P15.01.A Metabolic-imaging of human glioblastoma explants: a new precision-medicine model to predict treatment response early

Background

Glioblastoma (GB) is the most severe form of brain cancer, with a 12-15 month median survival. Although cell therapies for GB are on the near horizon, surgical resection, temozolomide (TMZ) and radiotherapy (RT) remain the primary therapeutic options for GB, and no new small-molecule therapies have been introduced in recent years. This therapeutic standstill is partially because preclinical models of GB do not reflect the complexities of GB cell biology. Furthermore, the aggressive progression of GB makes it critical to identify patient-tailored therapeutic strategies early.

Material and Methods

We developed a novel in-vitro 3D glioblastoma explants (GB-EXPs) model derived from patients’ resected tumors maintaining cytoarchitecture seen in the tumors. We then performed metabolic-imaging by fluorescence lifetime imaging microscopy (FLIM) on live GB-EXPs to predict drug response, using TMZ as test drug.

Results

The entire process was successfully completed within 1 week since surgery. A unique drug response sample stratification emerged that was well reflected at the molecular level, highlighting new targets associated with TMZ treatment and identifying a molecular signature associated with survival.

Conclusion

To the best of our knowledge, this is the first time that FLIM-based metabolic imaging is used on live glioblastoma explants to test anti-neoplastic drugs. FLIM-based readouts of drug response in GB explants could accelerate precision treatment of patients with GB and the identification of new anti-GB drugs.

P14.01.B Isolation and characterization of circulating tumor cells in a glioblastoma case with recurrence at distance and correlation with tumor mutational status

Background

Circulating Tumor Cells (CTCs) are considered to be one of the important causes of tumor recurrence and distant metastasis. For many years, glioblastoma (GB) was thought to be restricted to the brain. Nevertheless, a growing body of evidence indicates that, like many other cancers, hematogenic dissemination is a reality. The absence of a procedural uniformity in literature prompted us to develop an innovative and sensitive method to obtain CTCs in GB. Our aim is to define the genetic background of single CTCs compared with the primary GB tumor and its recurrence to assess whether or not their presence in the peripheral circulation correlates with GB migration and dissemination.

Material and Methods

CTCs were enriched from whole blood of one patient with recurrent GB with Parsortix Cell Separation System and analysed on DEPArray system. After that, CTCs Copy Number Aberrations (CNAs) and sequencing analysis was performed to compare CTCs genetic background with the same patient’s primary and recurrence tissues, analysed by NextSeq 500 (whole exome sequencing).

Results

We obtained 211 mutations in common between primary and recurrence tumor. Among these, three somatic mutations (c.430 G>A in PRKCB gene, c.815 C>T in TBX1 gene and c.1554 T>G in COG5 gene) were selected to investigate their presence in recurrence CTCs. Almost all of the sorted CTCs (9/13) had at least one of the mutations tested.

Conclusion

In confirmation of the hypothesis, the CTCs detected in the patient's blood were actually cancer cells deriving from GB tumor.

A multicenter LArge retrospectIve daTabase on the personalization of Stereotactic ABlative Radiotherapy use in lung metastases from colon-rectal cancer: the LaIT-SABR study

INTRODUCTION

stereotactic ablative radiotherapy (SABR) has been shown to increase survival in oligometastatic disease, but local control of colorectal metastases remains poor. We aimed to identify potential predictive factors of SBRT response through a multicenter large retrospective database and to investigate the progression to the polymetastatic disease (PMD).

MATERIAL AND METHODS

the study involved 23 centers, and was approved by the Ethical Committee (Prot. Negrar 2019-ZT). 1033 lung metastases were reported. Clinical and biological parameters were evaluated as predictive for local progression-free survival (FLP). Secondary end-point was the time to the polymetastatic conversion (tPMC).

RESULTS

Two-year FLP was 75.4%. Two-year FLP for lesions treated with a BED <100 Gy, 100-124 Gy, and ≥125 Gy was 76.1%, 70.6%, and 94% (p=0.000). Two-year FLP for lesion measuring ≤10 mm, 10-20 mm, and >20 mm was 79.7%, 77.1%, and 66.6% (p=0.027). At the multivariate analysis a BED ≥125 Gy significantly reduced the risk of local progression (HR 0.24, 95%CI 0.11-0.51; p=0.000). Median tPMC was 26.8 months. Lesions treated with BED ≥125 Gy reported a significantly longer tPMC as compared to lower BED. The median tPMC for patients treated to 1, 2-3 or 4-5 simultaneous oligometastases was 28.5, 25.4, and 9.8 months (p=0.035).

CONCLUSION

The present is the largest series of lung colorectal metastases treated with SABR. The results support the use of SBRT in lung oligometastatic colorectal cancer patients as it might delay the transition to PMD or offer relatively long disease-free period in selected cases. Predictive factors were identified for treatment personalization.

OS7.3 Health-related quality of life (HRQoL) evaluation in the REGOMA trial: a randomized, phase II clinical trial analyzing regorafenib activity in relapsed glioblastoma patients

BACKGROUND

REGOMA trial showed that regorafenib (REG) significantly improved OS and PFS in patients (pts) with relapsed GBM with respect to lomustine (LOM). REG showed a different toxicity profile compared to LOM. Here, we report final results of the HRQoL assessment, a secondary end point.

MATERIAL AND METHODS

HRQoL was measured using the European Organization for Research and Treatment of Cancer (EORTC) core questionnaire (QLQ-C30) and brain module (QLQ-BN20) administered before any MRI assessments, every 8 weeks (+/- 2 weeks) until disease progression. To evaluate treatment impact on HRQoL, questionnaires at progression were excluded. Mixed-effect linear models were fitted for each of the HRQOL domain to examine the change over progression-free time within and between arms. The models included the time of questionnaire assessment, the treatment group and their interaction, as fixed effects, and a compound symmetry covariance structure for the random effects. Differences of at least 10 points were classified as a clinically meaningful change. To correct for multiple comparisons and to avoid type I error, the level of significance was set at P=0.01 (2-sided).

RESULTS

Of 119 randomized pts, 117 partecipated in the HRQoL evaluation, and 114 had a baseline assessment (n=56 REG; n=58 LOM). No statistically significant differences were observed in any generic or cancer specific domain during treatment in the REG and LOM arms, or between the two arms, except for the appetite loss scale which was significantly worse in PTS treated with REG (Global mean 14.7 (SD=28.6) vs 7.6 (SD=16.0); p=0.0081). The rate of pts with a clinically meaningful worsening for appetite loss was not statistically different between the two arms (9 out of 24 and 0 out of 13 in the REG and LOM arm, respectively;p=0.02).

CONCLUSION

In the REGOMA trial, HRQoL did not change during regorafenib treatment. Pts treated with regorafenib and lomustine reported no significant difference in HRQoL.

Role of perfusion CT in the evaluation of metastatic nodal tumor response after radiochemotherapy in head and neck cancer: preliminary findings

OBJECTIVE

To assess changes of CT perfusion parameters (ΔPCTp) of cervical lymph node metastases from head and neck cancer (HNC) before and after radiochemotherapy (RT-CT) and their association with nodal tumor persistence.

PATIENTS AND METHODS

Eligibility criteria included HNC (Stage III-IV) candidates for RT-CT. Patients underwent perfusion CT (PCT) at baseline 3 weeks and 3 months after RT-CT. Blood volume (BV), blood flow (BF), mean transit time (MTT) and permeability surface (PS) were calculated. PET/CT examination was also performed at baseline and 3 months after treatment for metabolic assessment.

RESULTS

Between July 2012 and May 2016, 27 patients were evaluated. Overall, only 3 patients (11%) experienced tumor persistence in the largest metastatic lymph node. A significant reduction of all PCTp values (p<0.0001), except MTT (from 6.3 to 5.7 s; p=0.089), was observed at 3 weeks post-RT-CT compared to baseline. All PCTp values including MTT were significantly lower at 3-month follow-up compared to baseline (p<0.05). Moreover, a statistically significant association was observed between nodal tumor persistence and high BF values (p=0.045) at 3 months after treatment that did not occur for the other parameters.

CONCLUSIONS

Our preliminary findings show that all PCTp except MTT are significantly reduced after RT-CT. High BF values at 3 months post-RT-CT are predictive of nodal tumor persistence.

The role of clinicopathologic and molecular prognostic factors in the post-mastectomy radiotherapy (PMRT): a retrospective analysis of 912 patients

OBJECTIVE

To assess the association of clinicopathologic and molecular features with loco-regional recurrence (LRR) in post-mastectomy breast cancer patients with or without adjuvant radiotherapy (PMRT).

PATIENTS AND METHODS

We retrospectively reviewed data of patients undergone to mastectomy followed or not by PMRT between January 2004 and June 2013. The patients were divided according to clinicopathologic and molecular sub-classification features. LRR and Cancer Specific Survival (CSS) were calculated using the Kaplan-Meier method; the prognostic factors were compared using long-rank tests and Cox regression model.

RESULTS

A total of 912 patients underwent to mastectomy of whom 269 (29.5%) followed by PMRT and 643 (70.5%) not; among the PMRT group, 77 underwent to the chest wall (CW) and 202 to the chest wall and lymphatic drainage (CWLD) irradiation. The median follow-up was 54 months (range, 3-118). No significant difference in terms of LRR and CSS was found between non-PMRT and PMRT group (p=0.175; and p=0.628). The multivariate analysis of LRR for patients who did not undergo PMRT showed a significant correlation with the presence of extracapsular extension (ECE) (p=0.049), Ki-67>30% (p=0.048) and triple negative status (p=0.001). In the PMRT group, triple negative status resulted as the only variable significantly correlated to LRR (p=0.006) at the multivariate analysis and T-stage also showed a trend to significance (p=0.073). Finally, no difference in LRR control was shown between CW and CWLD-PMRT (p=0.078).

CONCLUSIONS

After mastectomy ECE, a cut off of Ki-67>30% and triple negative status were strictly correlated with LRR regardless of clinicopathologic stage. PMRT has a positive impact in decreasing LRR in patients with this molecular profile. Besides, CW might represent a valid option for patients with one to three positive nodes.

New approaches for imaging and therapy of solid cancer

Radionuclide therapy is a systemic treatment that aims to deliver cytotoxic radiation to cancer cells. Due to their properties, antibodies have been considered as suitable agent for the delivery of therapeutic radioisotopes, radioimmunotherapy (RIT). This article gives an overview of new approaches for imaging and therapy of solid cancer with particular attention to strategies to enhance treatment success. Examples of increased antibody uptake by targeting stromal constituent of tumor microenvironment such as fibronectin (FN) an important tumor-associated angiogenesis targeting agent, with specifically designed antibody format will be provided. Strategies oriented to identify patients most likely to benefit from RIT including identification of radiosensitivity profiles, in vivo target identification by teragnostic approach and better prediction of dosimetric estimates would be presents. Combination regimens such as with chemo-radiotherapy and immunotherapy would be also discussed as an approach to enhance RIT success.