Shared Decision Making on Radiation Dose for Lung Malignancies

Shared Decision Making on Radiation Dose for Stereotactic Body Radiotherapy of Malignancies Located Less Than 1 cm From the Thoracic Wall. A Randomized Trial

A Patient Decision Aid (PtDA) is developed during a workshop in close collaboration with selected patients. The PtDA is subsequently used in the consultation between patient and physician to facilitate their shared decision on the dose of stereotactic body radiation therapy (SBRT) for lung tumors located less than 1 cm from the thoracic wall.

Hypothesis: The use of a PtDA will increase the extent of Shared Decision Making (SDM) during the consultation and result in patients being more directly involved in the planning of their treatment.

When a lung tumor is located close to the thoracic wall, there is an increased risk of developing chest wall pain or rib fracture following SBRT of the tumor. A meta-analysis has shown the pooled risk of chest wall pain to be 11% and that of rib fracture to be 6.3% with significant differences between individual studies. These side effects may occur several years after the treatment.

SDM is a collaborative process allowing patients and healthcare professionals to make decisions together taking into account the best scientific evidence as well as patients' values, preferences, life situation, and knowledge about disease process and prognosis.

PtDAs are tools designed to assist caregivers in the process of informing patients about relevant treatment options. PtDAs contain factual and balanced information about the options and the pertaining pros, cons, and probabilities. The tools are relevant when the decision is preference-sensitive, that is, the right treatment cannot be decided based on professional knowledge alone. The use of PtDAs has shown to provide a number of positive effects on the patients, including increased knowledge of options, better understanding of risks, and clarity as to what matters most in their life situation. Other effects are decreased decisional conflict and a higher degree of involvement in decision making.

This is a randomized trial enrolling eligible patients during a period of 16 months. SDM will be used in the planning of SBRT to patients with peripheral non-small cell lung tumors or lung metastases and offer them the choice between high (66 Gy in 3 fractions) and low (45 Gy in 3 fractions) radiation dose.

A total of 40 patients will be included in the study, i.e. 20 patients in each arm.

Inclusion Criteria:

• Age ≥ 18 years
• Histologically confirmed or high probability of non-small cell lung cancer, or metastasis from other cancer, located ≤ 1 cm from the thoracic wall. High probability refers to consensus on the diagnosis at the local multi-disciplinary lung tumor conference.
• Eligible for stereotactic body radiation therapy in ablative doses (i.e. 66/45 Gy in 3 fractions) following national guidelines (2).
• Can read and understand Danish.
• Written and orally informed consent.
• Performance status 0-2
• Life expectancy > 6 months assessed by the physician during the consultation.

Exclusion Criteria:

• Previous radiation therapy in the thoracic region (lung, breast or mediastinum), if it is not possible to produce a new radiation plan of 66 or 45 Gy in 3 fractions that considers previous radiation therapy and still complies with all constraints, including dose to the thoracic wall. Previous surgery in the thorax is allowed.
• Mental or social conditions preventing full understanding of the information or the planned treatment and follow-up.