Jordy felt something was wrong with her breast; she just could not say what it was. She had a mammogram, which was negative, and Jordy exhaled a big sigh of relief.
But she read the mammogram report more closely, which said her breasts were “heterogeneously dense.” Heterogeneously dense? What does that mean? It means that her breasts look white on mammograms. The problem with white, or dense mammographic breasts is that cancers are also white.
On a mammogram that is predominately white because the breasts are dense, a white cancer can quite easily be missed.
Jordy’s radiologist recommended an ultrasound and Breast MRI. The ultrasound was negative but because Jordy’s mother had breast cancer at age 44, Jordy was eligible for a Breast MRI, which found a small 0.8 cm cancer in her left breast. Jordy chose to have a lumpectomy.
Jordy now had a decision to make. She knows she will need radiation therapy, but should she have standard photon radiation therapy, also known as “X-Ray radiation treatment?” Or should she consider the new technology of proton radiation therapy?
The names are very similar – photon versus proton – but there is a world of difference. Photons, or X-Rays, are pure energy, have no mass and are weightless. Protons have energy but are massive and heavy. Think of photons as “fluffy” and protons as “portly.”
Radiation therapy uses photons or protons to deliver energy to kill cancer. Of course, radiation also affects healthy cells. In the breast, the most common side effect, a sun burn, occurs as the proton or photon travels through the skin and into the breast. This burn can be a short term problem but also a long term complication leading to burn scars and occasionally an unsightly breast.
But the real concern is when the radiation energy hurts the heart and lungs. The problem arises when radiation energy is released as the photon or proton exits the breast because it can pass through the heart or lungs and deposit enough energy to permanently damage these organs.
Significant delivery of radiation energy to the heart can lead to heart attacks and heart failure. Likewise, significant radiation doses to the lungs can lead to chronic inflammation of the lungs and loss of lung function.
The promise of proton therapy is that protons, as opposed to photons, deposit most of the energy in the breast. Very little radiation energy from protons goes beyond the breast and therefore, theoretically, there should be less energy delivered to and less complications to the heart and lungs.
So why doesn’t everyone use proton therapy then?
Cost. The cost of proton therapy can be significantly more than for photon radiation therapy, but if the side effects are significantly less, then the increased cost of proton radiation therapy could be worth the benefit of decreased complications and organ injury.
Modern photon radiation therapy is delivered with much safer techniques today. Better planning with CT scanners and more accurate delivery with Intensity-Modulated Radiation Therapy (IMRT) can lead to significantly less radiation energy to the heart and lungs. Therefore, proton radiation energy may not prove to be safer than standard photon radiation therapy and not warrant the additional costs.
Unfortunately, very few, if any, clinical trials have been done with proton radiation therapy for breast cancer. Computer models predict less radiation to unwanted organs with proton radiation therapy, but few clinical studies have examined these models.
On the other hand, no clinical trials have disproved the benefits of proton radiation therapy, which, in the end, may prove to be substantial. Studies using proton radiation therapy for breast cancer need to be done.
For cancers including prostate, lung and brain tumors, studies do exist proving the benefit of proton radiation therapy. Likewise, in children, proton radiation therapy is the modality of choice.
The one clinical scenario where proton radiation therapy may be worth the extra costs in breast cancer is in women with pre-existing cardiac or existing pulmonary disease and perhaps those with breast implants.
Jordy chose to have radiation therapy for her small breast cancer and she chose to do Accelerated Partial Breast Irradiation Therapy (APBI). While APBI is usually delivered with photons (X-Rays), a number of radiation centers now offer proton energy to deliver APBI. Jordy chose to participate in a clinical trial for APBI delivered by proton radiation therapy.