About Lung Cancer Radiotherapy

If you’ve had symptoms requiring a chest x-ray showing a concern or even a chance finding of an abnormality on a chest x-ray or CT scan then further tests will be needed to check for lung cancer. Some individuals who have been identified as having a reasonable risk of lung cancer, may have routine surveillance low dose CTs that might pick up a lung cancer. Once lung cancer is suspected, the next step is to confirm it by getting a tissue sample and also assessing the extent the cancer may have spread. It is important you let your doctor know all the symptoms you have as this will help to ensure the right regions of the body are being scanned. For instance, a persistent bad headache also requires the head to be scanned in addition to the body to check if there are brain metastases.

The tissue sample can usually be obtained by one of several different specialists – a respiratory physician, an interventional radiologist or a cardiothoracic surgeon. The sample will be used to identify the type of lung cancer, the aggressiveness or grade, and if it harbors particular molecular features which can direct targeted therapies or immunotherapy treatment options.

Most cancer centers will have a panel of specialists called a multi-disciplinary team or tumor board. This panel has the required expertise in lung cancer diagnosis and treatment, who can then review your case and your medical history and make recommendations on treatment options. This group of specialists can include cardiothoracic surgeons, radiation oncologists, medical oncologists, radiologists, palliative care specialists, pathologist and nurses. If surgery is not a suitable means to treat you, then either radiotherapy alone or a combination of radiotherapy and chemotherapy may be the recommendation. In less common situations, a decision may be made that surgery is the best option but final review of the tissue specimen after the operation is done may find that you require additional treatment with radiotherapy and chemotherapy.

There may be a recommendation upfront of using radiotherapy with chemotherapy to shrink the tumour before surgery is used.

If radiotherapy is a suitable means to treat you, then the intent of the treatment, the sequencing of treatment, dose of radiotherapy, technique and duration of treatment as well as whether chemotherapy is given concurrently with the radiotherapy may be discussed. A discussion about possible side effects will also occur.

A radiotherapy planning session will be required and, in this session, you will undergo a CT simulation scan. Certain techniques called breath hold, or gating may be used amongst others to help assess suitability of certain radiotherapy techniques and plan the radiotherapy. In this session, we will discuss the radiotherapy treatment together with some background information to help you be prepared.

Broadly speaking, lung cancer can be divided into 2 main groups, Non-Small Cell Lung Cancer (NSCLC) or Small Cell Lung Cancer (SCLC). These cancers behave differently and require different treatment approaches.

Early NSCLC is stage 1 and that can be treated by an operation or Stereotactic Ablative Body Radiation therapy (SABR). The standard of care as this point in time remains surgery for these very early cancers. Speak to your cardiothoracic surgeon for more information and what this involves and the amount of lung needed to be removed and the likely impact this will have on you. Not everyone with stage 1 lung cancer can have or wants to have surgery, this is where SABR is used currently. There is work being done now to see if SABR can be a replacement for lung surgery. The most common SABR treatments is 4 sessions, 5 sessions or 8 sessions. It is usually 2 to 3 treatments per week on alternate days. Each of this session can take quite some time to deliver, possibly an hour, as great precision is required to deliver this treatment safely. Treatment is on an outpatient basis.

Stage 2 and 3 NSCLC are not suitable for surgery, and can be treated with radiotherapy or a combination of radiotherapy with chemotherapy. The most common radiotherapy duration is 30 sessions over 6 weeks. Each session may last approximately 20 or more minutes. Treatment is on an outpatient basis.

If the NSCLC has already metastasized, it is then a stage 4 disease and unfortunately, control rather than cure of the disease will be the goal of treatment. If you are fortunate enough to harbor certain molecular features, you will have targeted therapies in addition to chemotherapies as treatment options. Immunotherapy is also an option. Radiotherapy to help control some of your symptoms may also be used.

SCLC is treated differently compared to NSCLC. Most oncologists will divide this cohort of patients into those with limited stage vs extensive stage. Limited stage SCLC is treated in most instances with a combination of chemotherapy and radiotherapy. Extensive stage lung cancer is treated with the aim of tumor control rather than cure as the intent. The same treatments of radiation therapy and chemotherapy are used but the sequencing is different in that chemotherapy is first administered followed by possible radiotherapy to the lung. The duration of treatment with radiotherapy is also shorter in extensive stage SCLC.

SCLC has a high likelihood of spreading to the brain and studies have shown that treating the brain, before this happens, with radiotherapy might be the favored approach. Discuss this further with your radiation oncologist. In some situations, you may decide more on surveillance with an MRI of the brain as an alternative to having brain radiotherapy.

The side effects you can experience from having the lung cancer irradiated depends on a number of factors. This includes how large the tumour is and your underlying lung function, which can already be compromised due to lung disease such as emphysema amongst others. Some side effects depend on how close other structures are around the lung cancer being irradiated. These structures can include the throat, the gullet called the esophagus, the heart, the stomach and the rib cage amongst others.

Common side effects from radiotherapy can include: Fatigue, itchiness, skin inflammation, cough, sore throat, swallowing difficulties. Uncommon side effects can include a persistent cough, scarring of the lungs that result in a decreased exercise tolerance, persistent chest wall pain, inflammation of the heart called pericarditis, fluid accumulation in the linings of the lung called pleural effusion, rib fractures, injury to nerves in the neck called the brachial plexus, injury to the spinal cord called myelopathy, blockages of the gullet due to scar tissue. SABR to central lung tumors can also be associated with rare but lethal side effects of bleeding. There is also a rare side effect possibly many years post treatment of radiation-induced second cancer.

The purpose of your planning session and time afterwards prior to starting your treatment is used to ensure you get the most accurate treatment and least impactful in terms of side effects. Some of the more significant side effects are uncommon or rare. Talk to your radiation oncologist about these as it may be so rare that even your oncologist has never encountered them.

Modelling data has found that close to 80% of patients with lung cancer will require radiotherapy at some point. Radiation therapy is a very useful treatment in lung cancer.

I hope this information helps you and do recommend you clarify any concerns or further questions you have with your oncologist.

© Ramesh Pandey March 2025