Impact of Lymphopenia on Treatment Outcomes in Unresectable Non-Small Cell Lung Cancer

PURPOSE/OBJECTIVE(S)

The purpose of this study was to investigate associations between lymphopenia and radiotherapy (RT) parameters. Moreover, to investigate the prognostic role of lymphopenia, and treatment and patient-related factors. Definitive chemoradiation (CRT) with consolidative durvalumab offers the best chance for cure in patients with unresectable, locally advanced non-small cell lung cancer. However, treatment-related lymphopenia (TRL) may negatively impact outcomes.

MATERIALS/METHODS

Fifty-four patients treated with CRT and durvalumab from 2017 to 2021 at a single academic center were prospectively included. Absolute lymphocyte counts (ALC), absolute neutrophil counts (ANC), and neutrophil-to lymphocyte ratio (NLR) were analyzed before (TLR1), and after CRT (TRL2), before durvalumab initiation (TRL3), and 3 months after CRT (TRL4). Patients were prospectively enrolled in the study. Categorical variables were analyzed using Pearson's chi-squared or Fisher's Exact tests. Nonparametric continuous variables were analyzed using Wilcoxon Rank-Sum test. Association of continuous clinical and dosimetric variables with hematologic toxicity was performed with Spearman's correlation. Kaplan-Meier analysis and the log-rank test were used to assess the probability of PFS and OS Cox proportional hazard models were used to estimate the effect of covariates on disease control rate. Variables that were strongly associated in univariate Cox regression analyses were entered into a multivariable Cox model. All statistical tests were two-sided, and statistical significance was set at p < 0.05. All analyses were performed using STATA version 15.1.

RESULTS

The median follow-up was 28.4 months (m). N2-3 disease showed worse TRL2 compared to N0-1 (p = 0.013). Table 1 shows RT parameters related to TLR2. Median time to durvalumab initiation after CRT was 47 days. Patients who started durvalumab later than 42 days had a greater decrease in lymphocytes at the end of CRT compared to those who started earlier. (70.1 vs 58.8%, p = 0.025). Median overall survival (OS) and progression-free survival (PFS) were 39.4 and 22.4m, respectively. Disease control rate (DCR) with durvalumab consolidation was 70.8%. Patients with NLR >4 prior to durvalumab initiation achieved a lower DCR compared to those with a NLR ≤4 (85.7 vs 14.3%, p = 0.005).

CONCLUSION

CRT-related immunosuppression is associated with delayed durvalumab initiation and worse DCR. Larger PTV and higher lung and heart doses are associated with TRL. Median real-world OS and PFS are similar to those in the PACIFIC trial.

A Phase II Trial of Intraoperative Radiotherapy after Surgical Resection of Brain Metastases: Feasibility and Efficacy NCT04847284

PURPOSE/OBJECTIVE(S)

Intraoperative radiation therapy (IORT) is an alternative to local radiation therapy for brain metastases, reducing total treatment time, and improving patient comfort, but the most effective dose is unknown. The objective of this study is to evaluate the efficacy and safety of IORT in patients with surgical excision of brain metastases at a dose of 20 Gy.

MATERIALS/METHODS

This trial is a single-institution, open-label, prospective, non-randomized study for intraoperative radiotherapy immediately after resection of brain metastases. Registered in January 2021, currently ongoing, planned to enroll 25 patients with IK ≥70, brain damage newly diagnosed by MRI, without dural contact and at least 1 cm to the optic nerve, chiasm and brainstem. In the baseline visit, the General Cognitive State will be carried out: Minimum Mental State Exams. Specific cognitive study: 1- Processing speed (SYmbol digit modalities test), 2- Executive function (TMT, back and forward digit span test, phonological and semantic verbal fluency test, Stroop color-word test), 3- Verbal memory (FCSRT). Quality of life will be monitored by completing the EORTC QL-C30 and BN20 questionnaires. Intraoperative radiation therapy will be performed with a 50 kV low energy X-ray portable linear accelerator using spherical applicators ranging from 1.5 to 4 cm kV to deliver 20 Gy to the surface. During IORT a maximum dose (DMax) of 8 Gy will be allowed to the optic nerve/chiasm and brainstem structures. MRI will be performed 72 hours after IORT. Neurocognitive Test and MRI after 6 weeks and every 3 months. The primary endpoint will be local progression free survival (PFS). Secondary endpoints will be overall survival, time to save cancer therapy, cognitive performance and quality of life, as well as IORT-related neurotoxicity complications will be evaluated according to the scale of the CTACAE version 4. The analysis of the median local progression free survival, overall survival will be analyzed using the Kaplan-Meier curve (long range test). All results will be considered statistically significant with a p value < 0.05. The statistical analysis will be carried out with statistical software.

RESULTS

The trial is open and ongoing to recruitment; we have included 7 patients. The 85.7% were male, mean age was 61.4 years range (43-74). The 57.1% were lung cancer metastases. For now, no tumor recurrence or neurocognitive complications have been observed and then once you have the results ready, we will publish them.

CONCLUSION

The limited current literature on the use of IORT in brain metastases appears to show efficacy and safety, but the most effective dose is unknown as well as whether it is as effective as other radiotherapy alternatives. Our study is ongoing and needs to be completed and evaluated with more follow-up in order to reach definitive conclusions.

Diagnostic Utility of PSMA 18F-DCFPyL PET/TC in Occult Biochemical Recurrence of Prostate Carcinoma with PSA Values <2ng/ml More than Two Years of Experience

PURPOSE/OBJECTIVE(S)

To analyze the diagnostic capability of PET-PSMA in clinical practice in patients with occult biochemical recurrence of prostate carcinoma with PSA values less than 2ng/ml.

MATERIALS/METHODS

The first 116 patients who underwent PSMA 18F-DCFPyL PET/TC at the centers participating in the study for occult biochemical recurrence of prostatic neoplasia were selected. All patients had low PSA values (<2ng/ml). The studies were visually assessed by two experts in Nuclear Medicine, and classified dichotomously as positive or negative/inconclusive. The diagnostic capacity of the test was determined according to the PSA values, as well as the densities by groups. Descriptive statistical analysis was performed. The AUC was evaluated, determining the optimal cut-off point and its precision parameters.

RESULTS

The retrospective analysis showed that 66/116 patients (56.9%) were positive, with statistically significant differences in the medians of the positive group (AUC 0.77) and 50/116 (43.1%) patients were negative (AUC 0.42). The study of densities by group showed a marked clustering of the negative/ inconclusive studies in PSA values less than 0.5 ng/ml. Correlation was observed between the PSA values and the detection capability of the test (AUC: 0,74). The optimal cut-off point calculated was 0,55 which showed a sensitivity of 0,75 and specificity of 0,68.

CONCLUSION

PET-PSMA shows excellent diagnostic capability even in strictly selected patients with PSA values < 2ng/ml. Its indication with values < 0.5ng/mL should be assessed according to individual risk. In 56.9% of the patients in the study the positive result could influence changes in therapeutic strategy.

Change in Therapeutic Approach after PET/TC PSMA-18F DCFPyL in Occult Biochemical Recurrence of Prostate Carcinoma with Low PSA Values

PURPOSE/OBJECTIVE(S)

To analyze changes in therapeutic attitude after PET-PSMA. in patients with occult biochemical recurrence after primary treatment with low PSA values.

MATERIALS/METHODS

Retrospective study of patients diagnosed with prostate carcinoma who after primary treatment with curative intent present biochemical recurrence with low PSA values (<2ng/ml) and negative imaging tests (ultrasound, CT-Scan, MRI, GGO and/or PET-Choline). The assessment was performed by two expert nuclear physicians. All patients underwent a study with 300-350MBq PSMA-18F DCFPyL PET/TC, and after a follow-up of no less than six months we assessed whether there were changes in therapeutic attitude directly related to the results of the test. The clinical/therapeutic evaluation was performed by expert radiation oncologists. Descriptive statistical analysis was performed. RoC curves (sensitivity vs. 1-specificity) and the corresponding areas under the curve were calculated to assess the predictive power of the study.

RESULTS

PET-PSMA with complete follow-up was performed on 85 patients aged 48-78 years (mean age 69 years) with occult biochemical recurrence. Most patients were staged T2 (50.58%) - T3 (48.23%), cases N1 (10.58%), Gleason score ≥ 7 (96%) with mean PSA level 11.24 ng/ml at diagnosis. The mean nadir PSA values of 0.13 mg/dl following primary treatment with radical intent. In 48.2% of patients (41/85) had a positive PET-PSMA during follow-up, pre-study the median PSA levels were 0,62 ng/dl. There is a correlation between the PSA value and the ability to detect disease in the PET-PSMA study (AUC: 0,74). In 75% of patients with positive PET-PSMA (31/41) there were changes in the therapeutic approach. This proportion was significantly lower (25%) in those without pathological PET findings (11/44). In PET-PSMA-positive patients the therapeutic changes found were classified as indicating or changing the planning of salvage radiotherapy treatment and/or initiating systemic treatment with hormone therapy (median PSA levels after treatment changes were 0.08 ng/dl). In cases with negative PET-PSMA a watchful waiting attitude was adopted.

CONCLUSION

PET-PSMA is a powerful diagnostic tool that conditions significant changes in the therapeutic approach in those patients with occult biochemical recurrence with low PSA, changing the treatment in 75% of the cases when the study is positive.

Machine learning-based automated planning for hippocampal avoidance prophylactic cranial irradiation

PURPOSE

Design and evaluate a knowledge-based model using commercially available artificial intelligence tools for automated treatment planning to efficiently generate clinically acceptable hippocampal avoidance prophylactic cranial irradiation (HA-PCI) plans in patients with small-cell lung cancer.

MATERIALS AND METHODS

Data from 44 patients with different grades of head flexion (range 45°) were used as the training datasets. A Rapid Plan knowledge-based planning (KB) routine was applied for a prescription of 25 Gy in 10 fractions using two volumetric modulated arc therapy (VMAT) arcs. The 9 plans used to validate the initial model were added to generate a second version of the RP model (Hippo-MARv2). Automated plans (AP) were compared with manual plans (MP) according to the dose-volume objectives of the PREMER trial. Optimization time and model quality were assessed using 10 patients who were not included in the first 44 datasets.

RESULTS

A 55% reduction in average optimization time was observed for AP compared to MP. (15 vs 33 min; p = 0.001).Statistically significant differences in favor of AP were found for D98% (22.6 vs 20.9 Gy), Homogeneity Index (17.6 vs 23.0) and Hippocampus D mean (11.0 vs 11.7 Gy). The AP met the proposed objectives without significant deviations, while in the case of the MP, significant deviations from the proposed target values were found in 2 cases.

CONCLUSION

The KB model allows automated planning for HA-PCI. Automation of radiotherapy planning improves efficiency, safety, and quality and could facilitate access to new techniques.