CT density of pituitary gland is similar to brain. Upon contrast administration, the gland may become more hyperintense than brain due to the rich vascular supply. The anterior pituitary has 5 different types of cells, each with different radiosensitivity. Contouring of temporal lobe should include the hippocampus, parahippocampal gyrus and the uncus. The basal ganglia and insula are excluded from the contour. Cranially it starts for the superior end of sylvian fissure and ends inferiorly at the base of middle cranial fossa. Medial boundary is marked by cavernous sinus, sphenoid sinus and the sylvian fissure and laterally by the temporal bone.
The modern radiotherapy in HNC have revolutionized treatment outcome especially in terms of acute and late toxicity. It thus brings about a clear change in treatment outcome. We, as radiation oncologist are much aware about the importance of accurate delineation of these structures. Only an accurate delineation can lead to effective sparing and thus a desirable outcome in terms of QOL.
There were several isolated guidelines available. In this chapter we tried to summarize all the available guidelines. For certain organs like temporal lobe, multiple guidelines are available in the literature. We have tried to incorporate them together to put forward a single uniform consensus. Having said that the delineation and the attempted dose constraints should also be evaluated based on the target volume and tumor control. In case of parallel structures, the target volume coverage should be made priority and the risks and side effects of the same should be communicated to the patients.
In such cases the volume of OARs outside the planning target volume PTV may be delineated separately and similar dose constrains may be aimed for. It should also be kept in mind that even with the most sophisticated of technologies, not all of the dose constraints might not be achieved due the basic physics of the photon beam. In such situations a trade-off should be agreed upon. However, such liberties, should not be attempted with serial structures like spinal cord and brain stem.
Organs such as these should always be given hard constraints. If the PTV is overlapping such structures, under dose the area is accepted. There are several updates and the readers are encouraged to go through them at a regular interval. The second opportunity to work with IntechOpen publishers has been excellent. I must thank my colleague Dr. Nithin in crafting the manuscript and it was his enthusiasm which led to a detail manuscript. We both would like to thank our respective parents for all the support and blessings.
Nikhila respectively have been the greatest source of support. Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution 3. Help us write another book on this subject and reach those readers.
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Login to your personal dashboard for more detailed statistics on your publications. Edited by Dil Afroze. Edited by Pinar Erkekoglu. We are IntechOpen, the world's leading publisher of Open Access books. Built by scientists, for scientists.
Our readership spans scientists, professors, researchers, librarians, and students, as well as business professionals. Downloaded: Abstract With the advent of highly conformal and adaptive radiotherapy techniques, the significance of accurate delineation of organs at risk OARs is becoming more and more important.
Optic structures 2. Eye ball The entire eye ball is to be contoured as a single structure. Cornea The cornea is located anterior to the vitreous humor, iris, lens and ciliary body [ 2 ]. Retina It is the innermost layer of the globe and is about 0. Lens Biconvex structure in the aqueous humor, it is clearly visible in CT [ 2 ].
Optic nerve While moving craniocaudally, optic nerve is seen below the superior rectus. Optic chiasm A small structure is usually confined to 2 or 3 slices in the superior-inferior direction. Salivation related structures 3. Salivation related structures. Submandibular gland Situated in the floor of the mouth, it is a predominantly serous gland having a large superficial lobe and a small deep process separated by the fibers of mylohyoid.
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Sublingual gland Sublingual gland is the smallest of the three major salivary glands. Soft palate Soft palate contains numerous minor salivary glands. Other minor salivary glands These glands are distributed along the inner aspects of lips and buccal mucosa between the mucous membrane and the muscle layer. Lower lip glands The upper and posterior limit of the lip is better identified in sagittal sections.
Upper lip glands As of the lower lip, the lower and posterior extend is more easily made out in the sagittal plane. Orbicularis oris muscle can be used to delineate the glands anteriorly. Glands of buccal mucosa The glands of buccal mucosa are difficult to distinguish. Swallowing related structures 4. Swallowing related structures. Superior PCM They originate from sphenoid bone from its pterygoid hamulus and insert to the median raphe.
Middle PCM The fibers originate from the greater and lesser horns of hyoid bone and insert along the median raphe. Inferior PCM The thickest of the three constrictors, the inferior PCM has two parts—the thyropharengeal part which originate from the oblique line of thyroid cartilage and the cricopharyngeal part which originate from the lateral part of thyroid cartilage.
Cricopharyngeus Delineation starts cranially one slice below the level of arytenoids which also corresponds to the lower limit of inferior PCM. Supraglottic larynx The contour includes the supraglottic adductors oblique arytenoids and aryepiglottic muscles and epiglottis. Glottis The contour starts from the upper end of arytenoid cartilage and ends caudally at the lower edge of the cricoid.
Intra cranial structures 6. Ear structures Ear structures both the middle ear and inner ear should be contoured using the bone window. Cochlea It is a small spiral structure of about 0. All patients received adequate antiemetic and supportive medications during chemotherapy.. Response evaluation was done after 4—6 weeks of completion chemoradiotherapy and thereafter followed up every 1—3 months interval. Suspicious residual or recurrent lesions were confirmed by needle or tissue biopsy. Patients with residual or recurrent disease were offered salvage chemotherapy or possible surgical intervention or palliative treatment.
Toxicities appearing after 6 months were regarded as late toxicities and if occurred during treatment or up to 6 months following treatment were regarded as acute toxicities.. A two-sided level of significance of 0. Time-to-event data were described with the use of Kaplan—Meier curves. Confidence intervals were calculated for median progression-free survival and overall survival. Time-to-event intervals were compared between groups with the logrank test.. The median age for arm I was 54 years, while it was 50 years for arm II.
The majority of patients were males comprising 30 patients out of 32 in arm I and 34 patient out of 35 in arm II. Six patients Twenty one patients Ratio of oropharyx to hypopharyx in arm I and II were 1. Majority of patients in both groups had stage IV disease, constituting 22 patients Baseline characteristics of study population..
Same is true with partial and complete responses compared separately. Proliferative disease showed trend towards significance but could not reach the level of significance Table 2. For surviving patients in arm I, the median duration of follow-up was 22 months range 13—42 months while it was 23 months range 12—45 months in arm II. The 1 and 2 year PFS were The 1 and 2-year OS was There was a trend towards separation of two overall survival curve up to around 25 months but it was lost afterward.
It may signify effect of palliative treatment.. Response to treatment and survival.. The P value was calculated with the use of fisher test.. The P value was calculated with the use of chi-square test.. The P value was calculated with the use of log-rank test.. Progression free and overall survival.
Estimated with Kaplan—Meier method.. Acute toxicities were considered tolerable in both groups and except specific toxicities of gefitinib diarrhoea and skin rashes , no significance difference found in two groups Table 3. The most common acute adverse reactions encountered were, mucositis, radiation dermatitis, and dysphagia.
Most of them were grade 1 and 2 and were treated on an out patient basis. Late toxic effects recorded were xerostomia, subcutaneous fibrosis and laryngeal oedema.. Adverse Events of chemoradiotherapy acute and chronic.. Combined treatment approaches have become standard for patients with locally advanced squamous cell carcinoma of head and neck LA-SCCHN.
Multiple chemotherapeutic agents had been investigated; of which cisplatin was the most extensively used and was considered as the standard of care for patients with LA-SCCHN. Newer targeted therapy against EGFR receptor has shown response and benefit in palliative setting.
This study was done to see any advantage in response and survival, adding newer agent gefitinib with the most extensively used cisplatin as a chemoradiotherapy schedule.
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Advantages of concurrent chemoradiation over radiation alone for both definitive and post operative settings in head neck cancer, using cisplatin as the mainstay chemotherapy have proven in many large randomized studies and metanalyses. Cituximab, gefitinib and erlotinib were used in most of the studies. The role of these EGFR inhibitors in first-line, combined modality therapy for patients with head neck cancer remains undefined. Rao et al. Phase II studies published in , evaluating role of oral gefitinib as first-or second-line monotherapy in patients with recurrent or metastatic head neck cancer.
Preclinical studies strongly suggested that the combination of gefitinib and radiation completely inhibited the downstream signalling of EGFR and had a strong inhibitory effect on DNA-PKc pathways after. Whether addition of gefitinib can improve survival outcome in locally advanced SCCHN, considering encouraging response rates and minimal side effects in previous studies, this prospective study was designed. The two groups were comparable in terms of age and sex distribution, smoking habit, performance status, stage, and primary site.
In the study arm arm II , a greater proportion of patients achieved overall response Thirty one percent patients achieved CR in the control arm while However, this encouraging result could not be validated with a statistical significance. Addition of gefitinib to cisplatin based chemoradiotherapy regimen was well tolerated and toxicities in two treatment arms were comparable. Mucositis, radiation dermatitis, xerostomia, laryngeal oedema and dysphagia were most common radiation related grade III and IV reactions in both groups but no statistical significant difference in incidences Table 3.
None of the patients interrupted treatment due to radiation reaction and managed conservatively. No significant increase in late toxicities was noted as well. Exceptions to these findings were diarrhoea, and skin rashes which occurred significantly more in the gefitinib containing arm. However, both diarrhoea and skin rashes could be adequately managed conservatively and did not contribute to treatment delay.
Radiation Therapy for Head and Neck Cancer
Disease free survival DFS and overall survival analysis demonstrate difference in progression free survival and overall survival but it could not validate statistically. This is may be because of the underpowered study and small study population. Progression free survival as well as overall survival are comparable to other studies. As of now, we can comment that addition of gefitinib to classical cisplatin based chemoradiation is well-tolerated with encouraging results in terms of complete response in a subgroup of patients with proliferative morphology.
This study could not find statistically significant benefits in progression free survival and overall survival with addition of gefitinib. A larger and statistically powered study may find difference in survival.. The authors have no conflicts of interest to declare.. ISSN: Disponible online el 19 de Abril de Gefitinib with concurrent chemoradiation in locally advanced head neck cancer. Descargar PDF. Surendra Kumar Saini.
Autor para correspondencia. Under a Creative Commons license. Recibido 01 enero Aceptado 17 febrero Table 1. Background Chemoradiation is standard treatment in locally advanced oropharyngeal and hypopharyngeal cancer but only few surviving for long term. We compared cisplatin based concurrent chemoradiation with cisplatin and gefitinib based chemoradiation in patients with locoregionally advanced oro-hypo pharyngeal cancer.
Methods Patients of oro-hypo pharyngeal squamous cell carcinoma with age between 18 and 70 and with locally advanced stage III and IV, M0 were randomly assigned to receive either radiation with cisplatin mg 2 on d1, 23 and 43 or radiation with cisplatin in same dose plus gefitinib mg daily started two week before commencing radiotherapy till the end of radiation treatment. Primary and secondary end points were progression free and overall survival, respectively.
Results Out of total 67 patients randomized, 32 received cisplatin with radiation arm I and 35 received cisplatin plus gefitinib with radiation arm II. No statistically significant difference was found in toxicity profile of two arms. Conclusion Gefitinib and cisplatin combination is well tolerated concurrently with radiation but does not have impressive effect on response rate, progression free survival and overall survival, but encouraging result was seen in response rate in proliferative morphology. Palabras clave:.
Overview of Important “Organs at Risk” (OAR) in Modern Radiotherapy for Head and Neck Cancer (HNC)
Texto completo. Researchers cannot be sure if the way that radiation therapy is given affects how well the radiation stops or slows the growth of head and neck cancer. Researchers also cannot be sure if the way that radiation therapy is given affects how long you live. Radiation therapy can damage normal, healthy cells near and around your cancer. The damage may cause side effects. These side effects can be very different for different people.
Your side effects may depend on:. Side effects can appear around 2 weeks after the first radiation treatment or much later and can include:. Researchers do not know much about how side effects may differ for the different ways that radiation therapy can be given. There is only enough research to know about one side effect — dry mouth. Radiation therapy can damage the salivary glands the glands that make saliva, or spit. This can affect how much saliva is made and can lead to dry mouth.
Treatment Options: Johns Hopkins Head & Neck Cancer Center
Saliva is important for many things, and dry mouth can greatly affect quality of life. Saliva is needed as you eat to help you swallow your food. It also helps protect you from tooth decay and tongue and gum diseases by keeping bacteria from settling on your teeth, tongue, and gums.