Isolated Nodal Failure after Stereotactic Body Radiotherapy for Lung Cancer: The Role for Salvage Mediastinal Radiotherapy.

INTRODUCTION: Isolated nodal failure (INF) without synchronous local or distant failure is an uncommon occurrence after stereotactic body radiation therapy (SBRT) for lung cancer. Here we review the natural history and patterns of failure after post-SBRT INF with or without salvage mediastinal radiotherapy (SvRT). METHODS: Patients treated with SBRT for non-small cell lung cancer with definitive intent were identified. Patients who experienced hilar or mediastinal INF without synchronous distant, lobar, or local failure were included and grouped according to the use of SvRT. The rates of subsequent locoregional control, distant metastases, progression-free survival (PFS), and overall survival were assessed. RESULTS: Of 797 patients treated with definitive SBRT, 24 (3%) experienced INF and 15 (63%) received SvRT. The most common SvRT regimen (53%) was 45 Gy in 15 fractions. The median follow-up after INF was 11.3 months for survivors. There were no grade 3 or higher toxicities after SvRT. The 1-year Kaplan-Meier PFS and overall survival estimates were 33% and 56% for patients not receiving radiotherapy and 75% and 73% with SvRT. After SvRT, the rate of locoregional control at 1 year was 84.4%. Crude rates of distant failure were 20.0% with SvRT and 22.2% with no radiotherapy. Of the 13 deaths observed, five (38%) were related to distant progression of lung cancer, four (31%) to comorbidities, three (23%) to mediastinal progression, and one (8%) to an unknown cause. CONCLUSIONS: INF is uncommon after SBRT. Despite the significant comorbidities of this population, intrathoracic progression remains a contributor to morbidity and mortality. SVRT for INF is well tolerated and may improve PFS.

Outcomes for prostate glands >60 cc treated with low-dose-rate brachytherapy.

PURPOSE: We sought to analyze whether outcomes of biochemical relapse-free survival (bRFS), late genitourinary (GU), and late gastrointestinal toxicity are different for prostate cancer patients with small (≤60 cc) vs. large (>60 cc) prostates following low dose-rate brachytherapy. METHODS AND MATERIALS: The bRFS outcomes for 2076 low- or intermediate-risk prostate cancer patients from 1996 to 2012 were determined from a review of a prospectively maintained database. All patients were treated with (125)I monotherapy without androgen deprivation therapy. Biochemical failure was defined per the Phoenix definition. Patient-related factors and dosimetric values were examined in Cox regression analyses for bRFS and late toxicity. Late toxicity was scored according to a modified Common Terminology Criteria for Adverse Events version 4.0 scale. RESULTS: The median followup for all patients was 55 months. The 5-year bRFS rates for all patients, prostates >60 cc, and prostates ≤60 cc were 93.4% (95% confidence interval [CI]: 92.1%, 94.7%), 96.7% (95% CI: 94.4%, 98.9%), and 92.9% (95% CI: 91.4%, 94.3%), respectively. On multivariable analysis, prostate size >60 cc was significantly associated with improved bRFS (p = 0.01), as were initial prostate-specific antigen and biopsy Gleason score (p < 0.0001 and p = 0.0002, respectively). Patients with prostates >60 cc had significantly higher rates of Grade 3-4 late GU toxicity at 5 years than patients with smaller prostates; 7.2% (95% CI: 4.0%, 10.4%) and 3.2% (95% CI: 2.3%, 4.1%), respectively (p = 0.0007). The overall late gastrointestinal toxicity rate for all patients was 0.7% at 5 years with no significant difference between the two groups. CONCLUSIONS: Implantation of large prostates >60 cc results in favorable bRFS outcomes and is associated with increased but acceptable rates of Grade 3 and higher late GU toxicities.

Clinical and dosimetric implications of intensity-modulated radiotherapy for early-stage glottic carcinoma.

Conventional parallel-opposed radiotherapy (PORT) is the established standard technique for early-stage glottic carcinoma. However, case reports have reported the utility of intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) with or without image guidance (image-guided radiotherapy, IGRT) in select patients. The proposed advantages of IMRT/VMAT include sparing of the carotid artery, thyroid gland, and the remaining functional larynx, although these benefits remain unclear. The following case study presents a patient with multiple vascular comorbidities treated with VMAT for early-stage glottic carcinoma. A detailed explanation of the corresponding treatment details, dose-volume histogram (DVH) analysis, and a review of the relevant literature are provided. Conventional PORT remains the standard of care for early-stage glottic carcinoma. IMRT or VMAT may be beneficial for select patients, although great care is necessary to avoid a geographical miss. Clinical data supporting the benefit of CRT are lacking. Therefore, these techniques should be used with caution and only in selected patients.