Garces, Yolanda I.

Abstract Purpose: To quantitatively predict the impact of cardiopulmonary dose on overall survival (OS) after radiotherapy for locally advanced non–small cell lung cancer. Experimental Design: We used the NRG Oncology/RTOG 0617 dataset. The model building procedure was preregistered on a public website. Patients were split between a training and a set-aside validation subset (N = 306/131). The 191 candidate variables covered disease, patient, treatment, and dose-volume characteristics from multiple cardiopulmonary substructures (atria, lung, pericardium, and ventricles), including the minimum dose to the hottest x% volume (Dx%[Gy]), mean dose of the hottest x% (MOHx%[Gy]), and minimum, mean (Mean[Gy]), and maximum dose. The model building was based on Cox regression and given 191 candidate variables; a Bonferroni-corrected P value threshold of 0.0003 was used to identify predictors. To reduce overreliance on the most highly correlated variables, stepwise multivariable analysis (MVA) was repeated on 1000 bootstrapped replicates. Multivariate sets selected in ≥10% of replicates were fit to the training subset and then averaged to generate a final model. In the validation subset, discrimination was assessed using Harrell c-index, and calibration was tested using risk group stratification. Results: Four MVA models were identified on bootstrap. The averaged model included atria D45%[Gy], lung Mean[Gy], pericardium MOH55%[Gy], and ventricles MOH5%[Gy]. This model had excellent performance predicting OS in the validation subset (c = 0.89). Conclusions: The risk of death due to cardiopulmonary irradiation was accurately modeled, as demonstrated by predictions on the validation subset, and provides guidance on the delivery of safe thoracic radiotherapy.

7501 Background: The first objective of RTOG 0617 was to compare the overall survival(OS) of patients(pts) treated with standard-dose(SD)(60Gy) versus high-dose(HD)(74Gy) radiotherapy with concurrent chemotherapy(CT). Methods: This Phase III Intergroup trial randomized 464 pts with Stage III NSCLC to the SD(60Gy) vs. HD(74Gy) arms prior to closure of the HD arm. Concurrent CT included weekly paclitaxel(45 mg/m2) and carboplatin(AUC=2). Pts randomized to cetuximab received a 400 mg/m2 loading dose on Day 1 followed by weekly doses of 250 mg/m2. All pts were to receive consolidation CT. We are reporting the final results on radiation dose. Results: 464 pts were accrued prior to closure of the HD arm in 6/11, of which 419 were eligible for analysis. Median follow up was 17.2 months. There were 2 and 10 grade 5 treatment-related adverse events(AEs) on the SD and HD arms, respectively. Grade 3+AEs were 74.2% and 78.2% on SD and HD arms, respectively (p=0.34). The median survival times and 18-month OS rates for the SD and HD arms were 28.7 vs 19.5 months, and 66.9% vs 53.9% respectively (p=0.0007). The primary cause of death was lung cancer (72.2% vs 73.5%)(p=0.84). Local failure rates at 18 months were 25.1% vs 34.3% for SD and HD patients, respectively(p=0.03). Local-regional and distant failures at 18 months were 35.3% vs 44%(p=0.04) and 42.4% vs 47.8%(p=0.16) for SD and HD arms, respectively. Factors predictive of less favorable OS on multivariate analysis were higher radiation dose, higher esophagitis/dysphagia grade, greater gross tumor volume, and heart volume >5 Gy. Conclusions: In this setting of chemoradiation for locally-advanced Stage III NSCLC, 60 Gy is superior to 74 Gy in terms of OS and local-regional control. The effect of the anti-EGFR antibody (cetuximab) awaits further follow up. This project was supported by RTOG grant U10 CA21661, CCOP grant U10 CA37422, and ATC U24 CA 81647 from the National Cancer Institute (NCI) and Eli Lilly and Company. Clinical trial information: NCT00533949.

6095 Background: Prognosis for patients (pts) with locally-advanced, HPV-positive oropharynx squamous cell carcinoma (HPV+OPSCC) is significantly better than for pts with HPV-negative head and neck squamous cell carcinoma (HNSCC). Historic survival of pts with metastatic HNSCC is 6-9 months with palliative therapy. However, the prognosis and survival of pts with HPV+OPSCC with distant metastases is not known. Methods: Pts with HPV+OPSCC with distant metastatic disease were identified from databases from the departments of surgery, radiation, and medical oncology. Demographic and clinical data was abstracted from the medical record. All pts had confirmed HPV/p16+ disease. Results: Fifteen pts with metastatic HPV+ OPSCC were identified. The median age was 57 years (range 42-78, 15 male). The median pack-year smoking was 0 (range 0-120). Primary site included 10 tonsil and 5 tongue base. At diagnosis, one pt had stage III and 14 had stage IV disease (IVA: 9, IVB: 2, IVC: 3). T- and N-stage included T1 (1), T2 (10), T3 (3), T4 (1) and N1 (1), N2a (1), N2b (9), N2c (3), N3 (1). Extracapsular extension was seen in 8 pts, absent in 2, and unknown in 5. Seven pts had lymph node (LN) involvement at level IV/V. Initial therapy for locally-advanced disease included surgery followed by adjuvant radiation (RT) in 1 pt and chemoRT in 8, and definitive chemoRT in 3 pts. Three pts were metastatic at initial diagnosis. Of 6 pts with an isolated metastatic site, 3 pts are alive > 2 years from diagnosis of metastasis (median 1.97 years, range 0.49-2.29). Palliative therapy included surgery (3), RT (9), platinum chemo +/- cetuximab (8), cetuximab alone (2) or with a taxane (2). The most common sites of metastasis included bone (6), lung (5), and LNs (5). The 1-year survival rate after diagnosis of metastatic disease was 92%. The median time to diagnosis of metastatic disease after definitive therapy was 0.47 years (95% CI 0.19-1.29); 75% of pts who developed metastatic disease did so within 1 year of definitive therapy. Of note, 2 of the 15 pts developed a secondary immune-mediated malignancy (melanoma and non-HIV associated Kaposi’s sarcoma). Conclusions: The survival of pts with metastatic HPV+OPSCC is significantly better than that of historic controls.

19503 Background: This study was performed to assess the value of combined modality therapy in elderly patients by comparing the differences in outcome of those who received radiotherapy (RT) alone or RT plus chemotherapy for stage III NSCLC. Methods: North Central Cancer Treatment Group (NCCTG) performed 2 recent phase III trials for stage III NSCLC. The first trial, 90–24–51, included 3 arms: once-daily radiotherapy (QDRT) alone, twice daily RT (BIDRT) alone, and concurrent chemotherapy plus BIDRT. The second trial, 94–24- 52 included 2 arms and compared concurrent chemotherapy with either QDRT or BIDRT. The chemotherapy arms of both trials included etoposide and cisplatin administered concurrently with RT. Only the patients ≥65 years of age (elderly) who participated in these trials were included in this analysis. Results: Of the 166 elderly patients included in this analysis, 37 received RT alone and 129 received concurrent chemotherapy plus RT. The median and 5-year survival rates were 10.5 months and 5.4% for the RT alone group compared to 13.7 months and 14.7% for the RT plus chemotherapy group (log-rank p=0.05). Patients who received RT plus chemotherapy experienced significantly greater severe (grade ≥3) toxicity than those who received RT alone (89.9% versus 32.4%, p < 0.01). Conclusions: Elderly patients who participated in these trials appear to gain a survival advantage from RT and chemotherapy compared to RT alone. As is the case with younger patients, this benefit comes at the cost of additional toxicity. No significant financial relationships to disclose.

Abstract BACKGROUND Surgical resection is typically cited as the optimal treatment of patients with Spetzler-Martin Grade I-II arteriovenous malformation (AVM). OBJECTIVE To report our experience with single-fraction stereotactic radiosurgery (SRS) for Spetzler-Martin Grade I-II AVM. METHODS A prospectively maintained registry was reviewed for patients with nonsyndromic Spetzler-Martin Grade I-II AVM having SRS from 1990 to 2011. Patients with <24 mo of follow-up or prior radiotherapy/SRS were excluded, resulting in a study population of 173 patients. Actuarial analysis was performed using the Kaplan-Meier method, and Cox proportional hazards modeling was performed with excellent outcomes (obliteration without new deficits) as the dependent variable. RESULTS Median post-SRS follow-up was 68 mo (range, 24-275). AVM obliteration was achieved in 132 (76%) after initial SRS. Eleven additional patients achieved obliteration after repeat SRS for an overall obliteration rate of 83%. The rate of obliteration was 60% at 4 yr and 78% at 8 yr. Post-SRS hemorrhage occurred in 7 patients (4%), resulting in 3 minor deficits (2%) and 1 death (<1%). Radiation-induced complications occurred in 5 patients (3%), resulting in minor deficits only. One hundred and thirty-seven patients (79%) had excellent outcomes at last follow-up. CONCLUSION SRS is a safe and effective treatment for patients with Spetzler-Martin Grade I-II AVM. Selection bias is likely a contributing factor to explain the superior outcomes generally noted in reported series of microsurgery for patients with low grade AVM.

PURPOSE The purpose of this study was to determine if dose de-escalation from 60 to 66 Gy to 30 to 36 Gy of adjuvant radiotherapy (RT) for selected patients with human papillomavirus–associated oropharyngeal squamous cell carcinoma could maintain historical rates for disease control while reducing toxicity and preserving swallow function and quality of life (QOL). PATIENTS AND METHODS MC1273 was a single-arm phase II trial testing an aggressive course of RT de-escalation after surgery. Eligibility criteria included patients with p16-positive oropharyngeal squamous cell carcinoma, smoking history of 10 pack-years or less, and negative margins. Cohort A (intermediate risk) received 30 Gy delivered in 1.5-Gy fractions twice per day over 2 weeks along with 15 mg/m 2 docetaxel once per week. Cohort B included patients with extranodal extension who received the same treatment plus a simultaneous integrated boost to nodal levels with extranodal extension to 36 Gy in 1.8-Gy fractions twice per day. The primary end point was locoregional tumor control at 2 years. Secondary end points included 2-year progression-free survival, overall survival, toxicity, swallow function, and patient-reported QOL. RESULTS Accrual was from September 2013 to June 2016 (N = 80; cohort A, n = 37; cohort B, n = 43). Median follow-up was 36 months, with a minimum follow-up of 25 months. The 2-year locoregional tumor control rate was 96.2%, with progression-free survival of 91.1% and overall survival of 98.7%. Rates of grade 3 or worse toxicity at pre-RT and 1 and 2 years post-RT were 2.5%, 0%, and 0%. Swallowing function improved slightly between pre-RT and 12 months post-RT, with one patient requiring temporary feeding tube placement. CONCLUSION Aggressive RT de-escalation resulted in locoregional tumor control rates comparable to historical controls, low toxicity, and little decrement in swallowing function or QOL.

6071 Background: Phase III data suggests a benefit of HDC in the adjuvant setting, but the effect of HDC and WC on long term survival and for HPV+ HNSCC is unknown. Methods: Data from a published retrospective study (Geiger Oral Onc 2013) of HDC vs WC in resected HNSCC was updated. Overall survival (OS) and recurrence-free survival (RFS) was assessed by Kaplan-Meier method for all pts and by HPV status. Multivariate analyses were performed to assess impact of HPV status, smoking, age, HDC vs WC, and cumulative cisplatin dose ( < 200mg/m2 vs ≥200 mg/m2). Results: 51 patients (pts) received HDC and 53 WC. Median follow-up was 8.7 yrs (0.8-13.7). For the whole cohort, HDC had significantly improved OS over WC (p = 0.0095; 5- and 10-yr OS 84% and 80% vs 72% and 60%). No OS benefit for HDC was seen in pts with HPV+HNSCC (5- and 10-yr OS 90% and 87% for HDC and 81% and 81% for WC; p = 0.51). For HPV-negative HNSCC, OS had borderline significance with HDC vs WC (5- and 10-yr OS 73% and 68% vs 65% and 44%; p = 0.06). For the whole cohort, there was no difference in 5- and 10-yr RFS (78% and 74% for HDC vs 72% and 62% for WC; p = 0.32). When analyzed by HPV status, there was no difference in RFS with HDC or WC for either HPV+ (p = 0.43) or HPV-negative HNSCC (p = 0.97). On multivariate analyses of OS for all pts, only HPV status was significant (p = 0.0011; HR 0.27, CI 0.12-0.62). For HPV+ HNSCC, there was no significant predictor of OS. For non-HPV HNSCC, the benefit of HDC approached significance with a decreased risk of death (HR 0.38; p = 0.07). For all pts, those who received ≥200mg/m2 had significantly improved OS (5-yr 90% vs 72% and 10-yr 86% vs 61%; p = 0.004). By HPV status, cumulative dose had no significant effect on OS. Conclusions: OS is better with HDC and with cumulative dose > 200 mg/m2 in unselected patients. The benefit of cisplatin is likely higher for non-HPV HNSCC. A difference in OS with no difference in RFS suggests non cancer-related causes of death in the WC cohort. Ability to receive HDC could be a surrogate marker of comorbidity. [Table: see text]

Abstract BACKGROUND Patients with persistent or recurrent Cushing disease (CD) after prior transsphenoidal surgery require further treatment to reduce the disease's metabolic consequences. OBJECTIVE To assess patient outcomes after stereotactic radiosurgery (SRS) for persistent or recurrent CD from adrenocorticotropin hormone (ACTH)-secreting pituitary adenomas and propose a management algorithm. METHODS Retrospective review of 38 patients without prior radiation treatment having SRS for ACTH-secreting pituitary adenomas from 1990 to 2015. Favorable outcome was defined as biochemical remission and tumor growth control. Patients were evaluated separately if they underwent bilateral adrenalectomy (Adx). RESULTS Twenty patients (53%) were treated with Adx and SRS (median margin dose, 25 Gy) and 18 patients (47%) received SRS alone (median margin dose, 22.5 Gy). Median follow-up after SRS was 76 mo. Of patients undergoing Adx, 18/20 (90%) had a favorable outcome. Two patients (10%) had tumor growth requiring additional treatment. A favorable outcome was achieved in 13/18 patients (72%) having SRS alone (median, 14 mo; interquartile range, 8-23). Five patients (28%) required additional treatment due to persistent hypercortisolemia (n = 4) or hypercortisolemia and tumor growth (n = 1). Favorable outcomes were more frequent in the Adx and SRS group at 1 yr (100% vs 33%; P < .001) and 3 yr (100% vs 62%; P < .01), but no different at 5 yr (88% vs 77%; P = .63). CONCLUSION SRS was effective for patients with persistent or recurrent CD. Patients with mild to moderate CD can be safely managed with SRS alone; patients with severe CD should be considered for Adx with either concurrent SRS or SRS performed at a later date if tumor growth occurs.