Quality of Life and Depression Symptoms After Therapy De-Escalation in HPV+ Oropharyngeal Squamous Cell Carcinoma: A Nonrandomized Controlled Trial.

Importance: Despite interest in therapy de-escalation for survivors of human papillomavirus-mediated oropharyngeal squamous cell carcinoma (HPV-positive OPSCC), the association of de-escalated therapy with patient-reported quality of life (QoL) outcomes and burden of depressive symptoms remains unclear. Objective: To identify associations between clinicopathologic and therapeutic variables with patient-reported QoL outcomes and depression symptom burden in patients with HPV-positive OPSCC, who were enrolled in a therapy de-escalation trial. Design, Setting, and Participants: In this nonrandomized controlled, open-label, curative-intent therapy de-escalation clinical trial in adults with stage I, II, and III HPV-positive OPSCC, patients were recruited from a high-volume head and neck oncology practice. Main Outcomes and Measures: The main outcomes of this study included quantitative, patient-reported QoL and depression symptoms per well-validated inventories. Patient-reported QoL was based on Functional Assessment of Cancer Therapy-Head & Neck (FACT-HN) scores (range, 0-148; lower score indicates inferior QoL). Patient-reported depression-related symptom burden was based on Quick Inventory of Depressive Symptomatology-Self-Report (QIDS-SR) scores (range, 0-27; a higher score indicates a higher burden of depression symptoms). Baseline clinicopathologic and treatment variables were paired with FACT-HN and QIDS-SR scores at baseline, 3, 6, 12, 24, and 36 months. Linear mixed-effect models with a random intercept were used for each participant and fixed effects for other measures. Regression coefficients are reported with 95% CIs. Results: A total of 95 patients were followed up for a median (IQR) of 2.2 (1.6-3.2) years. Of these, 93 patients (98%) were male with a mean (SD) age of 60.5 (8.2) years. Overall, 54 participants (57%) had a history of current or former smoking, 47 (50%) underwent curative-intent surgery (with or without adjuvant therapy), and 48 (50%) underwent primary radiotherapy (with or without chemotherapy). The median (IQR) radiotherapy dose was 60 (60-70) Gy. Five deaths and 2 recurrence events were observed (mean [SD] recurrence interval, 1.4 [1.5] years). A higher radiotherapy dose was the only modifiable factor associated with inferior patient-reported QoL (lower FACT-HN) (coefficient, -0.66 [95% CI, -1.09 to -0.23]) and greater burden of depression-related symptoms (higher QIDS-SR) (coefficient, 0.11 [95% CI, 0.04-0.19]). With the 70-Gy dose as reference, improvements in FACT-HN and QIDS-SR scores were identified when patients received 51 to 60 Gy (coefficient, 12.75 [95% CI, 4.58-20.92] and -2.17 [-3.49 to -0.85], respectively) and 50 Gy or lower (coefficient, 15.03 [4.36-25.69] and -2.80 [-4.55 to -1.04]). Conclusions and Relevance: In this nonrandomized controlled, open-label, curative-intent therapy de-escalation trial, a higher radiotherapy dose was associated with inferior patient-reported QoL and a greater burden of depression-related symptoms. This suggests opportunities for improved QoL outcomes and reduced depression symptom burden with a reduction in radiotherapy dose. Trial Registration: ClinicalTrials.gov Identifier: NCT04638465.

Association of Pre- and Posttreatment Neutrophil-Lymphocyte Ratio With Recurrence and Mortality in Locally Advanced Non-Small Cell Lung Cancer.

OBJECTIVES: Neutrophil-lymphocyte ratio (NLR) has been associated with mortality in non-small cell lung cancer (NSCLC), but its association with recurrence in locally advanced NSCLC (LA-NSCLC), specifically, is less established. We hypothesized pre- and posttreatment NLR would be associated with recurrence and mortality. METHODS: We studied the association of pretreatment NLR (pre-NLR) and posttreatment NLR at 1 (post-NLR1) and 3 months (post-NLR3) with outcomes in patients with LA-NSCLC treated with chemoradiation. Pre-NLR was dichotomized by 5, an a priori cutoff previously shown to be prognostic in LA-NSCLC. Post-NLR1 and post-NLR3 were dichotomized by their medians. RESULTS: We identified 135 patients treated with chemoradiation for LA-NSCLC between 2007 and 2016. Median follow-up for living patients was 61.1 months. On multivariable analysis, pre-NLR ≥ 5 was associated with worse overall survival (HR = 1.82; 95% CI 1.15 - 2.88; p = 0.011), but not with any recurrence, locoregional recurrence, or distant recurrence. Post-NLR1 ≥ 6.3 was not associated with recurrence or survival. Post-NLR3 ≥ 6.6 was associated with worse overall survival (HR = 3.27; 95% CI 2.01- 5.31; p < 0.001), any recurrence (HR = 2.50; 95% CI 1.53 - 4.08; p < 0.001), locoregional recurrence (HR = 2.50; 95% CI 1.40 - 4.46; p = 0.002), and distant recurrence (HR = 2.53; 95% CI 1.49 - 4.30; p < 0.001). CONCLUSION: Pretreatment NLR is associated with worse overall survival and posttreatment NLR is associated with worse survival and recurrence. These findings should be validated independently and prospectively studied.

Primary vs nodal site PET/CT response as a prognostic marker in oropharyngeal squamous cell carcinoma treated with intensity-modulated radiation therapy.

BACKGROUND: Positron emission tomography/computed tomography (PET/CT) in staging of advanced oropharyngeal squamous cell carcinoma (OPSCC) and at 3 months posttreatment (PETpost) is often utilized to assess response. The significance of lymph node vs primary site treatment response is incompletely understood. METHODS: We reviewed 230 patients treated with radiation therapy. PETpost response was graded at primary and nodal sites and correlated with survival. RESULTS: Median age was 58, and 83% were p16-positive. Median follow-up was 24.3 months. Nodal response at PETpost predicted improved 2-year local recurrence-free survival (LRFS) (93% vs 72%, P =.004), 2-year disease-free survival (DFS) (80% vs 61.3%, P =.021), and 2-year overall survival (OS) (89% vs 83%, P =.051), while primary response only predicted improved 2-year LRFS (91% vs 76% P = .035). CONCLUSION: In OPSCC patients, both nodal and primary response at 3 months on PET/CT predicted for improved LRFS, but only nodal response predicted DFS and OS.

Platinum-based regimens versus cetuximab in definitive chemoradiation for human papillomavirus-unrelated head and neck cancer.

For patients ineligible for cisplatin with definitive radiotherapy (CP-CRT) for locally advanced head and neck squamous cell carcinoma (LA-HNSCC), concurrent cetuximab (C225-RT) is a popular substitute. Carboplatin-based chemoradiation (CB-CRT) is another option; however, relative efficacies of CP-CRT, CB-CRT and C225-RT are unclear, particularly in the human papillomavirus (HPV)-unrelated population. We identified 316 patients with stage III-IVB cancers of the oropharynx (24.7%), larynx (58.2%) and hypopharynx (17.1%) undergoing definitive C225-RT (N = 61), CB-CRT (N = 74) or CP-CRT (N = 181). Kaplan-Meier and cumulative incidence functions were generated to estimate overall survival (OS), locoregional failure (LRF) and distant metastasis (DM). Cox proportional hazards were used to determine the association of survival endpoints with clinical characteristics. Respectively, 3-year cumulative incidences for CP-CRT, CB-CRT and C225-RT were: LRF (0.19, 0.18 and 0.48, p ≤ 0.001), DM (0.17, 0.12 and 0.25, p = 0.32). Kaplan-Meier estimates for 3 year OS were: CP-CRT: 71%; CB-CRT: 59% and C225-RT: 54%; p = 0.0094. CP-CRT (hazard ratio [HR] 0.336; 95% confidence interval [CI] 0.203-0.557, p < 0.01) and CB-CRT (HR 0.279; 95% CI 0.141-0.551, p < 0.01) were associated with reduced hazard for LRF on multivariable analysis. CP-CRT (HR 0.548; 95% CI 0.355-0.845, p < 0.01) and CB-CRT (HR 0.549; 95% CI 0.334-0.904, p = 0.02) were associated with a reduced hazard for death on multivariable analysis. Propensity matching confirmed reduced hazards with a combined CP/CB-CRT group compared to C225-RT for LRF: HR 0.384 (p = 0.018) and OS: HR 0.557 (p = 0.045) and CB-CRT group compared to C225-RT for LRF: HR 0.427 (p = 0.023). In conclusion, CB-CRT is an effective alternative to CP-CRT in HPV-unrelated LA-HNSCC with superior locoregional control and OS compared to C225-RT.

Increasing Radiation Dose to the Thoracic Marrow Is Associated With Acute Hematologic Toxicities in Patients Receiving Chemoradiation for Esophageal Cancer.

Purpose: To test the hypothesis that increasing radiation dose to the thoracic marrow (TM) contributes to the development of hematologic toxicities (HT) in esophageal cancer (EC) patients receiving chemoradiation therapy (CRT). Methods: We identified EC cases treated with curative intent CRT at our institution from 2007 to 2016. The TM was contoured as the union of the vertebral bodies (VB) from T1-L1, the ribs from T1-L1, and the sternum. The TM-mean dose and the TM volume receiving at least 5-50 Gy (V5-V50) were collected. Grade ≥ 3 HT (HT3+) was the primary endpoint. Normal tissue complication probability (NTCP) was evaluated using the Lyman-Kutcher-Burman (LKB) model. Logistic regression was used to test associations between HT3+ and dosimetric parameters. Odds ratios (OR) and 95% confidence intervals (CI) are reported with p < 0.05 considered significant. Receiver operating characteristics analysis was used to determine optimal cut points. Results: We identified 137 EC cases, and most received concurrent carboplatin/paclitaxel (N = 83). Median radiation dose was 50.4 Gy (IQR = 50.4-50.4 Gy). The rate of HT3+ was 39.4%. Optimization of the LKB model yielded the results n = 0.70, m = 0.67, and TD50 = 20.1 Gy. The TM-V30 was most strongly associated with HT3+ and on multivariate analysis, patients with TM-V30 ≥ 14% had a 5.7-fold (95% CI 2.42-14.54, p < 0.001) increased odds of HT3+ in the entire cohort and a 4-fold (95% CI 1.54-11.11, p = 0.006) increased odds of HT3+ in the carboplatin/paclitaxel cohort compared to patients with TM-V30 < 14%. Radiation dose to the VB and rib sub-sites of the TM were also associated with HT3+, particularly VB-V40. Conclusion: We found that increasing TM radiation dose was associated with HT3+ in EC patients treated with CRT. Radiation dose to the VB and rib sub-sites were also associated with HT3+. These findings suggest that limiting radiation dose to the TM (or its sub-sites) may be sufficient to decrease HT3+, but further prospective evaluation of these results is needed.

Identifying Clinical Factors Which Predict for Early Failure Patterns Following Resection for Pancreatic Adenocarcinoma in Patients Who Received Adjuvant Chemotherapy Without Chemoradiation.

OBJECTIVES: The role of radiation therapy (RT) in resected pancreatic cancer (PC) remains incompletely defined. We sought to determine clinical variables which predict for local-regional recurrence (LRR) to help select patients for adjuvant RT. MATERIALS AND METHODS: We identified 73 patients with PC who underwent resection and adjuvant gemcitabine-based chemotherapy alone. We performed detailed radiologic analysis of first patterns of failure. LRR was defined as recurrence of PC within standard postoperative radiation volumes. Univariate analyses (UVA) were conducted using the Kaplan-Meier method and multivariate analyses (MVA) utilized the Cox proportional hazard ratio model. Factors significant on UVA were used for MVA. RESULTS: At median follow-up of 20 months, rates of local-regional recurrence only (LRRO) were 24.7%, LRR as a component of any failure 68.5%, metastatic recurrence (MR) as a component of any failure 65.8%, and overall disease recurrence (OR) 90.5%. On UVA, elevated postoperative CA 19-9 (>90 U/mL), pathologic lymph node positive (pLN+) disease, and higher tumor grade were associated with increased LRR, MR, and OR. On MVA, elevated postoperative CA 19-9 and pLN+ were associated with increased MR and OR. In addition, positive resection margin was associated with increased LRRO on both UVA and MVA. CONCLUSIONS: About 25% of patients with PC treated without adjuvant RT develop LRRO as initial failure. The only independent predictor of LRRO was positive margin, while elevated postoperative CA 19-9 and pLN+ were associated with predicting MR and overall survival. These data may help determine which patients benefit from intensification of local therapy with radiation.

Clinical outcomes and prognostic factors in cisplatin versus cetuximab chemoradiation for locally advanced p16 positive oropharyngeal carcinoma.

OBJECTIVES: Randomized trials evaluating cisplatin versus cetuximab chemoradiation (CRT) for p16+ oropharyngeal cancer (OPC) have yet to report preliminary data. Meanwhile, as a preemptive step toward morbidity reduction, the off-trial use of cetuximab in p16+ patients is increasing, even in those who could potentially tolerate cisplatin. The purpose of this study was to compare the efficacy of cisplatin versus cetuximab CRT in the treatment of p16+ OPC and to identify prognostic factors and predictors of tumor response. MATERIALS AND METHODS: Cases of p16+ OPC treated with cisplatin or cetuximab CRT at our institution from 2010 to 2014 were identified. Recursive partitioning analysis (RPA) classification was used to determine low-risk (LR-RPA) and intermediate-risk (IR-RPA) groups. Log-rank/Kaplan-Meier and Cox Regression methods were used to compare groups. RESULTS: We identified 205 patients who received cisplatin (n = 137) or cetuximab (n = 68) CRT in the definitive (n = 178) or postoperative (n = 27) setting. Median follow-up was 3 years. Cisplatin improved 3-year locoregional control (LRC) [92.7 vs 65.4%], distant metastasis-free survival (DMFS) [88.3 vs 71.2%], recurrence-free survival (RFS) [86.6 vs 50.6%], and overall survival (OS) [92.6 vs 72.2%] compared to cetuximab [all p < .001]. Concurrent cisplatin improved 3-year OS for LR-RPA (97.1 vs 80.3%, p < .001) and IR-RPA (97.1 vs 80.3%, p < .001) groupings. CONCLUSION: When treating p16+ OPC with CRT, the threshold for substitution of cisplatin with cetuximab should be maintained appropriately high in order to prolong survival times and optimize locoregional and distant tumor control. When cetuximab is used in cisplatin-ineligible patients, altered fractionation RT should be considered in an effort to improve LRC.

Radiation Dose to the Thoracic Vertebral Bodies Is Associated With Acute Hematologic Toxicities in Patients Receiving Concurrent Chemoradiation for Lung Cancer: Results of a Single-Center Retrospective Analysis.

PURPOSE: To test the hypothesis that increasing radiation therapy (RT) dose to the thoracic vertebral bodies (TVBs) contributes to the development of hematologic toxicities (HTs) in patients with lung cancer. METHODS AND MATERIALS: Cases of non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) treated with definitive chemoradiation with concurrent platinum-based doublet chemotherapy at our institution from 2007 to 2016 were identified. Mean TVB dose and the volume of TVBs receiving at least 5 to 60 Gy (V5-V60) were retrospectively recorded. Logistic regression was used to test associations between grade ≥3 HT (HT3+) and dosimetric/clinical parameters. Normal tissue complication probability was evaluated using the Lyman-Kutcher-Burman (LKB) model for HT3+, and receiver operating characteristics analysis was used to determine dosimetric cut-points. RESULTS: We identified 201 patients, the majority having NSCLC (n=162, 81%) and stage III to IV disease (n=179, 89%). All patients received either cisplatin/etoposide (n=107, 53%) or carboplatin/paclitaxel (n=94, 47%). Median RT dose was 60 Gy (range, 60-70 Gy). The rate of HT3+ was 49% (n=99). Increasing mean TVB dose (per Gy) was associated with higher odds of developing HT3+ (odds ratio 1.041, 95% confidence interval 1.004-1.080, P=.032), as were increasing TVB V5 to V20. These dosimetric correlates to HT3+ persisted on multivariate analysis. Constrained optimization of the LKB model for HT3+ yielded the parameters: n=1, m=1.79, and TD50=21.4 Gy. Optimal cut-points identified were V5=65%, V10=60%, V20=50%, and mean dose=23.5 Gy. Patients with values above these cut-points had an approximately 2-fold increased risk of HT3+. CONCLUSIONS: We found that mean TVB dose and low-dose parameters (V5-V20) were associated with HT3+ in chemoradiation for lung cancer. Per the LKB model, bone marrow behaves like a parallel organ (n=1), implying that mean TVB dose is a useful predictor for toxicity. These data suggest that efforts to spare dose to the TVBs may reduce rates of severe HT.

Re-irradiation for recurrent glioblastoma multiforme.

As our understanding of normal brain tissue tolerance and radiation technology have improved, central nervous system (CNS) re-irradiation has garnered more attention; whereas, in the past there had been hesitancy due to late toxicity concerns, particularly radionecrosis (RN). There is minimal prospective data evaluating repeat radiation in recurrent gliomas. In this review, the rationale for and different approaches to re-irradiation will be discussed, and the biology and clinical impact of late CNS toxicity will be reviewed.

Prognostic Value of Primary Tumor Volume Changes on kV-CBCT during Definitive Chemoradiotherapy for Stage III Non-Small Cell Lung Cancer.

INTRODUCTION: Kilovoltge cone beam computed tomography (kV-CBCT) allows for tumor localization and response assessment during definitive chemoradiotherapy for locally advanced NSCLC. We hypothesize that significant tumor volume loss occurs early during radiotherapy and that the extent of volume loss correlates with clinical outcomes. METHODS: A total of 52 patients with locally advanced NSCLC treated with definitive chemoradiotherapy were reviewed. kV-CBCT images were used to contour primary gross tumor volumes at four time points during treatment. Patients were dichotomized according to absolute and relative volume changes at each time point. Statistical analyses were performed to evaluate correlations between volume changes and clinical outcomes. RESULTS: The median gross tumor volumes were 77.1, 48.3, 42.5, and 29.9 cm3 for fractions 1, 11, 21, and final, respectively. Greater relative volume loss between fractions 1 and 21 correlated with improved distant control (hazard ratio [HR] = 0.35, 95% confidence interval [CI]: 0.13-0.94, p = 0.038) and overall survival (HR = 0.40, 95% CI: 0.16-0.98, p = 0.046). Greater relative volume loss between fractions 11 and 21 correlated with improved progression-free survival (HR = 0.39, 95% CI: 0.17-0.88, p = 0.02) and trended toward improved overall survival (HR = 0.43, 95% CI: 0.17-1.06, p = 0.07). On multivariate analysis, greater relative volume loss between fractions 11 and 21 correlated with improved progression-free survival (HR = 0.39, 95% CI: 0.16-0.97, p = 0.041) and overall survival (HR = 0.31, 95% CI: 0.11-0.88, p = 0.027). CONCLUSIONS: Significant primary tumor volume loss occurs early during radiotherapy for locally advanced NSCLC. Greater relative tumor volume loss during treatment correlates with improved disease control and overall survival. Thus, kV-CBCT has potential to be used as a practical prognostic imaging marker.

Synchronous Supraglottic and Esophageal Squamous Cell Carcinomas Treated with a Monoisocentric Hybrid Intensity-Modulated Radiation Technique.

Risk factors for squamous cell carcinomas (SCCs) of the head and neck (HN) and esophagus are similar. As such, synchronous primary tumors in these areas are not entirely uncommon. Definitive chemoradiation (CRT) is standard care for locally advanced HNSCC and is a preferred option for inoperable esophageal SCC. Simultaneous treatment of both primaries with CRT can present technical challenges. We report a case of synchronous supraglottic and esophageal SCC primary tumors, highlighting treatment with a monoisocentric hybrid radiation technique and normal tissue toxicity considerations.

Technique, outcomes, and acute toxicities in adults treated with proton beam craniospinal irradiation.

BACKGROUND: Proton craniospinal irradiation (p-CSI) has been proposed to reduce side effects associated with CSI. We evaluated acute toxicities and preliminary clinical outcomes in a series of adults treated with p-CSI. METHODS: We reviewed medical records for 50 patients (aged 16-63 y) with malignancies of varying histologies treated consecutively with vertebral body-sparing p-CSI at MD Anderson Cancer Center from 2007 to 2011. Median CSI and total boost doses were 30.6 and 54 Gy. Forty patients received chemotherapy, varying by histology. Median follow-up was 20.1 months (range, 0.3-59). RESULTS: Median doses to the thyroid gland, pituitary gland, hypothalamus, and cochleae were 0.003 Gy-relative biological effectiveness (RBE; range, 0.001-8.5), 36.1 Gy-RBE (22.5-53.0), 37.1 Gy-RBE (22.3-54.4), and 33.9 Gy-RBE (22.2-52.4), respectively. Median percent weight loss during CSI was 1.6% (range, 10% weight loss to 14% weight gain). Mild nausea/vomiting was common (grade 1 = 46%, grade 2 = 20%); however, only 5 patients experienced grade ≥2 anorexia (weight loss >5% baseline weight). Median percent baseline white blood cells, hemoglobin, and platelets at nadir were 52% (range, 13%-100%), 97% (65%-112%), and 61% (10%-270%), respectively. Four patients developed grade ≥3 cytopenias. Overall and progression-free survival rates were 96% and 82%, respectively, at 2 years and 84% and 68% at 5 years. CONCLUSIONS: This large series of patients treated with p-CSI confirms low rates of acute toxicity, consistent with dosimetric models. Vertebral body-sparing p-CSI is feasible and should be considered as a way to reduce acute gastrointestinal and hematologic toxicity in adults requiring CSI.

Transforming growth factor ß-1 (TGF-ß1) is a serum biomarker of radiation induced fibrosis in patients treated with intracavitary accelerated partial breast irradiation: preliminary results of a prospective study.

PURPOSE: To examine a relationship between serum transforming growth factor ß -1 (TGF-ß1) values and radiation-induced fibrosis (RIF). METHODS AND MATERIALS: We conducted a prospective analysis of the development of RIF in 39 women with American Joint Committee on Cancer stage 0-I breast cancer treated with lumpectomy and accelerated partial breast irradiation via intracavitary brachytherapy (IBAPBI). An enzyme-linked immunoassay (Quantikine, R&D, Minneapolis, MN) was used to measure serum TGF-ß1 before surgery, before IBAPBI, and during IBAPBI. Blood samples for TGF-ß1 were also collected from 15 healthy, nontreated women (controls). The previously validated tissue compliance meter (TCM) was used to objectively assess RIF. RESULTS: The median time to follow-up for 39 patients was 44 months (range, 5-59 months). RIF was graded by the TCM scale as 0, 1, 2, and 3 in 5 of 20 patients (25%), 6 of 20 patients (30%), 5 of 20 patients (25%), and 4 of 20 patients (20%), respectively. The mean serum TGF-ß1 values were significantly higher in patients before surgery than in disease-free controls, as follows: all cancer patients (30,201 ± 5889 pg/mL, P=.02); patients with any type of RIF (32,273 ± 5016 pg/mL, P<.0001); and women with moderate to severe RIF (34,462 ± 4713 pg/mL, P<0.0001). Patients with moderate to severe RIF had significantly elevated TGF-ß1 levels when compared with those with none to mild RIF before surgery (P=.0014) during IBAPBI (P≤0001), and the elevation persisted at 6 months (P≤.001), 12 months (P≤.001), 18 months (P≤.001), and 24 months (P=.12). A receiver operating characteristic (ROC) curve of TGF-ß1 values predicting moderate to severe RIF was generated with an area under the curve (AUC)ROC of 0.867 (95% confidence interval 0.700-1.000). The TGF-ß1 threshold cutoff was determined to be 31,000 pg/mL, with associated sensitivity and specificity of 77.8% and 90.0%, respectively. CONCLUSIONS: TGF-ß1 levels correlate with the development of moderate to severe RIF. The pre-IBAPBI mean TGF-ß1 levels can serve as an early biomarker for the development of moderate to severe RIF after IBAPBI.

Proton beam craniospinal irradiation reduces acute toxicity for adults with medulloblastoma.

PURPOSE: Efficacy and acute toxicity of proton craniospinal irradiation (p-CSI) were compared with conventional photon CSI (x-CSI) for adults with medulloblastoma. METHODS AND MATERIALS: Forty adult medulloblastoma patients treated with x-CSI (n=21) or p-CSI (n=19) at the University of Texas MD Anderson Cancer Center from 2003 to 2011 were retrospectively reviewed. Median CSI and total doses were 30.6 and 54 Gy, respectively. The median follow-up was 57 months (range 4-103) for x-CSI patients and 26 months (range 11-63) for p-CSI. RESULTS: p-CSI patients lost less weight than x-CSI patients (1.2% vs 5.8%; P=.004), and less p-CSI patients had >5% weight loss compared with x-CSI (16% vs 64%; P=.004). p-CSI patients experienced less grade 2 nausea and vomiting compared with x-CSI (26% vs 71%; P=.004). Patients treated with x-CSI were more likely to have medical management of esophagitis than p-CSI patients (57% vs 5%, P<.001). p-CSI patients had a smaller reduction in peripheral white blood cells, hemoglobin, and platelets compared with x-CSI (white blood cells 46% vs 55%, P=.04; hemoglobin 88% vs 97%, P=.009; platelets 48% vs 65%, P=.05). Mean vertebral doses were significantly associated with reductions in blood counts. CONCLUSIONS: This report is the first analysis of clinical outcomes for adult medulloblastoma patients treated with p-CSI. Patients treated with p-CSI experienced less treatment-related morbidity including fewer acute gastrointestinal and hematologic toxicities.