We investigated the dosimetric impact of the interplay effect during RapidArc stereotactic body radiation therapy for lung tumors using flattening filter-free (FFF) beams with different dose rates.Seven tumors with motion ≤20 mm, treated with 10-MV FFF RapidArc, were analyzed. A programmable phantom with sinusoidal longitudinal motion (30-mm diameter "tumor" insert; period = 5 s; individualized amplitude from planning 4-dimensional computed tomography) was used for dynamic dose measurements. Measurements were made with GafChromic EBT III films. Plans delivered the prescribed dose to 95% of the planning target volume, created by a 5-mm expansion of the internal target volume. They comprised 2 arcs and maximum dose rates of 400 and 2400 MU/min. For 2400 MU/min plans, measurements were repeated at 3 different initial breathing phases to model interplay over 2 to 3 fractions. For 3 cases, 2 extra plans were created using 1 full rotational arc (with contralateral lung avoidance sector) and 1 partial arc of 224° to 244°. Dynamic and convolved static measurements were compared by use of gamma analysis of 3% dose difference and 1 mm distance-to-agreement.For 2-arc 2400 MU/min plans, maximum dose deviation of 9.4% was found in a single arc; 7.4% for 2 arcs (single fraction) and <5% and 3% when measurements made at 2 and 3 different initial breathing phases were combined, simulating 2 or 3 fractions. For all 7 cases, >99% of the area within the region of interest passed the gamma criteria when all 3 measurements with different initial phases were combined. Single-fraction single-arc plans showed higher dose deviations, which diminished when dose distributions were summed over 2 fractions. All 400 MU/min plans showed good agreement in a single fraction measurement.Under phantom conditions, single-arc and single-fraction 2400 MU/min FFF RapidArc lung stereotactic body radiation therapy is susceptible to interplay. Two arcs and ≥2 fractions reduced the effect to a level that appeared unlikely to be clinically significant.

To describe the anatomic distribution of regionally recurrent disease in patients with stage III melanoma in the axilla after curative-intent surgery with and without adjuvant radiation therapy.A single-institution, retrospective analysis of a prospective database of 277 patients undergoing curative-intent treatment for stage III melanoma in the axilla between 1992 and 2012 was completed. For patients who received radiation therapy and those who did not, patterns of regional recurrence were analyzed, and univariate analyses were performed to assess for potential factors associated with location of recurrence.There were 121 patients who received adjuvant radiation therapy because their clinicopathologic features conferred a greater risk of regional recurrence. There were 156 patients who received no radiation therapy. The overall axillary control rate was 87%. There were 37 patients with regional recurrence; 17 patients had received adjuvant radiation therapy (14%), and 20 patients (13%) had not. The likelihood of in-field nodal recurrence was significantly less in the adjuvant radiation therapy group (P=.01) and significantly greater in sites adjacent to the axilla (P=.02). Patients with high-risk clinicopathologic features who did not receive adjuvant radiation therapy also tended to experience in-field failure rather than adjacent-field failure.Patients who received adjuvant radiation therapy were more likely to experience recurrence in the adjacent-field regions rather than in the in-field regions. This may not simply reflect higher-risk pathology. Using this data, it may be possible to improve outcomes by reducing the number of adjacent-field recurrences after adjuvant radiation therapy.

To evaluate, in the setting of breast cancer, the accuracy of registry radiation therapy (RT) coding compared with the gold standard of Medicare claims.Using Surveillance, Epidemiology, and End Results (SEER)-Medicare data, we identified 73,077 patients aged ≥66 years diagnosed with breast cancer in the period 2001-2007. Underascertainment (1 - sensitivity), sensitivity, specificity, κ, and χ(2) were calculated for RT receipt determined by registry data versus claims. Multivariate logistic regression characterized patient, treatment, and geographic factors associated with underascertainment of RT. Findings in the SEER-Medicare registries were compared with three non-SEER registries (Florida, New York, and Texas).In the SEER-Medicare registries, 41.6% (n=30,386) of patients received RT according to registry coding, versus 49.3% (n=36,047) according to Medicare claims (P<.001). Underascertainment of RT was more likely if patients resided in a newer SEER registry (odds ratio [OR] 1.70, 95% confidence interval [CI] 1.60-1.80; P<.001), rural county (OR 1.34, 95% CI 1.21-1.48; P<.001), or if RT was delayed (OR 1.006/day, 95% CI 1.006-1.007; P<.001). Underascertainment of RT receipt in SEER registries was 18.7% (95% CI 18.6-18.8%), compared with 44.3% (95% CI 44.0-44.5%) in non-SEER registries.Population-based tumor registries are highly variable in ascertainment of RT receipt and should be augmented with other data sources when evaluating quality of breast cancer care. Future work should identify opportunities for the radiation oncology community to partner with registries to improve accuracy of treatment data.

Long-term survival rates for patients with resected pancreatic ductal adenocarcinoma (PDAC) have stagnated at 20% for more than a decade, demonstrating the need to develop novel adjuvant therapies. Gemcitabine-erlotinib therapy has demonstrated a survival benefit for patients with metastatic PDAC. Here we report the first phase 2 study of erlotinib in combination with adjuvant chemoradiation and chemotherapy for resected PDAC.Forty-eight patients with resected PDAC received adjuvant erlotinib (100 mg daily) and capecitabine (800 mg/m(2) twice daily Monday-Friday) concurrently with intensity modulated radiation therapy (IMRT), 50.4 Gy over 28 fractions followed by 4 cycles of gemcitabine (1000 mg/m(2) on days 1, 8, and 15 every 28 days) and erlotinib (100 mg daily). The primary endpoint was recurrence-free survival (RFS).The median follow-up time was 18.2 months (interquartile range, 13.8-27.1). Lymph nodes were positive in 85% of patients, and margins were positive in 17%. The median RFS was 15.6 months (95% confidence interval [CI], 13.4-17.9), and the median overall survival (OS) was 24.4 months (95% CI, 18.9-29.7). Multivariate analysis with adjustment for known prognostic factors showed that tumor diameter >3 cm was predictive for inferior RFS (hazard ratio, 4.01; P=.001) and OS (HR, 4.98; P=.02), and the development of dermatitis was associated with improved RFS (HR, 0.27; P=.009). During CRT and post-CRT chemotherapy, the rates of grade 3/4 toxicity were 31%/2% and 35%/8%, respectively.Erlotinib can be safely administered with adjuvant IMRT-based CRT and chemotherapy. The efficacy of this regimen appears comparable to that of existing adjuvant regimens. Radiation Therapy Oncology Group 0848 will ultimately determine whether erlotinib produces a survival benefit in patients with resected pancreatic cancer.

To retrospectively compare the efficacy of radiation therapy (RT) and chemotherapy plus RT (CRT) for the postoperative treatment of node-positive thoracic esophageal squamous cell carcinoma (TESCC) and to determine the incidence and severity of toxic reactions.We retrospectively reviewed data from 304 patients who had undergone esophagectomy with 3-field lymph node dissection for TESCC and were determined by postoperative pathology to have lymph node metastasis without distant hematogenous metastasis. Of these patients, 164 underwent postoperative chemotherapy (cisplatin 80 mg/m(2), average days 1-3, plus paclitaxel 135 mg/m(2), day 1; 21-day cycle) plus RT (50 Gy), and 140 underwent postoperative RT alone.The 5-year overall survival rates for the CRT and RT groups were 47.4% and 38.6%, respectively (P=.030). The distant metastasis rate, the mixed (regional lymph node and distant) metastasis rate, and the overall recurrence rate were significantly lower in the CRT group than in the RT group (P<.05). However, mild and severe early toxic reactions, including neutropenia, radiation esophagitis, and gastrointestinal reaction, were significantly more common in the CRT group than in the RT group (P<.05). No significant differences in incidence of late toxic reactions were found between the 2 groups.Our results show that in node-positive TESCC patients, postoperative CRT is significantly more effective than RT alone at increasing the overall survival and decreasing the rates of distant metastasis, mixed metastasis, and overall recurrence. Severe early toxic reactions were more common with CRT than with RT alone, but patients could tolerate CRT.