3 februari 2013: Bron: National Cancer Institute’s Surveillance, Epidemiology and End Results Program (HHSN261201000140C)

Een volledige borstamputatie is in veel gevallen niet nodig bij beginnende borstkanker. Sterker een minder ingrijpende ingreep vergroot de kans om niet te overlijden aan borstkanker. Vooral voor vrouwen met hormoongevoelige borstkanker blijkt het verschil ca. 13 procent te bedragen. Wanneer alleen de tumor zelf wordt verwijderd gevolgd door bestraling geeft namelijk betere kansen om van borstkanker te genezen.

Dit blijkt uit een grote langjarige zogeheten postpectieve studie onder 112.154 vrouwen. Een onderzoeksteam van de Duke universiteit analyseerde de gegevens van 112.154 vrouwen die in de periode 1990 tot 2004 waren gediagnosteerd met borstkanker stadium fase I of II. Hiervan ondergingen 61.771 patiënten een borstbesparende operatie gevolgd door lokale bestraling en 50.383 vrouwen kregen een volledige borstamputatie zonder bestraling. De onderzoekers ontdekten dat een minder invasieve behandeling in alle leeftijdsgroepen gerelateerd was aan een grotere kans te overleven.

Vrouwen na de overgang (50 jaar en ouder)  en met hormoongevoelige borstkanker bleken het meest te profiteren van een minder invasieve behandeling. Volgens de onderzoekers hadden zij 13 procent minder kans om te overlijden aan borstkanker in vergelijking met diegenen die een volledige borstamputatie ondergingen. Hoeweel deze studie werd gedaan bij heel veel vrouwen over een lange periode zijn er toch teveel onzekerheden om defintief te kunnen zeggen dat een borstbesparende operatie een betere aanpak zou zijn dan een volledige borstamputatie, aldus de onderzoekers.

Persoonlijk lijkt mij het ook vreemd dat verschillende vormen van borstkanker waarvoor een totaal verschillende aanpak wordt geadviseerd zomaar 1 op 1 met elkaar kan worden vergeleken. Hormoongevoelige borstkanker, zeker voor vrouwen na de overgang is in principe behoorlijk goed onder controle te houden zonder welke operatie dan ook. Terwijl niet-hormoongevoelige borstkanker waarvoor bv. chemo plus bv. herceptin nodig is als behandeling een borstamputatie vaak wel levensverlengend is. Maar goed deze studie gaat over een periode waarin een borstamputatie nog werd gezien als levensverlengend.

Het volledige studierapport Survival after lumpectomy and mastectomy for early stage invasive breast cancer. The effect of age and hormone receptor status is tegen betaling in te zien. Hier het abstract van de studie en een persbericht van de Duke University over deze studie:

Less invasive treatment is associated with improved survival in early stage breast cancer

By Duke Medicine News and Communications

DURHAM, N.C. -- Patients with early stage breast cancer who were treated with lumpectomy plus radiation may have a better chance of survival compared with those who underwent mastectomy, according to Duke Medicine research.

The study, which appears online Jan. 28, 2013, in the journal CANCER, raises new questions as to the comparative effectiveness of breast-conserving therapies such as lumpectomy, where only the tumor and surrounding tissue is surgically removed.

“Our findings are observational but do suggest the possibility that women who were treated with less invasive surgery had improved survival compared to those treated with mastectomy for stage I or stage II breast cancer,” said E. Shelley Hwang, M.D., MPH, chief of breast surgery at Duke Cancer Institute and the study’s lead author.

Taking advantage of 14 years of data from the California Cancer Registry, a source of long-term outcome data for women diagnosed with and treated for breast cancer in California, the research team found improved survival to be associated with the less invasive treatment in all age groups, as well as those with both hormone-sensitive and hormone-resistant cancers. Women age 50 and older at diagnosis with hormone-sensitive tumors saw the largest benefit of choosing lumpectomy plus radiation: they were 13 percent less likely to die from breast cancer, and 19 percent less likely to die from any cause compared with those undergoing mastectomy. 

Prior randomized trials have shown that when it comes to survival, lumpectomy with radiation is as effective as mastectomy in treating early stage breast cancer. As a result, the rate of women electing lumpectomy with radiation has climbed in the past few decades.

However, a recent trend has emerged with more early stage breast cancer patients, often younger women with very early cancers, opting for mastectomy. These women may perceive mastectomy to be more effective at eliminating early stage cancer and therefore reducing the anxiety accompanying long-term surveillance.
 
“Given the recent interest in mastectomy to treat early stage breast cancers despite the research supporting lumpectomy, our study sought to understand what was happening in the real world, how women receiving breast-conserving treatments were faring in the general population,” Hwang said.
 
The team analyzed data from 112,154 women diagnosed with stage I or stage II breast cancer between 1990 and 2004, including 61,771 who received lumpectomy and radiation and 50,383 who had mastectomy without radiation.

The researchers looked at age and other demographic factors, along with tumor type and size to decipher whether each treatment had better outcomes for certain groups of women. Patients were followed on average for 9.2 years.

The researchers evaluated whether illnesses other than breast cancer, such as heart and respiratory disease, may have influenced whether women chose lumpectomy or mastectomy. Within three years of diagnosis, breast cancer patients who underwent lumpectomy and radiation had higher survival rates than those who chose mastectomy when all other illnesses were evaluated. This suggests that women choosing lumpectomy may have been generally healthier.
 
However, Hwang and her colleagues were surprised to also find that early stage breast cancer patients treated with breast-conserving treatment had a significantly better short-term survival rate from breast cancer than women who underwent mastectomy. A subset analysis limited to women with stage I cancer only showed consistent results.

“The hopeful message is that lumpectomy plus radiation was an effective alternative to mastectomy for early stage disease, regardless of age or tumor type,” said Hwang. “Our study supports that even patients we thought might benefit less from localized treatment, like younger patients with hormone-resistant disease, can remain confident in lumpectomy as an equivalent and possibly better treatment option.”

The authors emphasize that observational studies such as this one cannot establish causality between type of surgery and outcome and that longer follow up is needed.  Nevertheless, this is a provocative observation that requires more research to understand whether patient factors that were not available for analysis might contribute to these observed survival differences. 

In addition to Hwang, study authors include Daphne Y. Lichtensztajn, Scarlett Lin Gomez, and Christina A. Clarke of the Cancer Prevention Institute of California. Barbara Fowble of the University of California San Francisco Helen Diller Family Comprehensive Cancer Center also contributed to the research.

The study was supported by National Cancer Institute’s Surveillance, Epidemiology and End Results Program (HHSN261201000140C) awarded to the Cancer Prevention Institute of California. The collection of cancer incidence data used in this study was supported by the California Department of Health Services.

Survival after lumpectomy and mastectomy for early stage invasive breast cancer

Article first published online: 28 JAN 2013 DOI: 10.1002/cncr.27795 Copyright © 2013 American Cancer Society

Abstract

BACKGROUND:

Randomized clinical trials (RCT) have demonstrated equivalent survival for breast-conserving therapy with radiation (BCT) and mastectomy for early-stage breast cancer. A large, population-based series of women who underwent BCT or mastectomy was studied to observe whether outcomes of RCT were achieved in the general population, and whether survival differed by surgery type when stratified by age and hormone receptor (HR) status.

METHODS:

Information was obtained regarding all women diagnosed in the state of California with stage I or II breast cancer between 1990 and 2004, who were treated with either BCT or mastectomy and followed for vital status through December 2009. Cox proportional hazards modeling was used to compare overall survival (OS) and disease-specific survival (DSS) between BCT and mastectomy groups. Analyses were stratified by age group (< 50 years and ≥ 50 years) and tumor HR status.

RESULTS:

A total of 112,154 women fulfilled eligibility criteria. Women undergoing BCT had improved OS and DSS compared with women with mastectomy (adjusted hazard ratio for OS entire cohort = 0.81, 95% confidence interval = 0.80-0.83). The DSS benefit with BCT compared with mastectomy was greater among women age ≥ 50 with HR-positive disease (hazard ratio = 0.86, 95% CI = 0.82-0.91) than among women age < 50 with HR-negative disease (hazard ratio = 0.88, 95% CI = 0.79-0.98); however, this trend was seen among all subgroups analyzed.

CONCLUSIONS:

Among patients with early stage breast cancer, BCT was associated with improved DSS. These data provide confidence that BCT remains an effective alternative to mastectomy for early stage disease regardless of age or HR status. Cancer 2012;. © 2012 American Cancer Society.


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