CT 01 - Clinical Trials Session

1 - Eliminating Post-operative Radiation to the Pathologically Node Negative Neck: Long-Term Results of a Prospective Phase II Study

Sunday, October 21
3:15 PM - 3:25 PM
Location: Stars at Night Ballroom

Eliminating Post-operative Radiation to the Pathologically Node Negative Neck: Long-Term Results of a Prospective Phase II Study
J. Contreras1, C. R. Spencer2, L. E. Henke2, R. I. Chin3, T. A. DeWees2, R. C. Paniello4, J. Rich4, B. Haughey5, B. Nussenbaum6, D. Adkins7, H. A. Gay1, and W. L. Thorstad2; 1Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, 2Washington University School of Medicine, Department of Radiation Oncology, St. Louis, MO, 3Saint Louis University School of Medicine, St. Louis, MO, 4Washington University School of Medicine, Department of Otolaryngology, St. Louis, MO, 5Florida Hospital, Kissimmee, FL, 6American Board of Otolaryngology, Houston, TX, 7Washington University in St. Louis, Department of Medical Oncology, St. Louis, MO

Purpose/Objective(s): The volume treated with post-operative radiation therapy (PORT) is a mediator of toxicity and reduced volumes have resulted in improved in quality of life (QOL). In this prospective study we decreased treatment volumes by omitting PORT to the pathologically negative (PN0) contralateral (CL) and/or ipsilateral (IL) neck in patients with tumors of the oral cavity (OC), oropharynx (OPX), larynx (LX), hypopharynx (HPX), and unknown primary (UP). We hypothesized that elimination of PN0 neck PORT would result in > 90% control in the unirradiated neck (UN).

Materials/Methods: Patients with tumors of the OC, OPX, LX, HPX, and UP who underwent surgical resection and neck dissection (ND) with a PN0 neck and high risk features mandating PORT to the primary and/or involved neck were eligible. Our primary objective was to evaluate the rate of control in the UN. Secondary objectives included QOL, local control (LC), regional control (RC), progression free survival (PFS), and overall survival (OS). The CTV1 and CTV2 were treated to 66 Gy and 54 Gy in 33 fractions (fx) or 60 Gy and 52 Gy in 30 fx. Chemotherapy was delivered at the discretion of the treating oncologist. QOL was collected using the MD Anderson Dysphagia Inventory and the University of Michigan Patient reported Xerostomia questionnaire. The study required accrual of 69 patients to achieve 83% power with alpha = 0.10 to show equivalence of reduced volume PORT compared to bilateral neck PORT. LC, RC, PFS, and OS were analyzed via Kaplan-Meier method and mixed modeling was used with Tukey adjustment for multiple comparisons on QOL data.

Results: From 5/2007-9/2013, 73 patients enrolled and 72 were evaluable. Median age was 56 years (range 31-81), 58 (81%) were male, and 47 (65%) used tobacco. Sites included 14 (20%) OC, 37 (51%) OPX, 4 (6%) HPX, 16 (22%) LX, and 1 (1%) UP tumor, with AJCC 7th edition stage III/IV disease in 67 (93%) patients. 51% had T3/4 disease, 59% had N2/3, and 71% of tumors involved or crossed midline. We excluded T1/2 N0-2b lateralized tonsil patients because our policy was to use IL PORT without a required CL ND. 34 patients (47%) received chemotherapy and all completed PORT. Zero patients had CL neck PORT. All but 6 patients had a CL ND; 0/6 had isolated neck failure. At median follow up of 53 mo, there were 2 failures in the PN0 UN; both also had local failures. There were no isolated UN failures. UN control was 97% (95% CI 93.4-100.0%). 5 year actuarial rates of LC, RC, PFS, and OS were 84%, 93%, 60%, and 64% respectively. QOL scores for emotional (Em), physical (Ph), functional (Fxn), and xerostomia (Xe) declined from baseline to time of PORT completion (p<0.05). By 24 mo, these scores recovered with no difference from baseline (P>0.05), except Xe, for which QOL remained reduced post PORT (P<0.05). However, global QOL was improved from baseline 24 mo post PORT (P=0.04).

Conclusion: Eliminating PORT to the PN0 neck resulted in excellent rates of control in the UN without adverse effects on global QOL. This trial met the primary endpoint with 97% control in the UN.

Author Disclosure: J. Contreras: None. L.E. Henke: Research Grant; ViewRay, Inc, Varian. Speaker's Bureau; ViewRay, Inc. Travel Expenses; ViewRay, Inc. R. Chin: None. T.A. DeWees: None. R.C. Paniello: None. B. Haughey: None. D. Adkins: None. H.A. Gay: None.

Jessika Contreras, MD

Disclosure:
Employment
Barnes Jewish Hospital: Resident Physician: Employee

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