Is a total dose of 54 Gy with radiochemotherapy sufficient for treatment of intermediate-risk volumes in nasopharyngeal cancer?

BACKGROUND: The mainstay treatment of nasopharyngeal cancer (NPC) is radiation therapy (RT). The doses and volumes may differ from center to center. Most studies and guidelines recommend a total dose of 60 Gy for elective nodal and peritumoral volume treatment. This retrospective analysis aimed to analyze whether a dose reduction to 54 Gy to this volume would be associated with a higher risk of recurrence. METHODS: A total of 111 patients treated by intensity-modulated radiotherapy (IMRT) and concurrent chemotherapy were retrospectively analyzed. The recurrent tumor volume was classified as "in field" if 95% of the recurrent volume was inside the 95% isodose, as "marginal" if 20-95% of the recurrence was inside the 95% isodose, or as "outside" if less than 20% of the recurrence was inside the 95% isodose. RESULTS: Median follow-up was 67 months (range 6-142). The 2­ and 5­year overall survival (OS) rates were 88.6% and 70%, respectively. The 2­year locoregional control (LRC), disease-free survival (DFS), and distant metastasis-free survival (DMFS) were 93.3%, 89.3%, and 87.4%, and the 5­year LRC, DFS, and DMFS were 86.8%, 74%, and 81.1%, respectively. Ten patients (9%) had a local and or regional recurrence. Half of the patients with locoregional failure had in-field recurrences. For primary tumor, there was no recurrence in the volume of 54 Gy. For regional lymph node volume, recurrence was detected in two (1.8%) patients in the volume of 54 Gy. CONCLUSION: These retrospective data suggest that a dose reduction may be possible for intermediate-risk volumes, especially for the primary site.

Investigation of Radiochromic Film Use for Source Position Verification through a LINAC On-Board Imager (OBI).

Background and Objectives: Quality assurance is an integral part of brachytherapy. Traditionally, radiographic films have been used for source position verification, however, in many clinics, computerized tomography simulators have replaced conventional simulators, and computerized radiography systems have replaced radiographic film processing units. With these advances, the problem of controlling source position verification without traditional radiographic films and conventional simulators has appeared. Materials and Methods: In this study, we investigated an alternative method for source position verification for brachytherapy applications. Source positions were evaluated using Gafchromic™ RTQA2 and EBT3 film and visually compared to exposed RTQA radiochromic film when using a Nucletron Oldelft Simulix HP conventional simulator and a Gammamed 12-i brachytherapy device for performance evaluation. Gafchromic film autoradiography was performed with a linear accelerator (LINAC) on-board imager (OBI). Radiochromic films are very suitable for evaluation by visual inspection with a LINAC OBI. Results: The results showed that this type of low-cost, easy-to-find material can be used for verification purposes under clinical conditions. Conclusions: It can be concluded that source-position quality assurance may be performed through a LINAC OBI device.

Recurrence patterns of pancreatic cancer treated with adjuvant intensity modulated radiotherapy.

Background: The aim of this study was to investigate the recurrence patterns in pancreatic cancer patients treated with adjuvant intensity modulated radiotherapy (IMRT) and to correlate the sites of locoregional recurrence with radiotherapy target volumes. Materials and methods: Thirty-eight patients who had undergone resection and adjuvant chemoradiation for pancreatic cancer were evaluated. Radiotherapy (RT) was started after 1-3 cycles of adjuvant chemotherapy (CHT). Clinical target volume (CTV) was contoured according to the RTOG guideline. All patients were treated with IMRT with a dose of 45-50.4 Gy. Computerized tomography (CT) images at the time of recurrence were correlated with radiotherapy plans. Locoregional recurrences were classified as in-field, out-field and marginal. Results: Median overall survival (OS) was 19 months. One- and 2-year OS rates were 73.6% and 37.1%, respectively. Locoregional recurrence and distant metastases were observed in 11 (28.9%) and 23 (60.5%) patients, respectively. For the 11 locoregional recurrences, 7 were in-field, 1 was marginal, and 3 were out-of-field. One patient had isolated local, 2 patients had isolated regional and 15 (57.6%) patients had only distant failures. The first presentations of failures were mostly distant (58%). On multivariate analysis, tumor size ≥ 3 cm (p = 0.011) and positive vascular invasion (p = 0.014) predicted for worse OS rate. Conclusions: The majority of locoregional recurrences were in the radiation field among pancreatic cancer patients treated with postoperative IMRT. However, failures were predominantly distant, and improvement of systemic control may be of particular interest.

Selective local postoperative radiotherapy for T3-T4 N0 laryngeal cancer.

PURPOSE: We aimed to investigate the appropriate postoperative radiotherapy dose and selective volume in T3-4 N0 laryngeal cancer patients treated with either total or partial laryngectomy. METHODS: Patients who received radiotherapy for locally advanced (T3-T4) and pathologic node-negative (N0) squamous cell laryngeal cancer were retrospectively evaluated. Radiotherapy was applied to median 60 Gy (range 54-60 Gy) as selective local radiotherapy (±stoma). The local treatment areas included postoperative bed + laryngeal area for patients with a partial laryngectomy, and the postoperative bed only for patients with total laryngectomy. RESULTS: The median follow-up time was 59 months and 52 patients were included. The 2­year, 5­year, and 8­year locoregional recurrence controls (LRC) were 95.6%. The 2­year and 5­year OS rates were 93.8% and 78.9%, respectively. The 5­year OS for age < 60 years was 95.8%, for above 60 years 56.5%. CONCLUSION: Our data suggest that local selective irradiation to the postoperative bed + stoma is enough in patients with T3-4 N0 laryngeal cancer without applying elective nodal irradiation.

Erectile dysfunction in prostate cancer patients treated with intensity-modulated radiation therapy.

BACKGROUND: Sexual dysfunction is an important side-effect after radiotherapy (RT) for prostate cancer (PCa). The aim of this study was to compare sexual functions of PCa patients before and after intensity-modulated RT and to analyze their correlation with penile bulb (PB) doses and patient characteristics. MATERIALS AND METHODS: Forty-two patients who underwent RT ± hormone therapy for PCa between 2010 and 2013 were analyzed. Sexual functions assessed by patient-reported questionnaire and physician reported scale before and 3 years after treatment. The effect of patients' age, prostate volume, testosterone levels, comorbidity, smoking status, tumor stage, RT technique, hormone therapy, and PB doses to sexual functions were investigated. RESULTS: After 3 years of RT, 64.3% of all patients had a lower erectile score; and 75% of patients who were previously potent (n = 24) had become impotent after treatment. However sexual desire still remained in 75.8% of patients who had desire before treatment (n = 33). Statistical analysis showed that two parameters were correlated with postradiotherapy impotency outcome; PB mean radiation dose (P = 0.033) and testosterone levels (P = 0.032). CONCLUSIONS: RT, despite modern techniques, affects the sexual function of PCa patients in varying degrees. Reducing radiation doses to penile structures may play a role in preventing erectile dysfunction.

The investigation of fetal doses in mantle field irradiation.

To determine clinically the fetal dose from irradiation of Hodgkin's disease during pregnancy and to quantify the components of fetal dose using phantom measurements. The fetal dose was measured with phantom measurements using thermoluminescent dosemeters (TLDs). Phantom measurements were performed by simulating the treatment conditions on an anthropomorphic phantom. TLDs were placed on the phantom 41, 44, 46.5 and 49.5 cm from the centre of the treatment field. Two TLDs were placed on the surface of the phantom. The estimated total dose to all the TLDs ranged from 8.8 to 13.2 cGy for treatment with (60)Co and from 8.2 to 11.8 cGy for 4 MV photons. It was concluded that the doses in different sections were evaluated to investigate dose changes in different points and depths of fetal tissues in phantom. Precise planning and the use of supplemental fetal shielding may help reduce fetal exposure.