Breast cancer in young patients has a uniquely aggressive and poor prognosis, with features such as low differentiation, high proliferation index, and high incidence of lymph node invasion. Basal cell carcinoma or triple negative breast cancer is more common. Breast cancer in women younger than 35 years of age tend to be advanced at the time of diagnosis and have a lower survival rate. In addition, young breast cancer patients face a number of age-related issues in addition to concerns about diagnosis and treatment, such as fertility, treatment-induced menopause, and their considerations regarding offspring are unique to them. In addition, their own image and sexuality are potentially affected.
The incidence of breast cancer among young people in China is higher than in Europe and the United States
In 2006, 274,900 new cases of breast cancer were diagnosed in the United States, of which 40,970 patients died. Although only 2.7% of all breast cancer patients were aged ≤35 years old and 0.6% of all patients were younger than 30 years old, breast cancer still ranks as the leading cancer causing death among young women, accounting for 5% to 7% of cancer deaths among women aged 15-29 years. The American Cancer Society estimates that in 2005 there were 1,600 new cases of breast cancer in situ, 9,510 new cases of invasive breast cancer, and 1,110 deaths in patients younger than 40 years of age in the United States. Although the absolute number of patients younger than 40 years of age is increasing, the incidence of breast cancer in this age group has remained stable from 1975 to 2000.
The situation in Europe is similar to that in the United States. Young breast cancer accounts for approximately 3.5% of new diagnoses each year. In contrast, statistics from Korea show that young breast cancer accounts for about 9.5% of new cases diagnosed each year. In China, young breast cancer accounts for 10%-15% of new breast cancer cases each year, and this percentage has a tendency to increase further, significantly higher than the incidence reported in Europe and the United States.
Young breast cancer has a unique aggressiveness and poor prognosis
The clinical, pathological and biological characteristics of young breast cancer are
1. more advanced stage and worse prognosis even if the stage is the same, which is caused by different biological behaviors.
2. More likely to have bone marrow micrometastasis.
3.Most of them are invasive carcinoma, and about 70% are invasive ductal carcinoma.
4.The tumor cells are highly malignant, mostly accompanied by vascular cancer thrombus, extensive intraductal cancer component, HER2 positive (26%~44%), ER negative (39%~80%), high percentage of S stage cells and overexpression of P53 and Ki-67.
5. Basal-like breast cancer or triple-negative breast cancer is common. Triple-negative breast cancer is considered a subtype of independent factor for poor prognosis. Basal cell-like carcinoma accounts for 34% of breast cancers in those younger than 30 years of age, which is higher than the overall incidence of basal cell-like breast cancer (14%-16%).
Multigene microarray technology has now been applied to predict breast cancer recurrence and response to chemotherapy and hormone therapy. These ribonucleic acid expression profiles result in lymph node-negative, ER-positive breast cancers, and younger individuals may have a higher recurrence rate and worse prognosis than older individuals.
Recently, different biological behaviors have been found to be strongly associated with breast cancer prognosis and survival, and more strongly with younger patients. Special attention has been paid in recent years to basal cell-like breast cancers, especially BRCA1-associated breast cancers. Younger African American female breast cancer patients are also more likely to develop basal cell-like breast cancer, which could explain their worse prognosis than younger Caucasian women. Receptor status also affects disease outcome in younger patients; when ER is positive, younger patients have a worse prognosis than older patients. The results of a study by Van der Hage et al. of the European Cancer Institute and Cancer Care showed that histologic grade in women younger than 40 years was an independent prognostic factor, and the investigators suggested that it could be used to predict the efficacy of systemic chemotherapy in younger patients. A report from the Curie Institute in Paris says that age is the most important prognostic factor for recurrence of young locally advanced breast cancer. Prognostic factors involving surgical margin width are not important if the dose of radiation therapy is appropriate, the report said.
There are six risk factors for young breast cancer
Risk assessment models
There are no tools to accurately predict the risk of breast cancer in young women. The Geier model assesses the risk of invasive tumors based on age, menarche, past history, family history, and gestational age. Although the Geier model does have some shortcomings for all populations (e.g., it does not cover paternal family history and BRCA genetic status), it is particularly unconvincing when applied to young women. The Geier model has recently been modified to include breast density as a factor associated with breast cancer risk, which is a common finding in younger female populations.
1. Family history
Family history of breast cancer is an important marker of breast cancer risk in young women.
2.Race
For young women, race is an independent risk factor. Since the 1970s, analysis of the U.S. SEER database has shown that breast cancer is less common in African American populations than in Caucasian populations because African Americans experience earlier onset disease and higher breast cancer mortality, and socioeconomic factors, health care barriers, and tumor biology are all thought to play a role in significant racial differences.
3. Environment
The relationship between environmental exposures and breast cancer risk remains a highly controversial issue. The Long Island Breast Cancer Research Project has failed to link environmental exposures to breast cancer risk. Many greatly underestimate the role that environmental carcinogens play in the development of breast cancer in young adults. Assuming that women between the ages of 15 and 30 were not exposed to external carcinogens for a length of time sufficient to clinically detect the development of cancer, prenatal exposure to carcinogens (such as DES) would still significantly increase the risk of breast cancer.
4. Hodgkin’s disease
Because cape field radiation therapy increases the risk of breast cancer, women who have been treated for Hodgkin’s lymphoma should begin physical examinations early. For a 25-year-old woman who has received standard cape field radiation therapy, her risk of developing breast cancer at age 55 is 29%, compared to 3% for the overall population. Start annual screening mammography 5 years, 8 years or 40 years after radiation therapy (based on the time of the event that occurs first of the three).
5. Endocrine
Pregnancy can alter breast cancer risk. Women have an increased risk of breast cancer before they are about to give birth and in the 5 years following delivery, especially in the first pregnancy. Pregnancy-related factors such as excessive prematurity and early placental abruption all contribute to an increased risk of maternal breast cancer. Breast cancer risk is associated with pregnancy, but a recent study (53 cases) suggests that abortion does not increase the increased risk of breast cancer in women. Recent data from the Nurses’ Health Study II also show that neither abortion nor spontaneous abortion affects breast cancer incidence.
Premenopausal breast cancer is also associated with prenatal factors. Maternal risk of premenopausal breast cancer increases by 20% when the fetus weighs ≥4 kg. Maternal age is another risk factor: the older the mother, the greater the risk of breast cancer in the offspring, which may be due to the increased probability of mutation in the egg.
It is now believed that continuity of the menstrual cycle is associated with breast cancer risk, i.e., an increased risk of breast cancer in women with early menarche, delayed menopause and those who have not had children. For decades, not having given birth has been considered a risk factor, as evidenced by the high incidence of breast cancer among Catholic nuns. The synthetic nonsteroidal estrogen DES was used to prevent miscarriages from 1938 to 1971, and in 1971 it was recognized that DES taken by mothers during pregnancy increased the risk of clear cell adenocarcinoma of the vagina and cervix in their offspring. Women who take DES during pregnancy are at increased risk of breast cancer, and there is recent evidence that it may also increase the risk of breast cancer in their offspring. There is no evidence to the contrary for this conclusion. It has been hypothesized that prenatal exposure to high levels of estrogen increases the number of breast cancer stem cells at the time of delivery, which in turn increases the risk value for malignancy.
Because the ovulation-promoting drugs used during in vitro fertilization increase endogenous sex hormone levels, there is concern that artificial insemination may increase the risk of breast cancer. An analysis of 60,050 women in 15 studies by Salhab et al. showed no evidence that ovulation induction or in vitro fertilization could increase the risk of breast cancer.
6. Genetic factors
Most breast cancers are the result of germline mutations, such as BRCA1/BRCA2 mutation breast cancer accounts for 5-10% of all breast cancers. BRCA1/2 mutations are more common in women with early stage breast cancer, bilateral primary breast cancer, ovarian cancer, male breast cancer, and family history of ovarian cancer. 10 years earlier. A recent Meta-analysis of 6,965 breast cancer patients from 22 studies showed that the mean cumulative risk of breast cancer at age 70 years was 65% for BRCA1 mutation carriers and 45% for BRCA2 mutation carriers. For BRCA1 mutation carriers, the mean cumulative risk of breast cancer at ages younger than 40 years would be elevated, compared with a lifetime risk of 11% for breast cancer at age 85 years in the general population.
The understanding of breast cancer genetics is just beginning, and a newly discovered correlation between the CHEK2 gene and increased risk of breast cancer has identified an increased risk of contralateral breast cancer after radiation therapy in young women with germline mutations in the pathway of DNA damage repair.