Column: Breast Cancer Screening Does Save Lives
We read with interest the article published in the Nov. 22 Valley News headlined “Mammograms Have a Down Side,” which cited a recent paper co-authored by Dr. H. Gilbert Welch. As health care professionals who care for breast cancer patients at the Norris Cotton Cancer Center and Dartmouth-Hitchcock Medical Center, we feel it is important for residents of the Upper Valley to understand that Welch’s opinion does not represent the entire Dartmouth medical or scientific community and in particular does not reflect our personal view of breast cancer diagnosis and treatment.
In his recent paper, Welch concluded that 31 percent of breast cancers detected by screening mammography are overdiagnosed — that is, they will never cause the patient harm if left untreated. We disagree with Welch’s conclusion, which we believe is misleading and potentially harmful to women. In fact, there is general consensus among doctors who treat patients with breast cancer that, if left untreated, invasive breast cancer will grow, cause significant problems in the breast and may spread to other parts of the body, eventually causing death.
Welch’s paper is based on many assumptions that may or may not prove to be true. In contrast, there is very strong direct evidence that mammography saves lives from breast cancer. Routine mammography — screening — has been evaluated by randomized control trials, the gold standard of research studies. In this type of scientific trial, participants are randomly assigned to either have or not have an intervention, and outcomes are measured. Multiple randomized controlled trials have evaluated women 40- to 75-years-old who underwent screening mammography. When eight randomized control trials of screening mammography studying hundreds of thousands of women from all over the world were analyzed together, the data indicated that death from breast cancer decreased by 15 percent for women between the ages of 40 and 59, and decreased by 32 percent for women aged 60 to 70 in the group that had mammograms compared with those who were not screened with mammograms.
Welch’s paper also concluded that many breast cancer patients are being “overtreated” with unnecessary surgery and chemotherapy. In fact, the opposite is more likely to be true. Several studies have demonstrated that mammography benefits patients because it identifies breast cancer when it is smaller and is less likely to have spread to lymph nodes, thereby enabling patients to be effectively treated with less toxic therapy. In a study of New Hampshire women, two of the authors of this piece — Richard Barth and Steve Poplack — showed that patients whose cancers were discovered by routine mammography (when compared with patients whose cancers were found by physical exam) were twice as likely to be treated with lumpectomy (partial breast surgery) than mastectomy (entire breast removal) and were half as likely to be treated with chemotherapy.
At the Norris Cotton Cancer Center at Dartmouth-Hitchcock Medical Center, patients with a new diagnosis of breast cancer meet with a variety of health care professionals, including doctors of different medical disciplines, nurses, social workers and other specialists in a process called “shared decision making” to arrive at a personalized treatment plan. We strive to tailor individual therapy for each woman based on her personal preferences and the specific biology of her cancer. In this way, we seek to appropriately treat rather than overtreat, each patient.
In summary, the medical evidence suggests that a decision to not have routine mammography due to a fear of overdiagnosis will result in many women being diagnosed with more advanced breast cancers. This results in more toxic treatments that could have been avoided, and will lead to unnecessary loss of lives from breast cancer.
Steve Poplack, M.D. is a radiologist, Richard Barth, M.D., a surgical oncologist, Kari Rosenkranz, M.D., a surgical oncologist and Peter Kaufman, M.D. a medical oncologist. This commentary was signed by 12 other health care professionals at DHMC involved in treating cancer patients.