Category Archives: Cancer

Monthly, High-Dose Vitamin D Supplements Found Not to Prevent Cancers

High Dose monthly Vitamin D supplements don’t seem protective against cancer, a JAMA Oncology study reports. Previous studies have found an inverse relationship between serum vitamin D levels and cancer risk, but supplementation hasn’t produced consistent results.

Researchers used data from a New Zealand study examining the effect of high-dose supplements on cardiovascular health. In their post hoc analysis they used national cancer registries to compare cancer incidence and mortality in roughly 5000 participants randomized to vitamin D (200,000 IU oral bolus plus monthly 100,000 IU) or placebo. Participants ranged in age from 50 to 84 and were recruited from Auckland family practices.

During their median 3.3-year participation, cancer incidence was almost identical in the two groups: 6.5% with vitamin D and 6.4% with placebo.

The authors wondered whether daily or weekly doses — or a longer duration of supplementation — would bring different results.

LINK(S):

JAMA Oncology article (Free abstract)

Background: Physician’s First Watch coverage of vitamin D and lower colorectal cancer risk (Free)

ASPIRIN- to take or not to take 

The latest recommendation from the US preventive task force is to take aspirin (low dose) to prevent both heart disease and colon cancer in adults aged 50-59, who have significant risk factors.

The guidelines are published in the Annals of Internal Medicine:

  • Low-dose aspirin is recommended for adults aged 50–59 who have at least a 10% risk for a cardiovascular event in the next decade, low bleeding risk, and a life expectancy of at least 10 years; patients must also be willing to take aspirin daily for at least 10 years.
  • For adults aged 60–69 fitting the above criteria, the decision to start aspirin should be an individual one.
  • For patients younger than 50 and older than 69, there is not enough evidence to make recommendations.

Finally A Screening Recommendation For Ovarian Cancer

Lancet reports yearly screening for ovarian cancer, using a pelvic ultrasound and checking a blood marker CA125, might reduce deaths from ovarian cancers. The study was done in UK in over 200,000 post menopausal women with no family or personal history of ovarian cancer and they were followed for a period of 11 years.

During the follow-up, the incidence of ovarian cancer mortality was not significantly lower in the screening group  than in the no-screening group. However, the effect of screening became significant after 7 years. In addition, in a prespecified secondary analysis that excluded women with CA125 levels suggesting cancer at baseline, screening was associated with a 20% reduction in ovarian cancer mortality relative to no screening.

 

Vitamin B3 To The Rescue

Nicotinamide (a form of vitamin B3, Niacin) reduces the incidence of nonmelanoma skin cancers in high-risk adults. High risk was defined as having had 2 cases of skin cancer- either squamous cell or basal cell, in the past 5 years.

This study was done on over 400 adults in Australia, who were randomized to receive oral niacin (500 mg) or placebo twice daily for a year. During the study, the average number of new skin cancers was significantly lower with vitamin B3. Significant reductions were observed for both squamous cell and basal cell cancers. In addition, the number of actinic keratoses, which can turn cancerous, was significantly lower among niacin recipients as early as 3 months after supplementation began. Adverse events did not differ between the groups.

The authors conclude that “nicotinamide is widely accessible as an inexpensive over-the-counter vitamin supplement and presents a new chemopreventive opportunity against non-melanoma skin cancers.”

 

Which Cancers Should We Screen For?

The American College of Physicians has made the following recommendations on screening for five common cancers.

  • Breast: For women aged 40-49 years, mammography screening every 2 years should be offered if a woman requests it after a discussion of the potential benefits and harms. For women aged 50-74 years who are in good health, mammography should be encouraged every 2 years.
  • Cervical: For women aged 21-29 years, Pap smears are recommended every 3 years. For those aged 30-65, Pap smears with HPV testing can be done every 5 years (instead of Pap smears alone).
  • Colorectal: For patients aged 50-75 years, one of the following strategies should be encouraged: high-sensitivity stool blood testing (FOBT) or stool immunofluorescence testing (FIT) annually; sigmoidoscopy every 5 years; combined high-sensitivity FOBT or FIT every 3 years plus sigmoidoscopy every 5 years; or optical colonoscopy every 10 years.
  • Ovarian: Screening isn’t recommended.
  • Prostate: For men aged 50-69 with a life expectancy of at least a decade, discuss screening’s benefits and risks. If patients prefer screening, order prostate-specific antigen testing no more than once every 2-4 years.

 

Does Orange Juice Increase Your Risk Of Melanoma?

Consumption of orange juice and grapefruit are associated with an increased melanoma risk, says a study in the Journal of Clinical Oncology.

Nearly 100,000 white participants completed questionnaires about their consumption of citrus fruits and juices and were followed for roughly 25 years. Participants who reported consuming at least 1.6 servings of citrus daily had a 36% increased risk for melanoma, compared with those who ate less than two servings a week. In analyses by citrus type, the findings were significant only for orange juice (increased risk seen with 5-6 servings/week vs. <1/week) and grapefruit (increased risk with <1/week vs. never).

The authors speculate that the association could be due to the psoralen found in citrus fruits. Animal studies have found that psoralen has photocarcinogenic properties.

 

Hormone Replacement Therapy Tied to Ovarian Cancers

A meta-analysis of 17 prospective studies, published in the Lancet looking at over 12,000 women diagnosed with ovarian cancer, about half of the women with ovarian cancer had received hormone therapy, and the median duration of use was 6 years. Women with current hormone therapy use had roughly a 40% increased risk for developing ovarian cancer, even among those who used hormone therapy for less than 5 years. The risk decreased with time, but 10 years after stopping, there was still an increased risk for certain type of tumors.