Anand Desai

Effectiveness of image-guided radiotherapy for laryngeal sparing in head and neck cancer

We would like to compare the effectiveness of image-guided (IGRT) and intensity-modulated (IMRT) radiotherapy to spare the larynx in head and neck cancer patients. A retrospective review of 48 patients undergoing radiation for non-laryngeal and non-hypopharyngeal head and neck cancers. Mean laryngeal and hypopharyngeal dose was compared between 11 patients treated with IMRT and 37 patients treated with IGRT. Mean laryngeal dose was, respectively, 41.2 Gy and 22.8 Gy for the IMRT and IGRT technique (p<0.001). The radiation dose to the middle and inferior pharyngeal muscles was also significantly reduced with the IGRT technique. Mean pharyngeal dose was, respectively, 52 Gy and 26 Gy for the IMRT and IGRT technique (p=0.0001). Laryngeal sparing IGRT technique for head and neck cancer minimizes radiotherapy dose to the larynx and pharynx without sacrificing target coverage, even in the presence of neck lymph nodes.

Feasibility of tomotherapy to reduce normal lung and cardiac toxicity for distal esophageal cancer compared to three-dimensional radiotherapy

PURPOSE To compare the effectiveness of tomotherapy and three-dimensional (3D) conformal radiotherapy to spare normal critical structures (spinal cord, lungs, and ventricles) from excessive radiation in patients with distal esophageal cancers. MATERIALS AND METHODS A retrospective dosimetric study of nine patients who had advanced gastro-esophageal (GE) junction cancer (7) or thoracic esophageal cancer (2) extending into the distal esophagus. Two plans were created for each of the patients. A three-dimensional plan was constructed with either three (anteroposterior, right posterior oblique, and left posterior oblique) or four (right anterior oblique, left anterior oblique, right posterior oblique, and left posterior oblique) fields. The second plan was for tomotherapy. Doses were 45 Gy to the PTV with an integrated boost of 5 Gy for tomotherapy. RESULTS Mean lung dose was respectively 7.4 and 11.8 Gy (p=0.004) for tomotherapy and 3D plans. Corresponding values were 12.4 and 18.3 Gy (p=0.006) for cardiac ventricles. Maximum spinal cord dose was respectively 31.3 and 37.4 Gy (p < 0.007) for tomotherapy and 3D plans. Homogeneity index was two for both groups. CONCLUSIONS Compared to 3D conformal radiotherapy, tomotherapy decreased significantly the amount of normal tissue irradiated and may reduce treatment toxicity for possible dose escalation in future prospective studies.

Impact of image-guided radiotherapy to reduce laryngeal edema following treatment for non-laryngeal and non-hypopharyngeal head and neck cancers

We would like to determine the effectiveness of image-guided radiotherapy (IGRT) to reduce laryngeal edema following treatment for head and neck cancer and to assess patient perception of voice and speech after treatment. We conducted a retrospective review of 44 patients undergoing radiation for non-laryngeal and non-hypopharyngeal head and neck cancers. Endoscopic and/or mirror examinations of the larynx were performed following radiotherapy at each follow-up visit. Laryngeal edema was assessed based on the Radiation Therapy Oncology Group grading scale. Patients were also asked to rate about the voice and speech quality relative to their pre-radiotherapy status. The mean laryngeal dose was 16.3 Gy (range: 11.7-45.5 Gy). At a median follow-up of 14 months (range: 2-31 months), three patients (7%) developed laryngeal edema (one grade 1, two grade 2). The mean laryngeal dose was respectively 20.3 Gy in two patients and 20.7 Gy in the third patient developing laryngeal edema. Except for one patient who continued to smoke and drink after radiotherapy, no patient reported any significant change in voice and speech quality after treatment. IGRT results in low rates and low severity of laryngeal edema following treatment for non-laryngeal and non-hypopharyngeal head and neck cancers and may preserve voice quality.

Feasibility of tomotherapy for Graves’ ophthalmopathy

PurposeTo compare the dosimetry of tomotherapy and the conventional half-beam technique (HBT) or non-split beam technique (NSBT) for target coverage and radiation dose to the lacrimal glands and lens.Patients and MethodsA retrospective review of 7 patients with Graves’ ophthalmopathy who had radiotherapy because of disease progression on high steroid dose is reported: 3 patients were treated with tomotherapy and 4 patients with HBT.ResultsCompared to HBT, tomotherapy may provide better target coverage and significant reduction of radiation dose to the lacrimal glands and a higher dose to the lens. The NSBT improved target coverage but resulted in significantly higher doses to the lens and lacrimal glands.ConclusionTomotherapy may provide better coverage of the target volume and may be more effective in reducing severe exophthalmos compared to the conventional radiotherapy technique.ZusammenfassungZielVergleich zwischen Dosimetrie der Tomotherapie und der konventionellen Half-beam-Technik (HBT) oder Non-split-beam-Technik (NSBT) für die Erfassung des Zielvolumens und der Strahlendosis an Tränendrüsen und Linse.Patienten und MethodenEine retrospektive Analyse von 7 Patienten mit Graves’ Ophthalmopathie, die wegen Progression der Erkrankung zur Notwendigkeit hochdosierter Steroidgabe eine Strahlentherapie erhielten. 3 Patienten wurden mit Tomotherapie und 4 Patienten mit HBT behandelt.ErgebnisseIm Vergleich zu HBT konnte die Tomotherapie bessere Erfassung des Zielvolumens und signifikante Reduktion der Strahlendosis an den Tranendrüsen sowie eine höhere Strahlendosis an der Linse erreichen. NSBT verbesserte die Erfassung des Zielvolumens, resultierte aber in signifikant höherer Strahlendosis an Linse und Tränendrüsen.SchlussfolgerungTomotherapie kann – verglichen mit konventioneller Strahlentherapietechnik – zu besserer Erfassung des Zielvolumens und wirksamerer Verminderung des schweren Exophthalmus führen.

Feasibility of tomotherapy for Graves' ophthalmopathy: Dosimetry comparison with conventional radiotherapy.

PurposeTo compare the dosimetry of tomotherapy and the conventional half-beam technique (HBT) or non-split beam technique (NSBT) for target coverage and radiation dose to the lacrimal glands and lens.Patients and MethodsA retrospective review of 7 patients with Graves’ ophthalmopathy who had radiotherapy because of disease progression on high steroid dose is reported: 3 patients were treated with tomotherapy and 4 patients with HBT.ResultsCompared to HBT, tomotherapy may provide better target coverage and significant reduction of radiation dose to the lacrimal glands and a higher dose to the lens. The NSBT improved target coverage but resulted in significantly higher doses to the lens and lacrimal glands.ConclusionTomotherapy may provide better coverage of the target volume and may be more effective in reducing severe exophthalmos compared to the conventional radiotherapy technique.ZusammenfassungZielVergleich zwischen Dosimetrie der Tomotherapie und der konventionellen Half-beam-Technik (HBT) oder Non-split-beam-Technik (NSBT) für die Erfassung des Zielvolumens und der Strahlendosis an Tränendrüsen und Linse.Patienten und MethodenEine retrospektive Analyse von 7 Patienten mit Graves’ Ophthalmopathie, die wegen Progression der Erkrankung zur Notwendigkeit hochdosierter Steroidgabe eine Strahlentherapie erhielten. 3 Patienten wurden mit Tomotherapie und 4 Patienten mit HBT behandelt.ErgebnisseIm Vergleich zu HBT konnte die Tomotherapie bessere Erfassung des Zielvolumens und signifikante Reduktion der Strahlendosis an den Tranendrüsen sowie eine höhere Strahlendosis an der Linse erreichen. NSBT verbesserte die Erfassung des Zielvolumens, resultierte aber in signifikant höherer Strahlendosis an Linse und Tränendrüsen.SchlussfolgerungTomotherapie kann – verglichen mit konventioneller Strahlentherapietechnik – zu besserer Erfassung des Zielvolumens und wirksamerer Verminderung des schweren Exophthalmus führen.

Image-Guided Radiotherapy and -Brachytherapy for Cervical Cancer

Conventional radiotherapy for cervical cancer relies on clinical examination, 3-dimensional conformal radiotherapy (3D-CRT), and 2-dimensional intracavitary brachytherapy. Excellent local control and survival have been obtained for small early stage cervical cancer with definitive radiotherapy. For bulky and locally advanced disease, the addition of chemotherapy has improved the prognosis but toxicity remains significant. New imaging technology such as positron-emission tomography and magnetic resonance imaging has improved tumor delineation for radiotherapy planning. Image-guided radiotherapy (IGRT) may decrease treatment toxicity of whole pelvic radiation because of its potential for bone marrow, bowel, and bladder sparring. Tumor shrinkage during whole pelvic IGRT may optimize image-guided brachytherapy (IGBT), allowing for better local control and reduced toxicity for patients with cervical cancer. IGRT and IGBT should be integrated in future prospective studies for cervical cancer.

Image-guided radiotherapy for cardiac sparing in patients with left-sided breast cancer

Patients with left-sided breast cancer are at risk of cardiac toxicity because of cardiac irradiation during radiotherapy with the conventional 3-dimensional conformal radiotherapy technique. In addition, many patients may receive chemotherapy prior to radiation, which may damage the myocardium and may increase the potential for late cardiac complications. New radiotherapy techniques such as intensity-modulated radiotherapy (IMRT) may decrease the risk of cardiac toxicity because of the steep dose gradient limiting the volume of the heart irradiated to a high dose. Image-guided radiotherapy (IGRT) is a new technique of IMRT delivery with daily imaging, which may further reduce excessive cardiac irradiation. Preliminary results of IGRT for cardiac sparing in patients with left-sided breast cancer are promising and need to be investigated in future prospective clinical studies.

Feasibility of image-guided radiotherapy based on helical tomotherapy to reduce contralateral parotid dose in head and neck cancer

BackgroundTo evaluate the feasibility of image-guided radiotherapy based on helical Tomotherapy to spare the contralateral parotid gland in head and neck cancer patients with unilateral or no neck node metastases.MethodsA retrospective review of 52 patients undergoing radiotherapy for head and neck cancers with image guidance based on daily megavoltage CT imaging with helical tomotherapy was performed.ResultsMean contralateral parotid dose and the volume of the contralateral parotid receiving 40 Gy or more were compared between radiotherapy plans with significant constraint (SC) of less than 20 Gy on parotid dose (23 patients) and the conventional constraint (CC) of 26 Gy (29 patients). All patients had PTV coverage of at least 95% to the contralateral elective neck nodes. Mean contralateral parotid dose was, respectively, 14.1 Gy and 24.7 Gy for the SC and CC plans (p < 0.0001). The volume of contralateral parotid receiving 40 Gy or more was respectively 5.3% and 18.2% (p < 0.0001)ConclusionTomotherapy for head and neck cancer minimized radiotherapy dose to the contralateral parotid gland in patients undergoing elective node irradiation without sacrificing target coverage.

Potential Applications of Image-Guided Radiotherapy for Radiation Dose Escalation in Patients with Early Stage High-Risk Prostate Cancer

Patients with early stage high-risk prostate cancer (prostate specific antigen > 20, Gleason score > 7) are at high risk of recurrence following prostate cancer irradiation. Radiation dose escalation to the prostate may improve biochemical-free survival for these patients. However, high rectal and bladder dose with conventional three-dimensional conformal radiotherapy may lead to excessive gastrointestinal and genitourinary toxicity. Image-guided radiotherapy (IGRT), by virtue of combining the steep dose gradient of intensity-modulated radiotherapy and daily pretreatment imaging, may allow for radiation dose escalation and decreased treatment morbidity. Reduced treatment time is feasible with hypo-fractionated IGRT and it may improve patient quality of life.

Feasibility of Tomotherapy-Based Image-Guided Radiotherapy to Reduce Aspiration Risk in Patients with Non-Laryngeal and Non-Pharyngeal Head and Neck Cancer

Purpose The study aims to assess the feasibility of Tomotherapy-based image-guided radiotherapy (IGRT) to reduce the aspiration risk in patients with non-laryngeal and non-hypopharyngeal cancer. A retrospective review of 48 patients undergoing radiation for non-laryngeal and non-hypopharyngeal head and neck cancers was conducted. All patients had a modified barium swallow (MBS) prior to treatment, which was repeated one month following radiotherapy. Mean middle and inferior pharyngeal dose was recorded and correlated with the MBS results to determine aspiration risk. Results Mean pharyngeal dose was 23.2 Gy for the whole group. Two patients (4.2%) developed trace aspiration following radiotherapy which resolved with swallowing therapy. At a median follow-up of 19 months (1–48 months), all patients were able to resume normal oral feeding without aspiration. Conclusion and Clinical Relevance IGRT may reduce the aspiration risk by decreasing the mean pharyngeal dose in the presence of large cervical lymph nodes. Further prospective studies with IGRT should be performed in patients with non-laryngeal and non-hypopharyngeal head and neck cancers to verify this hypothesis.