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cations were noted in one study only after many years and differed according to individual patient reactions (Rapaport et al., 1996). Other surgeons reported complications after considerable delay, and these tended to be relentlessly progressive (Wustrack and Zarem, 1979). One author noted that "trying to provide an accurate timetable for these changes has proved futile" (Vinnik, 1978).

There are only anecdotal reports of breast malignancy in silicone-injected breasts (Ko et al., 1995; Kobayashi et al., 1988; Lewis, 1980; Maddox et al., 1993; Morgenstern et al., 1985; Okubo et al., 1992; Ortiz-Monasterio and Trigos, 1972; Pennisi, 1984; Smith et al., 1999; Suster et al., 1987; Talmor et al., 1995; Timberlake and Looney, 1986; see also Chapter 9 of this report). Although no epidemiological studies of the incidence of cancer in women with silicone-injected breasts have been reported, and thus there is no evidence of an elevated relative risk, case control studies of the frequency of breast implants in women with breast cancer indicate, if anything, a decreased odds ratio (Brinton et al., 1996; Glasser et al., 1989). Injected silicone clearly may handicap the diagnosis of breast cancer. Injected breasts are full of lumpy, radiopaque deposits of silicone that interfere with breast self-examination, physical examination, and mammography. Better visualization with magnetic resonance imaging (MRI) is helpful, but does not resolve this problem because MRI is not considered a screening technology and is used only when there is an indication for this more resource intensive modality (Helbich et al., 1997; Leibman and Sybers, 1994; Lewis, 1980; Maddox et al., 1993; Morgenstern et al., 1985; Okubo et al., 1992; Talmor et al., 1995; Timberlake and Looney, 1986; see Chapter 12). Although silicone injection for breast augmentation (or any cosmetic use) is not approved by the FDA, there are a number of reports advocating medical-grade silicone injection in other sites such as the face, using careful technique and small amounts—from a fraction of a milliliter to a few milliliters per treatment depending on location (Ashley et al., 1973; Hinderer and Escalona, 1990; Rees and Ashley, 1966; Rees et al., 1973a; Selmanowitz and Orentreich, 1977). Duffy (1990) reviewed thousands of such cases and himself reported more than 2,000 injections of 350-centistoke silicone fluid with good results, although his follow-up was limited to six years. The American Academy of Cosmetic Surgery (AACS) reported 7,170 women receiving such non-breast silicone injections from its members in 1994. Nevertheless, "FDA has not approved the marketing of liquid silicone for injection for any cosmetic purpose, including the treatment of facial defects or wrinkles..." (FDA, 1991). The history of silicone injection is relevant to the safety of silicone breast implants because of the possible analogy to silicone gel fluid diffusion through implant shells into breast tissue or the deposition of silicone gel (and gel fluid) in the breast on rupture of gel-filled implants.