Radiation-Associated Breast Cancer and Hormone Exposure: a CCSS* Report

Chest radiation is a well known risk factor for the subsequent development of breast cancer. This study was aimed at exploring the relationship between hormonal factors and the risk of radiation-associated breast cancer among survivors of childhood cancer.

Included in the study were 1,108 females diagnosed from 1970 to 1986 who were treated with chest radiation and survived to ages of >/= 20 years.

Results:

  • 195 women were diagnosed with breast cancer 80% of whom were estrogen receptor positive [ER+] and 112 of whom were diagnosed before they turned 40
  • The risk of developing ER+ breast cancer and breast cancer diagnosed before 40 years of age were significantly increased when women had had > 10 years of ovarian function when compared to those with < 10 years of ovarian function
  • A similar pattern as above was observed in women who received chest radiation within a year of menarche as opposed to > 1 year after menarche
  • Of the 259 women who were post-menopausal, their breast cancer risk was moderately higher in those treated with estrogen and progesterone therapy when compared to women who were not although this finding was not statistically significant
  • In survivors who went through menopause at < 20 years of age treated with estrogen + progesterone had a lower risk of breast cancer than premenopausal women

Conclusions:

  • Endogenous hormones, hormones naturally produced by the endocrine system are key contributors to radiation-associated breast cancer among childhood cancer survivors
  • The use of hormone therapy for premature ovarian insufficiency doesn’t appear to fully replace the function of endogenous hormones in the development of radiation-associated breast cancer

Questions to ask your healthcare provider:

  1. Is there a role for estrogen and progesterone given your personal treatment history?
  2. What are the benefits and what are the risks across time?
  3. Are there other options beside hormone therapy?
  4. Is it reasonable to consider prophylactic mastectomy subsequent to chest radiation?

Action steps for you to take:

  1. Know your breasts: monthly self breast exam and annual clinical breast exam by your healthcare provider
  2. Be faithful to breast screening as outlined survivorship guidelines recommended by the Childrens Oncology Group and those from the American Cancer Society

*Childhood Cancer Survivor Study

For the abstract of this study by Moscowitz et al click here

Breast Cancer: Survivor, Are You at Risk?

Breast Cancer: survivor, are you at risk?

Risk for developing a secondary breast cancer after treatment for a childhood, adolescent, or young adult cancer depends on the type of treatment one received for their original diagnosis. While secondary breast cancers affect primarily females, males are also at risk as they, too, have breast tissue.

Known Risk Factors:

  • Chest radiation (>/= 20 Gy)
  • TOTAL dose of chest radiation received
  • Early menstruation (before the age of 12)
  • Late Menopause (after age 55)
  • Never having a baby OR having a baby after the age of 30
  • Having a close relative with breast cancer
  • Leading an inactive lifestyle

Note: TBI should be factored into the total dose of chest radiation

Breast Cancer after Chest Radiation Therapy for Childhood Cancer

Possible Risk Factors:

  • High in fat diet
  • Drinking too much alcohol
  • Never having breastfed
  • Smoking
  • Birth control pills
  • Hormone replacement therapy taken for long periods of time

This risk for secondary breast cancer begins to rise between 5-9 years after the radiation therapy ends and continues to rise, thus breast cancer occurs in much younger women and the risk does not plateau.

Prevention:

There is no way to prevent the development of a secondary breast cancer; one must, therefore, be committed to surveillance in the name of early detection.

Early Detection:

If you receive 20 Gy or greater of radiation to your chest during you cancer treatment, then the monitoring recommendations are as follows:

  • Be Breast Aware: report any lumps, bumps, pain, discharge, or any other change to your healthcare provider immediately
  • Clinical Breast Exam [CBE] performed once a year until you are 25 years old, then every 6 months thereafter
  • Have a yearly mammogram and breast MRI starting at age 25 or 8 years after you received the radiation; ideally, alternating at 6 month intervals

What if I received less than 20 GY?

You may still be at increased risk; therefore, it is important for you to discuss this risk and devise a plan for monitoring with your primary care provider that is appropriate and acceptable to you.

Children’s Oncology Group Survivorship Guidelines

What if you didn’t received any chest radiation whatsoever?

You may still be at risk if you received akylators [i. e. cytoxan], anthracyclines [i. e. doxorubicin], DTIC, or carmustine as part of your therapy. In particular, survivors of sarcoma and leukemia seem to carry an increased risk for the subsequent development of breast cancer.

Breast Cancer Risk in Childhood Cancer Survivors Without a History of Chest Radiotherapy

LifeStyle Changes you may want to consider:

  • Eat more fruits and veggies
  • 30 minutes of exercise on most days of the week
  • Lose weight
  • Stop smoking
  • Limit alcohol intake
  • If you have a baby, try to breastfeed 3-4 months
  • If you need hormone replacement therapy or birth control pills, discuss the risks and benefits within the context of your cancer treatment history

Disclaimer: This content is intended for survivors of childhood cancers and is provided for educational purposes only. This is not medical advice; please consult your healthcare providers with questions and/or concerns.

Finally, there are a few specific diagnoses that are associated with an increased risk of secondary breast cancer: the sarcomas, the leukemias, and Hodgkin’s lymphoma.

Further Reading and Resources:

Guidelines on Survivorship Care from ASCO

American Cancer Society on MRI Screening

American Cancer Society on Breast Screening in Women of Average Risk