Proton versus photon craniospinal irradiation for adult medulloblastoma: A dosimetric, toxicity, and exploratory cost analysis.

Background: This study aimed to determine whether proton craniospinal irradiation (CSI) decreased the dose to normal tissue and resulted in less toxicity than photon CSI for adult patients. Methods: This single-institution retrospective analyzed differences in radiation doses, acute toxicity, and cost between proton and CSI for adult medulloblastoma patients. Results: Of 39 total patients, 20 were treated with photon CSI prior to 2015, and 19 were treated with proton CSI thereafter. Median age was 28 years (range 18-66). The molecular subtype was most commonly sonic hedgehog (68%). Patients most commonly received 36 Gy CSI in 20 fractions with a boost to 54-55.8 Gy (92%). Proton CSI delivered significantly lower mean doses to cochleae, lacrimal glands, lens, parotid glands, pharyngeal constrictors, esophagus, lungs, liver, and skin (all P < .001). Patients receiving proton CSI had significantly lower rates of acute dysphagia of any grade (5% versus 35%, P = .044) and decreased median weight loss during radiation (+1.0 versus -2.8 kg, P = .011). Weight loss was associated with acute hospitalization (P = .009). Median follow-up was 2.9 and 12.9 years for proton and photon patients, respectively, limiting late toxicity and outcome comparisons. At the last follow-up, 5 photon patients had died (2 of progressive disease, 3 without recurrence ages 41-63) and 21% had experienced major cardiovascular events. At 10 years, 89% were alive and 82% were recurrence free. Conclusions: This study demonstrates dosimetric improvements with proton CSI, potentially leading to decreased acute toxicity including dysphagia and weight loss during treatment.

Disease Profile and Oncologic Outcomes After Delayed Diagnosis of Human Papillomavirus-Associated Oropharyngeal Cancer.

OBJECTIVE: Diagnostic delay in human papillomavirus-associated oropharynx squamous cell carcinoma (HPV(+)OPSCC) is common due to nonspecific symptoms. We aim to describe the disease burden and oncologic outcomes of patients with HPV(+)OPSCC diagnosed >12 months after symptom onset. STUDY DESIGN: This is a retrospective cohort study of HPV(+)OPSCC patients receiving intent-to-cure treatment (including surgery ± adjuvant therapy or primary chemoradiation). SETTING: 2006-2016, tertiary care center. METHODS: Tumor stage was compared between patients with and without delayed diagnosis using χ2 tests. Kaplan-Meier survival analysis with univariate and multivariable Cox regressions were used to determine the effect of diagnostic delay on oncologic outcomes. RESULTS: In total, 664 patients were included. Compared to patients diagnosed <12 months from symptom onset (n = 601), those diagnosed at >12 months (n = 63) were more likely to have T4 disease and higher overall American Joint Committee on Cancer (AJCC) clinical stage at presentation (P < .01 for both). At 5 years, rates of overall survival, cancer-specific survival, progression-free survival, and distant metastases-free survival in the delayed diagnosis cohort were 80%, 90%, 80%, and 89%, respectively. A >12-month delay in diagnosis did not significantly impact overall survival (adjusted hazard ratio [aHR], 1.16; 95% CI, 0.58-2.31), cancer-specific survival (aHR, 0.83; 95% CI, 0.29-2.39), progression-free survival (aHR, 1.15; 95% CI, 0.56-2.37), or distant metastases-free survival (aHR, 1.00; 95% CI, 0.42-2.40) after adjusting for age, sex, and clinical AJCC stage (P > .05 for all). CONCLUSIONS: Delayed diagnosis of HPV(+)OPSCC is associated with greater burden of disease at presentation, but oncologic outcomes remain favorable across treatment modalities. When appropriate, intent-to-cure therapy should be pursued despite diagnostic delay. LEVEL OF EVIDENCE: Level III.