Treating Lung Cancer with Proton Therapy

Lung cancer accounts for almost 13 percent of all cancer diagnoses, with an estimated 224,390 new cases in 2016 alone.¹ Physicians and scientists, including those at the Northwestern Medicine Proton Center, work tirelessly on lung cancer treatments that improve outcomes while minimizing risks and side effects. Proton therapy is one method of treatment to come out of this research, especially for stage III non-small cell lung cancer (NSCLC).

Proton therapy uses precisely controlled protons so most of the radiation ends up directly in the tumor, reducing the risk of damage to surrounding healthy tissues. This is especially important when it comes to radiation treatment for lung cancer because the cancer may be close to critical organs.

Excess radiation to the healthy tissue surrounding a tumor can increase the risk of side effects. This is a major concern when it comes to radiation treatment for lung cancer because the cancer may be close to your heart, healthy lung, esophagus, and other critical organs. The unique properties of protons allow proton radiation to better conform to the tumor, reducing radiation to the healthy tissues and organs around it.

Proton therapy offers:

• Similar efficacy to other forms of radiation^2,3
• Less unnecessary radiation to your heart, lung, and esophagus⁴
• Significantly lower rates of pneumonitis and esophagitis (less inflammation of the lungs and esophagus) compared to X-ray radiation [3-D conformal radiation therapy (CRT) and Intensity-modulated radiation therapy (IMRT)]³

The image on the right shows the amount of radiation that the body receives during treatment for stage III NSCLC with proton therapy in comparison to X-ray/IMRT treatment. Colors indicate areas of the body that received radiation. Compared to IMRT, proton therapy significantly reduced the dose of radiation to surrounding tissue, especially the heart and the healthy lung.

The data in support of proton therapy and its unique advantages continues to grow. In a study with stage III NSCLC patients, proton therapy is estimated to reduce 34 percent of radiation to the heart and 45 percent to the healthy lung when compared to IMRT.⁴ A separate study from M.D. Anderson demonstrated that proton therapy had better than expected median survivorship, lower local recurrence, and improved side effects compared to historical controls.³ Comparison across studies evaluating high dose X-ray radiation and high dose proton radiation for locally advanced lung cancer suggests better treatment tolerability as well as outcomes with proton therapy.^2,5

Based on the data, the Proton Center has identified intrathoracic tumors, particularly lung cancers, as an area of where proton therapy can be a tremendous benefit for our patients. Since its inception, our center has treated intrathoracic tumors including many challenging primary and recurrent lung cancers. As our multidisciplinary thoracic oncology program continues to grow, we look forward to providing this leading-edge treatment to many more patients.

Proton therapy is considered safe, non-invasive and painless. Depending on the patient's diagnosis, treatments are usually given five days a week. Stage I lung cancer is typically treated over two weeks with anywhere from five to 12 treatments. For stage II and III lung cancer, the course of treatment is six to seven weeks with 30-35 sessions.

You should consider proton therapy if you:

• Have locally advanced lung cancer
• Need concurrent chemotherapy
• Have had prior radiation therapy
• Have limited or poor pulmonary function