Node Positive Bladder Cancer Can Be Treated With Intensity-Modulated Radiotherapy (IMRT)
Source: Thailand Medical News Jan 13, 2020 4 years, 10 months, 1 week, 2 days, 13 hours, 52 minutes ago
According to a new clinical trial, targeted forms of
radiotherapy can effectively treat
bladder cancer which has spread to the
lymph nodes of the pelvis. This form of
cancer, known as
node positive
bladder cancer has a particularly poor prognosis and hasn’t usually been treated with
radiotherapy. Patients are traditionally offered palliative treatment to manage their pain and other symptoms instead.
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Medical scientists at The Institute of Cancer Research, London, in conjunction with researchers and clinicians at The Royal Marsden NHS Foundation Trust, conducted a phase II clinical trial assessing the use of
radiotherapy in patients with
bladder cancer which had spread to the pelvic
lymph nodes.
Individuals whose
cancer had not yet spread to the pelvic l
ymph nodes, but who were considered to have cancer at a high risk of spreading to the
nodes, were also included in the study.
The research sought to assess the use of a type of
radiotherapy called
intensity-modulated radiotherapy (
IMRT) to treat the bladder and pelvic
lymph nodes and observe any toxic effects that resulted from the treatment.
Intensity-modulated radiotherapy or
IMRT is a type of
radiotherapy in which the shape of the
radiation beam is guided to fit closely around the shape of the tumour, while the machine moves around the patient’s body.
Certain patients who have chemotherapy and surgery to remove their
bladder and pelvic
lymph nodes do achieve control of their disease, but
radiotherapy is not typically offered as part of the treatment plan.
There are many concerns around the use of
radiotherapy in
bladder cancers centre on the risks involved in the toxicity caused by treatment of the whole pelvic area with
radiotherapy, which can cause symptoms such as diarrhoea, incontinence and rectal bleeding as the functions of the healthy tissues surrounding the
cancer are disrupted by the
radiation.
Typically, the severity of these symptoms is rated on a scale in grades from Grade 0 to Grade 4.
Dr Robert Huddart, Professor of Urological Cancer at the ICR and Consultant in Urological Oncology at The Royal Marsden, who led the study, told
Thailand Medical News, “We hypothesised that using
IMRT would give the best chance of maximising the dose of
radiation which is delivered to the tumours, while minimising the dose of
radi
ation delivered to healthy cells, reducing the risk of toxic side effects in patients.”
The research findings was published in the journal
Clinical Oncology and was conducted with part-funding from National Institute for Health Research’s Biomedical Research Centre at the Royal Marsden.
Certain of the patients in the study had already received chemotherapy to try to shrink the tumour before beginning
radiotherapy treatment, known as neoadjuvant chemotherapy. This allowed the researchers to assess whether chemotherapy alone, or chemotherapy in conjunction with
radiotherapy provides the best chances for these patients.
A total of 37 patients received
IMRT in this study.
Radiotherapy treatment was targeted at four separate areas ie the whole
bladder, pelvic l
ymph nodes, tumour bed and involved lymph nodes. CT scans were used to look at these four areas and plan the
radiotherapy treatment for each patient.
Daily,
radiotherapy was delivered to patients using
IMRT supported by cone-beam computed tomography imaging, a type of CT scan which allows clinicians to produce a virtual 3D image of the area to be treated.
Upon completion of the course of
radiotherapy, patients were reviewed at 4, 8 and 12 weeks to check for any toxic effects from treatment. Patients were then followed up every six months up to three years, and then annually up to five years.
Though most patients ie between 70.3% and 82.4%, suffered negative side effects, including diarrhoea and increased urinary frequency, most of these were mild to moderate and short-lived resolving in the weeks following treatment.
By twelve months after treatment, the levels of side effects had reduced dramatically. Just 5% of patients were experiencing side effects at the more severe end of the scale – Grades 3 and 4, one year after treatment. A check at four years reported that none of the patients was experiencing side effects at the more severe end of the scale.
It was observed that the five-year overall survival rate was 34%, which is comparable to the survival rate of node-positive
bladder cancer patients who receive chemotherapy and surgery alone.
Dr Huddart added, “This trial shows that delivering
IMRT to the pelvic
lymph nodes and
bladder is feasible as a part of a treatment plan for patients with node positive
bladder cancer, and patients are able to receive and tolerate appropriate doses of
radiation. More work needs to be done to combine
radiotherapy and chemotherapy to increase the chances of survival and decrease the chances of relapse but these results show that
IMRT radiotherapy is a promising new option for this group of patients.”
Reference: Tan, et al. (2020) The Intensity-Modulated Pelvic Node and Bladder Radiotherapy (IMPART) Trial: A Phase II Single-Centre Prospective Study. Clinical Oncology DOI: https://doi.org/10.1016/j.clon.2019.07.017
