Discuss about the Theoretical Model for Respiratory Motion.
Mastectomy does not guarantee complete cure for early breast cancer patients; instead it increases the chance of recurrence because some tumor might remain in the chest wall. In such situation, radiation therapy is regarded as a targeted treatment option to kill or reduce the number of those cancer cells, which may remain even after surgery (McGale et al., 2014). External radiation therapy is most commonly given to patients after mastectomy. However, respiratory motion has been found to cause severe error during the radiation therapy. Respiratory motion leads to displacement of the tumour location and localizing the tumor in the chest wall becomes difficult in such cases. Another issue is that respiratory motion during irradiation leads to overdosing of normal tissues and underdosing of the tumor tissue or cells (Lewis & Jiang, 2009). One report gives evidence regarding the issues in patient after the breast cancer radiotherapy. Link was found between radiation therapy and high risk of breast cancer and lung problems. The study was done with 40, 781 women diagnosed with early stage breast cancer and they randomly assigned to radiation therapy and surgery or surgery alone. The follow up study after 10 years revealed that 20, 345 women died and the other 6, 064 had no breast cancer recurrence. However, compared to women treated without radiation therapy, women with radiation therapy were most likely to be diagnosed with lung cancer and heart disease. This is linked to the high amount of radiation exposure to lungs and heart during radiation therapy and a technique was needed that reduced the exposure rate to the lungs and heart of breast cancer patient (Taylor et al. 2017).
Use of deep inspiration breath hold (DIBH) has been recognized as a technique to minimize irradiation of cardiac structures without compromising target coverage. Although no clinical studies has demonstrated the effectiveness of the technique in reducing morbidity, however it has been found to decrease dose to cardiac structure. In case of left sided breast cancer patient, the mean heart dose should not be greater than 4Gy (Yeung et al., 2015). Hence, adjusting dose limit through DIBH minimizes the risk of ischemic heart disease due to radiotherapy.
Respiratory movement always remain a challenge in radiotherapy. Lot of research has been done to develop a technique that reduce the dose of radiation to normal cell (heart dose) in breast cancer patients (Giraud & Houle, 2013). To control the effects of respiratory motion during radiotherapy, the respiratory gating technique has been regarded as a solution to protecting the normal cells and managing respiratory motion. These techniques used five techniques to mitigate the respiratory motion effects. This includes using breath hold technique, forced shallow breathing technique, respiratory gating technique and tracking techniques. The main advantage of integrating respiratory movement into treatment planning is that it leads to geometric precision and dosimetric improvements (Giraud & Houle, 2013).
The main goal of the respiratory gating technique is to separate the target area and heart as far as possible and the process of maximum inspiration promotes delivery of high dose to the breast wall and chest tissue and reduce the heart dose (Nissen and Appelt, 2013). Many studies studied the benefits of deep inspiration breath-hold (DIBH) technique for management of respiratory motion. The DIBH is the technique of making the patient inspire to a threshold limit and then holding that limit of inspiration until the delivery of radiation therapy. This leads to lower exposure to the heart and adequate coverage of the breast wall (Latty et al., 2015). A broad range of literature exists regarding the benefits of DIBH technique in the management of respiratory motion. However, there is lack of literature regarding the diverse role of DIBH in relation to left sided breast cancer patient. Future research on understanding the role of DIBH for breast cancer radiotherapy is necessary specially for life sided breast cancer patients because such patients are at increased risk of cardiac abnormalities such as ischemia, congestive heart failure and coronary artery disease. DIBH is specifically targeted for left sided breast cancer patients because it maximizes the gap between heart and chest wall and reduces the cardiac dose (Mc Parland et al., 2015). The review and critical appraisal of specific articles related to DIBH application for treatment of left sided breast cancer patients will help in categorizing different roles of DIBH in reducing the risk of cardiac complication as a result of overdose due to respiratory motion.
To get access to research articles related to the role of DIBH in breast cancer radiotherapy, the article will be searched from MedLine, CINAHL, Cochrane Library and Google Scholar. The main criteria for searching the article was that the article must be published between 2006 to 2017 and English language must be used in all articles. The method of setting the data helped to filter the articles and the search term further ensured that relevant literature related to the topic has been retrieved. The primary search term included ‘DIBH’, ‘DIBH for breast cancer patient’, ‘management of respiratory motion by DIBH’ and ‘role of DIBH in managing respiratory motion in breast cancer patient’.
The main search strategy was to start with broad search terms first such DIBH and management of breast cancer radiotherapy and then find unique articles specific to the purpose of study. The articles were first screened on the basis of the title of the study and then by analysing the abstracts. On this basis, about 40 articles related to the topic were retrieved. However, after the analysis of the content of the articles, some articles were excluded because it did not focused on breast cancer patient or no insight was given regarding the role of DIBH for management of respiratory motion. Hence, the search strategy led to final retrieval of about 12 articles. Finally the critical appraisal of the article is done by means of thematic analysis approach. This literature review presents the role of DIBH in managing respiratory motion breast cancer radiotherapy by means of thematic analysis process and categorization of roles into different themes.
The research study by Keall et al. (2006) discussed about the role of DIBH in managing respiratory motion in left sided breast cancer patients. The study gave an insight into the magnitude of respiratory motion and the radiotherapy specific problems caused by the respiratory motion. Secondly, the technique to effectively manage respiratory motion during radiotherapy was explained by the researcher. The main finding of this study related to the role of DIBH in breast cancer radiotherapy was that the technique reduces respiratory tumour motion and modifies the internal anatomy of the thoracic system to protect normal tissues from harm. However, the efficacy of the treatment was found to be limited by level of patient’s compliance to the procedure. This was because majority of patients in the research setting were found inefficient in performing the respiratory manoeuvre in a proper manner. Despite highlighting this limitation, the strength of the study was that it gave idea regarding improving the efficacy of DIBH technique by pulmonary function test and starting a simulation series to analyse the discomforts faced by the patients during performing the DIBH technique. The core limitation was that radiation delivery related limitations were also found in the study which may limit the generalizability of the research data.
Another literature was found to be very specific to the purpose of this literature review as it studies about the dosimetric and clinical benefits of DIBH for breast cancer radiotherapy. The quality and validity of the paper was further strengthened by comparing DIBH with free breathing technique. To evaluate the clinical benefits of DIBH during the radiotherapy, eight left sided breast cancer patients were taken and supervised to conduct breath hold technique during radiotherapy (Bruzzaniti et al., 2013). The data and outcome was evaluated by acquiring CT scans both with and without breath hold technique. After this procedure, the dose volume histogram and volume of heart and lung irradiated to specific dose was analysed. The study findings showed that application of DIBH led to 16% reduction in mean dose of lungs and 20% reduction in iiradiated pulmonary volumes (Bruzzaniti et al., 2013). Hence, the study gave the implication that patient training is an important component for successfully using the DIBH technique during treatment. In this study, the supervision of patients during the procedure resulted in reduction in irradiated lung/ heart volume. Stranzl & Zurl, (2008) has also emphasized on reducing the heart volume in the irradiation field to reduce the dose delivery and protect normal tissues. Therefore, DIBH has been found to be effective in managing respiratory motion issues if patients receive adequate training in performing the procedure. However, the limitation of the DIBH approach as mentioned by the researcher was that this process requires a more complex set up and time needed to complete the radiation therapy increased in applying this technique for breast cancer patients.
The research by Vikström et al., (2011) also presented the dose related advantage of utilizing DIBH technique for breast cancer patient. Many studies have documented about cardiac disease and pulmonary complications during breast irradiation in patients. Hence, the researcher investigated about the role of DIBH in reducing cardiopulmonary doses. The study participants included seventeen patients with early breast cancer and referred for adjuvant radiotherapy. This study was also consistent with the study by Bruzzaniti et al., (2013) as the DIBH plan was found lower cardiac and pulmonary doses during radiotherapy. Therefore, it gives validated evidence that DIBH technique reduces the radiation dose to the heart and lung tissues for tangential breast irradiation. However, there are limitations to this study because the dose reduction was obtained by restricting planning target volume coverage. Despite this limitation, the implementing DIBH technique is easier in clinical practice compared to other technique in radiotherapy.
Advantage of DIBH related to patient outcome and compliance with the procedure
Cardiac complication has been regarded as major complications in breast radiation therapy. Considering the efficacy of the DIBH technique in reduce irradiated heart volume and increasing lung sparing, Cervino et al., (2009) evaluated about the improvement in reproducibility of the technique by means of visual coaching. To analyze whether video coaching enhances patient’s compliance with the procedure or not, the left breast cancer patient were asked to conduct DIBH with and without visual coaching. The variable of measurement in this research was the reproducibility and the stability of the technique with and without visual feedback. The results of the study proved that the visual coaching improves the reproducibility of the technique and the compliance with correct DIBH technique in patient. Hence, this research gave idea regarding the process that is needed to improve the efficacy of DIBH technique for breast cancer patient. Therefore, this form of visual coaching will lead to healthy tissue sparing and improved target coverage for patient.
Radiation treatment is indispensable to the treatment and management of malignancy and carcinogenic conditions. However, as commented by Lattyet al. (2015), radiation treatment can have a number of positive and negative effects on the longevity and survival rate of an individual. Recent studies have revealed that high doses of radiation exposure to the left breast could be related to increased rate of cardiac morbidity and mortality. The deep inspiration breath hold technique helps in regulating the amount of cardiac morbidity due to radiation exposure (McGale et al. 2014). As commented by Koivumäki et al. (2016), the radiation therapy to the left breast has long been a concern with respect to the adverse effects the same upon the longevity and recuperation rate of a patient. The deep inspiration hold breathing has been found to be effective in controlling the doses of radiation exposure to the left breast. This could be further supported with the help of relevant figures and statistics, which presents significant decrease in the cardiac mortality rate from 1.21 to 1.08 between 1973-1982. The DIBH technique adopts the patient to a specific and controlled set of radiation. This helps in reducing the anxieties in the patients regarding the contradictions attached with a certain procedure.
There is a number of breath hold methods which could be utilized for the provision of controlled and tested levels of radiation doses for the treatment of high malignancy in breast cancer suspects. There are pre-dominantly two theories and methods covering the DIBH methods over here such as the spirometry- based active breathing coordinator (ABC) and the video based real-time position management (RPM).The ABC device was developed by a Michigan based hospital and had been under active scrutiny since its inception. The model had been found to possess a huge number of perks along with deficits which has been addressed accordingly. The device consisted of a mouth piece attached to a spirometer, where the nose of the patient had been blocked to divert the passage of oxygen only through the device. The spirometer is connected to a computer, enabling the radiologist to keep a tab over the patient’s inspiration level. Once, the threshold level is reached, the pinch valves in the device closes automatically. As asserted by Kraan & Admiraal (2016), such controlled measure helps in assuring that exhalation and inhalation of the patient outside the threshold level is controlled tightly. However, as argued by Sayan, Hopkins, & Heimann (2016), the ABC device is aggressive in nature and could paramount to increased levels of anxiety in the patient.
There are a number of limitations with the DIBH devices, as the device gets interlocked with the linear accelerator. Therefore, the radiologist is required to manually control the inhalation and exhalation levels of the patient (Stranzl & Zurl, 2008). The, the ABC device however, shows good and effective control over the rates of respiration limiting the amount of pulmonary tissue damage (Hong et al. 2016).On the contrary, the RPM system monitors the images through an infrared camera mounted on the wall of the infrared unit, which is further supported by the surrounding infrared lights. In this respect, the device auto controls the valves regulating the inhalation and exhalation rates of the patients based upon the threshold level.
The DIBH procedure is less aggressive in nature and therefore helps in reducing the patient grievances during the delivery of the required treatment (Volpe et al. 2015). Moreover, the system is linked to the linear accelerator and automatically triggers the beam during the scanning process in case the breathing of the patient falls below the threshold level. Therefore, the system is much more efficient in the sense that the radiologists don’t have to manually control the settings compared to other conventional devices (Hong et al. 2014). However, studies and recent evidence have shown that both RPM and the ABC reduce the impact of radiation on the heart of the patients. However as argued by Kathpal et al. (2014), the implementation of the DIBH is largely dependent upon the participant organization and is accompanied with huge investment cost.
Limitations of the application of the model
There are a number of limitations of the DIBH model which hinders the incorporation and the implementation of the model within the hospital set up. As commented by Giraud & Houle (2013), lack of knowledge regarding the applicability of the model along with lack of adequate amount of infrastructure can prevent the implication of the emergent technology in the treatment of breast cancer patients (Keall et al. 2006). Additionally, high installation and maintenance charges often prevent the hospices from installing the model. Moreover, lack of skills in the health care professional used to the conventional methods of treatment can affect the health care plan and processes related to designing of effective and less painful treatment procedures for the ones with breast cancer. Additionally, coping up with the anxieties present in the patients regarding the current methods and the affectivity of the emergent medical procedures remains a debatable topic (Latty et al. 2015).
A number of challenges have been faced in the conducting of the literature review. Some of the gaps could be attributed to the availability of insufficient amount of journals articles specifically for left sided breast cancer patients. The DIBH being a recent medical intervention, comprehensive research and evaluation is not available yet. Therefore, lack of peer reviewed articles along with less availability of direct information from the medical professionals was a challenge. Additionally, lack of sufficient time for the conduct of the thorough research was also a limiting factor. Some of the relevant articles were published in language other than English resulting in accessibility issues. Moreover, some of the articles were priced thus making accessibility an issue for those articles.
The lack of knowledge and transparent communication process can affect the end result of a treatment procedure. There was lack of articles which evaluated the experienced of left sided breast cancer patients after using DIBH. This would have given greater idea about the benefits of DIBH for health outcome. As commented by Cervino et al. (2009), the inculcation of effective communication procedures can help in the establishment of the desired results. However, as per the ethics standards and guidelines the necessary and relevant information need to be shared with the support service users (Giraud & Houle, 2013).
The effective implementation of the DIBH methods implied that the level of pulmonary tissue damage caused by adverse effects of radiation could be controlled. Several studies and findings have pointed at the negative outcomes of high doses of radiation on the health and longevity of the patient availing the particular services. Therefore, inculcation of such methods can help in achieving speedy recovery of the patients along with producing a positive impact on the health outcome. There has been huge amount of correlation between the radiation overdoses and cardiac morbidities (Vikstrom et al. 2011). However, one of the major challenges encountered over here is the patient compliance and agreeability with the procedures.
The development of DIBH could help in carving out new niches by implementing advanced technologies for the treatment of breast cancer. There are a number of contradictions attached with high amount of radiation exposure to the left breast of the patients. Therefore, implementation of the deep inhalation breathing program could be useful in controlling the amount of radiation exposure. However, lack of sufficient knowledge regarding the handling and management of the DIBH instruments along with huge infrastructural costs involved can hinder the outcomes of the process. Moreover, such therapies might act as a research base for designing more efficient and minimally invasive diagnostic tools and interventions for management of chronic illness in patients. Additionally, such interventions could be possibly used for controlling the radiation hazards associated with highly sophisticated diagnostic methods and tools such as Magnetic Resonance Imaging (MRI).
The current assignment focuses on the aspect of DIBH model on addressing the perils associated with radiation overdose and its effect on the long terms cardiac conditions and well being of an individual. Therefore, the implementation of the DIBH model could be developed further for providing effective treatment and care to the patient receiving the radiation therapies. However, there are a number of limitations of the application of the model .This is mainly attributable to the lack of knowledge and proper skills in the health care professionals regarding the relevant measures which hinders the rate of success of the concerned methods and design. Additionally, lack of standard policies and compliance measures can affect the progress of the method within the current scenario.
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