February 11, 2024, Dr Cécile Bour, Radiologist
After reading recent publications on carcinomas in situ and so-called "borderline" lesions of the breast, representing a useless over-detection of screening because they have no impact on women's lives, I'd like to make a few personal observations. They are based on my own practice and the findings I've been able to accumulate, having followed this screening closely from its genesis and generalization in 2004 as a young radiologist, all the way to the present day, at an age when my career is coming to an end.
It's important to remember, over and over again, that the main aim of screening is not to find as many lesions as possible, or to find as many things as possible, but to achieve three types of benefit:
- to reduce mortality from the disease,
- to reduce the number of advanced forms of breast cancer,
- to ease the burden of treatment, by reducing the need for total mastectomies and other major treatments.
The effect on breast cancer mortality is unproven (according to various hypotheses and meta-analyses, it would be necessary, broadly speaking, to monitor 700 to 2,500 women for fourteen to 20 years to find a single death avoided). In parallel:
- Excess diagnoses, called overdiagnoses, according to the most pessimistic assessments reach 30 to 50%.
- Interval cancers, despite all efforts at early detection, which are the most harmful and aggressive, still account for a third of all cancer cases.
-Aggressive treatments are on the increase. (Approximately 30 to 35% more chemotherapy and radiotherapy. Surgical procedures are not decreasing at all, on the contrary).
From the 1990s onwards, as screening became more widespread, there was a surge in the number of ductal cancers in situ.
This spectacular increase in the number of in situ cancers diagnosed was reported as early as 1996 by Virginia Ernster, an epidemiologist at the University of California, San Francisco (Ernster VL, Barclay J et al. Incidence of and treatment for ductal carcinoma in situ of the breast. JAMA. 1996 Mar 27;275(12):913-8. )
Atypical lesions and borderline lesions were already highlighted by Nielsen in a meta-analysis of autopsy studies, based on 13 studies from 10 different countries, over 6 decades (1948 to 2010), including 2363 autopsies with 99 cases of so-called "incidentalomas" ("incidental findings"), precancerous lesions, cancers in situ and atypical hyperplasia, but few invasive cancers.
Two studies also shed light on these lesions and the fact that their presence in the breast is frequent, without impacting women's lives: the Nashville, Tennessee study (Page Dl, Dupont WD et al. Continued local recurrence of carcinoma 15-25 years after a diagnosis of low grade ductal carcinoma in situ of the breast treated only by biopsy. Cancer. 1995 Oct 1;76(7):1197-200. ), and the Bologna study in Italy (Eusebi V, Feudale E, Foschini MP et al. Long-term follow-up of in situ carcinoma of the breast. Seminars in Diagnostic Pathology. 1989;6(2):165-173. )
They report cases of women for whom the diagnosis of carcinoma in situ was made ten to twenty years late. When the biopsies were first read, in the 1950s for one study and in 1960 for the other, the lesions were classified as benign.
The women had therefore not been treated.
But after a more recent re-reading of these same biopsies, it turned out that these women were in fact carriers of in situ cancer.
How did these cancers, which had escaped the vigilance of doctors, evolve? Ten years later, 25% of the Tennessee women who were still alive had invasive cancer, and twenty years later, 11% of the Italian women had invasive cancer. In other words, 75% and 89% respectively of these women with carcinoma in situ had NOT developed invasive cancer.
Of course, you could argue that it's a pity for the majority of women with in situ cancer to be treated unnecessarily to save the small minority with DCIS who will develop invasive cancer. But it's an acceptable harm all in all.
If this were indeed the case and if the treatment of DCIS were beneficial, we would see a reduction in the most serious forms of cancer among women screened, and a drastic drop in breast cancer mortality. But this is not happening.
A very recent study shows that screening does not prolong life.
The Toronto study shows that treating ductal cancer in situ does not reduce breast cancer mortality, and preventing recurrence by radiotherapy or mastectomy does not reduce breast cancer mortality either.
The diagnosis of in situ cancer by screening has a profound impact on the quality of life of women who, uninformed of the potential dangers to which screening exposes them, continue to undergo aggressive treatment and the profound fear of disease without any proven benefit.
Where are we now?
We're trying to "catch up". We've gone wrong, we've promised women the impossible, and since this Titanic of screening can't go backwards, we're trying to throw it a few lifelines by attempting, as best we can, to limit the damage and advocate therapeutic de-escalation.
But we are cynical enough to do this "in agreement with the patient", giving her the opportunity to make her "own decision".
So, yes, it's all very well and very modern to make a shared decision, and we're all in favor of it, who could be against ?
But in the end, after decades of terrorizing women that they might get breast cancer if we relaxed the pressure even a little, after telling them that every minute counts, that we mustn't leave even the smallest degraded cell in a breast, now we're putting the brakes on to reduce our abusive treatments. And we're putting all the weight of the decision, which women will always feel is fraught with consequences, on their shoulders. The questions "Did I do the right thing?" will hang over her like a sword of Damocles for the rest of her life, from exam to exam.
The therapeutic de-escalation we're calling for, will do nothing to relieve women of mortal anguish. We've just loosely shifted the burden of responsibility from the doctor to the woman. Instead of having the courage, all of us, to tell women that screening campaigns were introduced too quickly, too early, without sufficient proof, that we were on the wrong track, that we screwed up, that there's no real loss of chance in not going for screening, that we can do without it, that in the end, the further we go, the more we tinker, the more we change our "therapeutic cuisine" without getting to the end of the killer cancer, the only one we needed to curb, which screening has completely failed to do.
I believe it is incredibly cynical to place all of the responsibility on the shoulders of women.