Compared to matched health control women, women with breast cancer who remained free of the disease for at least 3 years after diagnosis were much more likely than healthy women to be absent from work for 4 weeks or more (85% vs. 18%). However, by the third year work absence patterns were similar. The authors also report work absence and its patterns for women who underwent chemotherapy, and describe factors that modulate absence patterns (such as being in a stable relationship and being self-employed).
Some of these absences exceeded the 15-week federal employment insurance available during periods of illness. The shorter patterns of work absence among the self-employed and those who were single may represent expressions of the financial burden of this common illness.
http://www.cmaj.ca/misc/press/pg765.pdf
p. 765 Work absence after breast cancer diagnosis : a population-based study -- E. Maunsell et al
Canadian Medical Association Journal