Is cancer “by far, the harder problem”? Reply

Really? Does everyone seem to have cancer? Compared to heart disease is cancer “by far, the harder problem”?

Half a century ago, the story goes, a person was far more likely to die from heart disease. Now cancer is on the verge of overtaking it as the No. 1 cause of death.

Troubling as this sounds, the comparison is unfair. Cancer is, by far, the harder problem — a condition deeply ingrained in the nature of evolution and multicellular life.

–George Johnson: Why Everyone Seems to Have Cancer, The New York Times

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Deja Vu All Over Again: Study Links Calcium-Channel Blockers To Breast Cancer Reply

A new observational study raises the possibility that calcium-channel blockers (CCBs) may be associated with a higher risk for breast cancer. Although previous studies examining this relationship have failed to turn up convincing evidence of a link, the authors of a paper published in JAMA Internal Medicine state that their study is the first to look at long-term use of CCBs in a contemporary population.`

Christopher Li and colleagues analyzed data from women in the Seattle area, including 880 women with invasive ductal breast cancer, 1,027 with invasive lobular breast cancer, and 1,027 controls with no cancer. They found that women taking other antihypertensive drugs, including diuretics, beta-blockers, and angiotensin II antagonists, had no increased risk for breast cancer. But women taking CCBs had significantly elevated risk for ductal breast cancer (OR 2.4, CI 1.2-4.9, p=0.04) and lobular breast cancer (OR 2.6, CI 1.3-5.3, p=0.01). The results were consistent for different types of CCBs.

In an accompanying editorial, Patricia Coogan writes that the study “provides valid evidence supporting the hypothesis that long-term CCB use increases the risk of breast cancer.”

Click here to read the full post on Forbes.

 

Radiotherapy For Breast Cancer Increases Heart Disease Risk 1

A new study published in the New England Journal of Medicine offers the best look yet at the increased risk for heart disease produced by radiotherapy for breast cancer. Further, this increased risk may just be the tip of the iceberg of more radiation-related problems, warns a cardio-oncologist in an accompanying editorial.

The new study, based on data from Sweden and Denmark of women treated with radiotherapy for invasive breast cancer, found a linear increase in the rate of heart disease associated with the dose of radiation received by the heart. Starting 5 years after radiotherapy, and with no sign of a threshold,  the risk for major coronary events increased by 7.4% per gray. The mean dose of radiation was 4 Gy. Although the relative risk was consistent throughout the study, the increase in absolute risk was greatest in women with cardiac risk factors or established heart disease.

Findings from the study, according to the authors, “make it possible to estimate” a patient’s risk for heart disease related to radiation. “This absolute risk can be weighed against the probable absolute reduction in her risk of recurrence or death from breast cancer that would be achieved with radiotherapy.” The authors estimated that for a 50-year-old woman without preexisting risk factors and with a mean radiation exposure of 3 Gy, her risk for death from ischemic heart disease by age 80 would rise from 1.9% to 2.4% and her risk for an acute coronary event would rise from 4.5% to 5.4%. The risk for death by age 80 for an otherwise similar woman with existing risk factors would rise from 3.4% to 4.1%. Women exposed to larger doses of radiation would be exposed to even greater risks.

In the accompanying editorial, Javid Moslehi writes that results of the study suggest that “cardiac risk factors should be assessed and aggressively managed — starting at the time of radiation treatment (or even before) and continuing throughout survivorship.” To make matters worse, the findings “may represent just the tip of the iceberg.” Radiation may also cause increases in pericardial disease, peripheral vascular disease, cardiomyopathy, valvular dysfunction, and arrhythmias, according to Moslehi, and other breast cancer therapies, such as anthracyclines and hormonal therapies, may have “additional cardiotoxic effects.”

Moslehi, who is in the Cardio-Oncology Program at the Dana–Farber Cancer Institute, writes about the emerging new discipline of “cardio-oncology”:

Given the widespread use of radiation therapy in the treatment of breast cancer, and the continually expanding arsenal of novel therapies, the current study calls for greater collaboration between oncologists and cardiologists. An important lesson for the oncologist may be that the time to address concerns about cardiovascular “survivorship” is at the time of cancer diagnosis and before treatment rather than after completion of therapy. Similarly, cardiologists need to assess prior exposure to radiation therapy as a significant cardiovascular risk factor in survivors of breast cancer.

Statins Use Linked To Reduction In Cancer Mortality 1

A large new population study rasies the possibility that statin use may lead to a decline in cancer mortality. Researchers in Denmark utilized health data from the entire population of the country and analyzed the information from nearly 300,000 patients who were diagnosed with cancer between 1995 and 2007. The authors note that the relationship is biologically plausible, since cholesterol synthesis is required for cell proliferation and other critical cellular functions.

In their paper published in the New England Journal of Medicine, the researchers compared 18,721 cancer patients who were statin users prior to their diagnosis with 277,204 had never used statins: Here is the adjusted hazard ratios for statin users:

  • All cause mortality: 0.85 (0.83-0.87)
  • Death from cancer: 0.85 (0.82-0.87)

There was no dose response relationship observed in the study. A similar and consistent pattern was observed for different types of cancer, though these differences not always achieve statistical significance.

In an accompanying editorial, Neil Caporaso notes that despite the considerable strengths of the study, which used data from the entire country of Denmark, the researchers were nevertheless unable to account for residual confouding differences between statin users and nonusers. The “consistent and substantial declines in mortality across diverse diverse cancers”  need to be interpreted with caution, he wrote. Caporaso suggests a variety of different research directions for further study of the important question of the relationship between statins and cancer.

 

Suicide and CV Death Increase After Diagnosis of Cancer Reply

The risk of suicide and cardiovascular death rises sharply after cancer is diagnosed, according to a new study from Sweden published in the New England Journal of Medicine. Fang Fang and colleagues analyzed data from more than 6 million Swedes, including more than half a million who received a first diagnosis of cancer.

Following a sharp initial increase in suicide and CV death, risk rapidly declined thereafter, but remained elevated during followup. The increased risk in suicide and CV death was greatest among people with highly fatal cancers. A second, case-crossover analysis confirmed the broad findings of the nationwide cohort study.

Here are the main results of the cohort study:

Relative risk (RR) compared with cancer-free people and incidence of suicide after cancer diagnosis:

  • First week: RR 12.6 (CI 8.6-17.8); incidence rate: 2.50 per 1000 person-years)
  • First year: RR 3.1 (2.7-3.5); incidence rate: 0.60 per 1000 person-years

Relative risk (RR) compared with cancer-free people and incidence of cardiovascular death after cancer diagnosis:

  • First week: RR 5.6 (CI 5.2-5.9); incidence rate: 116.80 per 1000 person-years)
  • First 4 weeks: RR 3.3 (3.1-3.4); incidence rate: 65.81 per 1000 person-years

The authors concluded that their “findings suggest that a cancer diagnosis constitutes a major stressor, one that immediately affects the risk of critical, fatal outcomes. We speculate that our findings show only a portion of the range of effects induced by the emotional distress associated with a cancer diagnosis.”

Meta-Analysis Adds New Evidence For Cancer Benefits Of Daily Aspirin 1

Although daily aspirin was originally proposed to reduce cardiovascular events, the effects on cancer of daily aspirin have become increasingly apparent while the vascular benefits, especially in primary prevention, have become less clear. Now a new meta-analysis in the Lancet adds significantly new details to our understanding about the effects of aspirin and increases the evidence in support of a long-term beneficial effect of aspirin in preventing cancer.

Peter Rothwell and colleagues analyzed data from 51 primary and secondary prevention trials including more than 80,000 patients. They reported several key findings

  • Daily aspirin reduced deaths from cancer by 15% (p=0·008).
  • After 5 years, there was a particularly striking 37% reduction in cancer deaths (p=0·0005), which largely accounted for a reduction in non-vascular deaths overall (p=0·003).
  • Aspirin was associated with an initial reduction in major vascular events, but this was offset by increases in major bleeding. With longer followup the vascular effects diminished, so that after 3 years only the reduced risk of cancer was significant.

The authors wrote that “in view of the very low rates of vascular events in recent and ongoing trials of aspirin in primary prevention, prevention of cancer could become the main justification for aspirin use in this setting…”

In an accompanying comment, Andrew Chan and Nancy Cook point out that the meta-analysis did not include the two largest primary prevention studies, the Women’s Health Study and the Physician’s Health Study, because they used alternate-day aspirin rather than daily aspirin. Both trials failed to find an effect on cancer. Nevertheless, they write, the researchers “show quite convincingly that aspirin seems to reduce cancer incidence and death across different subgroups and cancer sites, with an apparent delayed effect.”

“For most individuals, the risk-benefit calculus of aspirin seems to favour aspirin’s long-term anticancer benefit,” they state. However, current evidence does not support “a definitive conclusion about population-based recommendations regarding routine use of aspirin for cancer prevention.” They conclude that in the future guidelines “can no longer consider the use of aspirin for the prevention of vascular disease in isolation from cancer prevention.”
Click here to read the press release from the Lancet…