Radiation Therapy to Treat Cancer
The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy or brachytherapy). Systemic radiotherapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called irradiation and radiation therapy.
Read the full article on the National Cancer Institute website.
Dangers of Radiation
Source: Accuray (manufacturer of radiation therapy equipment)
Important Safety Statement: Most side effects of radiotherapy, including radiotherapy delivered with Accuray systems, are mild and temporary, often involving fatigue, nausea, and skin irritation. Side effects can be severe, however, leading to pain, alterations in normal body functions (for example, urinary or salivary function), deterioration of quality of life, permanent injury and even death.
Radiation therapy to the chest can cause:
Source: Leukemia and Lymphoma Society
- Lung damage (scarring, inflammation, breathing difficulties)
- Heart damage (scarring, inflammation, coronary heart disease)
- Osteosarcoma (bone cancer)
- Breast cancer
- Thyroid cancer
- Hypothyroidism or hyperthyroidism
Radiation therapy may double the incidence of solid cancers
Radiation treatment generates therapy-resistant cancer stem cells from less aggressive breast cancer cells
Source: Wiley Online Library
Researchers from the Department of Radiation Oncology at the UCLA Jonsson Comprehensive Cancer Center report that radiation treatment transforms cancer cells into treatment-resistant breast cancer stem cells, even as it kills half of all tumor cells.1
“When we look at early-stage cancer patients, we compare patients receiving exactly the same treatment, and some fail and some are cured, and we can’t predict who those patients will be,” says Frank Pajonk, MD, PhD, the study’s senior author and an associate professor of radiation oncology and Jonsson Cancer Center researcher.
In some cases, cancer stem cells are generated by the therapy, but scientists do not yet understand all the mechanisms that cause this to occur. If they can determine the pathway and remove the reprogramming of cancer cells, they ultimately may be able to reduce the amount of radiation given to patients along with its accompanying side effects, says Dr. Pajonk.
The investigators found that induced breast cancer stem cells (iBCSCs) were generated by radiation-induced activation of the same cellular pathways used to reprogram normal cells into induced pluripotent stem cells in regenerative medicine.
In the study, Dr. Pajonk and colleagues eliminated the smaller pool of BCSCs and then irradiated the remaining breast cancer cells and put them in mice. They were able to observe the initial generation into iBCSCs in response to the radiation treatment through a unique imaging system. These new cells were highly similar to the BCSCs that had been found in tumors that had not been irradiated. They also found that these iBCSCs had a more than 30-fold increased ability to form tumors than the nonirradiated breast cancer cells.
Their findings show that if tumors are challenged by certain stressors that threaten them (such as radiation), they generate iBCSCs that may, along with surviving cancer stem cells, produce more tumors.
The researchers’ work continues as they begin to identify the pathways and several classes of drugs to prevent this process from occurring. To date, they have identified 2 different targets and drugs that could prevent it. The group has published their results of the study in breast cancer but also has made similar observations in both glioblastoma and head and neck cancer.
Dr. Pajonk says the study does not discredit radiation therapy. “Patients come to me scared by the idea that radiation generates these cells, but it truly is the safest and most effective therapy there is.”
1 Lagadec, C, Vlashi, E, Della Donna, L, Dekmezian, C, Pajonk, F. Radiation-induced reprogramming of breast cancer cells. Stem Cells. 2012;30:833–844.
Breast irradiation causes breast and lung cancer
Young women treated with radiotherapy for Hodgkin’s disease (HD) experienced a threefold increased risk of breast cancer, which rose with higher radiation doses to the breast. HD patients treated with radiotherapy had a sixfold risk of lung cancer, with risk related to dose of radiation received.
Women who received pelvic radiotherapy for cervical cancer were found to have a twofold risk of new cancers in organs that were heavily irradiated.
Source: Second Cancers – Landmark Studies
The Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute
Radiotherapy treatments and their impact in reproductive health
Radiation therapy is a component of curative therapy for a number of diseases, including those presenting frequently in young patients such as breast cancer, Hodgkin’s disease, head and neck cancer and gynecologic cancers. It is often indicated for the treatment of prostate cancer as well.
It is known that cancer cells present with defects in their ability to repair sub-lethal DNA whereas normal cells have the ability to recover. Although radiation therapy is aimed to a loco-regional application and although cancer cells are the target, radiation may also induce damage to normal cells in the tissues.
The response to radiation therapy depends on various factors such as the phase of cell cycle the cells are (cells in late G1 and S are more resistant), the degree of cell ability to repair the DNA damage and other factors such as hypoxia (hypoxic cells are more resistant), tumor mass and growth fraction. Non-dividing cells are more resistant than dividing cells.
Except for the bone marrow, the most sensitive organs to radiation therapy in the body are the gonads, both the male testis and the female ovary. The extent of damage in the female and male gonads depends on the dose, fractionation schedule and irradiation field  . Radiation therapy can be administered as teletherapy, which aims at treating a large volume of tissue. For small volumes of tissue, such as in the case of cervix cancer in the female, radiation therapy can be administered in encapsulated sources of radiation that can be implanted directly into or adjacent to tumor tissue.
Whenever female reproductive organs are involved in the irradiated field, i.e., the ovaries, the uterus and the vagina may be compromised and damaged by direct irradiation. Scattered radiation may also damage reproductive organs. In the female, radiation therapy results in dose-related damage of the gonads by the destruction of primordial follicles, which constitute the nonrenewable follicle pool. In women, the degree and persistence of the damage is also influenced by age at the time of exposure to radiotherapy and due to a reduced reserve of primordial follicles in older women, the number of follicles remaining may be also be reduced at older ages . Table 2 presents a compilation of current knowledge on the impact of radiation doses and age at radiotherapy in male and female gonadal function . In general, a dose of about 2 Gy applied to the gonadal area destroys up to 50 % of the ovarian follicle reserve. In pediatric patients, failure in pubertal development may be the first sign of gonadal failure in both sexes. Total body irradiation (TBI) given in conjunction with myeloablative conditioning prior to bone marrow transplantation is one of the most toxic treatments for the gonads and it is highly related to gonadal failure in both sexes  .
In men, the gonadal stem cells responsible for the continual differentiation and production of mature spermatozoa, the spermatogoniae, are extremely sensitive to radiation. The Leydig cells, which are responsible for the hormonal production of testosterone, are on the contrary more resistant to radiotherapy and adult patients may thus preserve hormonal production although becoming infertile. In prepubertal boys, the sensitivity to radiation therapy of Leydig cells is greater than that of older males at very high doses . Prepubertal patients may retain Leydig cell function after radiation therapy during childhood and in those cases they will present with normal pubertal development and well-preserved sexual function later in life. Nevertheless, most of those patients present at adulthood with reduced testicular size, impaired spermatogenesis and infertility.
4.1. Gonadal shielding and ovarian transposition
The standard medical procedure currently offered to reduce scatter radiation to reproductive organs and preserve fertility in male and female patients, both adult and prepubertal, is the use of shielding. When shielding of the gonadal area is not possible, the surgical fixation of the ovaries in females far from the radiation field known as oophoropexy (ovarian transposition) may be considered. It is estimated that this procedure significantly reduces the risk of ovarian failure by about 50% and those patients may retain some menstrual function and fertility . Scattered radiation and damage of the blood vessels that supply the ovaries are related to the failure of this procedure .
4.2. Radiotherapy of the uterus
Radiotherapy of the uterus in young women and girls has shown to induce tissue fibrosis, restricted uterine capacity, restricted blood flow and impaired uterine growth during pregnancy, as shown by follow-up of cancer survivors  . The uterine damage seems to be more pronounced in the youngest patients at the time of radiotherapy. As a consequence, radiotherapy-treated female patients present with a high risk of unfavorable pregnancy outcomes such as spontaneous abortion, premature labor and low birth weight offspring  . Irradiation of the vagina is related to fertility and sexual issues due to loss of lubrication, anatomical impairments and in some cases vaginal stenosis.
4.3. Cranial irradiation and hormonal dysfunction
Cranial irradiation may induce disruption of the hypothalamic-pituitary-gonadal axis, which is a recognized potential complication that can lead to infertility in both female and male patients. Follow-up of female patients treated for brain tumors with cranial irradiation post- and pre-pubertally has evidenced a high incidence of primary hypothalamic and pituitary dysfunction with consecuent disturbance in gonadotropin secretion. In some cases, precocious puberty may also be induced by cranial irradiation in childhood, which has been attributed to cortical disruption and loss of inhibition by the hypothalamus.
Read the full article at Intech.com
Study: Radiation Therapy Can Make Cancers 30x More Malignant
Written By: Sayer Ji, Founder
Following on the heels of recent revelations that x-ray mammography may be contributing to an epidemic of future radiation-induced breast cancers, in a new article titled, “Radiation Treatment Generates Therapy Resistant Cancer Stem Cells From Aggressive Breast Cancer Cells,” published in the journal Cancer July 1st, 2012, researchers from the Department of Radiation Oncology at the UCLA Jonsson Comprehensive Cancer Center report that radiation treatment actually drives breast cancer cells into greater malignancy.
The researchers found that even when radiation kills half of the tumor cells treated, the surviving cells which are resistant to treatment, known as induced breast cancer stem cells (iBCSCs), were up to 30 times more likely to form tumors than the nonirradiated breast cancer cells. In other words, the radiation treatment regresses the total population of cancer cells, generating the false appearance that the treatment is working, but actually increases the ratio of highly malignant to benign cells within that tumor, eventually leading to the iatrogenic (treatment-induced) death of the patient.
Last month, a related study published in the journal Stem Cells titled, “Radiation-induced reprogramming of breast cells,” found that ionizing radiation reprogrammed less malignant (more differentiated) breast cancer cells into iBCSCs, helping to explain why conventional treatment actually enriches the tumor population with higher levels of treatment-resistant cells. [i]
A growing body of research now indicts conventional cancer treatment with chemotherapy and radiation as a major contributing cause of cancer patient mortality. The primary reason for this is the fact that cancer stem cells, which are almost exclusively resistant to conventional treatment, are not being targeted, but to the contrary, are encouraged to thrive when exposed to chemotherapy and radiotherapy.
In order to understand how conventional treatment drives the cancer into greater malignancy, we must first understand what cancer is….
What Are Cancer Stem Cells, And Why Are They Resistant To Treatment?
Tumors are actually highly organized assemblages of cells, which are surprisingly well-coordinated for cells that are supposed to be the result of strictly random mutation. They are capable of building their own blood supply (angiogenesis), are able to defend themselves by silencing cancer-suppression genes, secreting corrosive enzymes to move freely throughout the body, alter their metabolism to live in low oxygen and acidic environments, and know how to remove their own surface-receptor proteins to escape detection by white blood cells. In a previous article titled “Is Cancer An Ancient Survival Program Unmasked?” we delved deeper into this emerging view of cancer as an evolutionary throw-back and not a byproduct of strictly random mutation.
Because tumors are not simply the result of one or more mutated cells “going rogue” and producing exact clones of itself (multi-mutational and clonal hypotheses), but are a diverse group of cells having radically different phenotypal characteristics, chemotherapy and radiation will affect each cell type differently.
Tumors are composed of a wide range of cells, many of which are entirely benign.
The most deadly cell type within a tumor or blood cancer, known as cancer stem cells (CSCs), has the ability to give rise to all the cell types found within that cancer.
They are capable of dividing by mitosis to form either two stem cells (increasing the size of the stem population), or one daughter cell that goes on to differentiate into a variety of cell types, and one daughter cell that retains stem-cell properties.
This means CSCs are tumorigenic (tumor-forming) and should be the primary target of cancer treatment because they are capable of both initiating and sustaining cancer. They are also increasingly recognized to be the cause of relapse and metastasis following conventional treatment.
CSCs are exceptionally resistant to conventional treatment for the following reasons
- CSCs account for less than 1 in 10,000 cells within a particular cancer, making them difficult to destroy without destroying the vast majority of other cells comprising the tumor.[ii]
- CSCs are slow to replicate, making them less likely to be destroyed by chemotherapy and radiation treatments that target cells which are more rapidly dividing.
- Conventional chemotherapies target differentiated and differentiating cells, which form the bulk of the tumor, but these are unable to generate new cells like the CSCs which are undifferentiated.
The existence of CSCs explains why conventional cancer treatment has completely missed the boat when it comes to targeting the root cause of tumors. One reason for this is because existing cancer treatments have mostly been developed in animal models where the goal is to shrink a tumor. Because mice are most often used and their life spans do not exceed two years, tumor relapse is very difficult, if not impossible to study.
The first round of chemotherapy never kills the entire tumor, but only a percentage. This phenomenon is called the fractional kill. The goal is to use repeated treatment cycles (usually six) to regress the tumor population down to zero, without killing the patient.
What normally occurs is that the treatment selectively kills the less harmful populations of cells (daughter cells), increasing the ratio of CSCs to benign and/or less malignant cells. This is not unlike what happens when antibiotics are used to treat certain infections. The drug may wipe out 99.9% of the target bacteria, but .1% have or develop resistance to the agent, enabling the .1% to come back even stronger with time.
The antibiotic, also, kills the other beneficial bacteria that help the body fight infection naturally, in the same way that chemotherapy kills the patient’s immune system (white blood cells and bone marrow), ultimately supporting the underlying conditions making disease recurrence more likely.
The reality is that the chemotherapy, even though it has reduced the tumor volume, by increasing the ratio of CSCs to benign daughter cells, has actually made the cancer more malignant.
Radiotherapy has also been shown to increase cancer stem cells in the prostate, ultimately resulting in cancer recurrence and worsened prognosis.[iii] Cancer stem cells may also explain why castration therapy often fails in prostate cancer treatment.[iv]
Non-Toxic Natural Substances Which Target and Kill CSCs
Natural compounds have been shown to exhibit three properties which make them suitable alternatives to conventional chemotherapy and radiotherapy:
- High margin of safety: Relative to chemotherapy agents such as 5-fluorouracil natural compounds are two orders of magnitude safer
- Selective Cytotoxicity: The ability to target only those cells that are cancerous and not healthy cells
- CSCs Targeting: The ability to target the cancer stem cells within a tumor population.
The primary reason why these substances are not used in conventional treatment is because they are not patentable, nor profitable. Sadly, the criteria for drug selection are not safety, effectiveness, accessibility and affordability. If this were so, natural compounds would form an integral part of the standard of care in modern cancer treatment.
Research indicates that the following compounds (along with common dietary sources) have the ability to target CSCs:
- Curcumin (Turmeric)
- Resveratrol (Red Wine; Japanese Knotweed)
- Quercetin (Onion)
- Sulforaphane (Brocolli sprouts)
- Parthenolide (Butterbur)
- Andrographalide (Andrographis)
- Genistein (Cultured Soy; Coffee)
- Piperine (Black Pepper)
Additional research found on the GreenMedInfo.com Multidrug Resistance page indicate over 50 compounds inhibit multidrug resistance cancers in experimental models.
Sayer Ji is founder of Greenmedinfo.com, a reviewer at the International Journal of Human Nutrition and Functional Medicine, Co-founder and CEO of Systome Biomed, Vice Chairman of the Board of the National Health Federation, Steering Committee Member of the Global Non-GMO Foundation.
Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of GreenMedInfo or its staff.
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