The Radiosurgery Society Case-Based Discussion of the Management of Head and Neck or Skull Base Paragangliomas with Stereotactic Radiosurgery and Radiotherapy

Stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT) have been used for the treatment of head and neck or skull base paraganglioma for a considerable time, demonstrating promising local control rates and a favorable safety profile compared with surgical approaches. Nevertheless, the choice of treatment must be carefully tailored to each patient's preferences, tumor location, and size, as well as anticipated treatment-related morbidity. This case-based review serves as a practical and concise guide for the use of SRS and FSRT in the management of head and neck or skull base paragangliomas, providing information on the diagnosis, treatment, follow-up considerations, and potential pitfalls.

Distance Traveled by Patients Globally to Access Radiation Therapy: A Systematic Review

PURPOSE

This study aimed to systematically review the literature on the travel patterns of patients seeking radiation therapy globally. It examined the distance patients travel for radiation therapy as well as secondary outcomes, including travel time.

METHODS AND MATERIALS

A comprehensive search of 4 databases was conducted from June 2022 to August 2022. Studies were included in the review if they were observational, retrospective, randomized/nonrandomized, published between June 2000 and June 2022, and if they reported on the global distance traveled for radiation therapy in the treatment of malignant or benign disease. Studies were excluded if they did not report travel distance or were not written in English.

RESULTS

Of the 168 studies, most were conducted in North America (76.3%), with 90.7% based in the United States. Radiation therapy studies for treating patients with breast cancer were the most common (26.6%), while external beam radiation therapy was the most prevalent treatment modality (16.6%). Forty-six studies reported the mean distance traveled for radiation therapy, with the shortest being 4.8 miles in the United States and the longest being 276.5 miles in Iran. It was observed that patients outside of the United States traveled greater distances than those living within the United States. Geographic location, urban versus rural residence, and patient population characteristics affected the distance patients traveled for radiation therapy.

CONCLUSIONS

This systematic review provides the most extensive summary to date of the travel patterns of patients seeking radiation therapy globally. The results suggest that various factors may contribute to the variability in travel distance patterns, including treatment center location, patient residence, and treatment modality. Overall, the study highlights the need for more research to explore these factors and to develop effective strategies for improving radiation therapy access and reducing travel burden.

Definitive Chemoradiation with Concurrent Carboplatin and Paclitaxel for HPV-Mediated Oropharyngeal Cancer (p16+ OPSCC): Survival and Local Control

PURPOSE/OBJECTIVE(S)

Standard therapy for locally advanced p16+ OPSCC with cisplatin and bilateral nodal RT results in substantial acute and late toxicities. De-intensification strategies are under active investigation, including the de-escalation of RT dose and field size and use of less toxic RT sensitizing agents. We present our single-institution experience with definitive chemoRT using weekly carboplatin and paclitaxel and modified RT.

MATERIALS/METHODS

A retrospective review of 139 consecutive patients with non-metastatic p16+ OPSCC treated with definitive chemoRT from 2013 to 2019 was performed. IMRT dose ranged from 60 to 70 Gy (median 69.96 Gy) to gross disease and 44 to 59.4 Gy (median 54.45 Gy) to elective nodal sites. Modified RT included dose reduction from 70 Gy EQD2 to 60-67.8 Gy EQD2 (2.0-2.2 Gy/fraction) and/or field modified contralateral neck. All patients received concurrent weekly paclitaxel (30 mg/m2) and carboplatin (AUC 1); 34 (24.5%) received induction chemotherapy. Patients were classified as low or intermediate risk based on HPV status, smoking history, and nodal staging per RTOG 0129 risk stratification. OS, local and regional RFS, and DSS were estimated using Kaplan-Meier method.

RESULTS

Median FU was 40.5 months. Of 139 pts, 96 were low and 43 were intermediate risk. Median age 61 yrs (range, 40-81 yrs). 125 pts were male and 14 were female. TNM staging: 29 pts (20.9%) were T1 (22 N1, 7 N2), 68 (48.9%) T2 (4 N0, 52 N1, 12 N2), 27 (19.4%) T3 (5 N0, 15 N1, 7 N2), and 15 (10.8%) T4 (2 N0, 2 N1, 10 N2, 1 N3). Median smoking history of 22.5 pack-yrs (range, 0.25-150 pack-yrs); 59 never smoked. LR recurrence was noted in 6/96 (6.3%) low risk and 7/43 (16.3%) intermediate risk pts. DM developed in 11/96 (11.5%) low risk and 8/43 (18.6%) intermediate risk pts. Synchronous LR recurrence and DM were noted in 1/96 (1%) low risk and 2/43 (4.7%) intermediate risk pts. The 3-year LRC was 93.6% (95% CI, 86.3-97.1) in the low-risk and 77.8% (95% CI, 61.4-87.8) in the intermediate-risk group. The 3-year OS was 95.4% (95% CI, 88.3-98.3) in the low-risk and 77.6% (95% CI, 61.3 to 87.7) in the intermediate-risk group. The 3-year DSS was 96.6% (95% CI, 89.7-98.9) in the low-risk and 86.8% (95% CI, 71.0-94.3) in the intermediate-risk group.

CONCLUSION

Definitive chemoRT for p16+ OPSCC with concurrent carboplatin and paclitaxel and a modified RT regimen designed to minimize acute and late effects of therapy demonstrated comparable outcomes to standard cisplatin-based chemoRT, such as report on RTOG 0129, with a high rate of LRC at 3 years. Our analysis suggests a role for a less intensive regimen using paclitaxel and carboplatin as a less toxic, effective alternative to cisplatin in the curative management of p16+ OPSCC, particularly in low-risk patients. Strategies for combating distant metastases are needed. Toxicity analysis planned to be presented separately.

Tailoring Radiation to the Contralateral Neck for Midline HPV-Mediated Oropharyngeal Squamous Cell Carcinoma (p16+ OPSCC)

PURPOSE/OBJECTIVE(S)

De-intensification strategies for locally advanced p16+ OPSCC are under active investigation, including omission of contralateral neck radiation (RT) for well-lateralized T1-2N0-2a. This study evaluates the outcomes of omitting contralateral neck nodal levels for p16+ OPSCC that are not well-lateralized.

MATERIALS/METHODS

A retrospective review was done of 134 consecutive patients with non-metastatic p16+ OPSCC that were not well-lateralized (< 1 cm from midline or ≥ 1 cm extension to soft palate or base of tongue) who were treated with definitive chemoradiation from 2013 to 2019. IMRT to an EQD2 6364-6735 cGy (200-220 cGy per fraction) was used to treat the primary tumor and ipsilateral or bilateral neck, with tailored nodal level coverage and dose, and with concurrent paclitaxel and carboplatin. Contralateral neck RT was tailored in 121 patients: omitted in 11, limited to level II in 9, and limited to level II and III in 101 (contralateral lower neck omitted); the remaining 13 had bilateral level II-IV neck RT. Local and regional recurrences were evaluated.

RESULTS

Median follow up was 45.34 months. Local and/or regional recurrence was noted in 9/134 (6.7%). 3 (2%) recurred in the contralateral neck in unirradiated tissue (out-of-field). All three were salvaged. The remaining 6 recurrences (4%) were in-field; one was at the primary site and 5 were nodal (all ipsilateral). 4 of the 5 regional recurrences were in a location that was treated to EQD2 7000 cGy (all had PET avid nodal disease upfront that was included in the high dose level); the other region of recurrence was treated to an EQD2 6353 cGy (the only recurrence in a never smoker). 4 of the 5 neck recurrences underwent neck dissection; one further underwent adjuvant RT to 5940 cGy in 33 fractions and remains disease-free. 2 of those who underwent salvage neck dissection alone subsequently developed distant metastases. The majority of first recurrences were distant, 19.4% (26/134). 3-year progression free survival (PFS) was 74.41% (95% CI, 65.63-81.26). Taken together, regional recurrence rate in the contralateral, unirradiated neck was 2.5% (3/121) and ultimate locoregional control was 99% (132/134).

CONCLUSION

Our tailored approach demonstrates a contralateral neck local control of 97.5% (118/121) regardless of tumor lateralization; those who recurred in unirradiated cervical lymph nodes were successfully salvaged. Limiting this analysis is moderate sample size and retrospective nature, but it raises important alternative de-escalation strategies (RT volume reduction) for p16+ OPSCC aside from dose reduction, which is under active investigation in phase II/III trials. Improved systemic therapies are needed to combat distant metastases. Prospective randomized clinical trials are needed for further evaluation of nodal omission for definitive chemoradiation of non-well-lateralized p16+ OPSCC.

Residents Across the Globe: A Call for Education, Advocacy, and Collaboration

The fallout from the COVID-19 pandemic and the war in Ukraine have resulted in unprecedented delays in cancer care. The Global Coalition for Radiotherapy (GCR) has been working to alleviate this backlog and has been functioning as an emergency task force in Ukraine. Not only have patients been displaced by the war, but trainees and physicians have been greatly impacted as well. Given that radiation is needed to treat over half of all cancer cases, it is imperative to advocate for radiation oncology as a field and collaborate globally, especially as trainees.

Platelet MHC class I mediates CD8+ T-cell suppression during sepsis

Circulating platelets interact with leukocytes to modulate host immune and thrombotic responses. In sepsis, platelet-leukocyte interactions are increased and have been associated with adverse clinical events, including increased platelet-T-cell interactions. Sepsis is associated with reduced CD8+ T-cell numbers and functional responses, but whether platelets regulate CD8+ T-cell responses during sepsis remains unknown. In our current study, we systemically evaluated platelet antigen internalization and presentation through major histocompatibility complex class I (MHC-I) and their effects on antigen-specific CD8+ T cells in sepsis in vivo and ex vivo. We discovered that both human and murine platelets internalize and proteolyze exogenous antigens, generating peptides that are loaded onto MHC-I. The expression of platelet MHC-I, but not platelet MHC-II, is significantly increased in human and murine platelets during sepsis and in human megakaryocytes stimulated with agonists generated systemically during sepsis (eg, interferon-γ and lipopolysaccharide). Upregulation of platelet MHC-I during sepsis increases antigen cross-presentation and interactions with CD8+ T cells in an antigen-specific manner. Using a platelet lineage-specific MHC-I-deficient mouse strain (B2Mf/f-Pf4Cre), we demonstrate that platelet MHC-I regulates antigen-specific CD8+ T-cell proliferation in vitro, as well as the number and functional responses of CD8+ T cells in vivo, during sepsis. Loss of platelet MHC-I reduces sepsis-associated mortality in mice in an antigen-specific setting. These data identify a new mechanism by which platelets, through MHC-I, process and cross-present antigens, engage antigen-specific CD8+ T cells, and regulate CD8+ T-cell numbers, functional responses, and outcomes during sepsis.

Sequence Changes Modulate Peptoid Self-Association in Water

Peptoids, N-substituted glycine oligomers, are a class of diverse and sequence-specific peptidomimetics with wide-ranging applications. Advancing the functional repertoire of peptoids to emulate native peptide and protein functions requires engineering peptoids that adopt regular secondary and tertiary structures. An understanding of how changes to peptoid sequence change structural features, particularly in water-soluble systems, is underdeveloped. To address this knowledge gap, five 15-residue water-soluble peptoids that include naphthalene-functionalized side chains were designed, prepared, and subjected to a structural study using a palette of techniques. Peptoid sequence designs were based on a putative amphiphilic helix peptoid bearing structure-promoting (S)-N-(1-naphthylethyl)glycine residues whose self-association in water has been studied previously. New peptoid variants reported here include sequence changes that influenced peptoid conformational flexibility, functional group patterning (amphiphilicity), and hydrophobicity. Peptoid structures were evaluated and compared using circular dichroism spectroscopy, fluorescence spectroscopy, and size exclusion chromatography. Spectral data confirmed that sequence changes alter peptoids' degree of assembly and the organization of self-assembled structures in aqueous solutions. Insights gained in these studies will inform the design of new water-soluble peptoids with regular structural features, including desirable higher-order (tertiary and quaternary) structural features.

The human platelet transcriptome and proteome is altered and pro-thrombotic functional responses are increased during prolonged hypoxia exposure at high altitude

Exposure to hypoxia, through ascension to high altitudes (HAs), air travel, or human disease, is associated with an increased incidence of thrombosis in some settings. Mechanisms underpinning this increased thrombosis risk remain incompletely understood, and the effects of more sustained hypoxia on the human platelet molecular signature and associated functional responses have never been examined. We examined the effects of prolonged (≥2 months continuously) hypobaric hypoxia on platelets isolated from subjects residing at HA (3,700 meters) and, for comparison, matched subjects residing under normoxia conditions at sea level (50 meters). Using complementary transcriptomic, proteomic, and functional methods, we identified that the human platelet transcriptome is markedly altered under prolonged exposure to hypobaric hypoxia at HA. Among the significantly, differentially expressed genes (mRNA and protein), were those having canonical roles in platelet activation and thrombosis, including membrane glycoproteins (e.g. GP4, GP6, GP9), integrin subunits (e.g. ITGA2B), and alpha-granule chemokines (e.g. SELP, PF4V1). Platelets from subjects residing at HA were hyperactive, as demonstrated by increased engagement and adhesion to fibrinogen, fewer alpha granules by transmission electron microscopy, increased circulating PF4 and ADP, and significantly enhanced clot retraction. In conclusion, we identify that prolonged hypobaric hypoxia exposure due to HA alters the platelet transcriptome and proteome, triggering increased functional activation responses that may contribute to thrombosis. Our findings may also have relevance across a range of human diseases where chronic hypoxia, platelet activation, and thrombosis are increased.

Postoperative Changes in the Systemic Inflammatory Milieu in Older Surgical Patients

Dysregulated inflammation is a central component of wound healing following surgery. We prospectively enrolled older patients (n = 25, age 65 ± 7 years) undergoing elective total knee arthroplasty or total hip arthroplasty secondary to advanced osteoarthritis (OA) and healthy controls (n = 48). Inflammatory, proangiogenic (vascular endothelial growth factor [VEGF], monocyte chemoattractant protein-1 [MCP-1], and interleukin-8 [IL-8]), and antiangiogenic (interferon γ [IFN-γ] and IL-4) factors were measured using a high-sensitivity biochip. Patients with OA had significantly higher baseline VEGF (10.5 ± 1.2 pg/mL vs 4.8 ± 0.2 pg/mL, P < .001), MCP-1 (130.6 ± 7.7 pg/mL vs 88.6 ± 3.9 pg/mL, P < .0001), and IL-8 (4.0 ± 0.5 pg/mL vs 2.6 ± 0.1 pg/mL, P < .05). Postoperatively, the levels of VEGF (10.5 ± 1.2 pg/mL vs 18.8 ± 1.5 pg/mL, P < .001) and MCP-1 (130.6 ± 7.7 pg/mL vs 153.1 ± 11.5 pg/mL, P < .05) increased significantly. Baseline and postoperative MCP-1 levels correlated positively and significantly with age. The levels of IFN-γ and IL-4 (which has anti-inflammatory properties) did not significantly differ at baseline in patients with OA compared to controls and did not significantly rise postoperatively. We conclude that systemic levels of pro-inflammatory and angiogenic proteins are increased in patients with OA and rise further postoperatively, while proteins that restrain inflammation and angiogenesis do not coordinately rise. These findings implicate imbalance in inflammatory pathways in OA that may contribute to its pathobiology.