Prostate Cancer is an age related cancer, which means it mainly affects those over 40 years of age. Radiotherapy plays an important role in treating it and other Pelvic cancers as well,” explains Dr. Surendran J – Senior Consultant Radiation Oncology (at Dr. Kamakshi Memorial Hospital) as he discusses the efficacy of their latest linear accelerator in the treatment of Pelvic Tumors.
Q:What are the main cancers that occur in the Pelvic region that can be effectively treated with Radiotherapy?
Dr:This would include tumors in the Prostate (in men) or Uterine Cervix (in women), Rectum and Urinary Bladder. These types of cancer usually affect those over 40 years of age. Earlier Prostate Cancer was more common in western countries, but today we are seeing more cases here.
Q:Is Radiotherapy the first line of treatment for all Pelvic cancers?
Dr:It is the definitive choice when it comes to Prostate cancer and Uterine cervix cancer. In most Prostate cancer cases, the disease progresses extremely slowly and the person shows next to no symptoms for an extended period of time. When it comes to Uterine Cervix cancer, the preinvasive stage can last up to 8 years and therefore there are strategic screening tests to detect the cancer. In the invasive stage (except during stage 4), with Radiotherapy as the main modality of treatment it is highly curable. In both these types of cancers the possibility for a complete cure is high. This makes it necessary to escalate(increase) the dose in order to eliminate the cancerous cells and bring about a curative outcome facilitated by Brachytherapy (Internal Radiation).
Q:Does Radiotherapy find use in treating tumors in the bladder and rectum?
Dr:Yes. In the case of Rectal or Bladder Cancer, Radiation is used to shrink the tumor and surgery is used to remove it or part of the affected organ. Usually, if the tumor is in the upper part of the rectum, that part alone is surgically removed and the parts above and below are fixed together. However, if the cancer is in the middle or lower part of the rectum and nearer the anal canal, this method not possible. Earlier after the part with the tumor was surgically removed, a colostomy was performed creating an opening for the colon, or large intestine, through the abdomen. However, today’s trend is sphincter sparing procedures to avoid colostomy. Radiation helps to shrink the tumor and allow for surgery.
Q:What is Image Guided Radiation Therapy?
Dr:Radiation Therapy begins with Planning of the Treatment that involves first taking a CT scan of the tumor and the affected organ, along with the crucial organs in the vicinity of the tumor. This allows us to decide the extent of the dose to be delivered and also how much of the organ needs to be exposed. Before carrying out the planned treatment on the patient, it is verified on a simulated spatio-temporal localization on the planning system and the treatment room, to ensure our plan is on point. Once we have locked in on the dosage and region of exposure, this registered image and information is shared with the linear accelerator. At the time of treatment, the linear accelerator also does a CT scan on the targeted region. This acquired image is then compared with the registered image. If both match then the treatment is carried out. However, in the case of the prostate or uterus, since they lie in close proximity to the rectum and the bladder, their position depends on how full the other two organs are. A full bladder will push the prostate backwards. If the bladder is near empty, the prostate will be more towards the front. This is why the registered image and the acquired image need to be compared and matched before the radiotherapy session begins to ensure the dose is rightly targeted. This is Image Guided Radiation Therapy (IGRT).
Q:What is Adaptive Radiation Therapy?
Dr:During the course of radiation after delivering a satisfactory dose, tumors can show regression in size and volume. In such a situation, targeting the same region as decided upon earlier, will mean more normal cells getting affected. Once the tumor size reduces, the targeted region can be reduced and the dosage can be escalated. This is Adaptive Radiation Therapy(ART). IGRT and ART make it possible to carry out Stereotactic Body Radiotherapy (SBRT) which is a specialised radiation delivering technique to deliver ablative tumoricidal doses of radiation with definitive accuracy and minimising exposure of normal adjacent tissues to the dose.
Q:Can Radiotherapy benefit children diagnosed with cancer?
Dr:Yes, radiotherapy does play a part in treating pediatric cancers. While mostly we use chemotherapy for children, certain solid pediatric tumors can be completely cured by including Radiotherapy along with chemotherapy. The challenge is to reduce the morbidity or adverse impact on normal tissues. Craniospinal Irradiation for the treatment of pediatric brain tumours especially Medulloblastoma can be performed with increased precision using Volume Modulated Arc Therapy (VMAT) which shapes the radiation dose to the tumour while minimising the dose to the organs surrounding the tumour
Q:And is the linear accelerator at Dr. Kamakshi Memorial Hospital equipped to carry out procedures in adults and children?
Dr:The soon-to-be installed linear accelerator at Dr. Kamakshi Memorial Hospital is one of the finest radiotherapy equipment available in cancer treatment and can be adapted to be used on adults and children. It can be used to treat all body sites, using advanced techniques such as Image Guided Radiation Therapy (IGRT), Adaptive Radiation Therapy (ART), Volumetric Modulated Arc Therapy (VMAT), Stereotactic Radiotherapy (SRT) and Stereotactic Body RadioTherapy (SBRT).
SENIOR CONSULTANT – RADIATION ONCOLOGY
MBBS, MD R.T,