- Radiation Therapy
- Medical Oncology
- Surgical Oncology
What is radiation therapy?
With a history of nearly one hundred years, Radiation Oncology has made remarkable progress to occupy a very important place in the therapeutic armamentarium against cancer. Starting from radium and ordinary x-ray machines, the specialty has made tremendous strides with integration of information technology in radiation planning and delivery.
Radiation oncology uses photon beams (x-rays: artificially produced photons, gamma rays: photons emitted by radioactive atoms) and particulate radiation (electron beams, heavy particle radiation) for treatment of cancer. The basic principle of radiotherapy is that high-energy radiation has the capability of killing cells: both normal cells and cancer cells. The selectivity is achieved by delivering radiation to a target area containing the entire gross and microscopic tumor and minimizing the amount of normal tissue irradiated.
What is the role of radiation therapy in cancer treatment?
Radiation alone can cure more than 90% of early cancers of head & neck area, cancers of uterine cervix, and non-melanoma skin cancers. Concomitant radiation therapy and chemotherapy provides high cure rates in a large variety of cancers such as head & neck cancers, cancers of esophagus, cancer of uterine cervix, anal cancers, etc. In addition, post-operative adjuvant radiation therapy is a very important component of treatment for head & neck cancer, breast cancers, sarcomas, pelvic cancers, etc. In many situations, radiation therapy is administered before surgery for downstaging of tumours to improve the surgical results. For cases that cannot be cured, palliative radiation therapy has a very important role. Palliative radiotherapy can be used for relief of various symptoms such as pain, bleeding, obstruction, etc.
How is radiation therapy administered?
Radiation can be given by two different approaches: teletherapy (external beam radiotherapy) or Brachytherapy (internal radiotherapy).
External Beam Radiation Therapy
External beam radiotherapy can be delivered by cobalt (using gamma rays from radioactive cobalt) or by linear accelerators (using x-rays). Linear accelerators have the advantage of higher beam energies, more accurate radiation delivery minimizing damage to superficial tissues and less scatter at the periphery of the radiation field. Current linear accelerators have the capability to deliver both photons and electrons and multiple energy levels are available to tailor the radiation to the needs of a given patient.
Brachytherapy is the modality in which radiation is delivered by placing the radiation source within the tissues to be irradiated. There are many ways of doing this: intracavitary radiation (for cancer of the uterine cervix), intraluminal radiation (esophageal cancer, nasophaynx, ano-rectum), and interstitial radiation (breast cancer, soft tissue tumors, etc.), surface mould (skin tumors, palate tumors, eyelid tumors, etc.).
Brachytherapy was previously delivered using manual methods but such methods have a high risk of radiation exposure to doctors, staff and patient's family members. Remote after loading devices are the preferred methods for Brachytherapy. Remote after loading systems can be low dose rate (LDR) or high dose rate (HDR).
High dose rate systems have many advantages: they are more state-of-the-art, precise, safe and take much less time. With HDR equipment, a given dose of radiation can be delivered in a method of minutes compared to hours and days for LDR equipment. This has many advantages for the patient, as patient isolation for a long period is not necessary with HDR equipment. Admission to the hospital can be avoided when using HDR Brachytherapy.
What are the side effects of radiation therapy?
Radiation therapy is a modality that has a low rate of complications or side effects if properly planned and administered. However, certain symptoms do appear during radiation and it is important to be aware of them so that undue alarm or panic is not created.
Patients undergoing radiation therapy can have general symptoms such as
- Loss of appetite
- Nausea and vomiting
- Irradiated skin has some degree of swelling and becomes sensitive. If subjected to local trauma at this stage, there can be peeling of skin and oozing.
- Radiation to the head & neck area causes sensitivity in the mouth and throat (mucositis). This leads to some discomfort while swallowing. Attention to oro-dental hygiene and diet can usually minimize the symptoms and prevent development of secondary infections.
- Radiation to the lungs can cause symptoms such as cough and shortness of breath.
- Radiation to the abdomen can cause symptoms of nausea, vomiting and diarrhea.
- Radiation to the pelvis can cause symptoms such as discomfort in passing urine, increased frequency of micturition, diarrhea, straining at stools, etc.
- Radiation to any part of the body usually leads to loss of hair only in the area irradiated.
How can side effects of radiation be reduced?
There are two important approaches to reducing side effects of radiation therapy. One is the use of modern methods of radiation therapy planning and delivery and the other is the use of appropriate precautions as advised by the treating radiation oncologist.
Modern Methods in Radiation Therapy
With the availability of more powerful computers, two significant factors have contributed to advances in radiation oncology. One is the advance in imaging technologies. With more powerful CT scanners and MR imaging, a much more precise localization of the tumor and normal structures is possible at multiple levels of the body. This had led to the use of CT scan as the mode of choice for tumor localization and radiation field planning. The other change has been the development of more powerful radiation planning software that can utilize the sectional imaging information to develop more precise radiation plans that maximize the tumor dose, minimize the normal tissue dose and avoid dose heterogeneity within the radiation field. Three dimensional conformal radiation and intensity modulated radiotherapy has been the outcome of both these advances and are redefining the utility of radiation in management of cancer.
Precautions to be followed during radiotherapy:
- Do not rub the skin markings, if any.
- Do not apply anything (soap, powder, oil, cream) on the marked area / treated area.
- Do not scratch the treated area.
- If face is being treated, do not shave.
- Avoid spices and chillies in diet
- Do not smoke and do not take alcohol.
- Wear loose, cotton clothes around treated area.
- Take more fluids.
- Follow all other instructions given by the treating doctor.
- Consult your treating doctor once in a week for review.
- Consult your treating doctor anytime you have any unexpected symptoms.
What is medical oncology?
Medial oncology is the youngest branch of oncology and it deals with treatment of cancer using medicines and is also the most rapidly developing branch with new breakthroughs coming almost every day.
The specialty primarily originated from the identification of cytotoxic chemicals developed as part of chemical warfare. The "mustard" gases developed around World War II were found to be strongly cytotoxic to human beings with very strong effects on the hematopoietic system. It was this observation that led to attempts to use these agents and their derivatives in hematological malignancies first and solid cancers later.
Medical Oncology has taken a major leap and now forms a very important part of multimodality management of almost all cancers and specially hematological malignancies.
Initially developed for the administration of cytotoxic agents, the specialty has expanded its scope remarkably with newer agents that use many different mechanisms to treat cancer.
What is the role of medical oncology in treatment of cancer?
- Haematologic malignancies such as leukemias (blood cancers), lymphoma and multiple myeloma are treated primarily with medicines.
- Some of the solid cancers are potentially curable with chemotherapy. Examples of this include germ cell tumors and gestational trophoblastic disease. In such cases, chemotherapy has become the prime modality of treatment and may be complemented by limited surgery.
- Adjuvant chemotherapy has become an important modality in the treatment of many solid cancers such as breast cancer, colorectal cancer, etc. Adjuvant use of chemotherapy is based on the concept of micrometastases that can not be identified with any current imaging modalities but are responsible for the majority of recurrences after potentially curative local therapy.
- Neoadjuvant chemotherapy is chemotherapy administered up front to achieve downstaging of tumor, before use of a local modality such as surgery or radiation. Neoadjuvant chemotherapy can be used to make the disease operable if it was inoperable before or permit the use of limited local therapy. In breast cancer, neoadjuvant chemotherapy can be used in locally advanced breast cancer to make the tumors operable. In early disease, it is used to increase the chances of breast conservation surgery.
- In a number of situations, chemotherapy and radiotherapy are being used at the same time (not one after another) to treat malignancies. Chemotherapy here serves to enhance the efficacy of radiation and thus lead to improved loco-regional control rates. In some cases, this approach permits the use of organ conservation strategies. This has been used adequately at MTMH for cancer sites like head and neck cancers, cervix, lung and oesophagus.
- Palliative chemotherapy is a very important modality to improve the quality of life of a large proportion of cancer patients who present with advanced disease that is not amenable to curative treatment with surgery and/or radiotherapy. Here, chemotherapy can improve distressing symptoms and also lead to some prolongation of survival with good quality of life.
What are the medicines used in medical oncology?
Conventional chemotherapy drugs that kill dividing cells in the body. Since cancer cells are almost always rapidly dividing, they are preferentially killed.
Hormones and hormone antagonists
Hormonal antagonists and agonists have been very useful in the management of breast cancer in women and prostate cancer in men. A number of exciting new agents are becoming available that are enhancing the role of such interventions.
High dose chemotherapy
High dose chemotherapy is the use of more than the standard doses of chemotherapy and it is used in the management of more aggressive, relapsed, or advanced cancers that are often non-responsive to standard dose of chemotherapy.
Biological agents e.g. interferons, interleukins, etc
A number of biological agents such as interferons and interleukins have been found to have activity against some cancers. These agents have been particularly useful in the management of chronic myeloid leukemia, cancer of the kidney, superficial bladder cancers (follicular), non-Hodgkin lymphoma (follicular), Hairy cell leukemia, etc.
Immunotherapy: monoclonal antibodies.
A promising new field where exciting advances are taking place. Two monoclonal antibodies are currently available in the country (Trastuzumab or Herceptin for breast cancer, and rituximab or Mabthera for hematological maligancies).
Gene mutations are at the root of all cancers. Interventions at the genetic level are thus very attractive. Lot of research work has been going on and some products are expected to come into clinical practice soon.
Signal transduction inhibitors
Drugs such as tyrosine kinase inhibitors, anti angiogenesis drugs, farnesyl transferase inhibitors, etc are very tempting because they have the promise of being effective with oral administration and have negligible systemic toxicity. One of the top success stories is a new drug Gleevac (Imatinib) that has shown very high efficacy in chronic myeloid leukemia in all phases of disease. Newer products are expected to be available soon for a variety of cancers.
- Vascular access devices (ports / central lines).
- Arterial and Venous Pumps (elastomeric and / or electronic pumps).
- Growth factors to take care of low blood counts (febrile neutropenia).
- Blood component therapy including single donor platelets.
What is surgical oncology?
Surgical Oncology refers to the branch of medicine involved in treatment of cancers by surgery. Surgery was the first modality to be used in the treatment of cancer. With the developments of general anesthesia in the 19th century, major surgical procedures that are necessary for the treatment of cancer became possible. With advances in pre- and post-operative care, blood transfusion, antisepsis and development of antibiotics, such surgical procedures could be carried out with very low complication rates and negligible chances of death due to treatment. This led to an explosion in the field of surgical management of cancer. Originally, surgical treatment of cancers was carried out by general surgeons and other surgical specialists. Extensive surgical resections complemented with plastic and reconstructive surgery have been successful in the management of a large variety of cancers at all stages. Surgeons dedicated exclusively to cancer care are known as surgical oncologists.
Why should one prefer dedicated cancer surgeons?
With developments in the field of oncology leading to integration of multimodality management, it has become imperative that a surgeon dedicated exclusively to cancer care be involved in the surgical management of cancers in all cases. This leads to improved patient outcome in terms of better diagnostic and staging assessment, proper integration of surgical and non-surgical treatments, customization of surgery to the needs of the patient (extensive surgery in some cases to get cures and limited surgery in other cases for organ and function conservation).
Does surgery lead to a flare in the disease?
This is a dangerous misconception among the public. There is no evidence that surgery for cancer patients leads to the disease flaring up or becoming more aggressive. Because of this fear, a large number of cancer patients do not undergo the appropriate treatment at the right time. Delay often leads to the disease becoming advanced and the opportunity for cure is lost.
The basic nature of cancer is to grow. Often, there are cancer cells remaining in the body after the surgery even when the complete tumor has been removed adequately by surgery with a wide margin. These cells would grow over period of time and lead to the disease coming back. However, the recurrence is not caused by surgery. It is the inherent nature of disease.
Such remaining cancer cells need to be taken care of by post-operative adjuvant therapy such as radiotherapy or chemotherapy that significantly reduces the chances of the disease coming back. Currently, a large percentage of patients need to be treated with post-operative adjuvant therapy, either chemotherapy or radiation therapy or both to minimize the chances of disease recurrence. Thus, every cancer patient should have his case discussed in the tumor board after apparently complete surgery to decide about the need for further therapy.
It must be stressed that surgical treatment is one of the basic components of curative treatment in nearly all solid cancers. Often, if a patient's disease is inoperable, it may be beyond the chance of cure.
Is cancer surgery very disfiguring?
No! Cancer surgery is not a disfiguring surgery as it is practiced today. With the progress that has happened in the last century, majority of cancers can be managed without disfigurement.
One of the reasons for this is significant progress in plastic and reconstructive surgery. Use of various types of plastic surgical procedures leads to excellent cosmetic outcome and good functional status in almost all cases of cancer. In fact, it is possible to use plastic surgery to reconstruct breasts after they have been removed for breast cancer.
A thorough knowledge of plastic surgical procedures available and their application in the management of different cancers is another factor that distinguishes cancer surgeons. Proper selection of the plastic surgical reconstruction in a given case can make a lot of difference to the outcome.
Is cancer surgery very risky?
With the supportive services at the disposal of a surgeon in current times, the risk involved in major surgeries required for cancer treatment has become negligible. In fact, there are large series of a number of different major surgeries where there is no loss of life related to the surgical treatment.
There has been a significant reduction in the complication and mortality rates related to major surgeries over the last 20 to 30 years. Surgery for esophageal cancer can now be carried out with a mortality of less than 5%. Resection of liver, pancreatic surgery, extensive pelvic surgery, etc. can all be carried out now at low mortality rates if the modern methods of pre- and post-operative care are combined with a good surgical procedure.
What is the role of cancer surgery?
Surgery can be used for various purposes in the treatment of cancer.
Diagnosis: Biopsy of different tumors is a pre-requisite to treatment. Biopsy allows confirmation of malignancy and allows accurate typing of tumor. Nowadays, fine needle aspiration cytology (FNAC) is the preferred first investigation and biopsy is carried out if required. Biopsy can be incisional or excisional. Sometimes, frozen section examination is done to get intra-operative confirmation of diagnosis and carry out the necessary surgical treatment under the same anesthesia.
Curative Surgery: Surgery for cure of cancer is used in most of the solid cancers of the body e.g. cancers of the head & neck, salivary glands, thyroid, breast, lung and esophagus, liver, gastro-intestinal tract, kidney, urinary bladder and prostate, ovary, uterus and cervix, bone and soft tissues, external genitalia, etc. In a number of these cases, surgery may be followed by further treatment with radiation or chemotherapy to consolidate the gains.
Supportive and Palliative Surgery: Sometimes, surgery is required for relief of symptoms without cure of disease. Tracheostomy, feeding gastrostomy and jejunostomy, colostomy, and many such surgical procedures are carried out to provide relief of symptoms and be lifesaving without curing the disease. Surgery can also be done for control of bleeding from the tumor. Venous access surgery like placement of venous ports makes it easier for medical oncologists to do repeated administration of chemotherapy without causing distress to the patient. Arterial ports may be placed for intra-arterial chemotherapy.
Is cancer surgery very costly?
It is not so. In fact, a surgery carried out for cancer of any part is no more costly than a similar surgery carried out for non-cancerous diseases of the same area of body. Today, surgery for breast cancer is carried out at DCHRC at about the same cost as the surgery for gall bladder stones. There are a number of major surgical procedures in cancer surgery that are more extensive that surgery for non-cancerous diseases. In such cases, longer hospital stay may also be required and the overall cost of treatment may be slightly higher. Overall, at DCHRC, our objective is to minimize the hospital stay and treatment costs for the patients. With this in mind, one of the approaches followed is to minimize pre-operative hospital stay. Patients are many times called in the morning of surgery for admission if they do not have significant medical illness or do not need pre-operative preparation. Similarly, post-operative care is standardized to minimize post-operative hospital stay.