Women with breast cancer make no difference to their survival chances by deciding to have a double mastectomy, new research has shown.
A study in California found that women who had lumps removed followed by radiotherapy lived as long as those taking the drastic step of discarding both breasts.
Yet there is evidence of increasing numbers of women seeking double mastectomies after having cancer diagnosed in just one breast.
The same team of researchers who analysed data on 189,734 patients found that rates of the procedure soared from 2pc in 1998 to 12.3pc in 2011 - an annual increase of 14.3pc.
Lead scientist Dr Allison Kurian, from Stanford University, said: "We can now say that the average breast cancer patient who has bilateral mastectomy will have no better survival than the average patient who has lumpectomy plus radiation.
"Furthermore, a mastectomy is a major procedure that can require significant recovery time and may entail breast reconstruction, whereas a lumpectomy is much less invasive with a shorter recovery period."
Of the women recruited, just over half (55pc) had surgery to remove lumps followed by radiation treatment. Almost 40pc had one breast removed and 6.2pc on average underwent a double mastectomy over the 13-year study period.
Women electing to have complete breast removal were more likely to be white, younger than 50, and from the middle or upper social classes.
Long term survival rates did not differ significantly between women who underwent a double mastectomy and those who received a lumpectomy plus radiotherapy. After 10 years, just under 19pc of the patients had died.
The authors stressed that for some women with a genetic risk of breast cancer, a double mastectomy remained an effective treatment option.
It was also true that removal of both breasts might help alleviate a woman's fear of a second cancer occurring in the remaining breast.