On February 3, 2026, the Marseille administrative court delivered a hopeful verdict. Sylvie Pioli, nurse at Martigues hospital, obtained recognition that her cancer was due to her night work.
An unprecedented judgment that shakes up hospital administration
For 25 years, she provided around 140 nights per year. Diagnosed with breast cancer in 2014, she encountered repeated refusals from the administration.
To decide, the judges emphasized that other risk factors (genetic, environmental or health-dietary) were almost absent in the plaintiff. It was therefore the “sufficiently high probability” of the link with night work which took precedence.
Why is night work classified as “probably carcinogenic”?
Since 2007, the International Agency for Research on Cancer (IARC), an emanation of the World Health Organization (WHO), has classified night shift work as “probably carcinogenic to humans”.
The culprit? Disruption of the circadian rhythm. Our internal clock, set to 24 hours, regulates the production of melatonin. This hormone, normally secreted in the dark, has antioxidant and oncostatic properties (which slow down the growth of tumors).
Working under artificial light inhibits this production, creating a hormonal environment favorable to the development of so-called “hormone-dependent” cancers, such as breast cancer.
A risk multiplied by three, according to studies
Scientific data is accumulating to denounce the impact of repeated sleepless nights:
- The CECILE study demonstrated a 30% increase in the risk of breast cancer in women who worked night shifts, particularly if this exposure took place before the first pregnancy;
- According to Inserm conclusions, working night shifts more than twice a week for more than 10 years increases the risk of breast cancer by three;
- Recent research published in the journal
Oncogene show that desynchronization of the biological clock “turns off” certain immune defenses, making tumors more aggressive and promoting metastases.
Towards automatic recognition as an occupational disease?
Until today, obtaining compensation for cancer linked to night work has been an obstacle course.
In the absence of a dedicated table in the Social Security Code, each victim must prove the direct link before regional committees or courts.
This Marseille decision could accelerate the creation of a more protective legislative framework. In the meantime, experts recommend reinforced medical supervision for caregivers.
Screenings (mammograms) must be earlier or more frequent for personnel exposed to a long history of night work.
In short, the victory of this nurse from Martigues reminds us that occupational health does not only concern physical accidents. If you have been working night shift for more than 10 years, do not hesitate to raise the question of oncological risk with your occupational physician.