Patterns of locoregional failure in stage III non-small cell lung cancer treated with definitive chemoradiation therapy.

PURPOSE: Chemoradiation therapy (CRT) is the core treatment of locally advanced non-small cell lung cancer (LA-NSCLC), but potential toxicities limit radiation therapy dose. These toxicities, plus the advent of increasingly conformal radiation therapy, have prioritized target definition and the use of involved-field radiation therapy (IFRT). Published data largely focus on regional rather than local failure patterns. We report our pattern-of-failure experience treating patients with LA-NSCLC with definitive CRT, focusing on both local and regional recurrences with detailed dosimetric analyses of failure location. METHODS AND MATERIALS: Patients treated between December 2004-2010 were included. Imaging scans from date of failure were fused with the RT-planning CT scan, and recurrent nodes were contoured to determine if the recurrence was in a previously irradiated region, defined as involved nodal recurrence (INR) versus elective nodal recurrence (ENR). Local failures were contoured and identified as in-field, marginal, or out-of-field based on dose received. Actuarial overall survival (OS) and progression-free survival (PFS) were calculated, and the cumulative incidences of local, regional, locoregional, and distant recurrence (CILR, CIRR, CILRR, CIDR) were determined with death as a competing risk. RESULTS: One hundred five patients were included with a median survival of 21.8 months. The 3-year OS and PFS were 36% and 22%, respectively. The 3 year CILRR, CILR, CIRR, CIDR were 41%, 38%, 40%, and 58%, respectively. Thirty patients failed regionally, but only 7 patients developed an ENR with no concurrent local failure or INR, and only 1 of these patients did not develop distant metastases within 1 month of recurrence. A total of 21 patients (20%) developed an ENR with or without other areas of recurrence. CONCLUSIONS: Elective regional recurrences rarely occurred as the sole site of failure, despite the use of IFRT. Moreover, the pattern of local failure was entirely in-field. These data strongly support field design focusing on gross nodal and primary disease.

Prognostic significance of weight gain during definitive chemoradiotherapy for locally advanced non-small-cell lung cancer.

BACKGROUND: The successful treatment of locally advanced non-small-cell lung cancer (NSCLC) with chemoradiotherapy (CRT) is still compromised by poor locoregional and distant control rates. Given the morbidity associated with treatment, it is critical to determine clinical prognostic factors to risk stratify patients before and after aggressive therapy. This study aimed to discern the prognostic value of weight gain during CRT in patients with locally advanced NSCLC. PATIENTS AND METHODS: This was a retrospective analysis of 92 patients treated with definitive split-course CRT between 2004 and 2010 at Rush University Medical Center. Weight gain was defined as a weight change greater than the highest quartile of change between the start and finish of CRT (4.5 lb). Overall survival (OS), locoregional progression-free survival (PFS), and distant metastasis-free survival (DMFS) were determined using Kaplan-Meier analysis, and the cumulative incidences of locoregional and distant recurrence were calculated. Cox regression (multivariate analysis) was used to determine independent predictors of OS. RESULTS: With a median follow-up of 50 months for surviving patients, the median, 3- and 5-year OS probabilities were 25 months, 37%, and 29%, respectively. The 3-year cumulative risks of locoregional and distant metastases were 51% and 64%. Patients who experienced weight gain were significantly more likely to survive (3-year OS, 55% vs. 31%; P = .04) and prolonged DMFS resulted. Weight gain was the only significant predictor of survival on multivariate analysis. CONCLUSIONS: Weight gain during split-course CRT was associated with superior OS and DMFS. The presence of weight gain may have utility in risk stratification after CRT as well as in identifying novel treatment approaches for patients with locally advanced NSCLC.

Patterns of regional failure in stage III non-small cell lung cancer treated with neoadjuvant chemoradiation therapy and resection.

PURPOSE: Treatment of locally advanced non-small cell lung cancer (LA-NSCLC) involves definitive chemoradiation therapy (CRT) or neoadjuvant CRT and resection, but radiation treatment volumes remain in question. With CRT, involved-field radiation therapy (IFRT) is replacing elective nodal irradiation, reducing toxicity, and allowing dose escalation. However, prior reports of IFRT describe failures only after radical CRT; with improved local control after resection, IFRT may lead to more regional recurrences. Our objective is to evaluate pattern-of-failure in patients with LA-NSCLC treated with split-course IFRT, chemotherapy, and subsequent surgery. METHODS AND MATERIALS: Patients treated between December 2004 and 2010 were included. Imaging scans demonstrating failure were fused into the radiation therapy planning computed tomography, and recurrent nodes were contoured to determine pattern-of-failure (involved versus elective nodal failure [INF vs ENF]). Locoregional progression-free survival and distant metastasis-free survival were calculated using Kaplan-Meier methodology. The cumulative incidence of regional recurrence (CIRR) was determined with death as a competing risk. RESULTS: Forty-five patients met inclusion criteria, and patients with RR had a lower rate of pN0 than those without RR (20% vs 60%, P = .02). With a median follow-up of 2.9 years, median survival was not reached, and 3-year locoregional progression-free survival and distant metastasis-free survival were 53% and 35%, respectively. Two and 3-year CIRR were 25% and 33%, respectively. There were no local failures. Thirteen (29%) patients had RR, 8 with INF only and 5 with ENF alone or both, totaling 27 recurrences. Only 2 (4%) ENF occurred without INF, both with distant metastasis, and no elective node was the first and only site of failure. CONCLUSIONS: Our data suggest that IFRT does not compromise regional control in the neoadjuvant management of LA-NSCLC. Tailoring nodal volumes may improve treatment-related morbidity and allow for dose intensification of involved nodes. Further research is necessary to improve regional and distant control.

Psoas muscle metastases in non-small cell lung cancer.

Lung cancer is the leading cause of cancer-related death in the U.S. and often spreads via lymphatics or through hematogenous metastasis to the brain, bone and adrenal glands. Isolated metastases to skeletal muscle, including the psoas muscles, are very uncommon. The present report is a case series of three patients with psoas metastases from non-small cell lung cancer (NSCLC) and a review of the relevant literature. Three patients presented with psoas muscle metastases from NSCLC detected on diagnostic imaging. All patients were treated with radiotherapy to the psoas muscle, and two patients were treated with curative intent on an oligometastatic paradigm. Radiotherapy to the psoas muscle was effective and well tolerated.

High-grade glioma relationship to the neural stem cell compartment: a retrospective review of 104 cases.

PURPOSE: To assess the incidence of involvement of the neural stem cell (NSC) compartment by high-grade astrocytomas in a series of adult patients. METHODS AND MATERIALS: One hundred four initial diagnostic cranial magnetic resonance imaging series were reviewed. For each series, the gross tumor volume (GTV; enhancing tumor on T(1)), edema (hyperintensity on T(2) FLAIR), and the NSC compartment (hippocampal formation and lateral ventricle plus a 5-mm expansion) were identified. Involvement of NSC by GTV and edema was assessed. For tumors not involving NSC, we measured distances from NSC to GTV and edema. Maximum diameters of GTV were measured for each case. Subset analysis was performed for GTV of ≤ 2 cm and ≤ 3 cm in maximum diameter to assess the incidence of involvement of NSC by this group of smaller tumors. For 10 representative tumors, minimum distances from GTV center to NSC were calculated. RESULTS: A total of 103/104 (99.0%) tumors, regardless of GTV maximum diameter, demonstrated involvement of NSC. A total of 101/104 (97.1%) tumors had NSC involvement by GTV, and 2/104 (1.9%) patients showed edema only. For GTV not involving NSC, the mean distance from NSC to GTV was 0.8 cm (range, 0.5--1.4 cm). The mean shortest distance from the center of GTV to NSC was 1.5 cm (range, 0.9--2.6 cm). Involvement of NSC by GTV was 90.9% (10/11 tumors) for GTV of ≤ 2 cm and 95.7% (22/23 tumors) for GTV of ≤ 3 cm. CONCLUSIONS: Our results support the hypothesis that the NSC compartment represents the putative site of origin for these tumors. NSC involvement does not appear to represent a volumetric phenomenon.

Sparing of the hippocampus, limbic circuit and neural stem cell compartment during partial brain radiotherapy for glioma: a dosimetric feasibility study.

INTRODUCTION: The aim of this study was to assess the feasibility of sparing contralateral or bilateral neural stem cell (NSC) compartment, hippocampus and limbic circuit during partial brain radiotherapy (PBRT). METHODS AND MATERIALS: Treatment plans were generated for five hemispheric high-grade gliomas, five hemispheric low-grade gliomas and two brainstem gliomas (12 patients). For each, standard intensity-modulated radiotherapy (IMRT) plans were generated, as well as IMRT plans which spared contralateral (hemispheric cases) or bilateral (brainstem cases) limbic circuit, hippocampus, and NSC. Biologically equivalent dose for late effects (BED(late effects)) was generated for limbic circuit, hippocampus and NSC. Per cent relative reduction in mean physical dose and BED was calculated for each plan (standard vs. sparing). RESULTS: We were able to reduce physical dose and BED(late effects) to these critical structures by 23.5-56.8% and 23.6-66%, respectively. CONCLUSION: It is possible to spare contralateral limbic circuit, NSC and hippocampus during PBRT for both high- and low-grade gliomas using IMRT, and to spare the hippocampus bilaterally during PBRT for brainstem low-grade gliomas. This approach may reduce late cognitive sequelae of cranial radiotherapy.

Split-course chemoradiotherapy for locally advanced non-small cell lung cancer: a single-institution experience of 144 patients.

BACKGROUND: Concurrent chemoradiotherapy (CRT) is a standard of care in the treatment of unresectable locally advanced non-small cell lung cancer (NSCLC). At Rush University Medical Center, patients with locally advanced NSCLC are treated with split-course CRT in an attempt to maximize efficacy and tolerability. We reviewed our experience in advanced NSCLC since 1999. Subset analysis was performed on poor-risk patients. METHODS: All patients with a diagnosis of stage IIIA/IIIB NSCLC and treated with definitive split-course CRT between January 1999 and December 2008 were included in this retrospective study. The primary end point was overall survival. Poor-risk patients were defined in accordance with ongoing cooperative group trials. RESULTS: One hundred forty-four patients were identified, 35% stage IIIA and 65% stage IIIB. There were 52 poor-risk patients and 92 average-risk patients. Median survival for all patients was 20.4 months with an actuarial 32.1% 3-year overall survival rate. Poor-risk patients demonstrated a median survival of 22.1 months, statistically indistinguishable from the remainder of the cohort (p = 0.21). Acute esophagitis was mild, with a 3% rate of grade 3 esophagitis and no cases of grade 4 or 5. CONCLUSIONS: Split-course CRT appeared effective and was delivered with a favorable toxicity profile. Poor-risk patients experienced better than expected survival. Prospective evaluation of split-course CRT must be completed before it can be considered a standard treatment option in locally advanced NSCLC.

Weight gain in advanced non-small-cell lung cancer patients during treatment with split-course concurrent chemoradiotherapy is associated with superior survival.

BACKGROUND: Preoperative concurrent chemoradiotherapy (CRT) is an accepted treatment for potentially resectable, locally advanced, non-small-cell lung cancer (NSCLC). We reviewed a decade of single institution experience with preoperative split-course CRT followed by surgical resection to evaluate survival and identify factors that may be helpful in predicting outcome. METHODS AND MATERIALS: All patients treated with preoperative split-course CRT and resection at Rush University Medical Center (RUMC) between January 1999 and December 2008 were retrospectively analyzed. Endpoints included overall survival (OS), progression-free survival (PFS), local-regional progression-free survival (LRPFS), and distant metastasis-free survival (DMFS). Patient and treatment related variables were assessed for correlation with outcomes. RESULTS: A total of 54 patients were analyzed, 76% Stage IIIA, 18% Stage IIIB, and 6% oligometastatic. The pathologic complete response (pCR) rate was 31.5%, and the absence of nodal metastases (pN0) was 64.8%. Median OS and 3-year actuarial survival were 44.6 months and 50%, respectively. Univariate analysis revealed initial stage (p < 0.01) and percent weight change during CRT (p < 0.01) significantly correlated with PFS/OS. On multivariate analysis initial stage (HR, 2.4; 95% CI, 1.18-4.90; p = 0.02) and percent weight change (HR, 0.79; 95% CI, 0.67-0.93; p < 0.01) maintained significance with respect to OS. There were no cases of Grade 3+ esophagitis, and there was a single case of Grade 3 febrile neutropenia. CONCLUSIONS: The strong correlation between weight change during CRT and OS/PFS suggests that this clinical parameter may be useful as a complementary source of predictive information in addition to accepted factors such as pathological response.

Helical tomotherapy delivery of an IMRT boost in lieu of interstitial brachytherapy in the setting of gynecologic malignancy: feasibility and dosimetric comparison.

Interstitial brachytherapy is an important means by which to improve local control in gynecologic malignancy when intracavitary brachytherapy is untenable. Patients unable to receive brachytherapy have traditionally received conventional external beam radiation alone with modest results. We investigated the ability of Tomotherapy (Tomotherapy Inc., Madison, WI) to replace interstitial brachytherapy. Six patients were selected. The planning CT of each patient was contoured with the planning target volume (PTV), bladder, rectum, femoral heads, and bowel. Identical contour sets were exported to Tomotherapy and Nucletron PLATO (Nucletron B.V., Veenendaal, The Netherlands). With Tomotherapy, the PTV was prescribed 31 Gy in 5 fractions to 90% of the volume. With PLATO, 600 cGy × 5 fractions was prescribed to the surface of the PTV. Dose delivered was normalized to 2 Gy fractions (EQD2) and added to a hypothetical homogenous 45-Gy pelvic dose. Tomotherapy achieved a D90 of 87 Gy EQD2 versus 86 Gy with brachytherapy. PTV dose was more homogeneous with tomotherapy. The dose to the most at-risk 2 mL of bladder and rectum with Tomotherapy was of 78 and 71 Gy EQD2 versus 81 and 75 Gy with brachytherapy. Tomotherapy delivered more dose to the femoral heads (mean 1.23 Gy per fraction) and bowel. Tomotherapy was capable of replicating the peripheral dose achieved with brachytherapy, without the PTV hotspots inherent to interstitial brachytherapy. Similar maximum doses to bowel and bladder were achieved with both methods. Excessive small bowel and femoral head toxicity may result if previous pelvic irradiation is not planned accordingly. Significant challenges related to interfraction and intrafraction motion must be overcome if treatment of this nature is to be contemplated.

A dosimetric comparison between the supine and prone positions for three-field intact breast radiotherapy.

PURPOSE: Supine tangential radiotherapy for the intact breast is a standard component of breast conservation management; a supraclavicular (SCV) field can be added for patients at high risk for nodal failure. Treatment in the prone position has demonstrated improvements in lung sparing, but has been limited to early-stage patients in whom radiation to only the breast was indicated. We sought to investigate the dosimetric feasibility of treating women in the prone position, using a 3-field monoisocentric technique. METHODS: A total of 10 patients previously simulated supine and prone were selected for replanning. The heart, ipsilateral breast, contralateral breast, and axillary/SCV lymph node regions were contoured in accordance with Radiation Therapy Oncology Group guidelines. The 3-field monoisocentric plans were created for both the supine and prone scans. Target coverage, homogeneity, and organ at risk sparing were examined. RESULTS: Both plans achieved acceptable coverage of the breast. The mean percentage of the breast receiving at least 95% of the prescription dose (V95%) were similar in the prone and supine positions, 89.3% versus 90.7% (P = 0.29). Mean V95% of the level 3 axilla and SCV were 93.8% versus 97.0% prone versus supine (P = 0.16). The percentage of ipsilateral lung receiving >20 Gy was substantially reduced from 21.2% supine to 9.3% prone (P = 0.001). CONCLUSION: Three-field radiotherapy in the prone position appears to be dosimetrically equivalent to supine treatment with respect to target coverage, but the prone position decreases lung dose.

Cognitive Sparing during the Administration of Whole Brain Radiotherapy and Prophylactic Cranial Irradiation: Current Concepts and Approaches.

Whole brain radiotherapy (WBRT) for the palliation of metastases, or as prophylaxis to prevent intracranial metastases, can be associated with subacute and late decline in memory and other cognitive functions. Moreover, these changes are often increased in both frequency and severity when cranial irradiation is combined with the use of systemic or intrathecal chemotherapy. Approaches to preventing or reducing this toxicity include the use of stereotactic radiosurgery (SRS) instead of WBRT; dose reduction for PCI; exclusion of the limbic circuit, hippocampal formation, and/or neural stem cell regions of the brain during radiotherapy; avoidance of intrathecal and/or systemic chemotherapy during radiotherapy; the use of high-dose, systemic chemotherapy in lieu of WBRT. This review discusses these concepts in detail as well as providing both neuroanatomic and radiobiologic background relevant to these issues.

Sparing of the neural stem cell compartment during whole-brain radiation therapy: a dosimetric study using helical tomotherapy.

PURPOSE: To assess the feasibility of dosimetrically sparing the hippocampus and neural stem cell (NSC) compartment during whole-brain radiotherapy (WBRT) and prophylactic cranial irradiation (PCI). METHODS AND MATERIALS: We contoured the brain/brainstem on fused magnetic resonance /computed tomography images as the planning target volume (PTV) in 10 patients, excluding the hippocampus and NSC compartment as organs at risk. PCI and WBRT helical tomotherapy plans were prepared for each patient, with 1.0-cm field width, a pitch of 0.285, and a modulation factor of 2.5. We attempted to maximally spare the hippocampus and NSC compartment while treating the rest of the brain to 30 Gy in 15 fractions (PCI) or 35 Gy in 14 fractions (WBRT) with a V(100) of ≥95%. Plan quality was assessed by calculating mean dose, equivalent uniform dose (EUD), and biologically equivalent dose (BED) for organs at risk and the percent volume of the PTV receiving the prescribed dose of V(100). RESULTS: In the PCI plans, mean doses/EUD/BED for the hippocampus and NSC compartment were 11.5 Gy/13.1 Gy/15.7 Gy(2) (BED assuming alpha/beta ratio of 2Gy) and 11.5 Gy/13.1 Gy/12.3 Gy(10) (BED assuming alpha/beta ratio of 10Gy), respectively. In the WBRT plans, mean doses/EUD/BED for the hippocampus and NSC compartment were 11.8 Gy/14.8 Gy/16.8 Gy(2) and 11.8 Gy/14.8 Gy/12.8 Gy(10), respectively. The mean V(95) for the rest of the brain (PTV) was 96.9% for both the PCI and WBRT plans. Mean PCI and WBRT treatment times were 15.93 min (range, 14.28 min-17.50 min) and 20.18 min (range, 18.43 min-22.32 min), respectively. CONCLUSIONS: It is dosimetrically feasible to spare the hippocampus and NSC compartment using helical tomotherapy during the administration of whole-brain irradiation.

Intracranial metastatic disease rarely involves the pituitary: retrospective analysis of 935 metastases in 155 patients and review of the literature.

We present a case report of a patient recently treated at our institution for an isolated non-small cell lung cancer metastatic lesion to the sella, report the lack of involvement of the pituitary gland in a large single-institution series of treated intracranial parenchymal metastases, and review the pertinent literature. We reviewed cranial imaging studies (CT and MRI) for 935 metastases in 155 patients treated at our institution over the previous 3 years for intracranial metastatic disease. Special attention was paid to the skull base to document the presence of any metastatic disease involving the pituitary gland, infundibular stalk, sella turcica (including anterior and posterior clinoids), or diaphragm sellae. We found no other involvement of the pituitary gland or other sellar structures by metastatic disease in this series. Intracranial metastatic disease rarely involves the pituitary gland and infundibular stalk parenchyma, suggesting that this structure may be safely omitted from the treatment field during WBRT and prophylactic cranial irradiation (PCI). This treatment approach should reduce the late sequelae of treatment to this critical organ.

Intracranial metastatic disease spares the limbic circuit: a review of 697 metastatic lesions in 107 patients.

PURPOSE: We report the incidence of metastatic involvement of the limbic circuit in a retrospective review of patients treated at our institution. This review was performed to assess the feasibility of selectively sparing the limbic system during whole-brain radiotherapy and prophylactic cranial irradiation. METHODS AND MATERIALS: We identified 697 intracranial metastases in 107 patients after reviewing contrast-enhanced CT and/or MR image sets for each patient. Lesions were localized to the limbic circuit or to the rest of the brain/brain stem. Patients were categorized by tumor histology (e.g., non-small-cell lung cancer, small-cell lung cancer, breast cancer, and other) and by total number of intracranial metastases (1-3, oligometastatic; 4 or more, nonoligometastatic). RESULTS: Thirty-six limbic metastases (5.2% of all metastases) were identified in 22 patients who had a median of 16.5 metastases/patient (limbic metastases accounted for 9.9% of their lesions). Sixteen metastases (2.29%) involved the hippocampus, and 20 (2.86%) involved the rest of the limbic circuit; 86.2% of limbic metastases occurred in nonoligometastatic patients, and 13.8% occurred in oligometastatic patients. The incidence of limbic metastases by histologic subtype was similar. The incidence of limbic metastases in oligometastatic patients was 4.9% (5/103): 0.97%, hippocampus; 3.9%, remainder of the limbic circuit. One of 53 oligometastatic patients (1.9%) had hippocampal metastases, while 4/53 (7.5%) had other limbic metastases. CONCLUSIONS: Metastatic involvement of the limbic circuit is uncommon and limited primarily to patients with nonoligometastatic disease, supporting our hypothesis that it is reasonable to selectively exclude or reduce the dose to the limbic circuit when treating patients with prophylactic cranial irradiation or whole-brain radiotherapy for oligometastatic disease not involving these structures.

Variation in post-surgical lumpectomy cavity volume with delay in initiation of breast irradiation because of chemotherapy.

PURPOSE: The addition of a radiotherapy boost has been shown to improve local control in breast conservation therapy. Three dimensional planning provides more accurate targeting of the operative bed than clinical setup using the lumpectomy scar. However, contraction of the lumpectomy cavity over time may have implications for the volume of tissue included in the boost field. METHODS AND MATERIALS: The clinical variables and treatment planning volumes for patients receiving whole-breast radiotherapy at a single institution between July 1, 2006, and December 31, 2007 were analyzed retrospectively. RESULTS: Of the 93 patients identified, 29 received chemotherapy (CTX) and 64 did not; CTX was sequenced before radiotherapy in all patients. Patients receiving CTX were more likely to have higher T and N stage and a longer interval between definitive breast surgery and radiation. The lumpectomy specimens of women receiving CTX trended toward being larger than those of women not receiving CTX (113.4 cm(3) vs. 74.6 cm(3), p = 0.08). Despite this, the volume of the lumpectomy cavity measured on computed tomography was smaller in patients receiving CTX (9.1cm(3) vs. 16.8 cm(3), p = 0.02), as was the volume of the planning target volume (56.6 cm(3) vs. 79.9 cm(3), p = 0.02). CONCLUSIONS: Patients receiving CTX were at higher risk for local recurrence. However, as a result of lumpectomy bed contraction, these patients received a boost to a smaller volume than patients not receiving CTX. This finding is counterintuitive and supports re-evaluation of the optimal size of the boost field. In addition, these results may have implications for patients treated with partial breast irradiation.

Toxicity associated with bowel or bladder puncture during gynecologic interstitial brachytherapy.

PURPOSE: Interstitial brachytherapy for gynecologic malignancies is associated with significant toxicity. Some reports have correlated this toxicity with needle puncture of the visceral organs. This study examined our experience with interstitial brachytherapy and investigated the relationship between the visceral puncture and toxicity. METHODS AND MATERIALS: The outcomes of 36 patients treated with interstitial brachytherapy for gynecologic malignancies at a single institution between 2002 and 2007 were reviewed. Computed tomography was used to guide needle placement based solely on tumor coverage. No attempts were made to avoid visceral puncture; however, the source dwell times were minimized in these areas. RESULTS: At a median follow-up of 21 months, the crude locoregional control rate was 78%. Bowel puncture was noted in 26 patients and bladder puncture in 19. The mean operating time was 50 min, and 86% of patients were discharged in

Helical tomotherapy and larynx sparing in advanced oropharyngeal carcinoma: a dosimetric study.

Intensity-modulated radiation therapy (IMRT) is gaining acceptance as a standard treatment technique for advanced squamous cell carcinoma (SCC) of the oropharynx. Dose to the uninvolved larynx and surrounding structures can pose a problem in patients with significant neck disease, potentially compromising laryngeal function and quality of life. Tomotherapy may allow greater laryngeal sparing. Seven patients with stage IV SCC of the oropharynx were replanned using Tomotherapy version 3.1. All contours/planning target volumes (PTVs) from the original plans were preserved, with the exception of the larynx, which was drawn to include all soft tissue encompassed by the thyroid/cricoid cartilage. A simultaneous integrated boost technique was used with PTV 1, 2, and 3 receiving 69.96, 59.40, and 54.00 Gy, respectively in 33 fractions. Dosimetry was evaluated via the Pinnacle treatment planning system (TPS). Equivalent uniform dose (EUD) was calculated from the dose volume histogram (DVH) using the general method with "a" = 5.0. Mean larynx dose for all patients was 24.4 Gy. Mean EUD to the larynx was 34.2 Gy. Homogeneity was adequate; average maximum dose was 109.7% of the highest prescription. All other organs at risk (OAR) were adequately spared. Tomotherapy can spare the uninvolved larynx in the setting of advanced SCC of the oropharynx to levels that are similar to or better than those reported with other techniques. Sparing is achieved without compromising target coverage or other OAR sparing. The clinical benefit of this sparing remains to be determined in a prospective study.

A virtual matching technique for three-field breast irradiation using 3-D planning.

Patients with breast cancer are often treated with radiation to the breast (or chest wall) and draining regional lymph nodes. This is typically performed with a three-field technique in which an anterior supraclavicular field is matched to opposed tangent fields. A single isocenter technique is not always possible. Several techniques have been described to create a perfect match using a conventional simulator. We describe and test a simple, fast and accurate technique to estimate the couch and collimator angles required for a perfect geometric match using 3-D treatment planning software. This method requires no mathematical formulae and is verifiable relative to patient anatomy. An external skin contour is created on the axial slice at the match line and displayed with a 3-D representation. Using a beam's eye view (BEV) of a tangent field, small couch and collimator rotation adjustments are made sequentially until the contour edges are superimposed. The virtual external contour technique was easy to use, gave verification of the match in the BEV and yielded estimates of couch and collimator rotations very close to those calculated using published formulae.

Treatment of early stage thymic tumors: surgery and radiation therapy.

Tumors of the thymus are an uncommon entity, constituting 30% and 15% of anterior mediastinal masses in adults and children, respectively. The majority of these tumors are thymomas, with thymic carcinomas less common, and thymic carcinoids exceedingly rare. Recognition of the distinct clinicopathologic behavior of various thymic neoplasms is crucial to providing optimal treatment. Evidence guiding the treatment of early stage thymic tumors is limited secondary to the low incidence and resulting lack of randomized data. Proper management requires a careful analysis of the available literature with particular attention paid to limitations of the existing studies. This article provides a discussion of the presentation, evaluation, diagnosis, surgical techniques, and treatment outcomes relevant to early stage thymomas, thymic carcinomas, and thymic carcinoid tumors. The role of radiation therapy in the management of early stage thymic tumors remains controversial and is discussed in detail.