Thursday, December 04, 2008


The authors below think so and if their controls were as good as they think, that is a reasonable conclusion. Cancers in general do spontaneously regress a lot of the time. My skin cancers certainly do. The finding does tend to strengthen the current advice that random breast-cancer screening in general does more harm than good. Some indications (including family history) should be present before screening

The Natural History of Invasive Breast Cancers Detected by Screening Mammography

By Per-Henrik Zahl et al.

Background: The introduction of screening mammography has been associated with sustained increases in breast cancer incidence. The natural history of these screen-detected cancers is not well understood.

Methods: We compared cumulative breast cancer incidence in age-matched cohorts of women residing in 4 Norwegian counties before and after the initiation of biennial mammography. The screened group included all women who were invited for all 3 rounds of screening during the period 1996 through 2001 (age range in 1996, 50-64 years). The control group included all women who would have been invited for screening had there been a screening program during the period 1992 through 1997 (age range in 1992, 50-64 years). All women in the control group were invited to undergo a 1-time prevalence screen at the end of their observation period. Screening attendance was similar in both groups (screened, 78.3%, and controls, 79.5%). Counts of incident invasive breast cancers were obtained from the Norwegian Cancer Registry (in situ cancers were excluded).

Results: As expected, before the age-matched controls were invited to be screened at the end of their observation period, the cumulative incidence of invasive breast cancer was significantly higher in the screened group than in the controls (4-year cumulative incidence: 1268 vs 810 per 100 000 population; relative rate, 1.57; 95% confidence interval, 1.44-1.70). Even after prevalence screening in controls, however, the cumulative incidence of invasive breast cancer remained 22% higher in the screened group (6-year cumulative incidence: 1909 vs 1564 per 100 000 population; relative rate, 1.22; 95% confidence interval, 1.16-1.30). Higher incidence was observed in screened women at each year of age.

Conclusions: Because the cumulative incidence among controls never reached that of the screened group, it appears that some breast cancers detected by repeated mammographic screening would not persist to be detectable by a single mammogram at the end of 6 years. This raises the possibility that the natural course of some screen-detected invasive breast cancers is to spontaneously regress.

Archives of Internal Medicine, Vol. 168 No. 21, November 24, 2008.

Delays in radiation therapy lead to increased breast cancer recurrence

The conclusions below are certainly not waterproof but the steadily progressing nature of the adverse outcomes with longer and longer delays makes me inclined to go with them nonetheless. What is omitted is a more searching look at other characteristics associated with not getting prompt treatment. One guess: working class women get poorer treatment. And working class people have poorer prognoses anyway. The authors did have a measure of poverty so they should have partialled it out of the results before any further analyses were attempted. The findings, if accepted as is, have huge implications for socialized medicine systems where there are often long waits for treatment. The abstract is here

A new analysis of the National Cancer Institute's cancer registry has found that as many as one in five older women experience delayed or incomplete radiation treatment following breast-conserving surgery, and that this suboptimal care can lead to worse outcomes.

Dr. Heather Taffet Gold of Weill Cornell Medical College and colleagues found that among a nationally representative sample of nearly 8,000 breast cancer registry patients aged 65 and older, almost 1,300 women experienced delayed radiotherapy and approximately 270 had incomplete radiotherapy. Of these women, those with Stage 1 breast cancer had worse health outcomes associated with this less-than-ideal therapy, while those with a precancerous lesion called ductal carcinoma in situ (DCIS) were not as affected.

"Timeliness of post-surgical radiotherapy is important in reducing the risk of subsequent recurrence or new breast malignancies in patients with early breast cancer. Delaying treatment by eight weeks or more significantly increased the odds for recurrence," says Dr. Gold, the study's lead author and an assistant professor of public health in the Division of Health Policy in the Department of Public Health at Weill Cornell Medical College. "One possible reason for the delays is that the coordination of care can be a challenge as treatment is usually delivered by multiple providers from different specialties, including surgeons, radiation oncologists and medical oncologists."

Stage 1 breast cancer patients with radiation treatment delayed by eight weeks were 1.4 times more likely to have a recurrence or subsequent new primary breast tumor compared with those receiving timely treatment; they also had reduced survival. Patients whose radiotherapy was delayed by 12 weeks or longer were four times more likely to have a recurrence or subsequent new breast tumor. And women who had incomplete radiation treatment for Stage 1 breast cancer -- those who underwent fewer than three weeks of the typical five-to-seven-week regimen -- had a higher rate of overall mortality, with a 32 percent higher likelihood of death.

The researchers also found treatment disparities in subgroups of older women. "Older black women were more likely to delay radiation treatment, whereas women living in areas with a high concentration of radiation oncologists were less likely to delay. Additionally, older women living in high-poverty areas were less likely to complete radiation treatment," says Dr. Gold.

The work appears in the latest online issue of the journal Cancer and the Dec. 1, 2008, print issue. Research collaborators include Huong T. Do, M.A., and Andrew W. Dick, Ph.D., senior economist at the RAND Corporation in Pittsburgh, Pa.

The study is based on an evaluation of women aged 65 and older diagnosed with either DCIS or Stage 1 breast cancer from 1991 to 1999 and followed through 2002 in registries of the Surveillance, Epidemiology, and End Results (SEER) Program sponsored by the National Cancer Institute.

This nationally representative, population-based study of older women provided a unique opportunity to study the effects of suboptimal treatment in the community setting. "Our findings indicate that radiation treatment should be made easier for all patients to ensure completion and that delays should be minimized. To improve health outcomes following treatment for breast cancer, health care facilities and providers should implement supportive services, such as transportation, and provide educational materials to encourage and ease access to optimal radiation treatment, thereby improving disease-free and overall survival," said Dr. Andrew Dick, senior author on the study.


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