Radiation Yes or No?
Whether to have radiotherapy is a hard decision. This is especially true because it can only be done once. Should it be saved in case an invasive cancer occurs later or used now for non-invasive DCIS?
Doctors debate if everyone with breast conserving surgery needs radiation. The case for radiation comes from studies that have consistently shown radiation after a lumpectomy reduces the risk of recurrence by approximately 50 percent. While this may provide comfort to someone able to reduce her risk from 30 to 15 percent for instance, the benefits of radiotherapy may not outweigh the harms for someone with a recurrence risk of 10 percent or less.
A summary of harms appears in a 2007 article from the Journal of Surgical Oncology, by Dr. Melvin Silverstein and Dr. Michael Lagios. “Radiation therapy is expensive, time consuming and is accompanied by significant side effects in a small percentage of patients. Radiation fibrosis of the breast is a more common side effect… Radiation fibrosis changes the texture of the breast and skin, makes mammographic follow-up more difficult, and may result in delayed diagnosis if there is a local recurrence. Radiotherapy may do harm: Numerous studies have shown that radiation therapy for breast cancer may increase mortality from both lung cancer and cardiovascular disease.” However a recent study at the Netherlands Cancer Institute in Amsterdam seems to indicate this may not be true for DCIS.
Then too “although radiation reduces the risk of developing another tumor in the same breast, it does not improve survival,” according to Dr. Steve Shak, Genomic Health’s chief medical officer. A 2013 UCLA study published in the Cancer journal implies that ionizing radiation reprogrammed breast cancer cells into breast cancer stem cells that were able to regrow a tumor.
This may explain why in a study by Dr. Janie Weng Grumley, a fellow at USC Los Angeles, “the rate of invasive recurrence was higher for patients who had surgery plus radiation than for those who had lumpectomy alone. She goes on to say: “a small subgroup of irradiated DCIS patients may not be deriving maximum benefit from radiation therapy, or not benefiting from it at all.” One such group is postmenopausal women with early breast cancer, according to Dr. Corrado Tinterri. His May 2013 report of Breast Surgeons, showed that with radiation these women, aged 55 to 75, reduced their recurrence rate and increased their disease-free survival rate by only 1 percent.
With all this controversy, the key to making an intelligent decision is to know one’s own personal risk with and without radiation. One such tool is the Van Nuys Prognostic Index (VNPI) which uses several factors: patient age, size and grade of the DCIS and surgical margin widths. The higher the score, the greater the risk of recurrence and the more likely the benefits of radiation will outweigh the side effects.
Several studies have validated the use of the VNPI. In a study in 2008 in the World Journal of Surgical Oncology Dr. Onur Gilead verified that “the VNPI is a statistically significant determinant of local recurrence when local excision is the only treatment modality applied.” The VNPI was also validated in a study published in 2009 in the Journal of Clinical Oncology by Dr. Lorie Hughes. She concludes: “Rigorously evaluated and selected patients with low-to-intermediate grade DCIS with margins 3 mm or wider had an acceptably low rate of ipsilateral breast events at 5 years after excision without irradiation.” In fact, according to Dr. Mel Silverstein et al et al, “There was also no statistically significant benefit from postoperative radiation therapy among patients with margin widths of 1 to <10mm.”
Although DCIS recurrence is declining with the 5-year recurrence rate for 1978–1998 going from 13.6% to 6.6% for 1999–2010, according to an abstract presented at the 2015 Breast Cancer Symposium, the unexplained decline is limited to women not receiving radiation.
Another tool for calculating personal risk is the newer, less tested Oncotype DX test for DCIS. This looks at how cancer genes are expressed. “For women who really don’t want radiation therapy or a mastectomy, this might well be a way to determine whether they ‘should take the risk,” says surgeon Susan Love in a December 6, 2011 USA Today. “It is the first step to being able to figure out which DCIS is important and which is not.”
When it comes to radiation therapy, one size does not fit all. For some women radiation may provide peace of mind, while for others it may not be necessary.