Brachytherapy for brain cancerDecember 13, 2018
Brachytherapy is an age-old method that is effective for irradiating cancer cells, especially in cervical, prostate, breast and skin cancers. This radiotherapy technique involves the introduction of a sealed source of radiation close to the area requiring treatment. Because of the proximity to the cancer cells, there is reduced probability of unnecessary damage to the neighbouring healthy cells. It is therefore relatively less harmful, even though high doses of localized radiation are delivered.
Brachytherapy is a minimally invasive technique that reduces the treatment duration for certain types of cancer and is often considered to be an alternative treatment for challenging cases. Due to the simplicity of the technique, it offers the ease of an outpatient treatment regimen with a quicker recovery time. It has also been proposed that the short treatment duration of brachytherapy may also be of potential benefit in preventing cancer recurrence. With all these benefits, it could well have been the treatment of choice in such cases. However, it is effective only in cases when the tumour is accessible. Moreover, the survival rates are not consistently superior to other radiation oncology techniques.
In India, brachytherapy is widely used for treating gynecological cancers. Some of the other types of cancer where it is used are those affecting the skin, prostate, head and neck, breast and even eyes. Despite its overall acceptability, this form of irradiation has not been reported for the treatment of brain tumours in India. In perhaps one of the first brachytherapy treatment cases for brain cancer, Dr. Manish Chandra, a Radiation Oncologist at Jupiter Hospital, Thane, successfully used this method on a patient recently.
A 40-year old man, who had high grade glioblastoma (WHO Grade IV), had previously undergone tumour resection surgery, followed by radiation therapy. By the end of 18 months post treatment, the cancer recurred and the patient had to undergo a second surgical procedure, followed by chemotherapy. Unfortunately, within a span of 2 months after the second surgery, the tumour was found to have recurred again. Since the tumour was recurring and repeated brain surgery has adverse effects, the patient was referred to Dr. Chandra for further treatment and follow-up. After carefully considering the patient’s previous history, age, the accessibility of the tumour, and most importantly, the fact that the patient was otherwise healthy, Dr. Chandra proposed brachytherapy as the best choice to go forward. The patient was also explained the reasons behind the proposed choice, and was willing to undergo the procedure. One of the challenges of this technique is the need to anticipate possible brain damage as the needles go through the brain tissue to reach the tumour. This procedure was performed in local anaesthesia and patient was conscious during the procedure.
Pre-procedure planning was quite elaborate as the exact location of the tumour needed to be mapped. A team of doctors, including Dr. Chandra, Neurosurgeon Dr. Harshad Purandare and technical person Mr Devarsh (3D – Rendering), first set about preparing a grid-based model using 3D images from MRI scans to determine the location at which the holes would need to be drilled in the skull for needle insertion and the length of the individual needles. At the time of the procedure, the pre-designed grid was marked on the skull of the patient such that the specific points within the grid were identified with a label and each label corresponded to the depth of the hole that was to be drilled. The process of pre-fixing the depth of the needle insertion to deliver the radiation is a very delicate and complex process and must be done keeping in mind not just the location of the tumour, but also the positioning of underlying blood vessels and the surrounding healthy tissue. Dr. Purandare then drilled 17 holes in the skull for needle insertion. The entire procedure was carried out under local anaesthesia and the patient was able to communicate with the operating surgeons throughout the surgery. Once the needles were fixed, confirmatory MRI and CT scans were done. After computerized treatment planning, the radiation therapy was delivered. Approximately 36 Gy was delivered in six fractions over three days.
The needles were then removed in the operation theatre on the 3rd day, as some blood/fluid leakage was expected. However, anaesthesia was not required for the needle removal process. The patient was kept in the ICU, where he was closely monitored over the next two days. A CT scan was done immediately after the removal of the needles and was found to be normal. By 24 hours, the CT showed minor bleeding, which was expected, and by 48 hours, the condition was stable. The patient was discharged and advised to come for regular follow-ups every three months. In his latest follow-up at six months, the MRI showed that the tumour size was stable. The patient had been relieved of his pre-brachytherapy symptoms of nausea, vomiting, and headache.
Many patients and their families have approached Dr. Chandra since the success of this treatment procedure. However, Dr. Chandra is very careful in selecting only those cases that are likely to benefit from this treatment. He further cautions that this therapy only prolongs life by 6-9 months on average and is not a cure for brain tumour, but just another way of managing the condition.