Surgery May Boost Stage IV Breast Cancer Survival

Primary tumour surgery may be a significant predictor of stage IV breast cancer survival in the USA

medwireNews: A study of US women with stage IV breast cancer has revealed survival gains in recent years, especially among women who undergo breast surgery despite its decreasing use in this population.

The findings challenge the “dogma” that local therapy has little impact on systemic disease, say Mary Schroeder, from the University of Iowa in Iowa City, USA, and co-authors in JAMA Surgery.

The team believes that aggressive local therapy may be of particular benefit to patients with “an already established potential for durable remission, including those with oligometastatic disease or disease that is biologically vulnerable to newer systemic therapies”.

They write: “Removal of the primary breast tumor in such cases could improve survival by providing local control, eradicating a potential seed source and possibly a stimulant of distant disease sites, and perhaps also by modulating immune response.”

Review of medical records for 21,372 women who were diagnosed with stage IV breast cancer and did not undergo radiotherapy as part of their initial treatment showed that median survival increased from 20 months between 1988 and 1991 to 26 months between 2007 and 2011.

Surgery became less common over time, with rates falling from 67.8% in 1988, to 25.1% in 2011 (odds ratio [OR]=0.16).

But women who received surgery had better survival than those who did not, at a median 28 months versus 19 months, and a hazard ratio (HR) of 0.60 after adjusting for age at diagnosis, tumour size, hormone receptor status, year of diagnosis, and marital status and ethnicity. Women with tumours of less than 2 cm had an additional 11 months of survival with surgery compared with no resection, with a 7-month increase for those with tumours greater than 5 cm.

Indeed, while hormone receptor-positive status had the strongest impact on survival (HR=0.53), this was followed by receipt of surgery (HR=0.60) and then young age (age <45 years versus ≥65 years, HR=0.77 vs 1.54).

Women who underwent surgery at diagnosis were also more likely to survive for at least 10 years than those who did not, at 9.6% versus 2.9% (OR=3.61). This remained true in multivariate analysis, with the odds of surviving 6, 8 and 10 years increased 2.42-, 2.72- and 2.80-fold, respectively.

Acknowledging that systemic treatment cannot yet treat all macroscopic disease, the authors conclude: “Until then, local therapy with surgery to the primary tumor may offer critical disease control for select patients and could be an essential component of prolonged survival.”

Reference

Thomas A, Khan SA, Chrischilles EA, Schroeder MC. Initial surgery and survival in stage IV breast cancer in the United States, 1988–2011. JAMA Surg 2015; Advance online publication 2 December.doi:10.1001/jamasurg.2015.4539

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