Elective nodal irradiation (ENI) in definitive chemoradiotherapy (CRT) for squamous cell carcinoma of the thoracic esophagus

Background and purpose

There are some reports indicating that prophylactic three-field lymph node dissection for esophageal cancer can lead to improved survival. But the benefit of ENI in CRT for thoracic esophageal cancer remains controversial. The purpose of the present study is to retrospectively evaluate the efficacy of elective nodal irradiation (ENI) in definitive chemoradiotherapy (CRT) for thoracic esophageal cancer.

Materials and methods

Patients with squamous cell carcinoma (SCC) of the thoracic esophagus newly diagnosed between February 1999 and April 2001 in our institution was recruited from our database. Definitive chemoradiotherapy consisted of two cycles of cisplatin/5FU repeated every 5 weeks, with concurrent radiation therapy of 60 Gy in 30 fractions. Up to 40 Gy radiation therapy was delivered to the cervical, periesophageal, mediastinal and perigastric lymph nodes as ENI.

Results

One hundred two patients were included in this analysis, and their characteristics were as follows: median age, 65 years; male/female, 85/17; T1/T2/T3/T4, 16/11/61/14; N0/N1, 48/54; M0/M1, 84/18. The median follow-up period for the surviving patients was 41 months. Sixty patients achieved complete response (CR). After achieving CR, only one (1.0%; 95% CI, 0-5.3%) patient experienced elective nodal failure without any other site of recurrence.

Conclusion

In CRT for esophageal SCC, ENI is effective for preventing regional nodal failure. Further evaluation of whether ENI leads to an improved overall survival is needed.     

Is concurrent radiation therapy required in patients receiving preoperative chemotherapy for adenocarcinoma of the oesophagus? A randomised phase II trial

Introduction

Preoperative chemotherapy (CT) and preoperative chemoradiation therapy (CRT) for resectable oesophageal cancer have been shown to improve overall survival in meta-analyses. There are limited data comparing these preoperative therapies. We report the outcomes of a randomised phase II trial comparing preoperative CT and CRT for resectable adenocarcinoma of the oesophagus and gastro-oesophageal junction.

Methods

Patients were randomised to receive preoperative CT with cisplatin (80 mg/m²) and infusional 5 fluorouracil (1000 mg/m²/d) on days 1 and 21, or preoperative CRT with the same drugs accompanied by concurrent radiation therapy commencing on day 21 of chemotherapy and the 5 fluorouracil reduced to 800 mg/m²/d. The radiation dose was 35 Gy in 15 fractions over 3 weeks. The endpoints were toxicity, response rates, resection (R) status, progression-free survival (PFS), overall survival (OS) and quality of life.

Results

Seventy-five patients were enroled on the study: 36 received preoperative CT and 39 preoperative CRT. Toxicity was similar for CT and CRT. Eight patients (11%) did not proceed to resection. The histopathological response rate (CRT 31% versus CT 8%, p = 0.01) and R1 resection rate (CRT 0% versus CT 11%, p = 0.04) favoured those receiving CRT. The median PFS was 14 and 26 months for CT and CRT respectively (p = 0.37). The median OS was 29 months for CT compared with 32 months for CRT (p = 0.83).

Conclusions

Despite no difference in survival, the improvement from preoperative CRT with respect to margin involvement makes this treatment a reasonable option for bulky, locally advanced resectable adenocarcinoma of the oesophagus.     

Dosimetric correlates for acute esophagitis in patients treated with radiotherapy for lung carcinoma

PURPOSE: Acute esophagitis is a common complication of radiotherapy (RT) for non-small-cell carcinoma of the lung. Previous reports have related esophagitis to dosimetric parameters such as the length of the irradiated esophagus, maximal dose, or volume of the organ treated beyond a threshold dose. However, when using oblique beams, a portion of the esophageal circumference may be outside the treated field, resulting in partial esophageal irradiation. Therefore, our aim was to determine whether the irradiated esophageal surface area and/or esophageal volume are predictive of acute esophagitis in relation to other clinical and treatment-related factors. METHODS AND MATERIALS: Complete dose-volume information was gathered for 166 patients receiving definitive RT for Stage I-IIIB non-small-cell carcinoma of the lung at our institution. Seventy-eight patients received chemotherapy (37 before RT and 41 concurrently). All patients were treated to doses of 60-74 Gy (median, 70 Gy) delivered in single daily fractions of 1.8-2.1 Gy. The doses were prescribed to the isocenter without using heterogeneity corrections; however, the doses were corrected to account for lung heterogeneity in this report. Esophageal contrast was used to contour the esophagus from the cricoid to the gastroesophageal junction in each case. Esophagitis was scored according to the Radiation Therapy Oncology Group criteria with Grade 2 or worse considered clinically significant. To determine the importance of the irradiated surface area, the volumetric treatment plan for each patient was prepared for analysis by relating a surface area to each point of the esophagus contour. Spearman's rank correlation was used to correlate the esophagitis score with A(d), where A represents the surface area (in centimeters squared) receiving the dose, d, or greater (in Gray), or V(d), where V represents the volume (in centimeters cubed) receiving d (in Gray). The surface areas studied were A(5)-A(80) or V(5)-V(80) in 5-Gy increments. The clinical parameters studied in univariate analysis included patient age, stage, performance status, use of pretreatment chemotherapy, and use of concurrent chemotherapy. Step-wise regression analysis was then used to determine the statistically significant factors predicting acute esophagitis. RESULTS: Forty-five patients (27%) developed Grade 2 or worse esophagitis, 37 developed Grade 2, 7 Grade 3, and 1 Grade 4. No deaths resulted from this complication. The most statistically significant single parameters for predicting acute esophagitis were A(55), V(60), and the use of concurrent chemotherapy. Age, stage, performance status, and pre-RT chemotherapy had no statistically significant influence on the incidence of acute esophagitis. On logistic regression analysis, A(55) (p < or =0.0005), V(60) (p < or =0.001), and the use of concurrent chemotherapy (p = 0.001) emerged as statistically significant correlates of acute esophagitis. CONCLUSION: The esophageal surface area receiving > or =55 Gy, the esophageal volume receiving > or =60 Gy, and the use of concurrent chemotherapy were the most statistically significant predictive factors for early esophagitis. Adequate dosimetric coverage of the planning target volume remains the goal of RT planning. High values of A(55) and/or V(60) are indicative of the development of acute esophagitis and may indicate a need to explore alternative RT planning options.     

Weekly paclitaxel with concurrent radiotherapy followed by adjuvant chemotherapy in locally advanced nasopharyngeal carcinoma

Purpose

To evaluate the efficacy and toxicity of weekly paclitaxel with concurrent radiotherapy followed by adjuvant chemotherapy (AC) in patients with locally advanced nasopharyngeal carcinoma (NPC).

Methods and materials

Between 2004 and 2007, 54 patients with locally advanced NPC were included in this protocol. Patient characteristics: median age 48; 69% male; 52% World Health Organization (WHO) III; 50% stage III, 50% stage IV. The patients underwent a course of definitive conventional radiotherapy (70 Gy in 7 weeks with 2 Gy/fraction), with concurrent weekly paclitaxel 35 mg/m² from the first to the sixth week of radiation. AC was started 4 weeks after the end of the radiotherapy (RT), paclitaxel 135 mg/m² on day 1 and cisplatin 30 mg/m² on days 1-3 were administered every 4 weeks for two cycles.

Results

Median follow-up was 32 months. Eighty-five percentage of complete response and 15% partial response were achieved at the time of one month after AC. The 3-year actuarial rate of local regional control was 86%; distant metastases-free survival, progression-free survival and overall survival at 3 years were 81%, 69% and 76%, respectively. Forty-nine (91%) patients completed six courses of concurrent chemotherapy with weekly paclitaxel, and 4 (7%) patients delayed at the second cycle of AC. No patient developed severe acute toxicities.

Conclusions

Weekly paclitaxel with concurrent RT followed by AC is a potentially effective and toxicity tolerable method for locally advanced NPC. Further studies are needed to identify the optimal dose of weekly paclitaxel in this strategy.     

Concurrent high-dose radiotherapy with low-dose chemotherapy in patients with non-small cell lung cancer of the superior sulcus

Background and purpose

In the treatment of patients with tumours of the sulcus superior (SST), achieving local control is essential because residual or recurrent disease is associated with severe locoregional problems. This study evaluates the efficacy of concurrent daily low-dose cisplatin (6 mg/m²) and high-dose radiotherapy (66 Gy) followed by surgical resection in selected patients.

Material and methods

Clinical charts, imaging and pathology reports were retrospectively reviewed. Survival was analysed using the Kaplan-Meier method.

Results

Forty-nine patients with stage II/III SST were treated with concurrent high-dose radiotherapy and low-dose chemotherapy (CRT). Mean follow-up was 49 months (range 2-152).Nineteen patients underwent additional resection after CRT. In 53% a pathological complete response (pCR) was observed (10/19pts). Acute severe toxicity occurred in 49% (9/19pts). Late severe toxicity occurred in 3 patients. The 2- and 5-year overall survival was 74% and 33%, respectively. Local tumour control was 100%. Thirty patients received CRT only. Acute severe toxicity occurred in 23% (7/30pts). Treatment-related mortality was 2%. The 2- and 5-year overall survival was 31% and 18%, respectively. Locoregional disease-free survival was 48% at 5 years.

Conclusions

Concurrent high-dose (66 Gy) radiotherapy and daily low-dose cisplatin was associated with a high pCR rate. Excellent local control was achieved after additional resection in selected patients. However, the occurrence of severe toxicity in long-term survivors after concurrent chemoradiation followed by surgery must be considered.     

Three-dimensional conformal radiation therapy for squamous cell carcinoma of the esophagus: A prospective phase I/II study

Purpose

A prospective phase I-II study was conducted to determine the tolerance and local control rate of three-dimensional conformal radiotherapy (3-DCRT) for esophageal squamous cell carcinoma (SCC).

Methods and materials

Thirty patients underwent 3-DCRT for thoracic esophageal SCC. PTV1 composed of a 1.2-1.5 cm margin lateral around GTV and 3.0 cm margin superior/inferior of GTV. PTV2 encompassed GTV with a margin of 0.5-0.7 cm. The dose for PTV1 was 50 Gy in 2 Gy daily fractions; PTV2 received a boost of 16 Gy in 2 Gy daily fractions to a total dose of 66 Gy.

Results

Median follow-up time was 18 months. The most common acute toxicity was esophagitis in 63% of patients with RTOG grades 1-2, and in 3% with grade 3. RTOG grades 1-2 radiation pneumonitis developed in 27% of patients. One patient developed pulmonary fibrosis RTOG grade 2 and another patient experienced grade 3 pulmonary fibrosis. Two patients developed mild esophageal stricture requiring dilatation. Two-year overall survival, local disease progression-free rate, and distant metastasis-free rate were 69%, 36% and 56%, respectively.

Conclusions

Although 3-DCRT to 66 Gy for esophageal SCC was well tolerated, the local control was disappointing. The result supports the use of chemoradiation as the standard care for esophageal SCC.     

Time course of hypothalamic-pituitary deficiency in adults receiving cranial radiotherapy for primary extrasellar brain tumors

Background

No longitudinal data on hypothalamic-pituitary (HP) function are available in patients who had received cranial radiation therapy (CRT) for primary extrasellar brain tumors (PBT).

Purpose

To investigate the effects of CRT on HP function in adults with PBT.

Patients and methods

Twenty-six adults irradiated for PBT and six CRT naive controls were studied. CRT was delivered with 6 MV X-ray by a linear accelerator (2 Gy fraction schedule). Gross Tumor Volume (GTV) excluded the HP region that was contoured on the planning CT. Median dose to the HP region was 41.8 Gy (IQR: 30.7-49.8).

Results

All controls maintained normal HP function. Hypopituitarism developed in 38% of CRT patients (GH deficiency 29%, ACTH 22%, TSH 14%, gonadotropin 4%, no abnormal prolactin level or diabetes insipidus). All HP failures occurred within 32 months after CRT.

Conclusions

Adults undergoing CRT for PBT are at increased risk for HP dysfunction within 3 years from CRT. Endocrine surveillance is recommended also in adults patients exposed to CRT for primary brain tumors distant from HP region.     

Dosimetric predictors for acute esophagitis during radiation therapy for lung cancer: Results of a large statewide observational study

Purpose

The purpose of this study is to identify dosimetric variables that best predict for acute esophagitis in patients treated for locally advanced non–small cell lung cancer in a prospectively accrued statewide consortium.

Residual metabolic tumor activity after chemo-radiotherapy is mainly located in initially high FDG uptake areas in rectal cancer

Purpose

Recent literature suggests that tumor cells and areas within tumors with a high initial FDG uptake might be more resistant to (chemo)radiotherapy ((C)RT). This study was undertaken to test this hypothesis in rectal cancer using rigid and non-rigid image registration.

Patients and methods

Twenty-eight patients, diagnosed with locally advanced rectal cancer and referred for pre-operative treatment with CRT were included in this study. All patients underwent FDG-PET-CT imaging prior to and after CRT. Rigid and non-rigid image registration was performed to compensate organ deformations between the pre- and post-treatment PET-CT scans. The tumor was contoured on both PET-scans using SUV iso-contouring based on the SBR-method. The voxels with residual increased FDG uptake were studied and correlated to their pre-treatment FDG uptake level. Two SUV-volume-histograms were made based on the pre-treatment PET-data, one for the voxels within the pre-treatment tumor PET-based iso-contour and one for the voxels within the PET-based iso-contour of the residual tumor non-rigidly registered onto the pre-treatment scan.

Results

For the voxels with a pre-treatment FDG uptake of >50% of SUV_max, 70.6 ± 5.6% of the voxels were still metabolic active in the residual tumor, whereas for voxels with an FDG uptake of <50% of SUV_max only 51.1 ± 6.7% were present in the metabolic active residual tumor.

Conclusion

This study presents areas in rectal tumors with an initially high FDG uptake to be most likely to show residual disease after CRT. This could indicate a higher (C)RT-resistance for tumor regions with a high FDG uptake prior to treatment.     

Carcinoma of the Collecting Ducts of Bellini of the Kidney: Adjuvant Chemotherapy Followed by Multikinase Inhibition with Sunitinib

Background

Carcinoma of the collecting ducts (CDC) of Bellini of the kidney is very rare but is among the most aggressive urologic entities.

Patients and Methods

Radical nephrectomy revealed CDC in stage pT3a pN2 M0 G3 in 2 male patients. Four courses of adjuvant chemotherapy with cisplatin and gemcitabine were given.

Results

Subsequent restaging revealed local recurrence and lymph node metastases. Both patients were operated on again, and metastatic CDC was found. Second-line therapy with sunitinib was administered. After 2 cycles, multiple liver, lung, and bone metastases and mediastinal lymphopathy occurred. Eight weeks later, the patients died, with a survival of 8 months from initial diagnosis.

Conclusion

Nephrectomy, adjuvant gemcitabine/cisplatin, and sunitinib therapy did not alter the course of disease in these patients. Gross resection of disease was rapidly followed by local recurrence and, subsequently, widespread dissemination of disease. Clinical trial investigation is urgently needed because of the aggressive and refractory nature of CDC.     

Image-guided intensity-modulated radiotherapy (IG-IMRT) for biliary adenocarcinomas: Initial clinical results

Purpose

Biliary tract lesions are comparatively rare neoplasms, with ambiguous indications for radiotherapy. The specific aim of this study was to report the clinical results of a single-institution biliary tract series treated with modern radiotherapeutic techniques, and detail results using both conventional and image-guided intensity-modulated radiation therapy (IG-IMRT).

Methods and materials

From 2001 to 2005, 24 patients with primary adenocarcinoma of the biliary tract (gallbladder and extrahepatic bile ducts) were treated by IG-IMRT. To compare outcomes, data from a sequential series of 24 patients treated between 1995 and 2005 with conventional radiotherapy (CRT) techniques were collected as a comparator set. Demographic and treatment parameters were collected. Endpoints analyzed included treatment-related acute toxicity and survival.

Results

Median estimated survival for all patients completing treatment was 13.9 months. A statistically significant higher mean dose was given to patients receiving IG-IMRT compared to CRT, 59 vs. 48 Gy. IG-IMRT and CRT cohorts had a median survival of 17.6 and 9.0 months, respectively. Surgical resection was associated with improved survival. Two patients (4%) experienced an RTOG acute toxicity score > 2. The most commonly reported GI toxicities (?RTOG Grade 2) were nausea or diarrhea requiring oral medication, experienced by 46% of patients.

Conclusion

This series presents the first clinical outcomes of biliary tract cancers treated with IG-IMRT. In comparison to a cohort of patients treated by conventional radiation techniques, IG-IMRT was feasible for biliary tract tumors, warranting further investigation in prospective clinical trials.     

Induction chemotherapy with cisplatin and epirubicin followed by radiotherapy and concurrent cisplatin in locally advanced nasopharyngeal carcinoma observed in a non-endemic population

Background and purpose

Chemoradiotherapy (CRT) represents the main therapy choice in the treatment of locoregionally advanced nasopharyngeal carcinoma (NPC). The aim of this study was the clinical evaluation of neoadjuvant chemotherapy (NACT) followed by CRT in a non-endemic population affected by advanced NPC.

Materials and methods

Patients with locoregionally advanced NPC were treated with three cycles of induction chemotherapy (CHT) with cisplatin (100 mg/m²) plus epirubicin (90 mg/m²), followed by cisplatin (100 mg/m²) and concomitant radiotherapy (70 Gy).

Results

In 40 patients treated with such protocol, after the completion of induction CHT and CRT we observed the objective response rates of 90% and 100%, respectively. Treatment tolerability and toxicity were easily controllable. With a median follow-up time of 54 months, 3- and 5-year disease-free survival was 75% and 65% and 3- and 5-year overall survival was 84% and 77%.Three- and 5-year locoregional control was 82% and 70%, and 5-year distant metastases free survival was 75%.

Conclusions

NACT with cisplatin and epirubicin followed by concomitant CRT represents a feasible, efficient treatment for patients with advanced NPC. This regimen ensures an excellent locoregional disease control and overall survival with a low incidence of distant metastases.     

Monte Carlo-based analytical model for small and variable fields delivered by TomoTherapy

Background and purpose

Extend to very small fields the validity of a Monte Carlo (MC) based model of TomoTherapy called TomoPen for future implementation of the dynamic jaws feature for helical TomoTherapy.

Materials and methods

First, the modelling of the electron source was revisited using a new method to measure source obscuration for very small fields (<1 cm). The method consisted in MC simulations simulations and measurements of the central dose in a water phantom for a 10 cm × FW field scanned to deliver a 10 × 10 cm² fluence. FW, the longitudinal field width, was varied from 0.4 to 5 cm. The second part of the work consisted of adapting TomoPen to account for any configuration of the jaws in a fast and efficient way by using routinely only the phase-space file of the largest field (5 cm) and interpolated analytical information of phase-space files of smaller field widths.

Results

For the electron source fine tuning, it was shown that the best results were obtained for a 1.1 mm wide spot. Our single phase-space method showed no significant differences compared to MC simulations of various field widths even though only longitudinal intensity and angular analytical functions were applied to the 5 cm phase-space.

Conclusion

The designed model is able to simulate all jaw openings from the 5 cm field phase-space file by applying a bi-dimensional analytical function accounting for the fluence and the angular distribution in the longitudinal direction.     

Gemcitabine in the chemoradiotherapy for locally advanced pancreatic cancer: A meta-analysis

Aims

Whether gemcitabine based chemoradiotherapy (GEM-based CRT) is superior to 5-fluorouracil based chemoradiotherapy (5-FU-based CRT) for locally advanced pancreatic cancer (LAPC) remains uncertain. The aim of the present study was to evaluate the effect of GEM-based CRT compared with 5-FU-based CRT.

Methods

Electronic database including Medline, Embase, Cochrane controlled trials register, PubMed (update to December 2010) and manual bibliography searches were carried out. A meta-analysis of all randomized clinical trials (RCTs) or other comparative studies comparing GEM-based CRT and 5-FU-based CRT were performed.

Results

Three RCTs and one retrospective comparative study including 229 patients were assessed. Meta-analysis showed survival advantage of GEM-based CRT compared with 5-FU-based CRT for 12-month (12-mo) survival rates (SRs) (RR = 1.54, 95% CI 1.05-2.26, p = 0.03). Moreover, there were also trends of benefit for SR after 6-months (RR 1.13, 95% CI 0.98-1.30, p = 0.09) and 24-months (24-mo: RR 2.41, 95% CI 0.90-6.48, p = 0.08), though the trends did not reach statistical significance. More frequent severe acute hematologic toxicities were found in the GEM-based CRT group.

Conclusions

The meta-analysis found that GEM-based CRT was better than 5-FU-based CRT in the treatment of LAPC, especially for 12-mo SRs. However, the acute toxicity should be carefully regarded.     

Preoperative concomitant boost intensity-modulated radiotherapy with oral capecitabine in locally advanced mid-low rectal cancer: A phase II trial

Purpose

We aimed to assess the safety and efficacy of preoperative intensity-modulated radiotherapy (IMRT) with oral capecitabine in patients with locally advanced mid-low rectal cancer using a concomitant boost technique.

Materials and methods

Patients with resectable locally advanced mid-low rectal cancer (node-negative ?T3 or any node-positive tumor) were eligible. The eligible patients received IMRT to 2 dose levels simultaneously (50.6 and 41.8 Gy in 22 fractions) with concurrent capecitabine 825 mg/m² twice daily 5 days/week. The primary end point included toxicity, postoperative complication, and pathological complete response rate (ypCR). The secondary endpoints included local recurrence rate, progression-free survival (PFS), and overall survival (OS).

Results

Sixty-three eligible patients were enrolled; five patients did not undergo surgery. Of the 58 patients evaluable for pathologic response, the ypCR rate was 31.0% (95% CI 19.1-42.9). Grade 3 toxicities included diarrhea (9.5%), radiation dermatitis (3.2%), and neutropenia (1.6%). There was no Grade 4 toxicity reported. Four (6.9%) patients developed postoperative complications. Two-year local recurrence rate, PFS, and OS were 5.7%, 90.5%, and 96.0%, respectively.

Conclusions

The design of preoperative concurrent boost IMRT with oral capecitabine could achieve high rate of ypCR with an acceptable toxicity profile.     

Acute esophageal toxicity in non-small cell lung cancer patients after high dose conformal radiotherapy.

BACKGROUND AND PURPOSE: To correlate acute esophageal toxicity with dosimetric and clinical parameters for non-small cell lung cancer (NSCLC) patients treated with radiotherapy (RT) alone or with chemo-radiotherapy (CRT). PATIENTS AND METHODS: We analyzed the data of 156 patients with medically inoperable or locally advanced NSCLC. Seventy-four patients were irradiated with high dose RT only, 45 patients with sequential CRT (Gemicitabine/Cisplatin) and 37 patients with concurrent CRT (Cisplatin daily 6 mg/m(2)). The radiation dose delivered ranged from 49.5 to 94.5 Gy (2.25-2.75 Gy per fraction) with an overall treatment time of 5-6 weeks. For all patients the maximal acute esophageal toxicity (RTOG/EORTC criteria) was scored and related to dose-volume parameters, as well as to clinical and treatment-related parameters. All parameters were tested univariable and multivariable in a binary logistic regression model. The toxicity data of a homogeneous subgroup was fitted to the Lyman-Kutcher-Burman model. RESULTS: Grade 2 acute esophageal toxicity or higher occurred in 27% (n=42) of the patient population of which nine patients developed grade 3 toxicity and one patient grade 4. All 10 patients with grade>or=3 esophageal toxicity received concurrent CRT. At multivariable analysis, the most significant clinical parameter to predict acute esophageal toxicity was the concurrent use of CRT. The most significant dosimetric parameter was the esophagus volume that received at least 35 Gy. The data of the patients who did not receive concurrent CRT were well described by the Lyman-Kutcher-Burman normal tissue complication probability model. The optimal fit of the data of non-concurrent treated patients to this model was obtained using the following values for the parameters: TD(50)=47 Gy (41-60 Gy), n=0.69 (0.18-6.3) and m=0.36 (0.25-0.55) where the numbers between brackets denote the 95% confidence interval. Acute esophageal toxicity was not significantly increased for patients treated with sequential CRT. CONCLUSION: Both concurrent CRT and the volume that receives at least 35 Gy were predictors of acute esophageal toxicity.     

Site-specific lymphatic mapping relative to lingual septum in localizing the regional lymph nodes of tongue - an animal study

Background and Objectives

With technical adaptations, recent studies showed SLNB could predict cervical nodes status of head and neck carcinoma with high accuracy. However, as for tongue carcinoma, such technical adaptations seem to be not enough because the tongue has peculiar characteristic which may demand a specific procedure for accurate lymphatic mapping. This investigation explored the effect of lingual septum on lymphatic mapping of tongue to provide data for achieving an accurate lymphatic mapping for managing early tongue carcinoma.

Methods

Four doses of Methylene Blue were injected into various parts of 64 rabbits' tongue, then diffusion range of Methylene Blue in tongue and sites of cervical nodes stained blue were noted. Finally, the tongues were resected for further histological examination and morphometric assessments.

Results

There was lingual septum in the tongue and the diffusing of Methylene Blue could be terminated by lingual septum. Blue-stained nodes were identified in 84 lateral necks of 60 rabbits.

Conclusions

A site-specific way of lymphatic mapping relative to lingual septum should be developed for staging early tongue carcinoma.     

Double-scattered proton-based stereotactic body radiotherapy for stage I lung cancer: A dosimetric comparison with photon-based stereotactic body radiotherapy

Purpose

Stereotactic body radiotherapy (SBRT) has gained popularity in the treatment of early-stage non-small-cell lung cancer (NSCLC) because of its ability to deliver conformal radiation doses to small targets. However, photon-based SBRT (xSBRT) is associated with significant grade 3+ toxicities. In this study, we compare xSBRT treatment plans with proton-based SBRT (pSBRT) to determine whether dose to normal structures could be reduced if SBRT was delivered with protons.

Materials and methods

Eight patients with medically inoperable, peripherally located stage I NSCLC were treated with xSBRT to 48 Gy in 4 12-Gy fractions. These patients were retrospectively re-planned using the same treatment volumes with 3-dimensional conformal double-scatter proton therapy. A Wilcoxon paired test compared dosimetric parameters between the plans for each patient.

Results

Compared with xSBRT there was a dosimetric improvement with pSBRT for these volumes: lung V5 (median difference [MD] = 10.4%, p = 0.01); V10 (MD = 6.4%, p = 0.01); V20 (MD = 2.1%, p = 0.01); V40 (MD = 1.5%, p = 0.05); and mean lung dose (MD = 2.17 Gy, p = 0.01). There were also benefits (p = <0.05) in D0.1cm3 and D5cm3 with pSBRT to the heart, esophagus, and bronchus.

Conclusions

In a dosimetric comparison between photon and proton-based SBRT, protons resulted in lower doses to critical organs at risk and a smaller volume of non-targeted normal lung exposed to radiation (V5, V10, V20, and V40). The clinical significance and relevance of these dosimetric improvements remain unknown.