Assessing Patient Outcomes after Palliative Radiotherapy Using IG-IMRT ()
1. Introduction
Radiotherapy has long been proven as an effective tool in the palliation of symptoms caused by locally advanced and/or metastatic cancer [1-3]. Approximately 30% - 50% of a cancer center’s radiotherapy workload can consists of palliative treatments, all of which are focused towards managing patients’ symptoms which can adversely affect their quality of life [4,5]. Pain is the most common and burdensome symptom experienced by patients with advanced cancer and radiotherapy is very useful for treating this problem [6,7]. A meta-analysis completed in 2007 estimates that the prevalence of pain in patients with cancer at any stage of disease can be in excess of 50%, and in at least one third of the cases the pain is rated to be moderate or severe [8]. The instance of pain is even higher in patients with advanced and/or metastatic cancer.
Though exact numbers are difficult to determine from the published literature, radiotherapy has been estimated to effectively palliate symptoms in 50% - 80% of patients with advanced stage disease with relatively little toxicity [9]. An overview of the published literature [1-3,9] suggests palliative radiotherapy response rates in the range of 70% - 94% for at least partial relief of metastatic bone pain, 72% - 86% for hemoptysis, 60% - 90% for superior vena cava obstruction, and 64% - 73% spinal cord compression. These studies confirm that palliative radiotherapy plays a very significant role in the treatment of many patients and therefore worthwhile to investigate new approaches for treating these symptoms efficiently and effectively.
A typical palliative radiotherapy treatment plan is usually quite simple and often involves a strategy with either a single direct beam or parallel-opposed-pair technique [2,10]. Treatment planning for this process usually begins with the patient undergoing fluoroscopic (conventional) or computerized tomographic (CT) simulation, then the necessary treatment calculations and appropriate plans need to be developed before the patient can have the first treatment. In previously published study from our center [11], it was found that, on average at The Ottawa Hospital (TOH), it took 3 hours for the entire process using conventional fluoroscopic simulation and approximately 3.5 hours for those undergoing CT simulation. The patients typically send a considerable amount of time waiting after the simulation before they can have their treatment. They are usually moved to another area and wait before being brought in for treatment, and at the time of treatment they must be repositioned again on the treatment couch. However, more modern and sophisticated approaches to plan and deliver radiation are now available [12,13].
We have investigated the potential benefits of using helical TomoTherapy® with StatRT® software in a protocol called Tomo-PAL (Tomotherapy—Planning and Administration Linked) which integrates a built-in megavolt CT, dedicated inverse treatment planning, adaptive planning tools, and image-guided intensity-modulated radiotherapy (IG-IMRT) dose delivery into a single treatment unit [11]. The entire scan, plan, and treat process can be completed in approximately one hour on this single machine. The advantage is that the patient can remain on the treatment couch and in one room for the duration of the entire process and may only need to be set up once by a team of therapists. The patient does not have to repeatedly move from one area or room to another. This can limit the aggravation of painful symptoms form repeated movement and setups and reduces the number of staff involved ion the treatment. This also allows the patient to feel more comfortable and reduces the amount of time the patient spends in the radiotherapy department. Thus, the end result being a treatment process that is streamlined and more efficient for patients, and reduces their waiting in the radiotherapy department.
Our Tomo-PAL protocol has demonstrated how efficient the entire is purely from a time and resource utilization prospective. However, we hypothesized that palliative radiation treatment with this IG-IMRT approach should also provide clinically significant improvement in patient symptoms which would compare favourably with response rates cited in the literature with traditional approaches without increase in expected acute side effects. We therefore decided to retrospectively review clinical outcomes in patients treated on our previously published Tomo-PAL protocol.
2. Methods
After receiving ethics approval, a retrospective chart review was conducted on all patients treated on the TomoPAL protocol for advanced stage cancer. All the data was obtained from both TOH electronic records as well as hard-copy charts. Patients were treated on the TomoPAL protocol from February 2007-May 2009, and all are included in this study.
Data pertaining to symptom relief and acute side effects was extracted from electronic and paper records and entered into a Microsoft Excel spreadsheet. Data was collected at the time of patient treatment as well as for up to 5 follow up appointments. Data collected included diagnosis, presenting symptoms, treatment prescribe, as well as symptom response and side effects from treatment. If there was missing data in any category, it was classified not evaluable.
Once the data was collected the categorical means, maximum values and minimum values where calculated. Finally the data was analyzed to determine if there was any correlation between various aspects of patient, tumour and treatment factors and response rates. To measure the significant of these comparisons, Pearson’s Chisquare test was preformed.
3. Results
The study population consisted of 40 patients treated on the Tomo-PAL protocol and a total of 40 sites were treated. The median age of patients was 70 years, with a range of 16 - 94 years. There were slightly more male then female patients (62.5% versus 37.5%). The most common cancer diagnoses included prostate (22.5%), bladder (15%), and breast (10%). As shown in Figure 1, pain was overwhelmingly the most common symptom (80%) that patients presented with and for which they received palliative radiotherapy. Of the 40 patients, 32 appeared to have radiotherapy aimed towards pain relief. The causes of pain included the following: compression of vertebral bodies of the spine; bone fracture; pressure caused by bulky disease impinging on nerves; and total destruction of bone by cancer. Five patients (12.5%) were treated in an effort to stop bleeding and the remaining three patients were given palliative radiotherapy treatment for other symptoms.
Table 1 indicates that the sites of radiotherapy were mainly the axial skeleton (80%) including the spine, pelvis and sacrum. A small proportion (20%) of patients had radiotherapy to the abdomen, extremities or lungs. The