Expert cohort consists of providers with expertise in administering epidermal growth factor receptor inhibitors (EGFRI) or treating patients with EGFRI-associated skin toxicities. Experts will be asked open-ended questions about symptoms and issues as they relate to HRQL in patients with EFGRI skin toxicities. Experts will then be presented with a pool of potential items and will be asked through interview and questionnaire to relate items according to how common and how important they are when occurring in patients with this condition.

Patient cohort will consist of those treated with an epidermal growth factor receptor inhibitor (EGFRI) and referred to a specialized dermatology clinic for skin rash management. Patients will be asked open-ended questions about symptoms and issues as they relate to their HRQL to elicit personal experiences about how EGFRI skin toxicities and its treatment affects patients. Patients will be asked through interview and questionnaire to rate items according to how often they are experienced and how important they are to the patient.

Administered questionnaire

Patients were asked "How important is this symptoms or concern to your quality of life?" They were given a series of items (listed in the table) and instructed to assign each item a numerical value of 0 to 3, where 0 is equivalent to "not at all important" and 3 is equivalent to "extremely important." Experts were asked "How important is this symptom or concern to patients' quality of life?" They were given the same series of items and instructed to assign each item a numerical value of 0 to 3, where 0 is equivalent to "not at all important" and 3 is equivalent to "extremely important." For each item, a mean score was calculated using the values assigned to that item from all patients, and a second mean score was calculated using the values assigned to that item from all experts. An item's mean score may range from 0 to 3, where 0 is equivalent to "not at all important to quality of life" and where 3 is equivalent to "extremely important to quality of life."

Expert cohort consists of providers with expertise in administering epidermal growth factor receptor inhibitors (EGFRI) or treating patients with EGFRI-associated skin toxicities. Experts will be asked open-ended questions about symptoms and issues as they relate to health-related quality of life (HRQL) in patients with EFGRI skin toxicities. Experts will then be presented with a pool of potential items and will be asked through interview and questionnaire to relate items according to how common and how important they are when occurring in patients with this condition.

Questionnaire : Administered questionnaire

Patients were asked "How important is this symptoms or concern to your quality of life?" They were given a series of items (listed in the table) and instructed to assign each item a numerical value of 0 to 3, where 0 is equivalent to "not at all important" and 3 is equivalent to "extremely important." Experts were asked "How important is this symptom or concern to patients' quality of life?" They were given the same series of items and instructed to assign each item a numerical value of 0 to 3, where 0 is equivalent to "not at all important" and 3 is equivalent to "extremely important." For each item, a mean score was calculated using the values assigned to that item from all patients, and a second mean score was calculated using the values assigned to that item from all experts. An item's mean score may range from 0 to 3, where 0 is equivalent to "not at all important to quality of life" and where 3 is equivalent to "extremely important to quality of life."

Additional items that were variably collected and recorded have been omitted from the data set.

Expert cohort consists of providers with expertise in administering epidermal growth factor receptor inhibitors (EGFRI) or treating patients with EGFRI-associated skin toxicities. Experts will be asked open-ended questions about symptoms and issues as they relate to health-related quality of life (HRQL) in patients with EFGRI skin toxicities. Experts will then be presented with a pool of potential items and will be asked through interview and questionnaire to relate items according to how common and how important they are when occurring in patients with this condition.

Questionnaire : Administered questionnaire