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Breast cancer among women and the importance of early detection

Published online before print December 16, 2015. Disclosures of potential conflicts of interest may be found at the end of this article. Ponzone raises an important and timely question. This is a critically important issue, because researchers and health care providers strive to reduce the incidence and mortality from breast cancer by working to develop safe and effective methods to prevent breast cancer.

Acknowledgment

Mammography, although associated with reduced breast cancer-specific mortality in some studies [ 23 ], has not been found to reduce breast cancer-specific mortality in others [ 4 ]. In addition, mammograms can detect noninvasive cancers, some of which might not evolve to invasive breast cancer the problem of overdiagnosis [ 5 ].

For health care experts, interventions that reduce the incidence of disease in this case, cancerbreast cancer among women and the importance of early detection if incompletely, are considered to have prevented the disease in some individuals. The common perception is that an individual receiving preventive treatment will have no side effects and will never develop the disease to be prevented cancer, in this case.

There are currently available interventions that clearly prevent many breast cancers in high-risk women. These interventions prevent breast cancer in many women but are often not accepted because of the possible side effects. The behavioral interventions that Dr. Ponzone mentions avoidance of environmental carcinogens and lifestyle factors such as diet and exercise likely also prevent some cancers; however, these highly tolerable interventions are less effective than the surgical or medical interventions mentioned.

In clinical practice, these various preventive interventions are being used in a tiered fashion according to risk. Thus, for women at extremely high risk of breast cancer such as those carrying BRCA1 or BRCA2 mutationsbilateral prophylactic mastectomies are considered and frequently performed.

For women at moderately high risk e. The remaining women those at low to moderate risk of breast cancer might benefit from behavioral interventions such as exercise, diet, and alcohol avoidance alone.

The current interest in healthy lifestyles has led Dr. Although it is currently difficult to determine whether an individual woman will benefit from these behavioral interventions, such measures are generally healthful and thus should be recommended.

Ponzone also cites the recent report by Tomasetti and Vogelstein as evidence that cancer prevention interventions are unlikely to be generally useful. These investigators reached the provocative conclusion that only one third of cancer risk can be attributed to inherited predispositions or environmental factors, with the remaining two thirds of cancer risk attributable to random DNA mutations occurring in normal, noncancerous cells.

The conclusion that much of cancer risk can be attributed to DNA mutations is certainly correct; however, the conclusion that the rate of DNA mutation has little to do with endogenous and exogenous exposure to carcinogens and mutagens is unlikely to be true.

Breast cancer: prevention and control

The report by Drs. Tomasetti and Vogelstein has been criticized by others [ 16 — 18 ]. However, it is important to point out several major issues with their analysis here. Central to the study by Tomasetti and Vogelstein is the hypothesis that cancer risk can be directly related breast cancer among women and the importance of early detection the number of stem cell divisions in normal tissue [ 15 ].

In their report, they showed a positive linear relationship between the lifetime risk of cancer abstracted from incidence data from the Surveillance, Epidemiology, and End Results Program database and the number of stem cell divisions in normal tissues over an average lifetime estimated from immunostaining for stem cell markers or from biologic studies. However, they carefully selected the tumor types to include in their study.

Tomasetti and Vogelstein left out important common cancers that might not fit their linear relationship e. This process of selecting specific tumors that fit their hypothesis, and leaving out those that do not, greatly weakens the validity of their conclusion and does not allow their analysis to be generally applicable to many cancer types.

Mammograms are certainly able to detect breast cancer at an early stage. However, the current debate has been focused on whether mammograms detect too many cancers that are not life-threatening [ 2 — 5 ]. Thus, mammography remains the reference standard breast screening test.

However, a need certainly exists to develop breast screening tests that more effectively detect lethal cancers without identifying nonlethal cancers. Clinicians now use a risk-based approach to detect breast cancer. For low- to average-risk women, the generally accepted screening guidelines for the general population are being used. Although debate is ongoing concerning at what age mammographic screening should start 40 or 50 years old or older and whether mammograms should be obtained yearly or every other year [ 20 — 23 ], such screening approaches should only be applied to those women with the population or average risk.

For high-risk women, more aggressive screening approaches are generally used and are authorized for payment by Medicare and insurance companies. Bilateral breast ultrasonography is also often added to mammography for breast cancer screening in women with lobular premalignant lesions e.

Thus, a risk-based approach is also now being used for breast cancer screening.

  1. Raising general public awareness on the breast cancer problem and the mechanisms to control as well as advocating for appropriate policies and programmes are key strategies of population-based breast cancer control. For the highest risk women, the answer appears to be yes.
  2. These investigators reached the provocative conclusion that only one third of cancer risk can be attributed to inherited predispositions or environmental factors, with the remaining two thirds of cancer risk attributable to random DNA mutations occurring in normal, noncancerous cells. For such women, it is clear that additional research is needed to improve the ability to detect life-threatening cancer at an early curable stage and to prevent the development of these cancers.
  3. Promising preliminary results show that the age-standardized incidence rate for advanced-stage breast cancer is lower in the screened group compared to the unscreened group Sankaranarayanan, 2011.
  4. Ponzone mentions avoidance of environmental carcinogens and lifestyle factors such as diet and exercise likely also prevent some cancers; however, these highly tolerable interventions are less effective than the surgical or medical interventions mentioned.

For the highest risk women, the answer appears to be yes. However, for most women in particular, those at low to moderate riskthe answer is clearly no. For such women, it is clear that additional research is needed to improve the ability to detect life-threatening cancer at an early curable stage and to prevent the development of these cancers.

Many research groups are working to discover more effective and safer methods to detect and prevent life-threatening breast cancers. Promising prevention strategies include using novel medical therapies such as drugs targeting precancerous cells [ 24 ], natural products [ 25 ], cancer vaccines [ 26 ], and combinations of exercise, diet, and antidiabetic drugs such as metformin [ 2728 ].

Novel early detection strategies are also being developed that use blood-based DNA, RNA, or protein markers to detect life-threatening cancer [ 29 ].