Organ sparing treatment for penile cancer using a 3D-printed high-dose-rate brachytherapy applicator.

PURPOSE: We present a case study of the treatment of localized squamous cell carcinoma on the glans penis with a custom-fabricated high-dose-rate (HDR) brachytherapy applicator. METHODS AND MATERIALS: A cylindrically shaped applicator was fabricated with eight embedded channels suitable for standard plastic brachytherapy catheters. An additional custom silicone bolus/sleeve was designed to be used with the 3D-printed applicator to provide an additional offset from the source to skin to reduce the surface dose and for patient comfort. RESULTS: The patient (recurrent cT1a penile cancer) underwent CT simulation, and the brachytherapy plan was created with a nominal prescription dose of 40 Gy in 10 fractions given bidaily to the surface, and 35 Gy at 5 mm depth. Dose coverage to the clinical target volume was 94% (D90). Most fractions were treated with only 5-10 min of setup time. Follow up visits up to 1 year showed no evidence of disease with no significant changes in urinary and sexual function and limited cosmetic detriment to the patient. CONCLUSIONS: Patient-specific organ-sparing HDR plesiotherapy using 3D printing technology can provide reliable and reproducible patient setup and may be effective in achieving disease control for superficial penile cancer, although preserving patient quality of life.

Trends and Factors Associated With Receipt of Upfront Surgery for Stage II to III Rectal Adenocarcinoma in the United States, 2006 to 2016.

INTRODUCTION: The German rectal study published in 2004 established neoadjuvant chemoradiation as a standard of care for locally advanced rectal cancer and current National Comprehensive Cancer Network guidelines endorse several preoperative regimens. Upfront surgery, however, is considered substandard care. In the era of evolving treatment paradigms for locally advanced rectal cancer, we sought to assess trends and predictors of receipt of upfront surgery for stage II to III rectal cancer. METHODS: The National Cancer Database was used to identify patients diagnosed with clinical stage II to III rectal adenocarcinoma between 2006 and 2016. Multivariable logistic regression defined adjusted odds ratios and associated 95% confidence intervals of receipt of upfront definitive surgery. The timing of upfront surgery relative to day of diagnosis and rate of receipt of adjuvant therapy were also estimated. RESULTS: Among 51,562 patients, 6411 (12.4%) were treated with upfront surgery, which decreased from 16.7% in 2006 to 7.1% in 2016 (P<0.001). The majority of patients (5737 [89.5%]) had definitive surgery after initial diagnostic biopsy. Variables associated with receipt of upfront surgery included female sex, older age, higher comorbidity score, and treatment at a community cancer center (P<0.001). Among those receiving upfront surgery, 2904 (45.3%) received adjuvant radiation therapy, 3218 (50.2%) received adjuvant chemotherapy, and 2559 (39.9%) received no further treatment. CONCLUSIONS: The proportion of patients with clinical stage II to III rectal cancer treated with upfront surgery has steadily declined since 2006, however, certain subgroups appear to remain at greater risk. Further research is needed to better elucidate patient and systems-level factors contributing to these disparities in care.

Dose to the bladder neck is the most important predictor for acute and late toxicity after low-dose-rate prostate brachytherapy: implications for establishing new dose constraints for treatment planning.

PURPOSE: To identify an anatomic structure predictive for acute (AUT) and late (LUT) urinary toxicity in patients with prostate cancer treated with low-dose-rate brachytherapy (LDR) with or without external beam radiation therapy (EBRT). METHODS AND MATERIALS: From July 2002 to January 2013, 927 patients with prostate cancer (median age, 66 years) underwent LDR brachytherapy with Iodine 125 (n=753) or Palladium 103 (n=174) as definitive treatment (n=478) and as a boost (n=449) followed by supplemental EBRT (median dose, 50.4 Gy). Structures contoured on the computed tomographic (CT) scan on day 0 after implantation included prostate, urethra, bladder, and the bladder neck, defined as 5 mm around the urethra between the catheter balloon and the prostatic urethra. AUT and LUT were assessed with the Common Terminology Criteria for Adverse Events, version4. Clinical and dosimetric factors associated with AUT and LUT were analyzed with Cox regression and receiver operating characteristic analysis to calculate area under the receiver operator curve (ROC) (AUC). RESULTS: Grade ≥2 AUT and grade ≥2 LUT occurred in 520 patients (56%) and 154 patients (20%), respectively. No grade 4 toxicities were observed. Bladder neck D2cc retained a significant association with AUT (hazard ratio [HR], 1.03; 95% confidence interval [CI], 1.03-1.04; P<.0001) and LUT (HR, 1.01; 95% CI, 1.00-1.03; P=.014) on multivariable analysis. In a comparison of bladder neck with the standard dosimetric variables by use of ROC analysis (prostate V100 >90%, D90 >100%, V150 >60%, urethra D20 >130%), bladder neck D2cc >50% was shown to have the strongest prognostic power for AUT (AUC, 0.697; P<.0001) and LUT (AUC, 0.620; P<.001). CONCLUSIONS: Bladder neck D2cc >50% was the strongest predictor for grade ≥2 AUT and LUT in patients treated with LDR brachytherapy. These data support inclusion of bladder neck constraints into brachytherapy planning to decrease urinary toxicity.

Postoperative pelvic intensity-modulated radiotherapy and concurrent chemotherapy in intermediate- and high-risk cervical cancer.

OBJECTIVE: According to national surveys, the use of intensity-modulated radiation therapy (IMRT) in gynecologic cancers is on the rise, yet there is still some reluctance to adopt adjuvant IMRT as standard practice. The purpose of this study is to report a single-institution experience using postoperative pelvic IMRT with concurrent chemotherapy in intermediate- and high-risk early stage cervical cancer. METHODS: From 1/2004 to 12/2009, 34 patients underwent radical hysterectomy and pelvic lymph node dissection (28 median nodes were removed) for early stage cervical cancer. Median dose of postoperative pelvic IMRT was 50.4 Gy (range, 45-50.4). All patients received concurrent cisplatin. RESULTS: With a median follow-up of 44 months, 3 patients have recurred; 1 vaginal recurrence, 1 regional and distant, and 1 distant. The 3- and 5-year disease-free survival (DFS) was 91.2% (95% CI, 81.4-100%) and overall survival (OS) was 91.1% (95% CI, 81.3-100%). All failures and all deaths were in the high-risk group (n=3/26). There was 32.3% G3-4 hematologic toxicity, 2.9% acute G3 gastrointestinal toxicity, and no acute G3 or higher genitourinary toxicity. There were no chronic G3 or higher toxicities. CONCLUSIONS: Oncologic outcomes with postoperative IMRT were very good, with DFS and OS rates of >90% at median follow-up of 44 months, despite a preponderance (76.5%) of high-risk features. Toxicity was minimal even in the setting of an aggressive trimodality approach. Data from this study and emerging data from the Phase II RTOG study (0418) demonstrate the advantages of postoperative IMRT in early stage cervical cancer.

Intraoperative 32P high-dose rate brachytherapy of the dura for recurrent primary and metastatic intracranial and spinal tumors.

BACKGROUND: Treatment of spinal and intracranial tumors with dural involvement is complicated by radiation tolerance of sensitive structures, especially in the setting of previous treatment. OBJECTIVE: To evaluate whether intraoperative brachytherapy with short-range sources allows therapeutic dose delivery without damaging sensitive structures. METHODS: The median doses of previous treatment were 3000 cGy (range, 1800-7200 cGy) for 8 patients with primary/recurrent and 17 patients with metastatic spinal tumors and 5040 cGy (range, 1300-6040 cGy) for 5 patients with locally recurrent and 2 patients with metastatic intracranial tumors. Patients underwent gross total or maximal resection of the tumor and were then treated with an intraoperative brachytherapy plaque consisting of a flexible silicone film incorporating P. A dose of 1000 cGy was delivered to a depth of 1 mm; the percent depth dose was less than 1% at 4 mm from the prescription depth. Median postoperative radiation doses of 2700 cGy (range, 1800-3000 cGy) were delivered to 15 spinal tumor patients and 3000 cGy (range, 1800-3000 cGy) to 3 intracranial tumor patients. The median follow-up was 4.4 months (range, 2.6-23.3 months) for spinal tumor patients and 5.3 months (range, 0.7-16.2) for intracranial tumor patients. RESULTS: At 6-month follow-up, for all spinal tumor patients, local progression-free survival and overall survival rates were both 83.3% (95% confidence interval [CI]: 62.3%-94.3%); for all intracranial tumor patients, the local progression-free survival rate was 62.5% (95% CI: 23.8%-90.9%) and the overall survival rate was 66.7% (95% CI: 26.7%-92.9%). There were no intraoperative or postoperative complications secondary to radiotherapy. CONCLUSION: Use of the P brachytherapy plaque is technically simple and not associated with increased risk of complications, even after multiple radiation courses. Local control rates were more than 80% in patients with proven radiation-resistant spinal disease.