Intravascular coronary brachytherapy combined with a drug-coated balloon

BACKGROUND

Coronary artery disease leads to stenosis of the major cardiac vessels, resulting in ischemia and infarction. Percutaneous intervention (PCI) with balloon angioplasty can re-open stenosed vessels. Drug eluting stents (DES) and intravascular brachytherapy (IVBT) and drug-coated balloons (DCBs) are proven to decrease the likelihood of another restenosis after PCI, but neither is completely effective. Due to the limited long-term effectiveness of IVBT or DCB used separately for salvage PCI, we combined the two in some poor prognosis patients.

METHODS

Combined IVBT+DCB was intended for a total of 36 patients from 2015-2020. PCI with some combination of ballooning, laser and directional/rotational atherectomy was used to maximally open the stenotic region prior to IVBT+DCB. Beta-radiation brachytherapy for all patients was done with a Novoste Beta-Cath. Lutonix 4.0 x 40 mm paclitaxel-coated balloons (Bard, Murray Hill, NJ) were employed.

RESULTS

Overall survival at two years was 88%. Nine patients had follow-up angiograms, all for cardiac symptoms. Time from IVBT+DCB to follow-up angiography ranged from 4 to 33 months. The average months PCI-free interval before brachy therapy was 11.1 mos (95% CI 1.03-23.25) versus 23.3 mos after VBT (23.3 95% CI 12.3-32.3). The mean difference was 11.2 mos (95% CI 1.06-21.4, p < 0.031). None of the follow-up angiographic procedures displayed evidence of what could be interpreted as radiation damage.

CONCLUSIONS

In this uncontrolled series, IVBT plus DCB appeared to lengthen the ISR-free interval relative to what had been achieved prior to the combined intervention. We view these results as mildly encouraging, worthy of further study.

PTCOG Head and Neck Subcommittee Consensus Guidelines on Particle Therapy for the Management of Head and Neck Tumors

Purpose

Radiation therapy is a standard modality in the treatment for cancers of the head and neck, but is associated with significant short- and long-term side effects. Proton therapy, with its unique physical characteristics, can deliver less dose to normal tissues, resulting in fewer side effects. Proton therapy is currently being used for the treatment of head and neck cancer, with increasing clinical evidence supporting its use. However, barriers to wider adoption include access, cost, and the need for higher-level evidence.

Methods

The clinical evidence for the use of proton therapy in the treatment of head and neck cancer are reviewed here, including indications, advantages, and challenges.

Results

The Particle Therapy Cooperative Group Head and Neck Subcommittee task group provides consensus guidelines for the use of proton therapy for head and neck cancer.

Conclusion

This report can be used as a guide for clinical use, to understand clinical trials, and to inform future research efforts.

Timing of postoperative radiation therapy and survival in resected salivary gland cancers: Long-term results from a single institution

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Background: Timely administration of postoperative radiation therapy (PORT) impacts oncologic outcomes in resected squamous cell carcinomas of the head and neck. Salivary gland cancers (SGCs) are uncommon, and timing of PORT has not been extensively explored. We aimed to determine if the interval between surgery and PORT impacts outcomes in SGCs. Methods: We retrospectively identified patients with SGCs who underwent curative intent surgical resection followed by adjuvant PORT at our tertiary referral center. Demographic, tumor, and treatment data were collected. Patients with non-oncologic resections and/or delay of > 6 months to radiation start were excluded. Locoregional control (LRC), relapse free survival (RFS), and overall survival (OS) were estimated using the Kaplan Meier method. A multivariate analysis explored the association between demographics, tumor characteristics, and PORT timing with oncologic outcomes using a stepwise Cox proportional hazards model. Results: Between 1/1/1997 and 12/31/2017 180 eligible patients were identified. Patient characteristics are described in Table. The median time to PORT start was 61 (range 8-121) days, 169 (93.9%) of patients received neutron beam PORT. With a median follow up of 8.2 years in surviving patients, the 5-year OS and LRC estimates were 73% and 67%, respectively. In a multivariate analysis, only nodal involvement, histologic grade, and age at diagnosis were associated with OS, while nodal involvement, tumor size, and age at time of diagnosis were associated with LCR and RFS. Time to PORT start or completion was not statistically associated with survival outcomes on multivariate analysis. Conclusions: SGC patients who underwent surgery in our tertiary institution received PORT within a median of 61 days after surgery. With long term follow up, PORT timing in this retrospective series was not associated with worse oncologic outcomes, and support timely administration of PORT with 3 months of surgical resection. Further work is necessary to assess generalizability of these results.[Table: see text]

Impact of ECOG performance status on recurrent/metastatic head and neck squamous cell carcinomas treated with anti-PD1 inhibitors

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Background: Anti-PD1 checkpoint inhibitors (ICI) represent an established standard of care for patients with recurrent/metastatic head & neck squamous cell carcinoma (RMHNSCC). Landmark studies excluded patients with ECOG performance status (PS) ≥ 2; the benefit of ICI in this population is therefore unknown. Methods: We retrospectively reviewed RMHNSCC patients who received at least 1 dose of ICI at our institution. Demographic data and clinical outcomes were obtained; the latter included objective response to ICI (ORR), physician-documented CTCAE grade 2+ toxicity (irAE), and any unplanned hospitalization within 100-days of last ICI dose (UH). Associations between demographic data and clinical outcomes were explored using both uni- and multivariate analysis. Overall survival (OS) was estimated using a Cox proportional hazards model; ORR, irAE, and UH were evaluated with logistic regression. This project was approved by our institutional IRB. Results: We identified 152 RMHNSCC patients who were treated with ICI between 1/2013 and 1/2019. ECOG PS was 0 in 42 (27%), 1 in 75 (50%), 2 in 27 (18%), 3 in 2 (1%), and unknown in 6 (4%) patients. The median age was 61 (range: 25 - 90). 124 (82%) were male, 124 (82%) were white, and 69 (45%) were never-smokers. The most common primary sites were the oropharynx (n = 59, 40%), oral cavity (n = 39, 26%), nasopharynx (n = 11, 7%), and larynx (n = 10, 6%). 54 (36%) were p16+ oropharynx cancers. CPS score was available in 10 (6.6%). Single agent ICI was received by 118 (77%) patients. 66 (44%) had a documented irAE and 54 (36%) had an UH. A multivariate model for OS containing PS, smoking status and HPV status showed a strong association between inferior OS and ECOG 2/3 compared to 0/1 (p < 0.001; HR = 3.30, CI = 2.01-5.41), as well as former (vs. never) smoking status (p < 0.001; HR = 2.17, CI = 1.41-3.35). Current smoking (p = 0.25) did not reach statistical significance. On univariate analysis, poor PS was associated with inferior ORR (p = 0.03; OR = 0.25, CI = 0.06-0.77) and increased UH (p = 0.04; OR = 2.43, CI = 1.05—5.71). There was no significant association between irAE and any patient characteristic. Conclusions: We observed inferior overall survival among ICI-treated RMHNSCC patients with ECOG 2/3 in our single-institution, retrospective series. Our findings help frame discussion of therapeutic options in this poor-risk population. Further study must be done to determine which interventions are of greatest benefit for RMHNSCC patients with declining performance status.

Recommendations for postoperative radiotherapy in head & neck squamous cell carcinoma in the presence of flaps: A GORTEC internationally-reviewed HNCIG-endorsed consensus

INTRODUCTION

Head and neck reconstructive surgery using a flap is increasingly common. Best practices and outcomes for postoperative radiotherapy (poRT) with flaps have not been specified. We aimed to provide consensus recommendations to assist clinical decision-making highlighting areas of uncertainty in the presence of flaps.

MATERIAL AND METHODS

Radiation, medical, and surgical oncologists were assembled from GORTEC and internationally with the Head and Neck Cancer International Group (HNCIG). The consensus-building approach covered 59 topics across four domains: (1) identification of postoperative tissue changes on imaging for flap delineation, (2) understanding of tumor relapse risks and target volume definitions, (3) functional radiation-induced deterioration, (4) feasibility of flap avoidance.

RESULTS

Across the 4 domains, international consensus (median score ≥ 7/9) was achieved only for functional deterioration (73.3%); other consensus rates were 55.6% for poRT avoidance of flap structures, 41.2% for flap definition and 11.1% for tumor spread patterns. Radiation-induced flap fibrosis or atrophy and their functional impact was well recognized while flap necrosis was not, suggesting dose-volume adaptation for the former. Flap avoidance was recommended to minimize bone flap osteoradionecrosis but not soft-tissue toxicity. The need for identification (CT planning, fiducials, accurate operative report) and targeting of the junction area at risk between native tissues and flap was well recognized. Experts variably considered flaps as prone to tumor dissemination or not. Discrepancies in rating of 11 items among international reviewing participants are shown.

CONCLUSION

International GORTEC and HNCIG-endorsed recommendations were generated for the management of flaps in head and neck radiotherapy. Considerable knowledge gaps hinder further consensus, in particular with respect to tumor spread patterns.

A Combined Neutron and Proton Regimen for Advanced Salivary Tumors: Early Clinical Experience

Background and objective  Fast neutron radiotherapy (NRT) is a high linear energy transfer (LET) particle therapy that offers a local control (LC) advantage over low-LET X-rays in the treatment of advanced and unresectable salivary gland malignancies. However, in tumors approximating the base of skull (BOS), target volumes may be underdosed to minimize toxicity to the central nervous system (CNS). In this setting, a proton beam boost to the underdosed part of the tumor may improve LC. We report our early experience with a hybrid neutron-proton approach in patients with BOS involvement. Materials and methods We retrospectively reviewed 29 patients with locally advanced and unresectable salivary gland tumors involving the BOS between 2014-2018. The median age of the patients was 56 years, with the majority of them having adenoid cystic carcinomas (ACC) (79%) with advanced T4a/b disease (86%), pathologic perineural invasion (PNI) (55.2%), and orbital invasion (34.5%). Five patients (17.2%) were cases of re-irradiation. Surgical resection was attempted in 15 patients (51.7%), of which none achieved negative margins. The median neutron dose was 18.4 neutron Gray (nGy) with a sequential proton boost (PB) with a median dose of 25 Gy [relative biological effectiveness (RBE)] (range: 16-45 Gy). Toxicity was graded per the Common Terminology Criteria for Adverse Events (CTCAE) version 4.03. Descriptive statistics and the Kaplan-Meier method were used. Results At a median follow-up of 18.9 months [interquartile range (IQR): 6.1-32.5], the entire cohort's overall survival (OS) was 93.1%, progression-free survival (PFS) was 79.3%, and LC was 89.7%. Among patients who were not re-irradiated (n=24), the most commonly recorded acute grade 3 toxicities were mucositis (50%) and dermatitis (37.5%). There was no documented acute grade 4/5 events. Late grade 3/4 events included trismus (n=1), hearing loss (n=2), visual loss (n=6), and bone necrosis (n=1). There were no reported late grade 5 events in de novo patients. Conclusion In this challenging cohort with a poor prognosis, early outcomes for a hybrid neutron-proton approach were found to be promising. Further studies involving longer follow-ups with a larger cohort of patients are required to validate our findings.

How we treat Merkel cell carcinoma: within and beyond current guidelines

Merkel cell carcinoma (MCC) is an aggressive skin cancer associated with a high risk of local recurrence and distant metastasis. Optimal care of this potentially life-threatening cancer is critical but challenging because: physicians are often unfamiliar with its management due to rarity, and MCC management remains controversial, in part because it is rapidly evolving across multiple specialties. While guidelines offer a broad overview of management, they are often not sufficient when making decisions for individual patients. Herein, we present a literature review as well as practical approaches adopted at our institutions for staging, surveillance and therapy of MCC. Each of these areas are discussed in light of how they can be appropriately customized for prevalent but challenging situations. We also provide representative examples of MCC patient scenarios and how they were managed by a multidisciplinary team to identify suitable evidence-based, individualized treatment plans.

Merkel cell carcinoma (MCC) is a skin cancer with a high risk of recurrence and distant spread. Optimal care of this cancer is important. However, management is challenging because it is rare and its treatment is continuously evolving across multiple specialties. While treatment guidelines offer a broad overview of management, they are often not detailed enough to provide appropriate patient-specific assistance. Herein, we present a review of recent studies and our suggestions relevant to MCC staging, surveillance and treatment options. Each of these areas are discussed in light of how they can be appropriately customized for challenging situations often encountered by practitioners. We also provide representative examples of MCC patient scenarios and how they were managed by a multidisciplinary team to identify evidence-based, individualized treatment plans.

Postoperative, Single-Fraction Radiation Therapy in Merkel Cell Carcinoma of the Head and Neck

PURPOSE

Conventionally fractionated, postoperative radiation therapy (cPORT; 50 Gy in 25 fractions) is considered for patients with Merkel cell carcinoma (MCC) to improve locoregional control. However, cPORT is associated with acute toxicity, especially in the head and neck (H&N) region, and requires daily treatments over several weeks. We previously reported high rates of durable local control with minimal toxicity using 8-Gy single-fraction radiation therapy (SFRT) in the metastatic setting. We report early results on a cohort of patients with localized H&N MCC who received postoperative SFRT if a cPORT regimen was not feasible.

METHODS AND MATERIALS

Twelve patients with localized MCC of the H&N (clinical/pathologic stages I-II) and no prior radiation therapy to the region were identified from an institutional review board-approved prospective registry who underwent surgical resection followed by postoperative SFRT. Time to event was calculated starting from the date of resection before SFRT. The cumulative incidence of in-field locoregional recurrences and out-of-field recurrences was estimated with death as a competing risk.

RESULTS

Twelve patients with H&N MCC were identified with clinical/pathologic stages I-II H&N MCC. Median age at diagnosis was 81 years (range, 58-96 years); 25% had immunosuppression. At a median follow-up of 19 months (range, 8-34), there were no in-field locoregional recurrences. A single out-of-field regional recurrence was observed, which was successfully salvaged. There were no MCC-specific deaths. No radiation-associated toxicities greater than grade 1 (Common Terminology Criteria for Adverse Events v5) were observed.

CONCLUSIONS

Preliminary data suggest that SFRT could offer a potential alternative to cPORT to treat the primary site for localized H&N MCC, particularly in elderly or frail patients, with promising in-field local control and minimal toxicity. Further data with validation in larger cohorts are needed to confirm the sustained safety and efficacy of postoperative SFRT.

Narrow excision margins are appropriate for Merkel cell carcinoma when combined with adjuvant radiation: Analysis of 188 cases of localized disease and proposed management algorithm

BACKGROUND

Merkel cell carcinoma (MCC) management typically includes surgery with or without adjuvant radiation therapy (aRT). Major challenges include determining surgical margin size and whether aRT is indicated.

OBJECTIVE

To assess the association of aRT, surgical margin size, and MCC local recurrence.

METHODS

Analysis of 188 MCC cases presenting without clinical nodal involvement.

RESULTS

aRT-treated patients tended to have higher-risk tumors (larger diameter, positive microscopic margins, immunosuppression) yet had fewer local recurrences (LRs) than patients treated with surgery only (1% vs 15%; P = .001). For patients who underwent surgery alone, 7 of 35 (20%) treated with narrow margins (defined as ≤1.0 cm) developed LR, whereas 0 of 13 patients treated with surgical margins greater than 1.0 cm developed LR (P = .049). For aRT-treated patients, local control was excellent regardless of surgical margin size; only 1% experienced recurrence in each group (1 of 70 with narrow margins ≤1 cm and 1 of 70 with margins >1 cm; P = .56).

LIMITATIONS

This was a retrospective study.

CONCLUSIONS

Among patients treated with aRT, local control was superb even if significant risk factors were present and margins were narrow. We propose an algorithm for managing primary MCC that integrates risk factors and optimizes local control while minimizing morbidity.

Neutron Therapy for High-Grade Salivary Carcinomas in the Adjuvant and Primary Treatment Setting

OBJECTIVES/HYPOTHESIS

Our primary objective was to compare differences in survival of patients with high-grade salivary gland carcinomas (SGCs) receiving adjuvant neutron versus photon radiotherapy using a hospital-based national cohort and restricted mean survival time (RMST) analysis. Our secondary objective was to compare survival of similar patients treated with primary neutron versus photon radiation.

STUDY DESIGN

Multicenter, retrospective population-based study of patients within the National Cancer Database from 2004 to 2014.

METHODS

One thousand eight hundred forty-four patients were selected on diagnosis of high-grade parotid and submandibular malignancies. One thousand seven hundred seventy-seven patients receiving photon and 67 patients receiving neutron therapy were identified who met inclusion criteria. Patients were then categorized as having primary surgery with adjuvant radiation or primary radiation without prior surgery. Bivariate analysis was performed to assess for differences between groups, and RMST analysis was performed at 1-, 2-, and 5-year timepoints with controlling for available covariate data.

RESULTS

There was no significant difference in RMST for patients receiving neutrons over photons at 1, 2, and 5 years in the adjuvant setting. Among patients undergoing primary radiotherapy, there was a difference in RMST of 2.29 months at 1 year and 5.05 months at 2 years for neutrons over photons, though this benefit was not observed at 5 years post-therapy.

CONCLUSIONS

For patients with high grade SGCs undergoing adjuvant photon versus neutron radiotherapy, there was no difference in RMST. There was observed to be a significant difference in RMST at 1 and 2 years among patients undergoing primary neutron therapy of up to 5 months. Given the benefit observed with primary neutron therapy, it should be considered in both the primary and adjuvant treatment setting.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:541-547, 2021.

High somatostatin receptor expression and efficacy of somatostatin analogues in patients with metastatic Merkel cell carcinoma

BACKGROUND

Merkel cell carcinoma (MCC) is an aggressive, high-grade, cutaneous neuroendocrine tumour (NET). Agents blocking programmed death 1/programmed death ligand 1 have efficacy in metastatic MCC (mMCC), but half of patients do not derive durable benefit. Somatostatin analogues (SSAs) are commonly used to treat low- and moderate-grade NETs that express somatostatin receptors (SSTRs).

OBJECTIVES

To assess SSTR expression and the efficacy of SSAs in mMCC, a high-grade NET. Methods In this retrospective study of 40 patients with mMCC, SSTR expression was assessed radiologically by somatostatin receptor scintigraphy (SRS; n = 39) and/or immunohistochemically when feasible (n = 9). Nineteen patients (18 had SRS uptake in MCC tumours) were treated with SSA. Disease control was defined as progression-free survival (PFS) of ≥ 120 days after initiation of SSA.

RESULTS

Thirty-three of 39 patients (85%) had some degree (low 52%, moderate 23%, high 10%) of SRS uptake. Of 19 patients treated with SSA, seven had a response-evaluable target lesion; three of these seven patients (43%) experienced disease control, with a median PFS of 237 days (range 152-358). Twelve of 19 patients did not have a response-evaluable lesion due to antecedent radiation; five of these 12 (42%) experienced disease control (median PFS of 429 days, range 143-1757). The degree of SSTR expression (determined by SRS and/or immunohistochemistry) did not correlate significantly with the efficacy endpoints.

CONCLUSIONS

In contrast to other high-grade NETs, mMCC tumours appear frequently to express SSTRs. SSAs can lead to clinically meaningful disease control with minimal side-effects. Targeting of SSTRs using SSA or other novel approaches should be explored further for mMCC.

End-of-life health care utilization (EOLHCU) in patients with recurrent, metastatic head and neck squamous cell carcinoma (RMHNSCC) treated with immune checkpoint inhibitors (IO)

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Background: Demographic and EOLHCU trends are undefined in the growing population of IO-treated RMHNSCC; we sought to study these in a single institution retrospective study. Methods: We identified 228 RMHNSCC pts who received ≥1 IO dose between 01/2013 and 12/2018; of these, 74 were deceased with accessible EOLHCU data such as advanced care plan documentation (ACPD) or evidence of systemic therapy or ER/hospital/ICU admission within 30 days of death (DOD). Demographic, tumor and treatment data were obtained. Overall survival (OS) was estimated using the Kaplan Meier method; multivariable analysis was performed using a Cox proportional hazards model. In an exploratory analysis, EOLHCU was compared to a cohort of 379 deceased thoracic malignancy (TM) pts using a chi-square test. This project was approved by our institutional IRB. Results: Median pt age was 62 (25 – 90). Most were male (56, 75%), white (60, 81%), current/former smokers (46, 62%); 34 (46%) smoked ≥10 pack years. Common primary sites included the oral cavity (28, 37.8%) and oropharynx (24, 32.4%). ECOG PS at IO initiation was 0 in 15 pts (20%,) 1 in 37 (50%), 2 in 20 (27%), 3 in 1 (1%), and unknown in 1 (1%). Of the 42 (57%) treated off-trial, 18 (42%) had an ECOG ≥ 2. 71 (95%) had prior curative intent therapy. 42 (57%) had distant metastases. Compared to TM, IO-treated RMHNSCC pts were more likely to have ACPD (66% vs. 45% p < 0.01), an ED visit (42.3% vs 19.5%, p < 0.01) and/or a hospital admission (42.3% vs 17%, p < 0.01) within 30 DOD. There was no difference in ICU admissions within 30 DOD (9.9% vs. 8.2%, p = 0.81), ICU deaths (7% vs. 4%, p = 0.4), or systemic therapy within 7 (4.2% vs. 2.4%, p = 0.63), 14 (8.5% vs. 6.6%, p = 0.76) or 30 (25% vs 19%, p = 0.31) DOD. Among IO-treated RMHNSCC pts, multivariable analysis revealed inferior OS with worse PS (ECOG 2-3 vs. 0: HR = 7.76, p = 0.00002, 95% CI = 3.07 - 19.64; ECOG 1 vs. 0: HR = 2.97, p = 0.008, CI = 1.33 - 6.62). OS also decreased with smoking status (current/former vs. never: HR 2.18, p = 0.007, CI = 1.24-3.84). No association was observed between ECOG PS, age or smoking status at IO initiation and any EOLHCU metric. Conclusions: At our center, a significant proportion of deceased, IO-treated RMHNSCC pts had an ECOG PS ≥ 2 and an inferior OS compared to ECOG 0/1. Exploratory comparison with a non-RMHNSCC TM cohort suggests high rates of EOLHCU within 30 DOD despite ACPD, representing an opportunity for supportive care augmentation. Whether EOLHCU differs among IO vs non-IO treated RMHNSCC is unknown and merits further study.

Intratumoral Delivery of Plasmid IL12 Via Electroporation Leads to Regression of Injected and Noninjected Tumors in Merkel Cell Carcinoma

PURPOSE

IL12 promotes adaptive type I immunity and has demonstrated antitumor efficacy, but systemic administration leads to severe adverse events (AE), including death. This pilot trial investigated safety, efficacy, and immunologic activity of intratumoral delivery of IL12 plasmid DNA (tavo) via in vivo electroporation (i.t.-tavo-EP) in patients with Merkel cell carcinoma (MCC), an aggressive virus-associated skin cancer.

PATIENTS AND METHODS

Fifteen patients with MCC with superficial injectable tumor(s) received i.t.-tavo-EP on days 1, 5, and 8 of each cycle. Patients with locoregional MCC (cohort A, N = 3) received one cycle before definitive surgery in week 4. Patients with metastatic MCC (cohort B, N = 12) received up to four cycles total, administered at least 6 weeks apart. Serial tumor and blood samples were collected.

RESULTS

All patients successfully completed at least one cycle with transient, mild (grades 1 and 2) AEs and without significant systemic toxicity. Sustained (day 22) intratumoral expression of IL12 protein was observed along with local inflammation and increased tumor-specific CD8⁺ T-cell infiltration, which led to systemic immunologic and clinical responses. The overall response rate was 25% (3/12) in cohort B, with 2 patients experiencing durable clinical benefit (16 and 55+ months, respectively). Two cohort A patients (1 with pathologic complete remission) were recurrence-free at 44+ and 75+ months, respectively.

CONCLUSIONS

I.t.-tavo-EP was safe and feasible without systemic toxicity. Sustained local expression of IL12 protein and local inflammation led to systemic immune responses and clinically meaningful benefit in some patients. Gene electrotransfer, specifically i.t.-tavo-EP, warrants further investigation for immunotherapy of cancer.

Proton Therapy for Locally Advanced Oropharyngeal Cancer: Initial Clinical Experience at the University of Washington

Purpose

Proton therapy can potentially improve the therapeutic ratio over conventional radiation therapy for oropharyngeal squamous cell cancer (OPSCC) by decreasing acute and late toxicity. We report our early clinical experience with intensity-modulated proton therapy (IMPT).

Materials and Methods

We retrospectively reviewed patients with OPSCC treated with IMPT at our center. Endpoints include local regional control (LRC), progression-free survival (PFS), overall survival (OS), tumor response, and toxicity outcomes. Toxicity was graded as per the Common Terminology Criteria for Adverse Events v4.03. Descriptive statistics and Kaplan-Meier method were used.

Results

We treated 46 patients from March 2015 to August 2017. Median age was 58 years, 93.5% were male, 67% were nonsmokers, 98% had stage III-IVB disease per the 7th edition of the AJCC [American Joint Committee on Cancer] Cancer Staging Manual, and 89% were p16 positive. Twenty-eight patients received definitive IMPT to total dose of 70 to 74.4 Gy(RBE), and 18 patients received postoperative IMPT to 60 to 66 Gy(RBE) following transoral robotic surgery (TORS). Sixty-four percent of patients received concurrent systemic therapy. There were no treatment interruptions or observed acute grade 4 or 5 toxicities. Eighteen patients had percutaneous endoscopic gastrostomy (PEG) tube placement; the majority (14) were placed prophylactically. The most common grade 3 acute toxicities were dermatitis (76%) and mucositis (72%). The most common late toxicity was grade 2 xerostomia (30%). At a median follow-up time of 19.2 months (interquartile range [IQR], 11.2-28.4), primary complete response was 100% and nodal complete response was 92%. One patient required a salvage neck dissection owing to an incomplete response at 4 months. There were no recorded local regional or marginal recurrences, PFS was 93.5%, and OS was 95.7%.

Conclusion

Our early results for IMPT in OPSCC are promising with no local regional or marginal recurrences and a favorable toxicity profile. Our data add to a body of evidence that supports the clinical use of IMPT. Randomized comparative trials are encouraged.

Definitive and Postoperative Radiation Therapy for Basal and Squamous Cell Cancers of the Skin: Executive Summary of an American Society for Radiation Oncology Clinical Practice Guideline

PURPOSE

This guideline reviews the evidence for the use of definitive and postoperative radiation therapy (RT) in patients with basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC).

METHODS

The American Society for Radiation Oncology convened a task force to address 5 key questions focused on indications for RT in the definitive and postoperative setting for BCC and cSCC, as well as dose-fractionation schemes, target volumes, basic aspects of treatment planning, choice of radiation modality, and the role of systemic therapy in combination with radiation. Recommendations were based on a systematic literature review and created using a predefined consensus-building methodology and system for grading evidence quality and recommendation strength.

RESULTS

The guideline recommends definitive RT as primary treatment for patients with BCC and cSCC who are not surgical candidates while conditionally recommending RT with an emphasis on shared decision-making in those situations in which adequate resection can lead to a less than satisfactory cosmetic or functional outcome. In the postoperative setting, a number of indications for RT after an adequate resection are provided while distinguishing the strength of the recommendations between BCC and cSCC. One key question is dedicated to defining indications for regional nodal irradiation. The task force suggests a range of appropriate dose-fractionation schemes for treatment of primary and nodal volumes in definitive and postoperative scenarios. The guideline also recommends against the use of carboplatin concurrently with adjuvant RT and conditionally recommends the use of systemic therapies for unresectable primaries where treatment may need escalation.

CONCLUSIONS

Defining the role of RT in the management of BCC and cSCC has been hindered by a lack of high-quality evidence. This document synthesizes available evidence to define practice guidelines for the most common clinical situations. We encourage practitioners to enroll patients in prospective trials and to approach care in a multidisciplinary fashion whenever possible.

Advances in Diagnosis and Multidisciplinary Management of Oropharyngeal Squamous Cell Carcinoma: State of the Art

During the past decade and a half, the most common cause of oropharyngeal squamous cell carcinoma (OPSCC) has shifted from tobacco and alcohol to the human papillomavirus (HPV). HPV-driven p16-positive OPSCC and tobacco-related OPSCC differ in their underlying molecular and genetic profiles, socioeconomic demographics, and response to treatment. HPV-related OPSCC tends to occur in younger patients and has a significantly better response to treatment and excellent prognosis. The stark contrast in prognosis-with around 90% overall 5-year survival for HPV-related p16-positive OPSCC and 40% for non-HPV-related p16-negative OPSCC-has prompted major changes in the eighth edition of the staging manual of the AJCC (American Joint Committee on Cancer). The past 10-15 years have also witnessed major advances in surgery, radiation therapy (RT), and systemic therapy. Minimally invasive surgery has come of age, with transoral robotic procedures and laser microsurgery. Intensity-modulated RT (IMRT) and more recently proton-beam RT have markedly improved the conformity of RT, with an ability to precisely target the cancer and cancer-bearing regions while sparing normal structures and significantly reducing long-term treatment-related morbidity. Progress in systemic therapy has come in the form of immunotherapy and targeted agents such as cetuximab. Owing to the better prognosis of HPV-driven OPSCC as well as the morbidity associated with treatment, de-escalation of therapy via multiple strategies is being explored. The article reviews the advances in diagnosis and multidisciplinary management of OPSCC in the HPV era.^©RSNA, 2019.

Evolutionary action score of TP53 analysis in pathologically high-risk HPV-negative head and neck cancer from a phase II clinical trial: NRG Oncology RTOG 0234

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Background: An evolutionary action scoring algorithm (EAp53) based on phylogenetic sequence variations and speciation stratifies head and neck squamous cell carcinoma (HNSCC) patients bearing TP53 missense mutations as high-risk (high, EAp53≥75), associated with poor outcomes, or low-risk (low), with similar outcomes as TP53 wild-type (wt), and has been validated as a reliable prognostic marker. This study is designed to further validate prior findings that EAp53 is a prognostic marker for locally advanced HNSCC patients, and assess its predictive value for treatment outcomes to adjuvant bio-chemoradiotherapy. Methods: Eighty one resection specimens from patients treated surgically for stage III or IV human papillomavirus-negative (HPV(-)) HNSCC with high-risk pathologic features, who received either Arm 1) radiotherapy(RT)+cetuximab(CTX)+cisplatin or Arm 2) RT+CTX+docetaxel, as adjuvant treatment in a phase II randomized clinical trial (RTOG 0234) underwent TP53 targeted sequencing, and EAp53 scoring. The EAp53 scores were correlated with clinical outcomes. Due to limited sample sizes, patients were combined into 2 EAp53 groups: wt/low and high/other. Results: At median follow-up of 10 years, there was a significant interaction between treatment and EAp53 group for overall survival (OS) (p = 0.008), disease-free survival (DFS) (p = 0.05) and distant metastasis (DM) (p = 0.004). Within arm 2, high/other showed worse OS [HR 4.69 (1.52-14.50)], DFS [HR 2.69 (1.16-6.21)], and had higher DM [HR 11.71 (1.50-91.68)] than wt/low. Within arm 1, there was no significant difference by EAp53 in OS, DFS and DM. Within the wt/low group, arm 2 had better OS [HR 0.11 (0.03-0.36)], DFS [HR 0.24 (0.09-0.61)], and DM [HR 0.04 (0.01-0.31)] than arm 1 but this was not found in high/other. Conclusions: High/other EAp53 scores were associated with worse survival for patients in arm 2. Arm 2 is associated with better survival than arm 1 for patients with wt/low EAp53. This benefit appears to be largely driven by a reduction in DM. Further validation is required to determine whether EAp53 can be used for personalized post-operative treatment decisions in HPV(-) HNSCC.

Clinical Monte Carlo versus Pencil Beam Treatment Planning in Nasopharyngeal Patients Receiving IMPT

PURPOSE

Pencil beam (PB) analytical algorithms have been the standard of care for proton therapy dose calculations. The introduction of Monte Carlo (MC) algorithms may provide more robust and accurate planning and can improve therapeutic benefit. We conducted a dosimetric analysis to quantify the differences between MC and PB algorithms in the clinical setting of dose-painted nasopharyngeal cancer intensity-modulated proton radiotherapy.

PATIENTS AND METHODS

Plans of 14 patients treated with PB analytical algorithm optimized and calculated (PBPB) were retrospectively analyzed. The PBPB plans were recalculated using MC to generate PBMC plans and, finally, reoptimized and recalculated with MC to generate MCMC plans. The plans were compared across several dosimetric endpoints and correlated with documented toxicity. Robustness of the planning scenarios (PBPB, PBMC, MCMC) in the presence of setup and range uncertainties was compared.

RESULTS

A median decrease of up to 5 Gy (P < .05) was observed in coverage of planning target volume high-risk, intermediate-risk, and low-risk volumes when PB plans were recalculated using the MC algorithm. This loss in coverage was regained by reoptimizing with MC, albeit with a slightly higher dose to normal tissues but within the standard tolerance limits. The robustness of both PB and MC plans remained similar in the presence of setup and range uncertainties. The MC-calculated mean dose to the oral avoidance structure, along with changes in global maximum dose between PB and MC dosimetry, may be associated with acute toxicity-related events.

CONCLUSION

Retrospective analyses of plan dosimetry quantified a loss of coverage with PB that could be recovered under MC optimization. MC optimization should be performed for the complex dosimetry in patients with nasopharyngeal carcinoma before plan acceptance and should also be used in correlative studies of proton dosimetry with clinical endpoints.

Intratumoral G100, a TLR4 Agonist, Induces Antitumor Immune Responses and Tumor Regression in Patients with Merkel Cell Carcinoma

PURPOSE

G100 is a toll-like receptor 4 (TLR4) agonist that triggers innate and adaptive antitumor immune responses in preclinical models. This pilot study assessed the safety, efficacy, and immunologic activity of intratumoral (IT) administration of G100 in patients with Merkel cell carcinoma (MCC).

PATIENTS AND METHODS

Patients with locoregional MCC (n = 3; cohort A) received neoadjuvant IT G100 (2 weekly doses at 5 μg/dose) followed by surgery and radiotherapy; patients with metastatic MCC (n = 7; cohort B) received 3 doses in a 6-week cycle and could receive additional cycles with/without radiotherapy.

RESULTS

IT G100 was safe and feasible in both neoadjuvant and metastatic settings. Treatment-related adverse events were mostly grade 1 or 2 injection-site reactions. IT G100 led to increased inflammation in the injected tumors with infiltration of CD8+ and CD4+ T cells and activation of immune-related genes. These proinflammatory changes were associated with local tumor regression and appeared to promote systemic immunity. All 3 cohort A patients successfully completed therapy; 2 patients remain recurrence free at 44+ and 41+ months, including 1 with a pathologic complete response after G100 alone. In cohort B, 2 patients achieved sustained partial responses, both lasting 33+ months after 2 cycles of therapy.

CONCLUSIONS

In this first-in-human study, IT G100 induced antitumor immune responses, demonstrated acceptable safety, and showed encouraging clinical activity.See related commentary by Marquez-Rodas et al., p. 1127.