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D. Gelblum
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P2.02 - Poster Session with Presenters Present (ID 462)
- Event: WCLC 2016
- Type: Poster Presenters Present
- Track: Locally Advanced NSCLC
- Presentations: 1
- Moderators:
- Coordinates: 12/06/2016, 14:30 - 15:45, Hall B (Poster Area)
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P2.02-060 - SBRT and Sequential Chemotherapy for Stage IIA to IIIA Non-Small Cell Lung Cancer - A Phase I Dose Escalation Study (ID 5991)
14:30 - 14:30 | Author(s): D. Gelblum
- Abstract
Background:
Stereotactic Body Radiation Therapy (SBRT) has become the standard of care for inoperable early-stage non-small cell lung cancer (NSCLC) due to excellent local control and survival outcomes. Its role in larger tumors is undefined, and patients with inoperable locally advanced NSCLC patients are treated with conventionally fractionated radiation therapy and chemotherapy. Our phase I dose escalation trial evaluates the maximum tolerated dose (MTD) of SBRT in patients with stage IIA to IIIA NSCLC involving a larger primary tumor and/or hilar involvement.
Methods:
Patients with inoperable stage IIA to IIIA (T2b-T4N0M0 and TanyN1M0) NSCLC fit for SBRT and sequential chemotherapy were eligible. SBRT dose escalation levels in a classic 3+3 design were 40Gy, 50Gy, and 60Gy in 5 fractions, delivered every other day. Platinum-based doublet chemotherapy was initiated 6 to 8 weeks after SBRT. The primary endpoint was the MTD based on SBRT-related acute (<3 months) ≥ grade 4 or persistent ≥ grade 3 toxicities (per Common Terminology Criteria for Adverse Events [CTCAE] v4.03). Patient reported outcomes were assessed using the NCI PRO-CTCAE questionnaire.
Results:
Nine patients were enrolled, three at the 40 Gy and six at the 50 Gy dose level. All patients received SBRT to the prescribed dose. Two patients receiving 50 Gy were no longer eligible for chemotherapy after SBRT. Median follow-up time was 6.3 months (range: 2.5 - 28.9). At the 40 Gy dose level, there was one patient with late (≥3 months post-SBRT) grade 3 pneumonia and one with late grade 3 bronchial obstruction. The dose was escalated to 50 Gy. At the 50 Gy dose level, two patients experienced persistent grade 3 radiation pneumonitis. One patient also had acute grade 4 respiratory insufficiency and contralateral pneumothorax. In the expanded 50 Gy cohort, one patient experienced persistent grade 3 nausea, vomiting, and abdominal pain, and another developed grade 3 chest wall pain. Therefore 50 Gy was determined to be the MTD. On PRO-CTCAE questionnaires patients most frequently reported fatigue (75%), dyspnea (50%), cough (38%), and pain (38%) as interfering “quite a bit” or “very much” with their daily activities.
Conclusion:
We determined that 50 Gy in five fractions followed by sequential chemotherapy is the MTD for SBRT in patients with stage IIA to IIIA NSCLC. Long-term outcomes and larger trials will be needed to assess whether SBRT results in superior local control and survival compared to conventional chemoradiation. Made possible by the generous support of the DallePezze Foundation
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P2.05 - Poster Session with Presenters Present (ID 463)
- Event: WCLC 2016
- Type: Poster Presenters Present
- Track: Radiotherapy
- Presentations: 1
- Moderators:
- Coordinates: 12/06/2016, 14:30 - 15:45, Hall B (Poster Area)
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P2.05-003 - PIK3CA Mutation is Associated with Increased Local Failure in Lung Stereotactic Body Radiation Therapy (SBRT) (ID 5251)
14:30 - 14:30 | Author(s): D. Gelblum
- Abstract
Background:
Hyperactivation of the phosphatidylinositol-3-kinase (PI3K) pathway has been associated with radioresistance. It is unclear whether such mutations also confer suboptimal local control for patients who receive lung stereotactic body radiation therapy (SBRT). Our objective was to examine whether mutations in the EGFR/AKT/PIK3CA signaling pathway are associated with local failure (LF) after lung SBRT.
Methods:
We retrospectively reviewed 134 patients who underwent SBRT to primary or metastatic lung lesions from 2007-2015 for whom molecular testing data was available for EGFR, AKT, and PIK3CA genes. For tumors of lung origin (n=122), molecular testing data was included from the lung tumor. For metastatic tumors to the lung (n=12), molecular testing data from either a primary or metastatic tumor site was used. Association between clinical factors, including molecular mutation status, and LF was evaluated with Cox regression analysis. The Kaplan-Meier method was used to assess differences in LF rates based on PIK3CA mutation status.
Results:
The most common histology was adenocarcinoma (90%) among all tumors. Six patients (4%) had PIK3CA mutation, 31 patients (23%) had EGFR mutation, and one patient (0.7%) had AKT mutation. Median lesion size was 2.0 cm (range, 0.6–5.6 cm), median dose was 48 Gy (range 30–70 Gy), and median number of fractions was 4 (range, 3–10). Median follow-up was 20 months (range, 0.2–70 months). LF was observed for 16 patients (12%). Median time to local failure was 15 months (range, 7–31 months). On univariate analysis, PIK3CA mutation presence was associated with LF (HR 5.3 [95% CI 1.1-25.0], p=0.03), while tumor histology (adenocarcinoma vs. other), tumor size (≤2cm vs. >2cm), primary tumor site (lung vs. other), and EGFR or AKT mutation presence were not. By multivariate analysis, PIK3CA mutation trended toward association with LF (HR 5.0 [95% CI 1.0-25.3], p=0.051). At one year, probability of LF in lesions with PIK3CA mutations was 12.4% vs. 5.7% in lesions without mutations (p=0.02). Lesions with PIK3CA mutations were associated with a decreased time to LF (mean 17.9 months [95% CI 12.7–23.2 months]) compared to those without PIK3CA mutation (mean 58.6 months [95% CI 52.6–64.7 months]).
Conclusion:
We explored EGFR/AKT/PI3KCA pathway mutations and found that patients with PIK3CA mutations are at higher risk for LF after lung SBRT. Due to the limitation of small numbers, this data needs to be validated in a larger patient cohort. Nonetheless, this is a novel finding and hypothesis-generating for future studies.
