Cancer; Just who invited you?
Many cases of cancer are just caused by "bad luck" as two scientists "suggested in an article published last week in the journal Science. The bad luck comes in the form of random genetic mistakes, or mutations, that happen when healthy cells divide."
One of them, Dr. Tomasetti drew an analogy: the risks of a car accident where the "longer the trip, the higher the odds of a crash. Environmental factors like bad weather can add to the basic risk, and so can defects in the car....This is a good picture of how I see cancer,” he said. “It’s really the combination of inherited factors, environment and chance. At the base, there is the chance of mutations, to which we add, either because of things we inherited or the environment, our lifestyle.”
Random mutations may account for two-thirds of the risk of getting many types of cancer, leaving the usual suspects — heredity and environmental factors — to account for only one-third, say the authors, Cristian Tomasetti and Dr. Bert Vogelstein, of Johns Hopkins University School of Medicine."
Grady, Denise. "Cancer’s Random Assault." NY Times Jan. 5, 2015
Amazing New Directions:
byline: "New drugs and methods of altering a patient's own immune cells are helping some cancer patients - but not all - even when standard treatments fail."
Beyond chance [bad luck] and the further elucidation of the deep role of hereditary factors, clearly the environment must be cleaner.
"Some have argued that the substantial improvements in air quality over the past 40 years are sufficient to protect public health and that there is little evidence to support more stringent standards. [Studies, however,] suggest that further improvement in air quality may have beneficial public health effects. Four decades ago, most Americans were exposed to much higher levels of air pollution than those observed today. At that time, it was difficult to find communities with little or no exposure, which limited the ability of investigators to determine a 'no-effect level.' With the improvements in air quality, observational studies can now assess the benefits of reductions in air-pollution exposure into the range below those historical levels. These new observational studies often show that there are health benefits associated with improvements in air quality even when the pollution levels are within a range previously thought to be safe." [Emphasis added – jgk]
Douglas W. Dockery, Sc.D., and James H. Ware, Ph.D. "Cleaner Air, Bigger Lungs." N Engl J Med [Editorial] 3/5/2015; 372:970-972.
Gauderman WJ, Urman R, Avol E, et al. "Association of improved air quality with lung development in children." N Engl J Med 2015;372:905-913 Free Full Text | Medline
With 20 years' experience screening for breast or prostate cancer, I say "uh-oh"!
- These cancers seemed to be more prevalent.
- Relatively speaking the cancers are presenting at an earlier stage.
- The "incidence of regional cancers has not decreased at a commensurate rate."
"One possible explanation is that screening may be increasing the burden of low-risk cancers without significantly reducing the burden of more aggressively growing cancers and therefore not resulting in the anticipated reduction in cancer mortality. To reduce morbidity and mortality from prostate cancer and breast cancer, new approaches for screening, early detection, and prevention for both diseases should be considered." [Emphasis added, jgk]
Esserman L, Shieh Y, Thompson I. "Rethinking Screening for Breast Cancer and Prostate Cancer." JAMA. 2009;302(15):1685-1692.
A Canadian National Breast Screening (CNBS) Study is criticized because of having methodological flaws, which had been well documented for over two decades.
The National Cancer Institute's Robert E. Tarone stated in 1995 that a statistically significant excess of advanced cancers had been allocated to the mammography group in the Study (which, incidentally, was run in the '80s). Indeed, the World Health Organization (WHO) excluded the Study from its comparative analysis of screening mammography and its impact of breast cancer mortality. Others feel the same way–the American Cancer Society the American College of Radiology, the Society of Breast imaging and Breastcancer.org, for example.
As a result, the previous recommendation–regular mammograms for women ages 40, plus, lives on.
McGinty G, "Radiologists aren’t the only ones criticizing the new mammogram study." Physician | March 15, 2014
The following 23-year follow-up shows that men with early prostate cancer live longer if they're treated, instead of just being watched. Duh!
BACKGROUND: Radical prostatectomy reduces mortality among men with localized prostate cancer; however, important questions regarding long-term benefit remain.
METHODS: Between 1989 and 1999, we randomly assigned 695 men with early prostate cancer to watchful waiting or radical prostatectomy and followed them through the end of 2012. The primary end points in the Scandinavian Prostate Cancer Group Study Number 4 (SPCG-4) were death from any cause, death from prostate cancer, and the risk of metastases. Secondary end points included the initiation of androgen-deprivation therapy.
RESULTS: During 23.2 years of follow-up, 200 of 347 men in the surgery group and 247 of the 348 men in the watchful-waiting group died.
Of the deaths, 63 in the surgery group and 99 in the watchful-waiting group were due to prostate cancer; the relative risk was 0.56 (95% confidence interval [CI], 0.41 to 0.77; P=0.001), and the absolute difference was 11.0 percentage points (95% CI, 4.5 to 17.5). The number needed to treat to prevent one death was 8. One man died after surgery in the radical-prostatectomy group.
Androgen-deprivation therapy was used in fewer patients who underwent prostatectomy (a difference of 25.0 percentage points; 95% CI, 17.7 to 32.3).
The benefit of surgery with respect to death from prostate cancer was largest in men younger than 65 years of age (relative risk, 0.45) and in those with intermediate-risk prostate cancer (relative risk, 0.38). However, radical prostatectomy was associated with a reduced risk of metastases among older men (relative risk, 0.68; P=0.04).
CONCLUSIONS: Extended follow-up confirmed a substantial reduction in mortality after radical prostatectomy; the number needed to treat to prevent one death continued to decrease when the treatment was modified according to age at diagnosis and tumor risk. [However, a] large proportion of long-term survivors in the watchful-waiting group have not required any palliative treatment.
Bill-Axelson A, Holmberg L, Garmo H, et al. "Radical prostatectomy or watchful waiting in early prostate cancer." N Engl J Med. 2014 Mar 6;370(10):932-42. doi: 10.1056/NEJMoa1311593. (Original) PMID: 24597866 (Funded by the Swedish Cancer Society and others.)
A Study Indicates That in the U.S., Fewer Men Are Getting Prostate Biopsies
The US Preventive Services Task Force (USPSTF) 2012 guidelines recommend against using "prostate-specific antigen (PSA) testing on most healthy men for prostate cancer.”
Research published in JAMA Surgery shjow that such recommendations are steering most healthy men away from routine prostate cancer screening.
Prenatal exposure to maternal cancer with or without treatment did not impair the cognitive, cardiac, or general development of children in early childhood. Prematurity was correlated with a worse cognitive outcome, but this effect was independent of cancer treatment. (Funded by Research Foundation–Flanders and others; ClinicalTrials.gov number, NCT00330447.)
"Pediatric Outcome after Maternal Cancer Diagnosed during Pregnancy." N Engl J Med 2015; 373:1824-1834November 5, 2015 DOI: 10.1056/NEJMoa1508913