McGee, Lisa

Because proton beam therapy (PBT) can lower the dose of radiation to the heart, lungs, and breast, it is an established radiation modality for patients with Hodgkin lymphoma (HL). Pencil beam scanning (PBS) PBT facilitates the treatment of more extensive targets. This may be especially of value for lymphoma patients who require RT to both mediastinal and axillary targets, defined here as extended target RT (ETRT), given the target distribution and need to minimize the lung, heart, and breast dose. Using the Proton Collaborative Group registry, we identified patients with HL treated with PBT to both their mediastinum and axilla, for which DICOM-RT was available. All patients were treated with PBS. To evaluate the dosimetric impact of PBS, we compared delivered PBS plans with VMAT butterfly photon plans optimized to have the same target volume coverage, when feasible. Between 2016 and 2021, twelve patients (median 26 years) received PBS ETRT (median 30.6 Gy (RBE)). Despite the large superior/inferior (SI, median 22.2 cm) and left/right (LR, median 22.8 cm) extent of the ETRT targets, all patients were treated with one isocenter except for two patients (both with SI and LR > 30 cm). Most commonly, anterior beams, with or without posterior beams, were used. Compared to photons, PBS had greater target coverage, better conformity, and lower dose heterogeneity while achieving lower doses to the lungs and heart, but not to the breast. No acute grade 3+ toxicities were reported, including pneumonitis. Proton ETRT in this small cohort was safely delivered with PBS and was associated with an improved sparing of the heart and lungs compared to VMAT.

Purpose: As patients with mediastinal lymphoma are typically young with curable disease, advanced radiation techniques such as proton therapy are often considered to minimize subacute and late toxicity. However, it is unclear which mediastinal lymphoma patients are treated with proton therapy. Within a prospective, multi-institutional proton registry, we characterized mediastinal lymphoma patients treated with proton therapy and assessed concordance with consensus recommendations published in 2018 by the International Lymphoma Radiation Oncology Group (ILROG). Methods: Eligible patients included those with lymphoma of the mediastinum treated exclusively with proton therapy for whom digital imaging and communications in medicine (DICOM) treatment data were available for review. Given the challenge with reliably visualizing the left mainstem coronary artery, the inferior-most aspect of the left pulmonary artery (PA) was used as a surrogate. Extent of disease was characterized as upper mediastinum (above level of left PA), middle mediastinum (below left PA but at or above level of T8), or low mediastinum (below T8). Results: Between November 2012 and April 2019, 56 patients were treated and met inclusion criteria. Patients treated with proton therapy were young (median, 24 y; range: 12 to 88), with over half being female (55%). Patients were most commonly treated at initial diagnosis (86%) and had Hodgkin lymphoma (79%). Most patients (96%) had mediastinal disease that extended down to the level of the heart: 48% had middle and 48% had low mediastinal involvement. Nearly all patients (96%) met the ILROG consensus recommendations: 95% had lower mediastinal disease, 46% were young females, and 9% were heavily pretreated. Heart (mean) and lung dose (mean, V5, V20) were significantly associated with lowest extent of mediastinal disease. Conclusions: Mediastinal lymphoma patients treated with proton therapy are typically young with lower mediastinal involvement. Within a prospective, multi-institutional proton registry, nearly all treated patients fit the ILROG consensus recommendations regarding which mediastinal lymphoma patients may most benefit from proton therapy.

Objectives/HypothesisSarcomatoid carcinoma is a rare variant of squamous cell carcinoma of the head and neck. No consensus exists on its management. Our aim was to present our outcomes.Study DesignRetrospective study. Median follow‐up 45 months.MethodsThere were 38 patients with pathologically confirmed sarcomatoid carcinoma of the larynx treated at the Mayo Clinic from 1990 to 2014. Statistical analysis of overall survival (OS), progression‐free survival (PFS), and local control (LC) were conducted using the Kaplan‐Meier method.ResultsThe majority of patients were elderly males (92%) with a smoking history (74%) presenting with early‐stage disease (71%). Surgery alone was the primary treatment in 27 patients (71%). Nine patients (25%) were treated with adjuvant radiation due to initial stage or high‐risk pathologic features. Median radiation dose to the primary/surgical bed was 65 Gy (range, 60.3–75.0 Gy). A total of 15 patients (39%) had tumor recurrence, majority being local (n = 12). Sixty percent (n = 9) had multiple local recurrences. Five‐year OS, PFS, and LC were 63%, 46%, and 72%, respectively. Subgroup analysis by stage I versus higher stages (II–IV) showed an OS of 80% versus 43% (P = .030), PFS of 65% versus 18% (P = .003), and LC of 84% versus 57% (P = .039).ConclusionsSarcomatoid carcinoma of the larynx is rare, and frequently presents at an early stage in older men with history of smoking. Based on our outcomes and patterns of failure, it appears early‐stage tumors are treated appropriately with single‐modality therapy, whereas more advanced tumors require multimodality therapy. Validation in a larger cohort is warranted.Level of Evidence4. Laryngoscope, 128:373–377, 2018