Inflammatory Biomarkers, Hematopoietic Stem Cells, and Symptoms in Breast Cancer Patients Undergoing Adjuvant Radiation Therapy

Background

Fatigue and insomnia are common symptoms experienced by breast cancer patients undergoing adjuvant radiation therapy (RT), yet the underlying mechanisms of these symptoms are unclear. In particular, the roles of hematopoietic stem cells (HSCs) and inflammatory cytokines remain to be elucidated.

Methods

Breast cancer patients (n = 147) completed questionnaires to longitudinally assess symptoms before, during, and after adjuvant RT. Phlebotomies were performed prior to RT, at the second and fifth treatment fractions, end of treatment (EOT), and 1 month after completing RT, assessing for CD34⁺, CD45⁺, full hematology, and 17 inflammatory cytokines. The associations between symptoms and all biomarkers were evaluated. All statistical tests were 2-sided.

Results

General fatigue and insomnia worsened with RT, with peak levels observed at EOT, which remained statistically significant even after controlling for anxiety and depression (P < .05 for all). CD34⁺, CD45⁺, white blood cell, and lymphocyte counts decreased, with the lowest levels also observed at EOT (P < .001). Fatigue and insomnia were associated with changes in both interferon γ-induced protein 10 (IP-10) - (P = .03 and P = .01, respectively) and tumor necrosis factor receptor II (TNF-RII) (P = .02 and P = .006, respectively), while mental fatigue was associated with increased matrix metalloproteinases-2 (MMP-2) levels (P = .03). Patients who received prior chemotherapy demonstrated statistically significantly greater severity in all symptoms, with lower baseline HSC levels.

Conclusions

This is the first longitudinal study to examine linkages between symptoms, HSCs, and cytokines, demonstrating that fatigue and insomnia shared associations with increasing serum levels of IP-10 and TNF-RII, and mental fatigue was associated with increasing serum levels of MMP-2. Our findings highlight opportunities for further research into mechanisms and potential interventions for these symptoms.

Non-invasive imaging prediction of tumor hypoxia: A novel developed and externally validated CT and FDG-PET-based radiomic signatures

BACKGROUND

Tumor hypoxia increases resistance to radiotherapy and systemic therapy. Our aim was to develop and validate a disease-agnostic and disease-specific CT (+FDG-PET) based radiomics hypoxia classification signature.

MATERIAL AND METHODS

A total of 808 patients with imaging data were included: N = 100 training/N = 183 external validation cases for a disease-agnostic CT hypoxia classification signature, N = 76 training/N = 39 validation cases for the H&N CT signature and N = 62 training/N = 36 validation cases for the Lung CT signature. The primary gross tumor volumes (GTV) were manually defined by experts on CT. In order to dichotomize between hypoxic/well-oxygenated tumors a threshold of 20% was used for the [¹⁸F]-HX4-derived hypoxic fractions (HF). A random forest (RF)-based machine-learning classifier/regressor was trained to classify patients as hypoxia-positive/ negative based on radiomic features.

RESULTS

A 11 feature "disease-agnostic CT model" reached AUC's of respectively 0.78 (95% confidence interval [CI], 0.62-0.94), 0.82 (95% CI, 0.67-0.96) and 0.78 (95% CI, 0.67-0.89) in three external validation datasets. A "disease-agnostic FDG-PET model" reached an AUC of 0.73 (0.95% CI, 0.49-0.97) in validation by combining 5 features. The highest "lung-specific CT model" reached an AUC of 0.80 (0.95% CI, 0.65-0.95) in validation with 4 CT features, while the "H&N-specific CT model" reached an AUC of 0.84 (0.95% CI, 0.64-1.00) in validation with 15 CT features. A tumor volume-alone model was unable to significantly classify patients as hypoxia-positive/ negative. A significant survival split (P = 0.037) was found between CT-classified hypoxia strata in an external H&N cohort (n = 517), while 117 significant hypoxia gene-CT signature feature associations were found in an external lung cohort (n = 80).

CONCLUSION

The disease-specific radiomics signatures perform better than the disease agnostic ones. By identifying hypoxic patients our signatures have the potential to enrich interventional hypoxia-targeting trials.

Short-term and long-term unstimulated saliva flow following unilateral vs bilateral radiotherapy for oropharyngeal carcinoma

BACKGROUND

We aimed to compare unstimulated saliva flow using 3-minute modified Schirmer test (MST) following bilateral vs unilateral radiotherapy (RT) in oropharyngeal carcinoma (OPC).

METHODS

We reviewed OPC patients treated with definitive intensity-modulated radiation therapy (IMRT) between 2011 and 2017. MST was measured at baseline, 1-/6-/12-/24-month post-RT. MST values were compared between bilateral-RT vs unilateral-RT groups. Multivariable logistic regression analysis (MVA) identified predictors of hyposalivation (MST < 25 mm).

RESULTS

Total 498 bilateral-RT and 36 unilateral-RT patients were eligible. The MST values at 1-/6-/12-/24-month post-RT were all significantly reduced from baseline for the entire cohort. Baseline unilateral-RT and bilateral-RT MST values (in mm) were similar (P = .2), but much higher for unilateral-RT 1-month (mean: 19.1 vs 13.0, P = .03), 6-month (20.5 vs 9.3, P < .001), 12-month (20.1 vs 11.9, P < .01), and 24-month post-RT (22.2 vs 13.9, P = .04). MVA confirmed that unilateral RT reduced the likelihood of hyposalivation vs bilateral RT (OR 2.36, P = .006).

CONCLUSION

Unilateral RT reduces unstimulated salivary flow in OPC patients.

Pre- and Post-Radiotherapy Radiologic Nodal Features and Oropharyngeal Cancer Outcomes

OBJECTIVES

To assess the prognostic value of pre-/post-radiotherapy (pre-/post-RT) radiologic lymph node (LN) features in human papillomavirus (HPV)-positive and HPV-negative oropharyngeal carcinoma (OPC) patients treated with definitive (chemo-)RT.

METHODS

Clinical node-positive OPCs treated from 2011 to 2015 were reviewed. Nodal features were reviewed by a radiologist on pre-/post-RT computed tomography (CTs). Univariable analysis calculated hazard ratio (HR) for regional failure (RF), distant metastasis (DM), and deaths. Multivariable analysis estimated adjusted HR (aHR) of significant nodal features identified in univariable analysis adjusting for confounders.

RESULTS

Pre-RT CT was undertaken in 344 HPV-positive and 94 HPV-negative OPC patients, of whom 242 (70%) HPV-positive and 67 (71%) HPV-negative also had a post-RT CT. Median follow-up was 4.9 years. Pre-RT LN calcification (pre-RT_LN-cal) increased the risk of RF in HPV-negative (aHR: 5.3, P = .007) but not HPV-positive patients (P = .110). Pre-RT radiologic extranodal extension (pre-RT_rENE+) increased the risk of DM and death in both HPV-negative (DM: aHR 6.6, P < .001; death: aHR 2.1, both P = .019) and HPV-positive patients (DM: aHR 4.9; death: aHR 3.0, both P < .001). Increased risk of RF occured with < 20% post-RT LN size reduction in both HPV-negative (HR 6.0, P = .002) and HPV-positive cases (HR 3.0, P = .049). Post-RT_LN-cal did not affect RF, DM, or death regardless of tumor HPV status (all P > .05).

CONCLUSION

Pre-RT_LN-cal is associated with higher RF risk in HPV-negative but not in HPV-positive patients. Pre-RT_rENE increases risk of DM and death regardless of tumor HPV status. Minimal post-RT LN size reduction (< 20%) increases risk of RF in both diseases. Post-RT_LN-cal + has no apparent influence on outcomes in either disease.

LEVEL OF EVIDENCE

4 (a single institution case-control series) Laryngoscope, 131:E1162-E1171, 2021.

Non-operative management for oral cavity carcinoma: Definitive radiation therapy as a potential alternative treatment approach

PURPOSE

To determine the outcomes of oral cavity squamous cell cancer (OSCC) patients treated with non-surgical approach i.e. definitive intensity-modulated radiation therapy (IMRT).

METHODS

All OSCC patients treated radically with IMRT (without primary surgery) between 2005-2014 were reviewed in a prospectively collected database. OSCC patients treated with definitive RT received concurrent chemotherapy except for early stage patients or those who declined or were unfit for chemotherapy. The 5-year local, and regional, distant control rates, disease-free, overall, and cancer-specific survival, and late toxicity were analyzed.

RESULTS

Among 1316 OSCC patients treated with curative-intent; 108 patients (8%) received non-operative management due to: medical inoperability (n = 14, 13%), surgical unresectability (n = 8, 7%), patient declined surgery (n = 15, 14%), attempted preservation of oral structure/function in view of required extensive surgery (n = 53, 49%) or extensive oropharyngeal involvement (n = 18, 17%). Sixty-eight (63%) were cT3-4, 38 (35%) were cN2-3, and 38 (35%) received concurrent chemotherapy. With a median follow-up of 52 months, the 5-year local, regional, distant control rate, disease-free, overall, and cancer-specific survival were 78%, 92%, 90%, 42%, 50%, and 76% respectively. Patients with cN2-3 had higher rate of 5-year distant metastasis (24% vs 3%, p = 0.001), with detrimental impact on DFS (p = 0.03) and OS (p < 0.02) on multivariable analysis. Grade ≥ 3 late toxicity was reported in 9% of patients (most common: grade 3 osteoradionecrosis in 6%).

CONCLUSIONS

Non-operative management of OSCC resulted in a meaningful rate of locoregional control, and could be an alternative curative approach when primary surgery would be declined, unsuitable or unacceptably delayed.

Bioactive DNA from extracellular vesicles and particles

Extracellular vesicles (EVs) and particles (EPs) have recently emerged as active carriers of molecular biomarkers and mediators of intercellular communication. While most investigations have focused exclusively on the protein, lipid and RNA constituents of these extracellular entities, EV/EP DNA remains poorly understood, despite DNA being found in association with virtually all EV/EP populations. The functional potential of EV/EP DNA has been proposed in a number of pathological states, including malignancies and autoimmune diseases. Moreover, the effectiveness of cell-free DNA as the biomarker of choice in emerging liquid biopsy applications highlights the role that EV/EP DNA may play as a novel disease biomarker. In this review, we provide a comprehensive overview of EV/EP DNA studies conducted to date, with a particular focus on the roles of EV/EP DNA as a functional mediator and molecular biomarker in various pathologic states. We also review what is currently known about the origins, structure, localisation and distribution of EV/EP DNA, highlighting current controversies as well as opportunities for future investigation.

Sexual satisfaction in nasopharyngeal carcinoma survivors: Rates and determinants

OBJECTIVES

Sexual health problems have been identified as an unmet need in head and neck cancer (HNC) survivors. In particular, little is known about such outcomes in survivors of nasopharyngeal cancer (NPC).

MATERIALS AND METHODS

A cross-sectional study of NPC survivors with ≥4y follow-up was undertaken. Sexual satisfaction was assessed using the optional "I am satisfied with my sex life" item of the FACT-H&N. Other patient-reported outcomes measures were also captured including fatigue (FACIT-F), HNC symptom burden (MDASI-HN), emotional distress (HADS) and frontal function (FrSBE). Univariate and multivariate analyses were performed to determine factors influencing sexual satisfaction.

RESULTS

The sexual satisfaction item was answered by 85/103 (83%) enrollees. Female (p < 0.001) and non-partnered (p = 0.0045) patients were more likely to abstain from answering. The distribution of responses were: "very much" (26%), "quite a bit" (21%), "somewhat" (20%), "a little bit" (13%) and "not at all" (20%). Sexual satisfaction was associated with multiple patient-reported measures on univariate analysis, including quality of life, fatigue, a priori selected HNC symptoms (pain, taste), emotional distress, frontal lobe function, body image and relationship strength. On multivariate analysis, only relationship strength and emotional distress remained significant. Sociodemographic factors (age, sex, marital status) and other selected orofacial toxicities were not significant.

CONCLUSIONS

Nearly half (47%) of our sample reported being in the higher satisfaction range. While reassuring in the context of comparative population level data, a number of factors including toxicity, psychological and social factors were associated with sexual satisfaction responses. Prospective evaluation of this unmet need is required.

Abstract PR13: Comprehensive detection of ctDNA in localized head and neck cancer by genome- and methylome-based analysis

Head and neck squamous cell carcinoma (HNSCC) comprises 3% of all cancer cases worldwide. Despite intensive multimodal therapies, HNSCC patient outcomes remain heterogeneous with minimal improvements in survival. Utilization of fluid-based biomarkers for prognostication, risk stratification, and disease surveillance may improve patient outcomes by enabling more effective treatment decisions. Here, we describe the performance of comprehensive mutation and methylome analysis for highly sensitive detection of circulating tumor (ct)DNA in HNSCC plasma. To detect HNSCC-specific mutations and aberrant methylation in ctDNA, we conducted CAPP-Seq (CAncer Personalized Profiling by deep Sequencing) and cfMeDIP-seq (cell-free Methylated DNA ImmunoPrecipitation sequencing), respectively. For CAPP-Seq, we developed a HNSCC-specific hybrid capture panel and applied it to plasma DNA and peripheral blood leukocyte (PBL) genomic DNA from a cohort of HNSCC patients (n=32) and healthy controls (n=20). Single-nucleotide variants (SNVs) were identified by integrated digital error suppression (iDES). For cfMeDIP-seq, hypermethylated differentially methylated regions within regions of low PBL methylation were identified by DESeq2. A median of 3 mutations (range: 1-10) were detected by CAPP-Seq within plasma DNA of 20/32 (62.5%) HNSCC patients. Mean mutant allele frequency ranged from 0.1–5% (median: 0.92%) and correlated with tumor stage. Among these 20 patients, cfMeDIP-seq identified 860 DMRs that were enriched (hypermethylated) in HNSCC plasma DNA compared with healthy controls. These hypermethylated DMRs (hyper-DMRs) were over-represented by CpG islands and gene promoters and showed significant overlap with HNSCC-specific methylated regions in TCGA. When applied to all 32 HNSCC patients, hyper-DMR abundance was positively correlated with mutation-based ctDNA abundance (R=0.87; p=1e−16). Hyper-DMRs were capable of accurate discrimination of HNSCC patients and healthy controls (AUC=0.85). The median DNA fragment size within these hyperDMRs was lower in HNSCC patients compared to healthy controls—a characteristic of ctDNA described in previous studies—and correlated with both hyperDMR-based and mutation-based ctDNA abundance. We have conducted the first comparative analysis of genetic and epigenetic profiling approaches for ctDNA detection in HNSCC. Both CAPP-Seq and cfMeDIP-seq have the potential to detect ctDNA in patient plasma without prior knowledge of patient-specific tumor aberrations. With CAPP-seq, ctDNA was detectable at levels as low as 0.1%. Plasma methylome profiling using cfMeDIP-seq revealed hyper-DMRs with tumor-related features and that correlated with mutation-based ctDNA abundance. Future analysis will validate patient-specific mutations and methylation signals in tumor tissue and in longitudinally collected samples from this cohort.

This abstract is also being presented as Poster B47.

Citation Format: Justin M. Burgener, Jinfeng Zou, Zhen Zhao, Shu Y. Shen, Daniel D. De Carvalho, Scott V. Bratman. Comprehensive detection of ctDNA in localized head and neck cancer by genome- and methylome-based analysis [abstract]. In: Proceedings of the AACR Special Conference on Advances in Liquid Biopsies; Jan 13-16, 2020; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(11_Suppl):Abstract nr PR13.

Abstract A59: Biologic rationale for radiation-induced release of circulating tumor DNA

Purpose: Rapid release of circulating tumor DNA (ctDNA) during cytotoxic therapy could provide an early indication of treatment efficacy. However, the biologic basis for treatment-induced ctDNA release is poorly understood. To study this phenomenon, we evaluated ctDNA release in head and neck squamous cell carcinoma (HNSCC) treated with radiotherapy (RT) or chemoradiotherapy (CRT). We sought to characterize the kinetics and biologic underpinnings of this process.

Methods: 33 HPV+ HNSCC patients treated with RT (n=17) or CRT (n=16) had blood collected at baseline, after the 4th fraction of RT (early-RT), mid-RT, and 3 months post-RT. ctDNA was quantified using digital PCR for HPV-16. Nine HNSCC cell lines (3 HPV+, 6 HPV-) were used for in vitro ctDNA kinetic analysis. Apoptosis was measured by luminescent DEVD cleavage assay, triggered by staurosporine and blocked by z-vad-fmk. Senescence was measured by SA-β-galactosidase activity, triggered by HrasG12V-transduction of fibroblast cell lines and blocked by navitoclax. Three HNSCC cell lines (2 HPV+, 1 HPV-) were grown as xenografts in NRG mice for in vivo analysis. Endpoint xenograft tumors were assessed for necrotic area and for markers of apoptosis (cleaved-caspase 3) and senescence (p21) by immunohistochemistry. ctDNA was quantified from media or mouse plasma by quantitative PCR using human-specific LINE-1 primers.

Results: Of 30 patients with detectable HPV-16 ctDNA (90.9%), we observed variable kinetic patterns of release. We grouped patients into three categories: pattern 1, peak at early RT (12, 40%); pattern 2, peak at mid RT (7, 23.3%); pattern 3, no peak (11, 36.7%). Based on these findings, we characterized the mechanisms dictating RT-induced ctDNA release in preclinical models of HNSCC. Following RT, HNSCC cell lines exhibited variable kinetics of ctDNA release in vitro and in vivo with peak release observed after 72-96 hours. RT-induced ctDNA release was not associated with intrinsic radiosensitivity, HPV status, or propensity to undergo apoptosis. Although caspase inhibition resulted in a near-complete reduction in RT-induced caspase activity (-84%±8%), a comparatively minor reduction in ctDNA release (-29%±9%) was observed. There was an inverse association between RT-induced senescence and ctDNA release. HrasG12V-triggered senescence reduced ctDNA release, while navitoclax treatment reversed this effect. HNSCC models with greater RT-induced ctDNA release displayed more necrosis and less senescence in endpoint xenograft tumors.

Conclusion: Dynamic changes in HPV-16 ctDNA are observed during treatment, with variable patterns of release. Preclinical HNSCC models demonstrate RT-induced spikes within 3-4 days of treatment, revealing a complex interplay between distinct mechanisms of cell death and ctDNA release. Necrosis and senescence are the major determinants of RT-induced ctDNA release, while apoptosis has a comparatively minor impact. This study will inform future work on implementing ctDNA as a response biomarker.

Citation Format: Ariana Rostami, John N. Waldron, Scott V. Bratman. Biologic rationale for radiation-induced release of circulating tumor DNA [abstract]. In: Proceedings of the AACR Special Conference on Advances in Liquid Biopsies; Jan 13-16, 2020; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(11_Suppl):Abstract nr A59.

Hypofractionated radiotherapy alone with 2.4 Gy per fraction for head and neck cancer during the COVID-19 pandemic: The Princess Margaret experience and proposal

Background

The objective of this study was to identify a subgroup of patients with head and neck squamous cell carcinoma (HNSCC) who might be suitable for hypofractionated radiotherapy (RT‐hypo) during the COVID‐19 pandemic.

Methods

HNSCC cases (oropharynx/larynx/hypopharynx) treated with definitive RT‐hypo (60 Gy in 25 fractions over 5 weeks), moderately accelerated radiotherapy (RT‐acc) alone (70 Gy in 35 fractions over 6 weeks), or concurrent chemoradiotherapy (CCRT) during 2005‐2017 were included. Locoregional control (LRC) and distant control (DC) after RT‐hypo, RT‐acc, and CCRT were compared for various subgroups.

Results

The study identified 994 human papillomavirus–positive (HPV+) oropharyngeal squamous cell carcinoma cases (with 61, 254, and 679 receiving RT‐hypo, RT‐acc, and CCRT, respectively) and 1045 HPV– HNSCC cases (with 263, 451, and 331 receiving RT‐hypo, RT‐acc, and CCRT, respectively). The CCRT cohort had higher T/N categories, whereas the radiotherapy‐alone patients were older. The median follow‐up was 4.6 years. RT‐hypo, RT‐acc, and CCRT produced comparable 3‐year LRC and DC for HPV+ T1‐2N0‐N2a disease (seventh edition of the TNM system [TNM‐7]; LRC, 94%, 100%, and 94%; P = .769; DC, 94%, 100%, and 94%; P = .272), T1‐T2N2b disease (LRC, 90%, 94%, and 97%; P = .445; DC, 100%, 96%, and 95%; P = .697), and T1‐2N2c/T3N0‐N2c disease (LRC, 89%, 93%, and 95%; P = .494; DC, 89%, 90%, and 87%; P = .838). Although LRC was also similar for T4/N3 disease (78%, 84%, and 88%; P = .677), DC was significantly lower with RT‐hypo or RT‐acc versus CCRT (67%, 65%, and 87%; P = .005). For HPV– HNSCC, 3‐year LRC and DC were similar with RT‐hypo, RT‐acc, and CCRT in stages I and II (LRC, 85%, 89%, and 100%; P = .320; DC, 99%, 98%, and 100%; P = .446); however, RT‐hypo and RT‐acc had significantly lower LRC in stage III (76%, 69%, and 91%; P = .006), whereas DC rates were similar (92%, 85%, and 90%; P = .410). Lower LRC in stage III predominated in patients with laryngeal squamous cell carcinoma receiving RT‐acc (62%) but not RT‐hypo (80%) or CCRT (92%; RT‐hypo vs CCRT: P = .270; RT‐acc vs CCRT: P = .004). CCRT had numerically higher LRC in comparison with RT‐hypo or RT‐acc in stage IV (73%, 65%, and 66%; P = .336).

Conclusions

It is proposed that RT‐hypo be considered in place of CCRT for HPV+ T1‐T3N0‐N2c (TNM‐7) HNSCCs, HPV– T1‐T2N0 HNSCCs, and select stage III HNSCCs during the COVID‐19 outbreak.

Hypo‐fractionated radiotherapy has disease control comparable to that of chemoradiotherapy in select head and neck cancers, and it is a potential alternative for this subgroup during the COVID‐19 pandemic.

Abstract A45: HPV sequencing facilitates ultrasensitive detection of HPV circulating tumor DNA

Background: Human papillomavirus (HPV)-associated cancers often present with locoregionally confined disease and are treated with curative intent. An emerging treatment paradigm includes radical therapy (i.e., chemoradiotherapy or surgery) followed by adjuvant treatment. Accurate detection of minimal residual disease (MRD) following radical therapy could enable personalized use of adjuvant treatment. The HPV genome offers a convenient circulating tumor (ct)DNA marker for HPV-associated cancers, but current methods such as digital (d)PCR provide insufficient accuracy for accurate MRD detection and for other clinical applications in patients with low disease burden. We asked whether a next-generation sequencing approach (HPV-seq) could provide quantitative and qualitative assessment of HPV ctDNA in low-disease-burden settings.

Methods: We conducted preclinical technical validation studies on HPV-seq using cervix cancer cell lines. We then applied HPV-seq retrospectively to a prospective multicenter cohort study of locally advanced cervix cancer patients accrued from 2015 to 2016 (NCT02388698). Patients were treated with radical chemoradiotherapy with blood obtained at baseline, end of treatment, and 3 months post-treatment. Median follow-up was 27.5 months. In 38 plasma samples from 17 patients, HPV-seq results were compared with dPCR. The primary outcome was progression-free survival according to end-of-treatment HPV ctDNA detectability.

Results: HPV-seq achieved reproducible detection of HPV DNA at levels &lt;0.01%. HPV-seq and dPCR results were highly correlated (R=0.98, p=1.8E-22) with HPV-seq detecting ctDNA at levels down to 0.001% in dPCR-negative post-treatment samples. Detectable HPV ctDNA at the end-of-treatment timepoint was associated with inferior progression-free survival (log-rank p=0.05) with 100% sensitivity and 67% specificity for recurrence. Accurate HPV genotyping was successful from 100% of pretreatment plasma samples. HPV ctDNA fragment sizes were consistently shorter than non-cancer-derived cell-free DNA fragments (median fragment size difference: 22 bp) regardless of HPV genotype or clinical setting.

Conclusions: HPV-seq is a quantitative method for ctDNA detection that outperforms dPCR. HPV-seq also reveals qualitative information about ctDNA fragments such as HPV genotype and ctDNA fragment length distribution. Our findings will have implications for MRD detection in HPV-related cancers. Future prospective studies are needed to confirm that patients with undetectable HPV ctDNA following chemoradiotherapy have exceptionally high cure rates.

Citation Format: Eric Leung, Kathy Han, Jinfeng Zou, Zhen Zhao, Yangqiao Zheng, Ting Ting Wang, Lillian L. Siu, Trevor J. Pugh, Scott V. Bratman. HPV sequencing facilitates ultrasensitive detection of HPV circulating tumor DNA [abstract]. In: Proceedings of the AACR Special Conference on Advances in Liquid Biopsies; Jan 13-16, 2020; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(11_Suppl):Abstract nr A45.

Phase I trial of alpelisib in combination with concurrent cisplatin-based chemoradiotherapy in patients with locoregionally advanced squamous cell carcinoma of the head and neck

BACKGROUND

Deregulation of the PI3K signalling pathway is frequent in squamous cell carcinoma of the head and neck (SCCHN) and may be implicated in radioresistance. We report on the results from a phase I 3 + 3 dose escalation study of alpelisib, a class I α-specific PI3K inhibitor in combination with concurrent cisplatin-based chemoradiation (CRT) in patients with locoregionally advanced SCCHN (LA-SCCHN).

METHODS

Eligible patients had previously untreated LA-SCCHN and were candidates for CRT. The primary objective was to evaluate safety and determine the recommended phase II dose (RP2D). Alpelisib was given orally once daily at two dose levels: 200 mg and 250 mg. CRT consisted of cisplatin 100 mg/m² IV every three weeks and standard fractionation radiotherapy (IMRT) 70 Gy in 35 fractions.

RESULTS

Nine patients were enrolled (six alpelisib 200 mg, three 250 mg). Oropharynx was the primary site in all patients (seven p16-positive; five T1-2N2M0, four T3-4N2-3M0 [AJCC 7th edition]). All patients completed CRT within seven weeks. Grade 3 alpelisib-related toxicities occurred in four patients. No dose-limiting toxicity (DLT) was observed at 200 mg among three DLT-evaluable patients. Two of two DLT-evaluable patients treated at 250 mg experienced DLTs (inability to complete ≥75% alpelisib secondary to radiation dermatitis and febrile neutropenia). Thus, RP2D was declared at 200 mg. After median follow-up of 39.7 months, two patients developed pulmonary metastases despite locoregional control. Three-year overall survival was 77.8% (95% CI 36.5%-93.9%).

CONCLUSION

Alpelisib at 200 mg has a manageable safety profile in combination with cisplatin-based CRT in LA-SCCHN.

The Utility of Liquid Biopsies in Radiation Oncology

The use of therapeutic radiation is primarily guided by clinicopathologic factors and medical imaging, whereas molecular biomarkers currently play a comparatively minor role in most settings. Liquid biopsies provide a rich source of noninvasive tumor-specific biomarkers and are amenable to repeated and noninvasive assessment. Here, we review the current status of liquid biopsies and their potential impact on the field of radiation oncology. We focus on established and emerging approaches to analyze circulating tumor DNA and circulating tumor cells from peripheral blood. These promising classes of biomarkers could have an outsized impact on cancer management by meaningfully stratifying patients into risk groups, tracking radiation therapy efficacy during and after treatment, and identifying patients with radiosensitive or radioresistant disease. Finally, we highlight opportunities for future investigation including the need for prospective interventional studies employing liquid biopsies to guide the management of radiation therapy-treated patients.

Impact of cumulative cisplatin dose and adjuvant chemotherapy in locally-advanced nasopharyngeal carcinoma treated with definitive chemoradiotherapy

BACKGROUND

Both adjuvant chemotherapy and higher cumulative cisplatin dose (CDDP-D) given as part of multimodality therapy for locally-advanced nasopharyngeal carcinoma (LA-NPC) have improved survival in Asian series. We evaluated their impact in a contemporary single-institution Canadian cohort of LA-NPC.

METHODS

Patients with EBV-related stage II-IV LA-NPC by 7th edition TNM (TNM-7) treated with IMRT plus high-dose CDDP followed by adjuvant chemotherapy with CDDP/Carboplatin - 5-FU (maximum total/adjuvant CDDP-D = 540/240 mg/m²) between 2003 and 2016 were analyzed. 5-year overall survival (OS) and recurrence-free survival (RFS) were calculated and compared using log-rank test by stage, adjuvant chemotherapy (yes/no) and total CDDP-D (>300 vs ≤300 mg/m²). Multivariable analysis (MVA) was performed to identify survival predictors.

RESULTS

A total of 312 patients were evaluated: TNM-7 stage II/III/IV = 2%/51%/47%; T4 = 36%; N3 = 17%; adjuvant chemotherapy = 83% (79% 21% CDDP/carboplatin); median total/adjuvant CDDP-D = 380/160 mg/m²; median follow-up 76 years (range 06-149). 5-year OS differed by stage II-III vs IV (95% vs 80%, p < 0.001) and by total CDDP-D >300 (n = 210) vs ≤300 (n = 102) mg/m² (89% vs 83%, p = 0.02). Adjuvant chemotherapy and total CDDP-D impacted on 5-year OS in stage IV but not stage II-III. 5-year RFS was higher in stage IV patients with total CDDP-D >300 vs ≤300 mg/m² (74% vs 59%, p = 0.03), with a trend seen in locoregional (LRC) (91% vs 80%, p = 0.05) but not distant control (DC) (78% vs 72%, p = 0.36).

CONCLUSIONS

Adjuvant chemotherapy and total CDDP-D >300 mg/m² improved OS and RFS in stage IV but not stage II-III LA-NPC, mainly due to effect on LRC rather than DC.

Development and validation of a clinical prediction-score model for distant metastases in major salivary gland carcinoma

BACKGROUND

The most common pattern of failure in major salivary gland carcinoma (SGC) is development of distant metastases (DMs). The objective of this study was to develop and validate a prediction score for DM in SGC.

PATIENTS AND METHODS

Patients with SGC treated curatively at four tertiary cancer centers were divided into discovery (n = 619) and validation cohorts (n = 416). Multivariable analysis using competing risk regression was used to identify predictors of DM in the discovery cohort and create a prediction score of DM; the optimal score cut-off was determined using a minimal P value approach. The prediction score was subsequently evaluated in the validation cohort. The cumulative incidence and Kaplan-Meier methods were used to analyze DM and overall survival (OS), respectively.

RESULTS

In the discovery cohort, DM predictors (risk coefficient) were: positive margin (0.6), pT3-4 (0.7), pN+ (0.7), lymphovascular invasion (0.8), and high-risk histology (1.2). High DM-risk SGC was defined by sum of coefficients greater than two. In the discovery cohort, the 5-year incidence of DM for high- versus low-risk SGC was 50% versus 8% (P < 0.01); this was similar in the validation cohort (44% versus 4%; P < 0.01). In the pooled cohorts, this model performed similarly in predicting distant-only failure (40% versus 6%, P < 0.01) and late (>2 years post surgery) DM (22% versus 4%; P < 0.01). Patients with high-risk SGC had an increased incidence of DM in the subgroup receiving postoperative radiation therapy (46% versus 8%; P < 0.01). The 5-year OS for high- versus low-risk SGC was 48% versus 92% (P < 0.01).

CONCLUSION

This validated prediction-score model may be used to identify SGC patients at increased risk for DM and select those who may benefit from prospective evaluation of treatment intensification and/or surveillance strategies.

Finding/identifying primaries with neck disease (FIND) clinical trial protocol: a study integrating transoral robotic surgery, histopathological localisation and tailored deintensification of radiotherapy for unknown primary and small oropharyngeal head and neck squamous cell carcinoma

INTRODUCTION

Carcinomas of unknown primary site (CUP) of the head and neck have historically been worked up and managed heterogeneously. Failure to identify a primary site may result in large radiotherapy mucosal volumes. Transoral approaches such as Transoral Robotic Surgery (TORS) may improve the yield of identifying hidden primaries. We aim to assess the oncological and functional outcomes of a combined treatment approach with TORS and tailored radiotherapy.

METHODS AND ANALYSIS

Twenty-five patients with metastatic squamous cell carcinoma to the neck without clinical or radiographic evidence of a primary site will be enrolled in a phase II trial. Patients will undergo a diagnostic or therapeutic approach with TORS based on specific algorithms incorporating tailored radiotherapy according to the location and laterality of the primary tumour. The primary outcome is to evaluate the out-of-field failure rate over a 2-year period. Secondary outcomes include identification rates, survival outcomes, patient reported outcomes and functional swallowing outcomes.

ETHICS AND DISSEMINATION

The University Health Network Research Ethics Board approved this study (ID 15-9767). The results will be published in an open access journal.

TRIAL REGISTRATION NUMBER

NCT03281499.

Functional significance of U2AF1 S34F mutations in lung adenocarcinomas

The functional role of U2AF1 mutations in lung adenocarcinomas (LUADs) remains incompletely understood. Here, we report a significant co-occurrence of U2AF1 S34F mutations with ROS1 translocations in LUADs. To characterize this interaction, we profiled effects of S34F on the transcriptome-wide distribution of RNA binding and alternative splicing in cells harboring the ROS1 translocation. Compared to its wild-type counterpart, U2AF1 S34F preferentially binds and modulates splicing of introns containing CAG trinucleotides at their 3' splice junctions. The presence of S34F caused a shift in cross-linking at 3' splice sites, which was significantly associated with alternative splicing of skipped exons. U2AF1 S34F induced expression of genes involved in the epithelial-mesenchymal transition (EMT) and increased tumor cell invasion. Finally, S34F increased splicing of the long over the short SLC34A2-ROS1 isoform, which was also associated with enhanced invasiveness. Taken together, our results suggest a mechanistic interaction between mutant U2AF1 and ROS1 in LUAD.

Patient-Derived Xenografts for Prognostication and Personalized Treatment for Head and Neck Squamous Cell Carcinoma

Overall survival remains very poor for patients diagnosed as having head and neck squamous cell carcinoma (HNSCC). Identification of additional biomarkers and novel therapeutic strategies are important for improving patient outcomes. Patient-derived xenografts (PDXs), generated by implanting fresh tumor tissue directly from patients into immunodeficient mice, recapitulate many of the features of their corresponding clinical cancers, including histopathological and molecular profiles. Using a large collection of PDX models of HNSCC, we demonstrate that rapid engraftment into immunocompromised mice is highly prognostic and show that genomic deregulation of the G1/S checkpoint pathway correlates with engraftment. Furthermore, CCND1 and CDKN2A genomic alterations are predictive of response to the CDK4and CDK6 inhibitor abemaciclib. Overall, our study supports the pursuit of CDK4 and CDK6 inhibitors as a therapeutic strategy for a substantial proportion of HNSCC patients and demonstrates the potential of using PDX models to identify targeted therapies that will benefit patients who have the poorest outcomes.

High efficiency error suppression for accurate detection of low-frequency variants

Detection of cancer-associated somatic mutations has broad applications for oncology and precision medicine. However, this becomes challenging when cancer-derived DNA is in low abundance, such as in impure tissue specimens or in circulating cell-free DNA. Next-generation sequencing (NGS) is particularly prone to technical artefacts that can limit the accuracy for calling low-allele-frequency mutations. State-of-the-art methods to improve detection of low-frequency mutations often employ unique molecular identifiers (UMIs) for error suppression; however, these methods are highly inefficient as they depend on redundant sequencing to assemble consensus sequences. Here, we present a novel strategy to enhance the efficiency of UMI-based error suppression by retaining single reads (singletons) that can participate in consensus assembly. This 'Singleton Correction' methodology outperformed other UMI-based strategies in efficiency, leading to greater sensitivity with high specificity in a cell line dilution series. Significant benefits were seen with Singleton Correction at sequencing depths ≤16 000×. We validated the utility and generalizability of this approach in a cohort of >300 individuals whose peripheral blood DNA was subjected to hybrid capture sequencing at ∼5000× depth. Singleton Correction can be incorporated into existing UMI-based error suppression workflows to boost mutation detection accuracy, thus improving the cost-effectiveness and clinical impact of NGS.

Toronto Workshop on Late Recurrence in Estrogen Receptor-Positive Breast Cancer: Part 2: Approaches to Predict and Identify Late Recurrence, Research Directions

Late disease recurrence (more than 5 years after initial diagnosis) represents a clinical challenge in the treatment and management of estrogen receptor-positive breast cancer (BC). An international workshop was convened in Toronto, Canada, in February 2018 to review the current understanding of late recurrence and to identify critical issues that require future study. The underlying biological causes of late recurrence are complex, with the processes governing cancer cell dormancy, including immunosurveillance, cell proliferation, angiogenesis, and cellular stemness, being integral to disease progression. These critical processes are described herein as well as their role in influencing risk of recurrence. Moreover, observational and interventional clinical trials are proposed, with a focus on methods to identify patients at risk of recurrence and possible strategies to combat this in patients with estrogen receptor-positive BC. Because the problem of late BC recurrence of great importance, recent advances in disease detection and patient monitoring should be incorporated into novel clinical trials to evaluate approaches to enhance patient management. Indeed, future research on these issues is planned and will offer new options for effective late recurrence treatment and prevention strategies.

Toronto Workshop on Late Recurrence in Estrogen Receptor-Positive Breast Cancer: Part 1: Late Recurrence: Current Understanding, Clinical Considerations

Disease recurrence (locoregional, distant) exerts a significant clinical impact on the survival of estrogen receptor-positive breast cancer patients. Many of these recurrences occur late, more than 5 years after original diagnosis, and represent a major obstacle to the effective treatment of this disease. Indeed, methods to identify patients at risk of late recurrence and therapeutic strategies designed to avert or treat these recurrences are lacking. Therefore, an international workshop was convened in Toronto, Canada, in February 2018 to review the current understanding of late recurrence and to identify critical issues that require future study. In this article, the major issues surrounding late recurrence are defined and current approaches that may be applicable to this challenge are discussed. Specifically, diagnostic tests with potential utility in late-recurrence prediction are described as well as a variety of patient-related factors that may influence recurrence risk. Clinical and therapeutic approaches are also reviewed, with a focus on patient surveillance and the implementation of extended endocrine therapy in the context of late-recurrence prevention. Understanding and treating late recurrence in estrogen receptor-positive breast cancer is a major unmet clinical need. A concerted effort of basic and clinical research is required to confront late recurrence and improve disease management and patient survival.

Modeling Cellular Response in Large-Scale Radiogenomic Databases to Advance Precision Radiotherapy

Radiotherapy is integral to the care of a majority of patients with cancer. Despite differences in tumor responses to radiation (radioresponse), dose prescriptions are not currently tailored to individual patients. Recent large-scale cancer cell line databases hold the promise of unravelling the complex molecular arrangements underlying cellular response to radiation, which is critical for novel predictive biomarker discovery. Here, we present RadioGx, a computational platform for integrative analyses of radioresponse using radiogenomic databases. We fit the dose-response data within RadioGx to the linear-quadratic model. The imputed survival across a range of dose levels (AUC) was a robust radioresponse indicator that correlated with biological processes known to underpin the cellular response to radiation. Using AUC as a metric for further investigations, we found that radiation sensitivity was significantly associated with disruptive mutations in genes related to nonhomologous end joining. Next, by simulating the effects of different oxygen levels, we identified putative genes that may influence radioresponse specifically under hypoxic conditions. Furthermore, using transcriptomic data, we found evidence for tissue-specific determinants of radioresponse, suggesting that tumor type could influence the validity of putative predictive biomarkers of radioresponse. Finally, integrating radioresponse with drug response data, we found that drug classes impacting the cytoskeleton, DNA replication, and mitosis display similar therapeutic effects to ionizing radiation on cancer cell lines. In summary, RadioGx provides a unique computational toolbox for hypothesis generation to advance preclinical research for radiation oncology and precision medicine. SIGNIFICANCE: The RadioGx computational platform enables integrative analyses of cellular response to radiation with drug responses and genome-wide molecular data. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/79/24/6227/F1.large.jpg.See related commentary by Spratt and Speers, p. 6076.