DeWees, Todd A

Abstract Purpose: Head and neck (HN) radiotherapy contour quality directly impacts local control (LC) and survival; however, few departments peer review (PR) contours prior to radiotherapy planning (RTP). This study reports outcomes of a single institution’s formal HN contour PR process. Methods: A formal HN contour PR process was implemented. Prior to RTP, HN radiation oncologists reviewed contours, provided feedback and assigned contour grades as follows: R0 (no change), R1 (minor revision, not high risk) or R2 (major revision; high risk). The PR task was completed and the contour grade was recorded. Cochran-Armitage trend test was performed. Results: Pilot PR process was performed over a 7-month period for 88 patients, followed by a maintenance phase. Contours were graded as follows: R0 ( N = 51), R1 ( N = 20) and R2 ( N = 17). Over time, the number of R2 revisions decreased ( p = 0.0001); month 1 ( N = 7), month 2 ( N = 3), month 3 ( N = 5), month 4 ( N = 2) and months 5–7 ( N = 0). Conversely, the number of R0 revisions improved over time ( p = 0.0203); month 1 ( N = 5), months 2–3 ( N = 9), month 4 ( N = 5), month 5 ( N = 8), month 6 ( N = 12) and month 7 ( N = 3). Each radiation oncologist demonstrated reduction in R2 revisions during the pilot. During maintenance, all 3 radiation oncologists demonstrated low rates of R2 revisions of less than 3 cases per year. Conclusion: Incorporation of HN contour PR into routine clinical workflow is feasible. The collective experience of multiple high-volume HN radiation oncologists led to improved contour quality in the pilot for each radiation oncologist and continued to ensure high quality in the maintenance phase.

Abstract Purpose: Chemoradiotherapy for locally advanced cervical cancer fails in over a third of patients. Biomarkers with therapeutic implications are therefore needed. We investigated the relationship between an established prognostic marker, maximum standardized uptake value (SUVmax) on 18F-fluorodeoxyglucose positron emission tomography, and the inflammatory and immune state of cervical cancers. Experimental Design: An SUVmax most prognostic for freedom from progression (FFP) was identified and compared with known prognostic clinical variables in a cohort of 318 patients treated with definitive radiation with prospectively collected clinical data. Gene set enrichment analysis (GSEA) and CIBERSORT of whole-transcriptome data from 68 patients were used to identify biological pathways and immune cell subpopulations associated with high SUVmax. IHC using a tissue microarray (TMA, N = 82) was used to validate the CIBERSORT findings. The impact of macrophages on cervical cancer glucose metabolism was investigated in coculture experiments. Results: SUVmax <11.4 was most prognostic for FFP (P = 0.001). The GSEA showed that high SUVmax is associated with increased gene expression of inflammatory pathways, including JAK/STAT3 signaling. CIBERSORT and CD68 staining of the TMA showed high SUVmax tumors are characterized by a monocyte-predominant immune infiltrate. Coculture of cervical cancer cells with macrophages or macrophage-conditioned media altered glucose uptake, and IL6 and JAK/STAT3 signaling contribute to this effect. Conclusions: SUVmax is a prognostic marker in cervical cancer that is associated with activation of inflammatory pathways and tumor infiltration of myeloid-derived immune cells, particularly macrophages. Macrophages contribute to changes in cervical cancer glucose metabolism. See related commentary by Williamson et al., p. 4136

AbstractPurposePatient‐Specific Quality Assurance (PSQA) measurement analysis depends on generating metrics representative of calculation and measurement agreement. Considering the heightened capability of discrete spot scanning protons to modulate individual dose voxels, a dose plane comparison approach that maintained all of the capabilities of the well‐established γ test, but that also provided a more intuitive error parameterization, was desired.MethodsAnalysis was performed for 300 dose planes compared by searching all calculated points within a fixed radius around each measured pixel to determine the dose deviation. Dose plane agreement is reported as the dose difference minimum (DDM) within an empirically established search radius: ΔDmin(r). This per‐pixel metric is aggregated into a histogram binned by dose deviation. Search‐radius criteria were based on a weighted‐beamlet 3σ spatial deviation from imaging isocenter. Equipment setup error was mitigated during analysis using tracked image registration, ensuring beamlet deviations to be the dominant source of spatial error. The percentage of comparison points with <3% dose difference determined pass rate.ResultsThe mean beamlet radial deviation was 0.38mm from x‐ray isocenter, with a standard deviation of 0.19mm, such that 99.9% of relevant pencil beams were within 1 mm of nominal. The dose‐plane comparison data showed no change in passing rate between a 3%/1mm ΔDmin(r) analysis (97.6 +/‐ 3.6%) and a 3%/2mm γ test (97.7 +/‐ 3.2%).ConclusionsPSQA dose‐comparison agreements corresponding to a search radius outside of machine performance limits are likely false positives. However, the elliptical shape of the γ test is too dose‐restrictive with a spatial‐error threshold set at 1 mm. This work introduces a cylindrical search shape, proposed herein as more relevant to plan quality, as part of the new DDM planar‐dose comparison algorithm. DDM accepts all pixels within a given dose threshold inside the search radius, and carries forward plan‐quality metrics in a straightforward manner for evaluation.

OBJECTIVE The internal high-dose volume varies widely for a given prescribed dose during stereotactic radiosurgery (SRS) to treat brain metastases (BMs). This may be altered during treatment planning, and the authors have previously shown that this improves local control (LC) for non–small cell lung cancer BMs without increasing toxicity. Here, they seek to identify potentially actionable dosimetric predictors of LC after SRS for melanoma BM. METHODS The records of patients with unresected melanoma BM treated with single-fraction Gamma Knife RS between 2006 and 2017 were reviewed. LC was assessed on a per-lesion basis, defined as stability or a decrease in lesion size. Outcome-oriented approaches were utilized to determine optimal dichotomization for dosimetric variables relative to LC. Univariable and multivariable Cox regression analysis was implemented to evaluate the impact of collected parameters on LC. RESULTS Two hundred eighty-seven melanoma BMs in 79 patients were identified. The median age was 56 years (range 31–86 years). The median follow-up was 7.6 months (range 0.5–81.6 months), and the median survival was 9.3 months (range 1.3–81.6 months). Lesions were optimally stratified by volume receiving at least 30 Gy (V30) greater than or equal to versus less than 25%. V30 was ≥ and < 25% in 147 and 140 lesions, respectively. For all patients, 1-year LC was 83% versus 66% for V30 ≥ and < 25%, respectively (p = 0.001). Stratifying by volume, lesions 2 cm or less (n = 215) had 1-year LC of 82% versus 70% (p = 0.013) for V30 ≥ and < 25%, respectively. Lesions > 2 to 3 cm (n = 32) had 1-year LC of 100% versus 43% (p = 0.214) for V30 ≥ and < 25%, respectively. V30 was still predictive of LC even after controlling for the use of immunotherapy and targeted therapy. Radionecrosis occurred in 2.8% of lesions and was not significantly associated with V30. CONCLUSIONS For a given prescription dose, an increased internal high-dose volume, as indicated by measures such as V30 ≥ 25%, is associated with improved LC but not increased toxicity in single-fraction SRS for melanoma BM. Internal dose escalation is an independent predictor of improved LC even in patients receiving immunotherapy and/or targeted therapy. This represents a dosimetric parameter that is actionable at the time of treatment planning and warrants further evaluation.

Many American Indian (AI) and Alaska native (AN) patients do not complete guideline-concordant cancer care for the 4 most common cancers. Our aim was to better understand AI/AN attitudes toward radiation therapy (RT). Patients eligible for this survey study were AI/AN patients with cancer at the Phoenix Indian Medical Center who either received previous RT or were recommended to receive RT. An 18-item questionnaire was administered to each of the 50 participants from October 1, 2018, through February 15, 2019. Willingness to travel for RT was compared to respondent characteristics, concerns regarding RT, and obstacles to obtain RT. Duration of RT was important to 78% of patients: 24% would consider traveling 25 miles or more for a standard course, and 48% would travel that distance for a shorter course ( P < .001). The top-ranked barriers to RT were transportation, cost of treatment, and insurance compatibility. The top-ranked concerns about RT were adverse effects, cost of treatment, and fear of RT. Concerns about adverse effects were associated with the radiation team’s inability to explain the treatment ( P = .05). Transportation concerns were significantly associated with accessibility ( P = .02), communication with the RT team ( P = .02), and fear of RT ( P = .04). AI/AN patients are concerned about the adverse effects of RT and the logistics of treatment, particularly costs, transportation, and insurance compatibility. Use of culturally specific education and hypofractionation regimens may increase acceptance of RT for AI/AN patients with cancer, and this hypothesis will be tested in a future educational intervention-based study.

Objectives: To report long-term outcomes of nonmelanoma skin cancer (NMSC) in immunosuppressed cardiac and liver transplant recipients (CLTR). Materials and Methods: The authors reviewed CLTR at the Mayo Clinic in Arizona from 1986 to 2013. Patient and tumor characteristics were recorded. Survival rates were calculated using the Kaplan-Meier method. Patient-specific and lesion-specific analyses were performed. Univariate and multivariate cox regressions were performed for comparisons. Results: Seven-hundred and forty-seven patients underwent cardiac (138) or liver (609) transplantation and of these, 97 patients (13%) developed 382 invasive NMSC. The median follow-up was 11 (range, 3 to 27) years for surviving patients. Primary treatment was mainly surgery alone. At 10 years, the local recurrence (LR) rate was 20% (95% confidence interval, 15%-28%), and 14% of patients had multiple LRs. At 10 years, LR rates were higher for T3/T4 tumors when compared with T1/T2 tumors (32.5% vs. 20%, P=0.05). At 10 years, overall survival was 79% (95% confidence interval, 64%-88%). On multivariate analysis, age 61 years and more demonstrated inferior overall survival (P<0.01). Conclusions: This is the first study describing the AJCC 8th edition stage-based patterns of recurrence and long-term outcomes of surgically managed NMSC in a large cohort of immunosuppressed CLTRs. T3 and T4 tumors recur more often than early stage tumors. Further study is required to identify factors related to recurrence and guide upfront treatment intensification in this high-risk population.

AbstractObjectivesWe investigated how tonsillectomy during childhood may influence the distribution of human papillomavirus (HPV) positive cancer of the tonsils in adult life using p16 as a surrogate marker for HPV infection.Study DesignRetrospective observational study.MethodsA total of 280 patients diagnosed with oropharyngeal squamous cell carcinoma (OPSCC) and known p16 status were eligible for this study. Each participant was called to obtain the childhood tonsillectomy history. Respondents were subgrouped by p16 status and the primary tumor location. Patient demographic and clinical information was analyzed for association with Fisher's exact and Wilcoxon rank sum tests. Location of tumor was modeled using univariate (UVA) and multivariate (MVA) logistic regression with associated odds ratios (OR) and 95% confidence intervals.ResultsOf the 280 patients, 115 (41%) were respondents: 104 (90.4%) were p16 positive and 11 (9.6%) were p16 negative. For p16 positive patients, we observed a majority (93%) of intact tonsils in those with tonsil cancer, compared to 45% of intact tonsils in patients with p16 positive cancer elsewhere in the oropharynx (P < .001). MVA logistic regression showed that female gender (OR = 4.16, P = .0675), prior smoking history (OR = 2.6, P = .0367), and intact tonsils (OR = 15.2, P < .0001) were associated with tonsillar OPSCC.ConclusionWe found that patients with p16 positive OPSCC at a non‐tonsil site were much more likely to have had prior tonsillectomy vs those with p16 positive OPSCC arising within the tonsil. Nevertheless, we do not advocate tonsillectomies as a public health policy to reduce HPV‐related OPSCC.Level of Evidence6

PurposeApproximate dose calculation methods were used in the nominal dose distribution and the perturbed dose distributions due to uncertainties in a commercial treatment planning system (CTPS) for robust optimization in intensity‐modulated proton therapy (IMPT). We aimed to investigate whether the approximations influence plan quality, robustness, and interplay effect of the resulting IMPT plans for the treatment of locally advanced lung cancer patients.Materials and methodsTen consecutively treated locally advanced nonsmall cell lung cancer (NSCLC) patients were selected. Two IMPT plans were created for each patient using our in‐house developed TPS, named “Solo,” and also the CTPS, EclipseTM (Varian Medical Systems, Palo Alto, CA, USA), respectively. The plans were designed to deliver prescription doses to internal target volumes (ITV) drawn by a physician on averaged four‐dimensional computed tomography (4D‐CT). Solo plans were imported back to CTPS, and recalculated in CTPS for fair comparison. Both plans were further verified for each patient by recalculating doses in the inhalation and exhalation phases to ensure that all plans met clinical requirements. Plan robustness was quantified on all phases using dose‐volume‐histograms (DVH) indices in the worst‐case scenario. The interplay effect was evaluated for every plan using an in‐house developed software, which randomized starting phases of each field per fraction and accumulated dose in the exhalation phase based on the patient's breathing motion pattern and the proton spot delivery in a time‐dependent fashion. DVH indices were compared using Wilcoxon rank‐sum test.ResultsCompared to the plans generated using CTPS on the averaged CT, Solo plans had significantly better target dose coverage and homogeneity (normalized by the prescription dose) in the worst‐case scenario [ITV D95%: 98.04% vs 96.28%, Solo vs CTPS, P = 0.020; ITV D5%–D95%: 7.20% vs 9.03%, P = 0.049] while all DVH indices were comparable in the nominal scenario. On the inhalation phase, Solo plans had better target dose coverage and cord Dmax in the nominal scenario [ITV D95%: 99.36% vs 98.45%, Solo vs CTPS, P = 0.014; cord Dmax: 20.07 vs 23.71 Gy(RBE), P = 0.027] with better target coverage and cord Dmax in the worst‐case scenario [ITV D95%: 97.89% vs 96.47%, Solo vs CTPS, P = 0.037; cord Dmax: 24.57 vs 28.14 Gy(RBE), P = 0.037]. On the exhalation phase, similar phenomena were observed in the nominal scenario [ITV D95%: 99.63% vs 98.87%, Solo vs CTPS, P = 0.037; cord Dmax: 19.67 vs 23.66 Gy(RBE), P = 0.039] and in the worst‐case scenario [ITV D95%: 98.20% vs 96.74%, Solo vs CTPS, P = 0.027; cord Dmax: 23.47 vs 27.93 Gy(RBE), P = 0.027]. In terms of interplay effect, plans generated by Solo had significantly better target dose coverage and homogeneity, less hot spots, and lower esophageal Dmean, and cord Dmax [ITV D95%: 101.81% vs 98.68%, Solo vs CTPS, P = 0.002; ITV D5%–D95%: 2.94% vs 7.51%, P = 0.002; cord Dmax: 18.87 vs 22.29 Gy(RBE), P = 0.014].ConclusionsSolo‐generated IMPT plans provide improved cord sparing, better target robustness in all considered phases, and reduced interplay effect compared with CTPS. Consequently, the approximation methods currently used in commercial TPS programs may have space for improvement in generating optimal IMPT plans for patient cases with locally advanced lung cancer.