Imaging X-rays Cause Cancer: A Call to Action for Caregivers and Patients

"Imaging and Cancer: Kids Most in Peril

The above being said, the indisputable fact, and in my opinion rendered truly indisputable by the BEIR VII report, is that medical x-rays cause cancer. BEIR VII also emphasizes that there may be no safe lower limit. This statement taken as said has the potential to cause considerable alarm, so my intuitive modification is that perhaps below the dose of a standard body CT, which is approximately 10 mSieverts (mSv; units that radiation dose is measured in), there is likely negligible if any risk for an individual test.

However, even 1 body CT scan (1 CT scan of only 1 of the following regions: the chest region, the abdominal region, or the pelvic region) carries with it some element of risk. The risk that BEIR VII reports is 1 in 1000 chance of developing cancer from a 10 mSv radiation dose. In my prior report, I described what is written on the US Food and Drug Administration Web site, which is a 1 chance in 2000 of developing cancer from a dose of 10 mSv. The BEIR VII report doubles that risk. The risk in children is even higher, with a reported chance of 1 in 550 of developing cancer."

A table then follows with radiation doses for each procedure, of which I'm listing a few here:

X-rays:
Chest - 0.02 (mSv)
Head - 0.07
Upper GI - 3.6
Lower GI - 6.4
Mammogram - 0.13

CT Scan:
Head - 2.0
Abdomen - 10.0
Chest - 20-40
Pulmonary angiography - 20-40

PET - CT - 25

This article then says "Risk escalates with multiphase acquisition in a single CT study, and with multiple individual CT tests."

If you can, sign up to Medscape; you can access articles like this which may not make it to the news.

Which Cut Is Older? (It's a Trick Question) - New York Times

Which Cut Is Older? (It's a Trick Question) - New York Times: "Both of these steaks were red when bought on Feb. 3. Kept refrigerated, they were then photographed on Feb. 16. Why the difference? The one at top was treated with a process that has some consumer groups angered."



I'll just go ahead and kill the punchline - carbon monoxide.

Fat-Reduced Diet May Not Reduce Risk for Cancer or CVD

Fat-Reduced Diet May Not Reduce Risk : "Feb. 7, 2006 - At 8 years of follow-up, a fat-reduced diet was not associated with reduced risk for breast or colon cancer, heart disease, stroke, or cardiovascular disease (CVD), according to the results of the randomized Women's Health Initiative (WHI) dietary modification trial reported in 3 articles published in the February 8 issue of JAMA. Two accompanying editorials note the limitations of this trial, particularly that the diet studied is not consistent with current guidelines for a heart-healthy diet.
'The hypothesis that a low-fat dietary pattern can reduce breast cancer risk has existed for decades but has never been tested in a controlled intervention trial,' write Ross L. Prentice, PhD, from the Fred Hutchinson Cancer Institute in Seattle, Washington, and colleagues. 'Supported by early rodent experiments, country-to-country comparisons linked higher dietary fat intake to breast cancer risk. However, case-control and cohort studies have had mixed results.'

The WHI dietary modification trial took place at 40 US clinical centers from 1993 to 2005 and enrolled 48,835 postmenopausal women, aged 50 to 79 years, without previous history of breast cancer. Of these participants, 18.6% were of minority race or ethnicity. Women were randomized to the dietary modification intervention group (40%; n = 19,541) or to the comparison group (60%; n = 29,294).

The diet was designed to reduce intake of total fat to 20% of energy and to increase consumption of vegetables and fruit to at least 5 servings daily and grains to at least 6 servings daily. Women in the comparison group were not asked to make dietary changes. The primary endpoint was incidence of invasive breast cancer."

In my mind, the most shocking part of this article is actually the bolded portion.

Who does these studies?

In the hormone-migraine study, I came across a reference to this study -

Sexual experience interacts with steroid exposure to shape the partner preferences of rats.: "A three-phase experiment manipulated sexual experience and hormone exposure (perinatally and in adulthood) in female rats housed individually from weaning so as to limit peripubertal social and sexual experience. Noncontact partner preference for a male or estrous female rat was measured both before and after sexual experience, first while rats were under the influence of circulating testosterone propionate (TP) and later after priming them with ovarian hormones (estradiol benzoate and progesterone; EB & P). When implanted with TP capsules and tested while sexually naive, all groups of female rats preferred females to males without differing statistically. However, following three sexual experience sessions with estrous females, differences emerged between the masculinized and control groups in the magnitude of their female-directed preference, with masculinized females demonstrating a significantly greater preference for estrous females. Sexual experience with male rats under EB & P did not result in a significant shift in preference in any group. Histological assessment indicated that the volume of the sexually dimorphic nucleus of the preoptic area (SDN-POA) was increased by exposure to TP postnatally, and SDN-POA volume correlated positively with partner preference scores but only when rats were both sexually experienced and exposed to circulating TP in adulthood. These results suggest that sexual experience interacts with steroid exposure to shape partner preference."

I narrowly missed being able to get into a lab class when I started pursuing a psych degree, back in 1991. Later, I was glad I had missed it when I went with my friend Kristen to feed her lab rat, which she was doing as part of that class. Rats, with their slinky tails, just kind of gross me out. And when I read articles like this, I'm even more glad I didn't end up firmly on the lab science track. Like, who drew the short straw for this one?

Summation on Ovarian Hormones and Migraines

Ovarian Hormones and Migraine Headache: "A number of neurotransmitter systems and pain processing networks thought to be important to the pathogenesis of migraine headache can be modulated by estrogen and progesterone. Estrogen appears to enhance neurotransmission within the TNC in rat models of trigeminal activation, while progesterone has been shown to inhibit neurotransmission. Knowledge of the effects of ovarian hormones on the central nervous system is essential to an understanding of the pathogenesis of migraine headache."

More on Ovarian Hormones and Migraines

Ovarian Hormones and Migraine Headache: "While ovarian hormones could potentially affect numerous loci within the trigeminal vascular pain pathways, their effect on the trigeminal nucleus caudalis (TNC) has been best studied. Modulation of neurotransmission within the TNC by ovarian hormones could play an important role in the pathophysiology of migraine headache. ... Progesterone may also affect neurotransmission within the TNC as well as decrease plasma extravasations in an animal model of migraine headache. Fos expression in the TNC was decreased by 42% in animals pretreated with allopregnanolone (a progesterone metabolite) after activation of the trigeminal nerve with capsaicin."

This is more like it.

Ovarian Hormones and Migraine Headache

Ovarian Hormones and Migraine Headache: "Cortical GABA levels may vary during different phases of the menstrual cycle. Epperson et al. examined cortical GABA levels with magnetic resonance spectroscopy in 9 menstruating women with premenstrual dysphoric disorder (PMDD) and 14 healthy controls. The women with PMDD demonstrated increased cortical GABA levels during the luteal phases (high progesterone/high estrogen) of the menstrual cycle when compared to the follicular phases (high estrogen/low progesterone). The control group showed the opposite results with higher cortical GABA levels within the follicular phases than the luteal phases."

This seems significant but I wish I knew what this actually means, in terms of treatment options.