25 maart 2011: bron: J Natl Cancer Inst. 2011 Mar 16;103(6):478-88. Epub 2011 Mar 11.

Vrouwen waarbij borstkanker al wordt geconsteeerd als de tumorcellen nog beperkt zijn tot de melkgangen (ductaal in situ - DICS)  overleven steeds langer hun borstkanker en krijgen geen recidief. Dit blijkt uit twee grote gerandomiseerde placebo gecontroleerde langjarige studies. De onderzoekers beweren dat dit zou komen door de behandeling van operatie en daarna bestraling en/of tamoxifen. Opmerkelijk is wel dat in de groep operatie en bestraling de kans op overlijden aan de ziekte groter was als er zich een recidief voordeed dan wanneer zich een recidief voordeed in de operatie plus placebogroep of operatie plus tamoxifengroep (4,7% t.o. 2,7%.) Volgens de onderzoekers betekent dit dat als zich een recidief voordoet dit in de groep die werd bestraald de kanker agressiever is. In beide studies is geen onderzoek gedaan naar niet operatief ingrijpen en de resultaten van een wait and see beleid. In Medscape is een groot artikel gepubliceerd over deze studies en interessant is daar ook de discussie over wel of niet afwachten bij een beginnende vorm van borstkanker. Het hele artikel van Medscape is hier te lezen: Long-Term Data Show That DCIS Has Excellent Prognosis 

Hier enkele citaten uit het artikel van Medscape en daaronder het officiele abstract van de studie:

Risk for Invasive Breast Cancer

The long-term results show that over the course of 15 years, there were 490 IBTR events, 263 (53.7%) of which were invasive.

Combination treatment with lumpectomy plus radiation plus tamoxifen (triple therapy) halved the risk of developing invasive breast cancer (hazard ratio , 0.48; P < .001). Over the 15 years of follow-up, invasive IBTR occurred in 19.4% of women treated with lumpectomy and in 8.5% of women treated with triple therapy — a 52% reduction in risk.

Results on women who were treated with lumpectomy plus radiation but no tamoxifen come from slightly different groups in the 2 trials.

In the B-17 trial, invasive IBTR occurred in 8.9% of women treated with lumpectomy plus radiation, which is similar to the 8.5% seen in women treated with triple therapy.

However, in the larger of the 2 trials — B-24 — there was a significant difference. In that trial, invasive IBTR occurred in 10% of women treated with lumpectomy and radiation plus placebo, and in 8.5% of those treated with triple therapy (HR, 0.68; P = .0025). These results show the benefit of adding tamoxifen to the combination treatment, say the researchers.

Invasive Cancer Alters the Prognosis

Developing invasive breast cancer alters the subsequent prognosis, the researchers note. The mortality risk increased approximately 2-fold in women who developed invasive IBTR, compared with those who did not.

Developing invasive IBTR is the dominant, but not the sole, pathway by which a breast-cancer-related death occurs in women with DCIS, they add.

The exact incidence of breast cancer death varied with the treatment received; the 15-year cumulative incidence of breast cancer death was 3.1% for those treated with lumpectomy alone, and 2.3% for those treated with triple therapy.

For treatment with lumpectomy and radiation, the equivalent figures were 4.7% for those in the B-17 trial (lumpectomy and radiation) and 2.7% for those in the in the B-24 trial (lumpectomy, radiation, and placebo).

"We speculate that an invasive IBTR after radiation therapy may be biologically more aggressive, and that many of the invasive IBTRs in the lumpectomy-alone group are biologically indolent," the researchers note.

Concerns Over Overtreatment

There has been concern within the oncology community about the overtreatment of DCIS; there have even been suggestions that it should not be treated automatically, but followed with an active surveillance approach. There have also been proposals that radiation be omitted in cases where the initial DCIS lesion is small or low grade.

Dr. Wapnir herself acknowledged "that critics will point out that the majority of women who were treated with lumpectomy alone didn't have a recurrence."

However, she noted that these 2 trials show a significant benefit from adding radiation to lumpectomy, and that most of the DCIS lesions were small — the great majority were 1 cm or less.

Tumor size was not a significant prognostic factor, nor was it an indicator of which patients could forego radiotherapy.

"We were not able to identify a group that did not benefit from either radiation or radiation plus tamoxifen," Dr. Wapnir commented in a statement.

"I tell my patients when discussing treatment options that I don't know how to identify which patients will be in that category," she said.

Long-Term Outcomes of Invasive Ipsilateral Breast Tumor Recurrences After Lumpectomy in NSABP B-17 and B-24 Randomized Clinical Trials for DCIS.

Long-Term Outcomes of Invasive Ipsilateral Breast Tumor Recurrences After Lumpectomy in NSABP B-17 and B-24 Randomized Clinical Trials for DCIS

  1. Irene L. Wapnir,
  2. James J. Dignam,
  3. Bernard Fisher,
  4. Eleftherios P. Mamounas,
  5. Stewart J. Anderson,
  6. Thomas B. Julian,
  7. Stephanie R. Land,
  8. Richard G. Margolese,
  9. Sandra M. Swain,
  10. Joseph P. Costantino and
  11. Norman Wolmark

+ Author Affiliations

  1. Affiliations of authors: National Surgical Adjuvant Breast and Bowel Project (NSABP) Operations and Biostatistical Centers, Pittsburgh, PA (ILW, JJD, EPM, SJA, TBJ, SRL, RM, JPC, NW); Department of Surgery, Stanford University School of Medicine, Stanford, CA (ILW); Department of Health Studies, University of Chicago, Chicago, IL (JJD); Department of Surgery, University of Pittsburgh, Pittsburgh, PA (BF); Aultman Cancer Center, Northeastern Ohio State University, Canton, OH (EPM); Department of Biostatistics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA (SJA, SRL, JPC); Department of Human Oncology, Allegheny General Hospital, Pittsburgh, PA (TBJ, NW); Department of Oncology, Jewish General Hospital, Montreal, QC, Canada (RM); Washington Cancer Institute, Washington, DC (SMS)
  1. Correspondence to:
    Irene L. Wapnir, MD, Department of Surgery; 300 Pasteur Dr H3625, Stanford University School of Medicine, Stanford, CA 94305-5655 (e-mail: wapnir@stanford.edu).
  • Received January 5, 2010.
  • Revision received January 11, 2011.
  • Accepted January 12, 2011.

Abstract

Background Ipsilateral breast tumor recurrence (IBTR) is the most common failure event after lumpectomy for ductal carcinoma in situ (DCIS). We evaluated invasive IBTR (I-IBTR) and its influence on survival among participants in two National Surgical Adjuvant Breast and Bowel Project (NSABP) randomized trials for DCIS.

Methods In the NSABP B-17 trial (accrual period: October 1, 1985, to December 31, 1990), patients with localized DCIS were randomly assigned to the lumpectomy only (LO, n = 403) group or to the lumpectomy followed by radiotherapy (LRT, n = 410) group. In the NSABP B-24 double-blinded, placebo-controlled trial (accrual period: May 9, 1991, to April 13, 1994), all accrued patients were randomly assigned to LRT+ placebo, (n=900) or LRT + tamoxifen (LRT + TAM, n = 899). Endpoints included I-IBTR, DCIS-IBTR, contralateral breast cancers (CBC), overall and breast cancer–specific survival, and survival after I-IBTR. Median follow-up was 207 months for the B-17 trial (N = 813 patients) and 163 months for the B-24 trial (N = 1799 patients).

Results Of 490 IBTR events, 263 (53.7%) were invasive. Radiation reduced I-IBTR by 52% in the LRT group compared with LO (B-17, hazard ratio of risk of I-IBTR = 0.48, 95% confidence interval = 0.33 to 0.69, P < .001). LRT + TAM reduced I-IBTR by 32% compared with LRT + placebo (B-24, HR of risk of I-IBTR = 0.68, 95% CI = 0.49 to 0.95, P = .025). The 15-year cumulative incidence of I-IBTR was 19.4% for LO, 8.9% for LRT (B-17), 10.0% for LRT + placebo (B-24), and 8.5% for LRT + TAM. The 15-year cumulative incidence of all contralateral breast cancers was 10.3% for LO, 10.2% for LRT (B-17), 10.8% for LRT + placebo (B-24), and 7.3% for LRT + TAM. I-IBTR was associated with increased mortality risk (HR of death = 1.75, 95% CI = 1.45 to 2.96, P < .001), whereas recurrence of DCIS was not. Twenty-two of 39 deaths after I-IBTR were attributed to breast cancer. Among all patients (with or without I-IBTR), the 15-year cumulative incidence of breast cancer death was 3.1% for LO, 4.7% for LRT (B-17), 2.7% for LRT + placebo (B-24), and 2.3% for LRT + TAM.

Conclusions Although I-IBTR increased the risk for breast cancer–related death, radiation therapy and tamoxifen reduced I-IBTR, and long-term prognosis remained excellent after breast-conserving surgery for DCIS.


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