Next-generation sequencing and clinical outcomes of patients with lung adenocarcinoma treated with stereotactic body radiotherapy.

BACKGROUND: Genetic aberrations are well characterized in lung adenocarcinomas (LACs) and clinical outcomes have been influenced by targeted therapies in the advanced setting. Stereotactic body radiotherapy (SBRT) is the standard-of-care therapy for patients with nonoperable, early-stage LAC, but to the authors' knowledge, no information is available regarding the impact of genomic changes in these patients. The current study sought to determine the frequency and clinical impact of genetic aberrations in this population. METHODS: Under an Institutional Review Board-approved protocol, the records of 242 consecutive patients with early-stage lung cancers were reviewed; inclusion criteria included LAC histology with an adequate tumor sample for the successful use of next-generation sequencing and fluorescence in situ hybridization testing. Univariate analysis was performed to identify factors associated with clinical outcomes. RESULTS: LAC samples from 98 of the 242 patients were reviewed (40.5%), of whom 45 patients (46.0%) had genetic testing. The following mutations were noted: KRAS in 20.0% of samples, BRAF in 2.2% of samples, SMAD family member 4 (SMAD4) in 4.4% of samples, epidermal growth factor receptor (EGFR) in 15.6% of samples, STK1 in 2.2% of samples, tumor protein 53 (TP53) in 15.6% of samples, and phosphatase and tensin homolog (PTEN) in 2.2% of samples. The following gene rearrangements were observed: anaplastic lymphoma kinase (ALK) in 8.9% of samples, RET in 2.2% of samples, and MET amplification in 17.8% of samples. The median total delivered SBRT dose was 50 grays (range, 48-60 grays) over a median of 5 fractions (range, 3-8 fractions). The KRAS mutation was associated with worse local control (odds ratio [OR], 3.64; P<.05). MET amplification was associated with worse regional (OR, 4.64; P<.05) and distant (OR, 3.73; P<.05) disease control. CONCLUSIONS: To the authors' knowledge, the current series is the first to quantify genetic mutations and their association with clinical outcomes in patients with early-stage LAC treated with SBRT. KRAS mutations were associated with worse local control and MET amplification was associated with worse regional and distant disease control, findings that need to be validated in a prospective setting. Cancer 2017;123:3681-3690. © 2017 American Cancer Society.

The omission of intentional primary site radiation following transoral robotic surgery in 59 patients: No local-regional failures.

BACKGROUND: We assessed locoregional control with omission of intentional primary site radiation after transoral robotic surgery (TORS) and quantified nontargeted primary site dose. METHODS: Following Institutional Review Board (IRB) approval, patients treated with primary TORS resection for squamous cell carcinomas of the oropharynx were reviewed. Patients with cT1-2 tumors, >2 mm margins, in whom the surgeon resected the primary without revising specimen-driven margins, qualified for omission of primary site radiation. RESULTS: From 2014 to 2019, 112 patients met criteria. Fifty-nine (52%) patients did not receive radiation targeting the primary site; of whom, 22 received no radiation. In this group, there were no local failures; mean age was 58 years and median follow-up was 25 months. Thirty-seven patients received adjuvant radiation targeting the neck, mean bystander dose to the primary site was 28.8 Gy (range, 13.3-50.6 Gy). CONCLUSION: In a 59 patient population, omission of radiation to the primary site after TORS resulted in no locoregional failures.

The Influence of Histologic Grade on Outcomes of Elderly Women With Early Stage Breast Cancer Treated With Breast Conserving Surgery With or Without Radiotherapy.

BACKGROUND: Two large randomized trials, CALGB 9343 and PRIME II, support omission of radiotherapy after breast conserving surgery (BCS) in elderly women with favorable-risk early stage breast cancer intending to take endocrine therapy. However, patients with grade 3 histology were underrepresented on these trials. We hypothesized that high-grade disease may be unsuitable for treatment de-escalation and report the oncologic outcomes for elderly women with favorable early stage breast cancer treated with BCS with or without radiotherapy. MATERIALS AND METHODS: The Surveillance, Epidemiology, and End Results database was queried for women between 70 and 79 years of age with invasive ductal carcinoma diagnosed between 1998 and 2007. This cohort was narrowed to women with T1mic-T1c, N0, estrogen receptor-positive, invasive ductal carcinoma treated with BCS with or without external beam radiation (EBRT). The primary endpoints were 5- and 10-year cause-specific survival (CSS). Univariate and multivariate analyses were performed. Propensity-score matching of T-stage, year of diagnosis, and age was utilized to reduce selection bias while comparing treatment arms within the grade 3 subgroup. RESULTS: A total of 12,036 women met inclusion criteria, and the median follow-up was 9.4 years. EBRT was omitted in 22% of patients, including 21% with grade 3 disease. Patients in the EBRT cohort were slightly younger (median, 74 vs. 75 years; P < .01) and had fewer T1a tumors (11% vs. 13%; P = .02). Histologic grades 1, 2, and 3 comprised 36%, 50%, and 14% of the cohort, respectively, and there were no differences in EBRT utilization by grade. Utilization of EBRT decreased following the publication of the CALGB trial in 2004 decreasing from 82% to 85% in 1998 to 2000 to 73% to 75% in 2005 to 2007 (P < .01). Unadjusted outcomes showed that in grade 1 disease, there were no differences in CSS with or without EBRT at 5 (99%) and 10 years (95%-96%). EBRT was associated with an improvement in CSS in grade 2 histology at 5 years (97% vs. 98%) and 10 years (92% vs. 95%) (P = .004). The benefit was more pronounced in grade 3 disease with CSS increasing from 93% to 96% at 5 years and from 87% to 92% at 10 years (P = .02) with EBRT. In the grade 3 subgroup, propensity-score matching confirmed EBRT was associated with superior CSS compared with surgery alone (hazard ratio, 0.58; 95% confidence interval, 0.34-0.98; P = .043). CONCLUSION: In this database analysis, omission of radiotherapy after BCS in elderly women with favorable-risk, early stage, grade 3 breast cancer was associated with inferior CSS. Further prospective data in this patient population are needed to confirm our findings and conclusions.

Predictors of pneumonitis-free survival following lung stereotactic body radiation therapy.

BACKGROUND: Radiation pneumonitis is a common toxicity following lung stereotactic body radiation therapy (SBRT). We explored whether motion management technique, in conjunction with patient and treatment characteristics, is a predictor of radiation pneumonitis-free survival (PNFS). METHODS: A single institution multi-center lung SBRT database was retrospectively reviewed. PNFS was defined as time to earliest onset of radiation pneumonitis or last clinical follow-up. Patients were simulated using a 4-dimensional approach, and those with 1 cm or greater tumor motion were selected for respiratory-gated treatment. Real-time Position Management and phase-based gating were employed. Univariate and multivariable Cox proportional hazard models were fit for relevant covariates to determine the impact of free-breathing versus respiratory-gated treatment on PNFS. RESULTS: The initial treatment courses of 208 patients were included, with a median follow-up length of 23 months. The median age at treatment was 71 years. About 91.8% of patient had early stage (T1-2) non-small cell lung cancer and were treated with common regimens including 10 Gy ×5, 12 Gy ×4 and 18 Gy ×3; 26.4% underwent respiratory-gated SBRT. The overall rate of grade 3 or higher radiation pneumonitis was 10.1%. PNFS was not significantly different between patients treated with respiratory-gated versus free-breathing SBRT (HR =0.88; P=0.707); tumor location and fractionation were predictors of PNFS in the multivariate setting. CONCLUSIONS: The method of motion management does not appear to impact PNFS when the tolerance for tumor displacement is 1 cm or less for free-breathing treatment planning and delivery. This approach may be appropriate when selecting patients for respiratory gating.