (NR vs 2.9 m; p = 0.015), whereas improved OS was related with LT (18.9 vs 6.6 m; p = 0.03), DM (p = 0.04), ECOG (p = 0.004), and no relapse after SBRT (NR vs 9.8 m; p <0.001). Exposure to < 3 systemic agents prior to SBRT portended better PFS (6.7 vs 2.6 m; p = 0.04) without any impact by IO. At site level, 20.4% of sites had local relapse with 4 being the first event. Site was related with PFS (p = 0.009) with order of increased relapse risk being liver > bone > soft tissue > node > lung. No dosimetric feature was related with recurrence risk. On MVA, both DM (p = 0.02) and LT (p = 0.002) were predictive for PFS. Only recurrence after SBRT predicted for OS on MVA (HR: 6.7, 95% CI: 1.4-31; p = 0.014). In the IO subset, median PFS was 5.3 m and OS was 9.4 m, with no difference seen with IO-SBRT sequence or PDL1 status.

CONCLUSION

Optimized selection criteria for metastasis-directed therapy in patients with UT tumors is unclear, notably with IO. Future studies may benefit by assessing circulating tumor markers prior to SBRT.

Multidisciplinary Management of Primary Urethral Cancer with Radiotherapy

PURPOSE/OBJECTIVE(S)

Primary urethral cancer (PUC) is a rare form of genitourinary malignancy with a paucity of data to guide management. We analyzed PUC patients for clinicopathologic characteristics and treatment approach (radiotherapy [RT] with/without consolidative surgery) to identify predictors of outcome and RT response.

MATERIALS/METHODS

We conducted a single-institution retrospective review of patients treated with RT for PUC between 2002 to 2020. Each patient underwent multidisciplinary evaluation (including cystoscopy) as well as imaging to confirm tumor origin in the urethra. The linear quadratic formula was used to calculate the biologically effective dose (BED) using an α/β of 10 for tumor. Descriptive statistics were used to characterize the cohort. Fisher's Exact test was used to compare groups. Time-to-event analyses was conducted with the Kaplan-Meier method; outcomes included overall survival (OS) and time to recurrence (TTR) from diagnosis. Cox regression analysis assessed predictors of outcomes.

RESULTS

A total of 17 patients were identified for analysis. Median age was 63 years (range: 34-86); the majority were female (76.5%) and white (82.4%). Tumors were localized in the proximal (n = 6) or distal (n = 11) urethra. Histology included urothelial (11.8%), squamous (35.3%), adenocarcinoma (29.4%) and mixed (23.5%). Ten patients (58.8%) had cT3 or higher disease with 10 being cN0 (58.8%), 1 cN1 (5.9%), 5 cN2 (29.4%) and 1 cNx (5.9%). Median tumor size was 4.8 cm (range: 0.5-12 cm). The majority (88.2%) were treated with definitive chemoRT with 70.5% receiving platinum therapy. Median RT dose was 59.4 Gy (range: 39.6-70.2) with a median of 30 fractions. One patient underwent upfront cystourethrectomy and 6 (35.3%) underwent consolidative surgery at a median of 2.3 months after RT. Five patients (29.4%) had a complete response (CR) and 70.6% had a partial response (PR) to RT. Of the 7 patients who underwent surgical resection the final pathology was ypTis (28.5%), ypT1 (14.2%), ypT2 (14.2%), ypT4 (28.5%) and pT2 (14.2%). A median of 16 lymph nodes were removed with 1 patient having pN2 and all others pN0. Four patients (66.6%) were downstaged by chemoRT prior to surgery. At a median follow-up time of 8.4 years, the median OS was 37.9 months (range: 23.2-52.7), which was associated with a 5-year OS of 37.2%. Twelve (70.5%) patients recurred with a median TTR of 6.3 months (range 4.8-7.7). No demographics, staging methods, or tumor characteristics were associated with OS or TTR. Urothelial histology was associated with CR following chemoRT (p = 0.02). RT dose (continuous) was associated with OS (p = 0.018) as well as a BED (HR: 0.90, 95% CI: 0.84-0.97; p = 0.01). A BED > 55 Gy was associated with improved median OS (56.4 vs 9.13 months, p = 0.006).

CONCLUSION

Analysis of PUC patients treated with multimodal therapy found higher rates of CR in patients with urothelial histology and increased OS in patients treated with a BED > 55 Gy. Neoadjuvant chemoRT may downstage disease prior to surgical extirpation.

[Conventional grading vs. molecular grading : Decision aids for clinical routine]

Conventional histopathological grading of a cancer is of utmost importance for the management and prognosis of the patient. Histopathological grading is predominantly a function of the differentiation and proliferation of tumor cells, the amount of necrosis present and the pattern of invasion. In addition, the molecular set-up of a given cancer which can be determined to some degree by immunohistochemistry or by methods analyzing genetic and epigenetic alterations can be used in some instances to improve the information gained by conventional histopathologic grading. Indeed, this latter option implies the promise of individualized tumor therapy. While this promise is on the horizon, the clinical implications for penile cancer are not yet transferable to individualized penile cancer treatment.

Exploratory use of docetaxel loaded acid-prepared mesoporous spheres for the treatment of malignant melanoma

Introduction

Five year survival for metastatic melanoma (MM) is very low at <10%. Therapeutic options have been limited secondary to systemic toxicity. As a result there has been a growing movement towards developing targeted drug delivery models. Prior research of this group has demonstrated the effectiveness of acid-prepared mesoporous spheres (APMS-TEG) in delivering chemotherapeutic agents at a lower effective dose than systemic administration. This study aims to assess the ability of the previously developed APMS-TEG particles to deliver therapeutic doses of docetaxel for the treatment of melanoma.

Methods

In vitro experiments were performed to assess docetaxel loading onto APMS-TEG particles and release kinetics. Toxicity experiments were performed using docetaxel and docetaxel loaded APMS-TEG. The effect on cell growth was assessed using the MelJuSo, UACC903, and WM1205 melanoma cell lines.

Results

Docetaxel demonstrated statistically significant dose dependent reduction in growth of melanoma cells. In all three cell lines, doses of 1 nM were sufficient to produce statistically significant reduction in cell growth. Scanning electron micrographs demonstrate increased uptake of APMS-TEG particles by melanoma cells in the first 24 hours, with the majority within the first 4 hours. Unloaded APMS particles had no effect on the melanoma cells, demonstrating that the particles themselves are not toxic. APMS-TEG particles had a peak release of drug within the first hour, with equilibration thereafter. The 5, 10, and 20 nM loaded particles all had statistically significant reduction in cell growth than the control groups.

Discussion

The high potency against melanoma cells makes docetaxel a suitable choice for loading into APMS-TEG particles. Docetaxel loaded APMS-TEG particles demonstrate significant activity against malignant melanoma and thus offer an innovative approach to the treatment of metastatic melanoma.

Asbestos modulates thioredoxin-thioredoxin interacting protein interaction to regulate inflammasome activation

BACKGROUND

Asbestos exposure is related to various diseases including asbestosis and malignant mesothelioma (MM). Among the pathogenic mechanisms proposed by which asbestos can cause diseases involving epithelial and mesothelial cells, the most widely accepted one is the generation of reactive oxygen species and/or depletion of antioxidants like glutathione. It has also been demonstrated that asbestos can induce inflammation, perhaps due to activation of inflammasomes.

METHODS

The oxidation state of thioredoxin was analyzed by redox Western blot analysis and ROS generation was assessed spectrophotometrically as a read-out of solubilized formazan produced by the reduction of nitrotetrazolium blue (NTB) by superoxide. Quantitative real time PCR was used to assess changes in gene transcription.

RESULTS

Here we demonstrate that crocidolite asbestos fibers oxidize the pool of the antioxidant, Thioredoxin-1 (Trx1), which results in release of Thioredoxin Interacting Protein (TXNIP) and subsequent activation of inflammasomes in human mesothelial cells. Exposure to crocidolite asbestos resulted in the depletion of reduced Trx1 in human peritoneal mesothelial (LP9/hTERT) cells. Pretreatment with the antioxidant dehydroascorbic acid (a reactive oxygen species (ROS) scavenger) reduced the level of crocidolite asbestos-induced Trx1 oxidation as well as the depletion of reduced Trx1. Increasing Trx1 expression levels using a Trx1 over-expression vector, reduced the extent of Trx1 oxidation and generation of ROS by crocidolite asbestos, and increased cell survival. In addition, knockdown of TXNIP expression by siRNA attenuated crocidolite asbestos-induced activation of the inflammasome.

CONCLUSION

Our novel findings suggest that extensive Trx1 oxidation and TXNIP dissociation may be one of the mechanisms by which crocidolite asbestos activates the inflammasome and helps in development of MM.

Identification of a T-cell receptor from a therapeutic murine T-cell clone

Tumor-infiltrating lymphocytes (TIL) have been successfully used for the treatment of metastatic malignancies in clinical trials and in experimental animal models. Tumor-specific reactivity by TIL is mediated via receptors expressed on the surface of T cells (TcRs), which recognize tumor-associated antigens (TAA) presented in the context of MHC molecules on the surface of tumor cells. The current study was performed to identify the TcR alpha and beta chains from a tumor-specific therapeutic TIL clone that can be used to develop a preclinical animal model for genetically modifying lymphocytes and hematopoietic progenitors with TcR genes. TIL 205 was generated from a subcutaneous implant of MCA-205 fibrosarcoma and at 21 days was cloned by limiting dilution. TIL clone 8, obtained from a culture seeded at one cell/well, mediated specific lysis and specific secretion of gamma-interferon to MCA-205 and WP6, a subclone of MCA 205. No reactivity was observed against other syngeneic sarcoma lines. Anchor polymerase chain reaction analysis determined that antigen recognition by clone 8 was mediated by a TcR consisting of V alpha 3/J alpha 27 and V beta 8.2/D beta 2.1/D beta 2.4. Immunofluorescent staining with V beta subfamily specific monoclonal antibodies revealed that > 95% of the T cells in TIL clone 8 expressed V beta 8.2, confirming that TIL clone 8 was indeed a clone. In contrast, approximately 30% of the T cells in the parental TIL 205 expressed V beta 8.2. The transfer of as few as 500,000 TIL clone 8 cells in conjunction with the systemic administration of recombinant human interleukin-2 mediated regression of established 3-day WP6 lung metastases. Thus, clone 8 recognizes a biologically relevant tumor rejection antigen, making the V alpha 3/J alpha 27-V beta 8.2/D beta 2.1/J beta 2.4 TcR isolated from this clone useful as a probe for cloning the tumor-rejection antigen in the WP6 tumor as well as modeling, in mice, the TcR-based gene therapies being developed for humans.

Cloning and characterization of the genes encoding the murine homologues of the human melanoma antigens MART1 and gp100

The recent identification of genes encoding melanoma-associated antigens has opened new possibilities for the development of cancer vaccines designed to cause the rejection of established tumors. To develop a syngeneic animal model for evaluating antigen-specific vaccines in cancer therapy, the murine homologues of the human melanoma antigens MART1 and gp100, which were specifically recognized by tumor-infiltrating lymphocytes from patients with melanoma, were cloned and sequenced from a murine B16 melanoma cDNA library. The open reading frames of murine MART1 and gp100 encode proteins of 113- and 626-amino acids with 68.8 and 77% identity to the respective human proteins. Comparison of the DNA sequences of the murine MART1 genes, derived from normal melanocytes, the immortalized nontumorgenic melanocyte line Melan-a and the B16 melanoma, showed all to be identical. Northern and Western blot analyses confirmed that both genes encoded products that were melanocyte lineage proteins. Mice immunized with murine MART1 or gp100 using recombinant vaccinia virus failed to produce any detectable T-cell responses or protective immunity against B16 melanoma. In contrast, immunization of mice with human gp100 using recombinant adenoviruses elicited T cells specific for hgp100, but these T cells also cross reacted with B16 tumor in vitro and induced significant but weak protection against B16 challenge. Immunization with human and mouse gp100 together [adenovirus type 2 (Ad2)-hgp100 plus recombinant vaccinia virus (rVV)-mgp100], or immunization with human gp100 (Ad2-hgp100) and boosting with heterologous vector (rVV-hgp100 or rVV-mgp100) or homologous vector (Ad2-hgp100), did not significantly enhance the protective response against B16 melanoma. These results may suggest that immunization with heterologous tumor antigen, rather than self, may be more effective as an immunotherapeutic reagent in designing antigen-specific cancer vaccines.

Antigen-specific tumor vaccines. Development and characterization of recombinant adenoviruses encoding MART1 or gp100 for cancer therapy

The human melanoma tumor Ags, MART1 and gp100, are specifically recognized by HLA-A2-restricted CD8+ CTLs derived from melanoma patients and appear to be involved in tumor regression. In order to develop immunizing vectors for the treatment of patients with metastatic melanoma, replication-defective recombinant adenoviruses, Ad2CMV-MART1 and Ad2CMV-gp100, which encode these tumor Ags, have been generated. Infection of non-Ag expressing HLA-A2+ cell lines A375 and MDA-231 with the vectors resulted in recognition by Ag-specific CTLs as demonstrated by specific target cell lysis and release of cytokines, including IFN-gamma, TNF-alpha, and granulocyte-macrophage-CSF. Sodium butyrate and TNF-alpha can further augment adenovirus-mediated transgene expression and increase recognition by specific CTLs. Although adenovirus-infected cells expressed the E3/19K protein at detectable levels, significant reduction of surface MHC class I expression was observed in only 3 of 10 tumor cell lines infected with either Ad2CMV-MART1 or Ad2CMV-gp100. Because of the suspected homology between the human MART1 and gp100 genes and their murine counterparts, we immunized C57BL/6 mice with these recombinant adenoviruses and demonstrated that immunization with Ad2CMV-gp100 could protect mice from murine melanoma B16 challenge administered intradermally. Depletion of CD8+ but not CD4+ T cells in vivo from Ad2CMV-gp100-vaccinated mice eliminated the protective effect. The anti-gp100 T cells induced by Ad2CMV-gp100 vaccinated appeared to be responsible for the protection. Thus, these recombinant adenoviruses encoding tumor Ags may be useful as vaccines to induce specific T cell immunity for cancer therapy.

Antigen-specific tumor vaccines. Development and characterization of recombinant adenoviruses encoding MART1 or gp100 for cancer therapy

The human melanoma tumor Ags, MART1 and gp100, are specifically recognized by HLA-A2-restricted CD8+ CTLs derived from melanoma patients and appear to be involved in tumor regression. In order to develop immunizing vectors for the treatment of patients with metastatic melanoma, replication-defective recombinant adenoviruses, Ad2CMV-MART1 and Ad2CMV-gp100, which encode these tumor Ags, have been generated. Infection of non-Ag expressing HLA-A2+ cell lines A375 and MDA-231 with the vectors resulted in recognition by Ag-specific CTLs as demonstrated by specific target cell lysis and release of cytokines, including IFN-gamma, TNF-alpha, and granulocyte-macrophage-CSF. Sodium butyrate and TNF-alpha can further augment adenovirus-mediated transgene expression and increase recognition by specific CTLs. Although adenovirus-infected cells expressed the E3/19K protein at detectable levels, significant reduction of surface MHC class I expression was observed in only 3 of 10 tumor cell lines infected with either Ad2CMV-MART1 or Ad2CMV-gp100. Because of the suspected homology between the human MART1 and gp100 genes and their murine counterparts, we immunized C57BL/6 mice with these recombinant adenoviruses and demonstrated that immunization with Ad2CMV-gp100 could protect mice from murine melanoma B16 challenge administered intradermally. Depletion of CD8+ but not CD4+ T cells in vivo from Ad2CMV-gp100-vaccinated mice eliminated the protective effect. The anti-gp100 T cells induced by Ad2CMV-gp100 vaccinated appeared to be responsible for the protection. Thus, these recombinant adenoviruses encoding tumor Ags may be useful as vaccines to induce specific T cell immunity for cancer therapy.

Treatment of murine primary brain tumors with systemic interleukin-2 and tumor-infiltrating lymphocytes

Methods have recently been described for the isolation and expansion of lymphocytes that have trafficked into animal and human tumors. These CD8-positive tumor-infiltrating lymphocytes (TIL's) have exceptional trafficking ability to, and efficacy against, tumor targets in extracranial sites. Prior to Phase I clinical trials for patients with gliomas, adoptive immunotherapy with TIL's was studied in a mouse model of primary brain tumors to determine if intracerebral tumors have a similar response. Glioma 261 (GL261) tumors were grown in the subcutaneous space of C57BL/6 mice. After enzymatic digestion, the cells were incubated in vitro with interleukin-2 (IL-2) until a confluent population of T lymphocytes was present. The in vitro efficacy of these TIL's was tested against fresh GL261 targets with a chromium release assay; the in vivo efficacy was tested against GL261 tumors in the liver and against irradiated and nonirradiated GL261 tumors in the brain. Mice received one of the following: intraperitoneal saline; intraperitoneal IL-2 (7500 to 50,000 U three times daily for 5 days); IL-2 plus intravenous TIL's (1 to 3 x 10(7) cells); 10 Gy cranial irradiation; irradiation plus IL-2; or irradiation plus IL-2 plus TIL's. The TIL preparation killed 77% of tumor targets in 4 hours at an effector:target ratio of 100:1. In animals with GL261 tumors in the liver, at 2 weeks there were 93 +/- 37, 128 +/- 45, and 21 +/- 14 liver metastases in the control, IL-2, and IL-2 plus TIL groups, respectively. However, in animals with GL261 tumors in the brain, no treatment group had an increased survival rate compared to the control group. It is concluded that, although TIL and IL-2 immunotherapy can be used effectively to treat brain tumors in vitro and at sites outside the central nervous system, it is ineffective against the same type of tumor in the brain. Different methods of delivery or different combinations of these immunomodulators may be more effective; however, based on these findings, treatment of patients with IL-2 and TIL cannot be recommended until efficacy has been demonstrated in an animal model.

A new approach to the adoptive immunotherapy of cancer with tumor-infiltrating lymphocytes

The adoptive transfer of tumor-infiltrating lymphocytes (TIL) expanded in interleukin-2 (IL-2) to mice bearing micrometastases from various types of tumors showed that TIL are 50 to 100 times more effective in their therapeutic potency than are lymphokine-activated killer (LAK) cells. Therefore the use of TIL was explored for the treatment of mice with large pulmonary and hepatic metastatic tumors that do not respond to LAK cell therapy. Although treatment of animals with TIL alone or cyclophosphamide alone had little impact, these two modalities together mediated the elimination of large metastatic cancer deposits in the liver and lung. The combination of TIL and cyclophosphamide was further potentiated by the simultaneous administration of IL-2. With the combination of cyclophosphamide, TIL, and IL-2, 100% of mice (n = 12) bearing the MC-38 colon adenocarcinoma were cured of advanced hepatic metastases, and up to 50% of mice were cured of advanced pulmonary metastases. Techniques have been developed to isolate TIL from human tumors. These experiments provide a rationale for the use of TIL in the treatment of humans with advanced cancer.

Adoptive chemoimmunotherapy of a syngeneic murine lymphoma with long-term lymphoid cell lines expanded in T cell growth factor

Recently techniques have been developed for the long-term growth of cytotoxic T-lymphoid cells in vitro with T cell growth factor (TCGF). We have investigated the use of these in vitro-expanded T cells for the immunotherapy of a disseminated syngeneic murine FBL-3 lymphoma. In this model, mice with disseminated tumor were treated on day 5 with 180 mg cytoxan/kg and then 5 h later were given lymphoid cells IP. In vivo-immunized lymphocytes resulted in significantly improved survival in three of three experiments, curing 52% of 38 animals, compared with treatment with cytoxan alone (0 of 31 cured) or cytoxan plus unimmunized cells (0 of 40 cured) (P<0.0005). In vivo-immunized lymphocytes were re-exposed to FBL-3 tumor in vitro for 5 days in complete medium (CM) or lectin-free TCGF (LF-TCGF). Both groups showed significantly improved survival in six of six experiments. Cytoxan cured 17% of 66 animals, while cytoxan plus normal lymphocytes after IVS cured 6% of 47 animals. In vivo-immunized cells resensitized in vitro to FBL-3 in CM or LF-TCGF cured 82% of 50 animals (P<0.001) and 72% of 61 animals (P<0.001), respectively. Cells from in vivo- and in vitro-sensitized lymphocytes exhibited no cytotoxicity in our in vitro 51Cr-release assay; expansion of these cells resulted in significant specific lysis of fresh FBL-3 targets. Adoptive transfer of immune lymphocytes resensitized to FBL-3 tumor in vitro and expanded in LF-TCGF conferred a significant survival benefit (P<0.001, curing 7 of 27 animals) compared with all controls. These expanded cells were then continuously grown in LF-TCGF for 2 1/2 months. Again, in vivo-immunized lymphocytes resensitized to FBL-3 tumor and expanded in LF-TCGF for 2 1/2 months cured 56% of the animals with disseminated tumor, significantly prolonging survival over that recorded in any control group (P<0.0002). Irradiation of these same cells totally abolished their efficacy. Clones were generated from IVS and continuously grown in LF-TCGF. Two of these clones were very cytotoxic for fresh FBL-3 (>4,000 lytic units/106 cells). When adoptively transferred to mice in this chemoimmunotherapy model these cytotoxic clones significantly enhanced survival over that recorded following treatment with cytoxan alone (P<0.00001), though prolongation of survival was small. Implications of these results for application of these techniques to other less antigenic tumors and human cancers are discussed.