Author of

• 20157

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  P1.08 - Locally Advanced NSCLC (ID 694)

  • Event: WCLC 2017
  • Type: Poster Session with Presenters Present
  • Track: Locally Advanced NSCLC
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/16/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)

  • 22715

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    P1.08-003 - Concomitant Chemotherapy and Radiotherapy with SBRT Boost for Unresectable, Stage III Non-Small Cell Lung Cancer: A Phase I Study (ID 8181)

    09:30 - 09:30  |  Author(s): Z. Chen
    • Abstract

    Background:
    Stereotactic Body Radiation Therapy (SBRT) is now the standard of care in medically inoperable stage I non-small cell lung cancer, yielding high rates of local control. It is unknown if SBRT can be safely utilized in the locally advanced NSCLC setting. This multi-institution phase I study evaluated the safety of 44 Gy conventionally fractionated thoracic radiation with concurrent chemotherapy plus a dose escalated SBRT boost to both the primary tumor and involved mediastinal lymph nodes. The primary endpoint of this study was to establish the maximum tolerated dose (MTD) of the SBRT boost.
    
    Method:
    Inclusion criteria included unresectable stage IIIA or IIIB disease, primary tumor ≤8 cm, and N1 or N2 lymph nodes ≤5 cm. Tumors were staged with PET/CT while four dimensional CT simulation was employed for radiation planning. The treatment schema was 44 Gy thoracic radiation (2 Gy/day) with weekly carboplatin and paclitaxel chemotherapy. A second CT simulation was obtained after 40 Gy was delivered, and a SBRT boost was planned to the remaining gross disease at the primary site and involved lymph nodes. Four SBRT boost dose cohorts were tested: Cohort 1 (9 Gy x 2); cohort 2 (10 Gy x 2); cohort 3 (6 Gy x 5); and cohort 4 (7 Gy x 5). Patients were treated in cohorts of three patients and using Bayesian Escalation with Overdose Control (EWOC) method to determine Maximum tolerated dose of the SBRT boost. Dose limiting toxicities (DLT) were defined as any grade 3 or higher toxicities within 30 days of treatment attributed to treatment, not including hematologic toxicity, or any grade 5 toxicity attributed to treatment.
    
    Result:
    The study enrolled 19 patients from 11/2012-12/2016. There were 4 screen failures and 15 patients were treated on study. There were no DLTs in dose cohort 1 (n = 3) and 2 (n = 6). One patient in dose cohort 3 (n = 3) developed a DLT, and 2 patients in dose cohort 4 (n = 3) developed a DLT. The calculated MTD was 6 Gy x 5. The DLT observed at this dose level was a tracheoesophageal fistula; given this substantial toxicity, there was investigator reluctance to enroll further patients in this dose level. Thus the calculated MTD is 6 Gy x5, however 10 Gy x 2 is felt to be a reasonable dose as well given no grade 5 toxicities occurred with this dose.
    
    Conclusion:
    The MTD of a SBRT boost combined with 44 Gy thoracic chemoradiation is 6 Gy x 5. A SBRT boost dose of 10 Gy x 2 could be considered very safe with no grade 3 or higher toxicities observed at this dose level.