A major advance in treating high blood pressure

The most common type of non-invasive breast cancer is called ductal carcinoma in situ (DCIS). Traditionally, DCIS is diagnosed when cancer cells seen under the microscope are localized only to the breast’s duct system but have not invaded surrounding tissue.

The standard treatment for DCIS is to remove the affected tissue, making sure that there are no cancer cells left within the breast (“clear margins”). That surgery might be a mastectomy or a lumpectomy, which may be followed with radiation therapy.

DCIS carries an excellent prognosis. That’s why this non-invasive cancer is also called “stage 0” breast cancer.
Reconsidering the best treatment for DCIS

Last month, JAMA Oncology published a study that suggests the standard treatment may be too aggressive. Perhaps some women with DCIS would do just as well without lumpectomy or mastectomy. As expected, this has generated a lot of controversy and confusion.

The researchers studied more than 108,000 women who had been diagnosed with DCIS at some point during a 20-year period. They found that women who received a lumpectomy followed by radiation had a lower risk of cancer returning in the affected breast. But the addition of radiation did not change the ultimate rate of death due to breast cancer. Nor did performing a mastectomy instead of a lumpectomy.

This type of research is known as an observational study. Observational studies can show possible associations between therapies and outcomes. They don’t prove that one therapy is actually better.

Because this was an observational study, there are many questions about what could have affected the study outcomes. These include why each specific treatment was chosen for each patient, the accuracy of the DCIS diagnoses, whether each surgery truly had “clear margins,” and the quality of follow-up care, including regular mammograms to watch for the possible return of cancer.

In addition, this study didn’t document which patients, if any, also received hormonal therapy such as tamoxifen or aromatase inhibitors. These treatments can help prevent recurrence. For these reasons, it is hard to interpret these study data, and even harder to use that information when deciding how to treat any one woman with DCIS.

What this study does tell us is that not all DCIS is the same. In this study, approximately 500 patients died of breast cancer without ever having invasive cancer in the breast. This suggests that for some very small subset of women, distant or metastatic disease occurred despite treatment of DCIS — a concerning finding.

Also, death rates were higher for women diagnosed with DCIS before the age of 35, and for black women compared to non-Hispanic white women. This suggests that these women may need more aggressive intervention.

The good news: The study also reaffirmed the fact that overall, mortality associated with DCIS is exceedingly low. Fewer than 1% of patients in this 20-year study died from breast cancer.
Did the media send the wrong message about the study results?

Some media coverage of this study tended to leave the impression that DCIS doesn’t need to be treated. In fact, all patients in the study received some form of treatment. What the study does say is that none of the specific treatments the researchers compared against each other (lumpectomy with or without radiation or mastectomy) differed very much from one another with respect to ultimate survival.

Ongoing trials are looking at whether “watchful waiting” may be reasonable for certain women — that is to say, closely following low-risk patients (for example, those with small tumors or low- to intermediate-grade cancers) to determine if and when treatment is needed. However, we don’t have those results yet.

For some women, DCIS is a “precursor” to invasive breast cancer, but in many others, it may not progress. Yet right now, we don’t understand these cancers well enough, nor can we accurately predict the biological behavior of these abnormal cells for any given woman. More research is necessary to determine the specific optimal treatment for each individual woman diagnosed with DCIS.

Ultimately, decisions about the diagnosis and treatment of DCIS must be made by a woman and her doctor and must take into account certain risk factors (age and race among them), as well as that woman’s personal preferences in the face of the limitations of current scientific knowledge. I expect that results from ongoing and future research will soon allow physicians to better guide these difficult decisions. Fortunately, the bottom line for DCIS is that no matter what treatment is pursued, the outcomes are excellent for the majority of patients. This week, a preliminary study in JAMA Internal Medicine reported that older women in Spain who ate a traditional Mediterranean diet enhanced with extra-virgin olive oil were less likely to be diagnosed with breast cancer.

To be sure, it’s no shock that a tasty, wholesome diet that’s already been proven to sharply reduce the number of heart attacks can also help to fight breast cancer. “Am I surprised that the Mediterranean diet is beneficial for breast cancer? No, because it seems to be beneficial across the board,” says Dr. Beth Overmoyer, a breast cancer specialist at the Harvard-affiliated Dana-Farber Cancer Institute.
The new findings

The breast cancer study was bootstrapped onto a landmark clinical trial in Spain called Prevención con Dieta Mediterránea (PREDIMED).  In 2013, the first results from this study established that people who ate a Mediterranean diet — rich in extra-virgin olive oil, fruits and vegetables, nuts and legumes, and other superstars of healthy eating — were 30% less likely to have heart attacks or strokes or to die from heart-related causes, compared with people who were just told to eat less fat.

But the PREDIMED researchers were not done. They also kept track of how many women were diagnosed with breast cancer during the study period so they could see if the rates were different across three different groups—women who followed the diet plus extra servings of olive oil, women who followed the diet plus extra servings of nuts, and women who were simply advised to reduce fat intake. They followed about 4,300 women ages 60 to 80.

Out of a total of 35 breast cancers diagnosed during the study period, there were 62% fewer cancers in the women who ate the olive-oil–enhanced diet, compared with women just told to cut their fat intake. The rate of breast cancer in women who ate the Mediterranean diet plus extra servings of nuts was not statistically different from that in the women told to reduce fat intake.
Is it true?

That’s great news — but it isn’t definite proof that eating Mediterranean prevents breast cancer. The scientists acknowledge that their findings need to be confirmed in a study that catches a larger number of breast cancers. That could mean a larger study, or a longer study.

The study’s conclusions are based on just 35 cases of breast cancer. The small numbers leave the study more vulnerable to factors besides diet that could have skewed the math — such as how often the women had mammograms. The researchers did not keep track of which women were having mammograms — and fewer mammograms translates into fewer cancers diagnosed. But they argue that the process that randomly assigned study participants was so thorough — like shuffling a deck of cards over and over — that any pre-existing differences between participants would have averaged out.
How good is the good news?

Dr. Overmoyer stresses that women should keep in mind that a healthy diet is only one influence of lifestyle on the risk of breast cancer. “It says a healthy diet may be very important — plus you need to exercise, plus you need to lose weight,” she says.

If diet helps, how much does it help? Based on the study’s numbers, in a group of 1,000 women who eat a Mediterranean-style diet with extra olive oil for 10 years, 14 women would be diagnosed with breast cancer. A similar group of women who only cut fat from their diet without eating in the Mediterranean style would see 29 cases, meaning 15 additional breast cancers over a decade in every 1,000 women.

That sounds much less dramatic than “62% lower risk,” and might even make you wonder how big the benefit really is. But of course, each new case of breast cancer is an actual woman facing a serious disease. “If we are looking at an individual — if you are one of those women who gets breast cancer — then that’s important,” Dr. Overmoyer says.

This study has some important limitations. It could, like other “encouraging” preliminary studies, burn brightly like a meteor for a while before subsequent research with more sobering results causes it to peter out. Fortunately, we know that the Mediterranean eating pattern prevents heart disease, a leading killer. The evidence for whether it fights breast cancer may be preliminary, but women can still consider it a smart bet.

“What is the actual risk of choosing a Mediterranean diet high in olive oil? It’s not much,” Dr. Overmoyer says. “It may be a little more expensive, but it’s still a healthy choice. There might not be a huge upside for you personally, but the downside is very low.” There are few advances in medicine that truly warrant an immediate change in practice, but the SPRINT trial appears to be one such study. In a recent press release, the SPRINT researchers announced that their study results showed aiming for a systolic blood pressure (the top number) of 120 mm Hg was superior to a target of 140 mm Hg. This one change reduced the risk of death by almost 25% and reduced the rate of overall cardiovascular problems, including heart attacks, strokes, and heart failure, by almost a third — welcome news to every doctor and patient.

The SPRINT trial was a randomized clinical trial that followed over 9,000 Americans for several years. All participants in the trial were ages 50 and older, had high blood pressure, and also either were at increased risk for heart disease or had kidney disease. Half the participants were given a blood pressure target of 120 mm Hg and the other half were given a target of 140 mm Hg. On average, the 120 mm Hg group needed 3 blood pressure medications to achieve this goal, and the 140 mm Hg group needed 2.

This study was sponsored primarily by the National Heart, Lung, and Blood Institute of the National Institutes of Health. This trial is a wonderful example of the kind of long-term, large-scale clinical trials that are necessary to advance patient care meaningfully. The study results also illustrate the importance of randomized clinical trials — that is, studies in which patients are randomly assigned to one of two treatment arms. Lastly, credit must be given to the participants who consented to be enrolled in the study. They have generously and selflessly contributed to advancing medical science and improving the care of patients worldwide. Ultimately, they also helped improve their own care.

While the results are very exciting, it will be important to see the details in the full text of the study, which has yet to be published. Sometimes a published paper provides more subtle interpretations of the findings than an initial press release. Those usual caveats notwithstanding, these results appear to be an important discovery with instant applicability.

It usually takes years before the effects of high blood pressure (at least, in the range being studied in this trial) cause serious cardiovascular problems. So, for people with reasonably well-controlled blood pressure, there is no need to rush to see your doctor right away.

However, even if your blood pressure is considered well-controlled under current standards, it would be worthwhile to discuss with your primary care physician whether a lower target blood pressure would be in order. Of course, you and your physician would need to balance the benefits noted in the SPRINT trial against the potential risks of taking additional blood pressure medications and their possible side effects. The risk of side effects might be higher in certain groups of patients, such as older people taking several different types of drugs. Still, the availability of multiple generic blood pressure medicines should allow these results to be applied in the vast majority of people with high blood pressure.

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