Abstract 3375: Ultrasensitive ctDNA minimal residual disease monitoring in early NSCLC with PhasED-Seq

Background: Circulating tumor DNA (ctDNA) minimal residual disease (MRD) detection is a promising approach for personalization of adjuvant therapy in non-small cell lung cancer (NSCLC). First generation ctDNA MRD assays that employ tumor-informed approaches to track single nucleotide variants (SNVs) have limits of detection (LOD95) of ~1E-4 and have high positive predictive values for recurrence. However, they have suboptimal clinical sensitivity, with false negative results at the completion of therapy in most patients who will ultimately recur. PhasED-Seq is a novel ctDNA MRD method that tracks multiple “phased” variants (PVs) within individual DNA fragments with a LOD95 ~100-fold better than first generation assays. Here we report PhasED-Seq ctDNA MRD results for the first prospective cohort of early stage NSCLC patients.

Methods: Tumor tissues (n=46), PBMCs (n=46) and plasma samples (n=169) from 46 Stage I-III NSCLC patients treated with curative intent were prospectively collected at Memorial Sloan Kettering Cancer Center. All patients underwent resection and received neoadjuvant +/- adjuvant therapy (n=14), adjuvant therapy only (n=17), or neither (n=15). Samples were analyzed in Foresight Diagnostics' CLIA laboratory (Aurora, CO) using personalized PhasED-Seq. Briefly, PVs were identified via whole genome sequencing of tumors and matched blood germline DNA. Custom capture panels targeting PVs were synthesized and used to assess MRD status in pre-, on- and post-treatment plasma samples. Detection of ctDNA MRD was assessed at a post-treatment landmark, defined as the first post-therapy sample or when not available the last post-surgical sample taken during therapy. To enable comparisons, the same plasma samples were analyzed using an SNV-based ctDNA MRD approach.

Results: PVs were identified in tumor tissue from all 46 patients. Across all plasma samples PhasED-Seq achieved a median LOD95 of 1.3E-6 and as low as 2.5E-7. Of 74 plasma samples with detectable ctDNA, 38 (51%) contained concentrations below 1E-4 and the lowest level of ctDNA MRD detected was 1.7E-7. For post-treatment landmark samples (n=45), the median time from end of therapy was 2 months. Cancer recurred in all patients (n=10) with detectable MRD at the landmark. Furthermore, PhasED-Seq better stratified freedom from recurrence (log-rank p=3E-8, Cox HR=10.8) than the SNV-based approach (log-rank p=0.08, Cox HR=2.5) and detected MRD at the landmark in more patients who ultimately recurred (56% vs 28%). PhasED-Seq also achieved longer lead times, including detecting MRD in 66% of samples collected 12 to 24 months prior to recurrence versus only 33% using SNV-based monitoring.

Conclusion: PhasED-Seq achieves ctDNA detection below 1 part per million and appears to be significantly more sensitive than SNV-based MRD monitoring. These results suggest that PhasED-Seq is a promising approach for use in risk adapted trials in early stage NSCLC.

Citation Format: James M. Isbell, Bob T. Li, Pedram Razavi, Jorge Reis-Filo, Si-Yang Liu, Pier Selenica, Prasad Adusumilli, Matthew Bott, David R. Jones, Valerie W. Rusch, Smita Sihag, Darren J. Buonocore, Justin Jee, Emily Lebow, Daniel Gomez, Andreas Rimner, Fernando C. Santini, Charles M. Rudin, Jordan E. Eichholz, Andres Martinez, Daphne Alerte, Gregory J. Hogan, Andre Schultz, Ronald P. Schuyler, Alanna Roff, Dustin Hite, Jacob J. Chabon, David M. Kurtz, Ash A. Alizadeh, Maximilian Diehn. Ultrasensitive ctDNA minimal residual disease monitoring in early NSCLC with PhasED-Seq [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3375.

Long-term assessment of efficacy with a novel thoracic survivorship program for patients with lung cancer

OBJECTIVE

We developed a novel, nurse practitioner-run Thoracic Survivorship Program to aid in long-term follow-up. Patients with non-small cell lung cancer who were disease-free at least 1 year after resection could be referred to the Thoracic Survivorship Program by their surgeon. Our objectives were to summarize follow-up compliance and assess long-term outcomes between Thoracic Survivorship Program enrollment and non-Thoracic Survivorship Program.

METHODS

Patients who underwent R0 resection for stages I to IIIA between 2006 and 2016 were stratified by enrollment in Thoracic Survivorship Program versus surgeon only follow-up (non-Thoracic Survivorship Program). Follow-up included 6-month chest computed tomography scans for 2 years and then annually. Lack of follow-up compliance was defined by 2 or more consecutive delayed annual computed tomography scans/visits ± 90 days. Relationships between Thoracic Survivorship Program and second primary non--small cell lung cancers, extrathoracic cancers, and survival were quantified using multivariable Cox proportional hazards regression with time-varying covariate reflecting timing of enrollment.

RESULTS

A total of 1162 of 3940 patients (29.5%) were enrolled in the Thoracic Survivorship Program. The median time to enrollment was 2.3 years; 3279 of 3940 (83%) had complete computed tomography scan data, and 60 of 3279 (1.8%) had 2 or more delayed scans; 323 of 9082 (3.6%) non-Thoracic Survivorship Program visits were noncompliant versus 132 of 4823 (2.7%) of Thoracic Survivorship Program visits (P = .009); 136 of 1146 Thoracic Survivorship Program patients developed second primary non-small cell lung cancer, and 69 of 1123 developed extrathoracic cancer, whereas 322 of 2794 of non-Thoracic Survivorship Program patients developed second primary non-small cell lung cancer and 225 of 2817 patients developed extrathoracic cancer. In multivariable analyses, Thoracic Survivorship Program enrollment was associated with improved disease-free survival (hazard ratio, 0.57; 95% confidence interval, 0.48-0.67; P < .001).

CONCLUSIONS

Our novel nurse practitioner-run Thoracic Survivorship Program is associated with high patient compliance and outcomes not different from those seen with physician-based follow-up. These results have important implications for health care resource allocation and costs.

IASLC Multidisciplinary Recommendations for Pathologic Assessment of Lung Cancer Resection Specimens After Neoadjuvant Therapy

Currently, there is no established guidance on how to process and evaluate resected lung cancer specimens after neoadjuvant therapy in the setting of clinical trials and clinical practice. There is also a lack of precise definitions on the degree of pathologic response, including major pathologic response or complete pathologic response. For other cancers such as osteosarcoma and colorectal, breast, and esophageal carcinomas, there have been multiple studies investigating pathologic assessment of the effects of neoadjuvant therapy, including some detailed recommendations on how to handle these specimens. A comprehensive mapping approach to gross and histologic processing of osteosarcomas after induction therapy has been used for over 40 years. The purpose of this article is to outline detailed recommendations on how to process lung cancer resection specimens and to define pathologic response, including major pathologic response or complete pathologic response after neoadjuvant therapy. A standardized approach is recommended to assess the percentages of (1) viable tumor, (2) necrosis, and (3) stroma (including inflammation and fibrosis) with a total adding up to 100%. This is recommended for all systemic therapies, including chemotherapy, chemoradiation, molecular-targeted therapy, immunotherapy, or any future novel therapies yet to be discovered, whether administered alone or in combination. Specific issues may differ for certain therapies such as immunotherapy, but the grossing process should be similar, and the histologic evaluation should contain these basic elements. Standard pathologic response assessment should allow for comparisons between different therapies and correlations with disease-free survival and overall survival in ongoing and future trials. The International Association for the Study of Lung Cancer has an effort to collect such data from existing and future clinical trials. These recommendations are intended as guidance for clinical trials, although it is hoped they can be viewed as suggestion for good clinical practice outside of clinical trials, to improve consistency of pathologic assessment of treatment response.

Protocol-driven multidetector SPECT/CT: integration of hybrid imaging into the routine workflow of whole-body bone scintigraphy in oncology patients

AIM

To analyse the additional clinical value of protocol-driven and selective use of multidetector single-photon-emission tomography/computed tomography (SPECT/CT) in oncology patients undergoing whole-body bone scintigraphy (BS) and to analyse reporter confidence in diagnosis with and without SPECT/CT.

MATERIALS AND METHODS

During a 2-year period, 2,954 whole-body BS examinations were performed in oncology patients, with 444 (15%) undergoing additional protocol-driven SPECT/CT. Retrospective evaluation of planar BS and SPECT/CT images was performed by two experienced dual-trained nuclear medicine radiologists. The BS and SPECT/CT images were graded blindly using a five-point scale designed to evaluate the likelihood of a lesion being benign or malignant. Interpretation was applied on a per-patient basis.

RESULTS

There was a 74.5% increase in definitive diagnostic classification and a 26.6% reduction in equivocal findings with SPECT/CT when compared to BS alone (p<0001). Of cases initially classified as "probably benign" on BS, 5.1% (10/193) were reclassified to "probably malignant" (1%) or "malignant" (4.1%) using the SPECT/CT data. The highest impact in reporter confidence was seen with SPECT/CT in the interpretation of lesions within the pelvis (34%), ribs (23%), lumbar spine (22%), and thoracic spine (21%).

CONCLUSION

Protocol-driven, selective use of SPECT/CT imaging to augment planar BS reduces equivocal findings and improves reporter confidence whilst minimising the impact on patient and reporting workflows.

Does pyloric drainage have a role in the era of minimally invasive esophagectomy?

INTRODUCTION

Pyloric drainage during minimally invasive esophagectomy (MIE) may be more technically challenging than with an open approach. Alternatives to classic surgical drainage have increased in popularity; however, data are lacking to demonstrate whether one technique is superior in MIE. The purpose of this study was to compare post-operative outcomes after MIE between different pyloric drainage methods.

METHODS

We performed a retrospective review of a prospectively maintained database of patients undergoing MIE at a single academic institution. Patients were divided into three groups for analysis: no drainage, intrapyloric Botulinum Toxin injection, and surgical drainage (pyloroplasty or pyloromyotomy). The primary outcome was any complication within 90 days of surgery; secondary outcomes included reported symptoms and need for pyloric dilation at 6 and 12 months post-operatively. Comparisons among groups were conducted using the Kruskal Wallis and Chi Square tests.

RESULTS

There were 283 MIE performed between 2011 and 2017; of these, 126 (45%) had drainage (53 Botulinum injection and 73 surgical). No significant difference in the rate of post-operative complications, pneumonia, or anastomotic leak was observed between groups. At 6 and 12 months, patients that received Botulinum injection and surgical drainage had significantly more symptoms than no drainage (p < 0.0001) and higher need for pyloric dilation at 6 months (p = 0.007).

CONCLUSIONS

Pyloric drainage was not significantly associated with lower post-operative complications or long-term symptoms. While Botulinum injection appears safe post-operatively, it was associated with increased morbidity long-term. Pyloric drainage in MIE may be unnecessary.

Pulmonary large cell neuroendocrine carcinoma with adenocarcinoma-like features: napsin A expression and genomic alterations

Pulmonary large cell neuroendocrine carcinoma (LCNEC) is a highly aggressive malignancy, which was recently found to comprise three major genomic subsets: small cell carcinoma-like, non-small cell carcinoma (predominantly adenocarcinoma)-like, and carcinoid-like. To further characterize adenocarcinoma-like subset, here we analyzed the expression of exocrine marker napsin A, along with TTF-1, in a large series of LCNECs (n=112), and performed detailed clinicopathologic and genomic analysis of napsin A-positive cases. For comparison, we analyzed napsin A expression in other lung neuroendocrine neoplasms (177 carcinoids, 37 small cell carcinomas) and 60 lung adenocarcinomas. We found that napsin A was expressed in 15% of LCNEC (17/112), whereas all carcinoids and small cell carcinomas were consistently negative. Napsin A reactivity in LCNEC was focal in 12/17 cases, and weak or moderate in intensity in all cases, which was significantly lower in the extent and intensity than seen in adenocarcinomas (P<0.0001). The combination of TTF-1-diffuse/napsin A-negative or focal was typical of LCNEC but was rare in adenocarcinoma, and could thus serve as a helpful diagnostic clue. The diagnosis of napsin A-positive LCNECs was confirmed by classic morphology, diffuse labeling for at least one neuroendocrine marker, most consistently synaptophysin, and the lack of distinct adenocarcinoma component. Genomic analysis of 14 napsin A-positive LCNECs revealed the presence of mutations typical of lung adenocarcinoma (KRAS and/or STK11) in 11 cases. In conclusion, LCNECs are unique among lung neuroendocrine neoplasms in that some of these tumors exhibit low-level expression of exocrine marker napsin A, and harbor genomic alterations typical of adenocarcinoma. Despite the apparent close biological relationship, designation of adeno-like LCNEC as a separate entity from adenocarcinoma is supported by their distinctive morphology, typically diffuse expression of neuroendocrine marker(s) and aggressive behavior. Further studies are warranted to assess the clinical utility and optimal method of identifying adenocarcinoma-like and other subsets of LCNEC in routine practice.

Heart Dosimetry is Correlated With Risk of Radiation Pneumonitis After Lung-Sparing Hemithoracic Pleural Intensity Modulated Radiation Therapy for Malignant Pleural Mesothelioma

PURPOSE

To determine clinically helpful dose-volume and clinical metrics correlating with symptomatic radiation pneumonitis (RP) in malignant pleural mesothelioma (MPM) patients with 2 lungs treated with hemithoracic intensity modulated pleural radiation therapy (IMPRINT).

METHODS AND MATERIALS

Treatment plans and resulting normal organ dose-volume histograms of 103 consecutive MPM patients treated with IMPRINT (February 2005 to January 2015) to the highest dose ≤50.4 Gy satisfying departmental normal tissue constraints were uniformly recalculated. Patient records provided maximum RP grade (Common Terminology Criteria for Toxicity and Adverse Event version 4.0) and clinical and demographic information. Correlations analyzed with the Cox model were grade ≥2 RP (RP2+) and grade ≥3 RP (RP3+) with clinical variables, with volumes of planning target volume (PTV) and PTV-lung overlap and with mean dose, percent volume receiving dose D (V_D), highest dose encompassing % volume V, (D_V), and heart, total, ipsilateral, and contralateral lung volumes.

RESULTS

Twenty-seven patients had RP2+ (14 with RP3+). The median prescription dose was 46.8 Gy (39.6-50.4 Gy, 1.8 Gy/fraction). The median age was 67.6 years (range, 42-83 years). There were 79 men, 40 never-smokers, and 44 with left-sided MPM. There were no significant (P≤.05) correlations with clinical variables, prescription dose, total lung dose-volume metrics, and PTV-lung overlap volume. Dose-volume correlations for heart were RP2+ with V_D (35 ≤ D ≤ 47 Gy, V₄₃ strongest at P=.003), RP3+ with V_D (31 ≤ D ≤ 45 Gy), RP2+ with D_V (5 ≤ V ≤ 30%), RP3+ with D_V (15 ≤ V ≤ 35%), and mean dose. Significant for ipsilateral lung were RP2+ with V_D (38 ≤ D ≤ 44 Gy), RP3+ with V₄₁, RP2+ and RP3+ with minimum dose, and for contralateral lung, RP2+ with maximum dose. Correlation of PTV with RP2+ was strong (P<.001) and also significant with RP3+.

CONCLUSIONS

Heart dose correlated strongly with symptomatic RP in this large cohort of MPM patients with 2 lungs treated with IMPRINT. Planning constraints to reduce future heart doses are suggested.

Detection of Recurrence Patterns After Wedge Resection for Early Stage Lung Cancer: Rationale for Radiologic Follow-Up

BACKGROUND

Wedge resection for selected patients with early stage non-small cell lung cancer is considered to be a valid treatment option. The aim of this study was to evaluate the recurrence patterns after wedge resection, to analyze the survival of patients under routine follow-up, and to recommend a follow-up regimen.

METHODS

A retrospective analysis was done of 446 consecutive patients between May 2000 and December 2012 who underwent a wedge resection for clinical stage I non-small cell lung cancer. All patients were followed up with a computed tomography scan with or without contrast. The recurrence was recorded as local (involving the same lobe of wedge resection), regional (involving mediastinal or hilar lymph nodes or a different lobe), or distant (including distant metastasis and pleural disease).

RESULTS

Median follow-up for survivors (n = 283) was 44.6 months. In all, 163 patients died; median overall survival was 82.6 months. Thirty-six patients were diagnosed with new primary non-small cell lung cancer, and 152 with recurrence (79 local, 45 regional, and 28 distant). There was no difference in the incidence of recurrence detection detected by computed tomography scans with versus without contrast (p = 0.18). The cumulative incidence of local recurrences at 1, 2, and 3 years was higher than the cumulative incidence for local, regional, and distant recurrences: 5.2%, 11.1%, and 14.9% versus 3.7%, 6.6%, and 9.5% versus 2.3%, 4.7%, and 6.4%, respectively. Primary tumor diameter was associated with local recurrence in univariate analysis.

CONCLUSIONS

Wedge resection for early stage non-small cell lung cancer is associated with a significant risk for local and regional recurrence. Long-term follow-up using noncontrast computed tomography scans at consistent intervals is appropriate to monitor for these recurrences.