Risk Factors For Progression
While it may take years for cervical dysplasia to progress to cancer, the cancer can quickly spread throughout the body once established. If left untreated, cervical cancer has a relatively high mortality rate, although the survival rate for properly treated early-stage cervical dysplasia and cervical cancer is high.
Early symptoms of cervical cancer, such as altered vaginal discharge and abnormal vaginal bleeding, are rare. Advanced cervical cancer may present with pelvic, back, or leg pain, leaking of urine or feces from the vagina, loss of appetite, weight loss, and bone fracture.
Not all cases of cervical dysplasia progress into cancer (Marshall 2003). Rather, it appears that certain factors may hasten the progression from cervical dysplasia to cervical cancer:
- Decreased methylation. DNA hypomethylation is significantly associated with the grade of CIN (Fowler 1998; Goodman 2001).
- Multiple HPV types. One study showed a significantly increased risk of CIN in women with several HPV subtypes (Ho 1998).
- Viral load. A high level of the virus is a significant risk factor for CIN (Li 2004; Schlecht 2003; Dalstein 2003; Ylitalo 2000; Josefsson 2000; Ho 1998; Romney 1997; Flores 2005).
- High-risk HPV variants. Certain virus strains are an independent risk factor for cervical dysplasia (Thomson 2000; Liu 1995).
- Persistence of HPV infection. Persistent infection with HPV increases the risk of cervical cancer (Giuliano 1997; Romney 1997).
- Smoking. Smoking is a serious independent risk factor for advanced cervical dysplasia (Palan 1991). Passive cigarette smoking via a spouse also has been associated with a higher incidence of high-grade squamous intraepithelial lesions (Tay 2004). Women with abnormal Pap smears absolutely should avoid smoking.
- Obesity. In one large study, fewer overweight and obese women (78 percent in each group) underwent cervical cancer screening with Pap smears (Wee 2000). Because this group of women have a higher mortality rate for cervical cancer compared with women of normal weight, special attention should be paid to increasing screening among overweight and obese women.
- Number of sexual partners. The number of sexual partners increases the risk of cervical dysplasia (Thomson 2000), perhaps by increasing the chances of encounters with HPV strains.
- Multiple pregnancies. Multiple pregnancies have been cited as a possible risk factor for cervical dysplasia (Munoz 2002; Liu 1993; Thomson 2000).
- Lower socioeconomic status and lack of Pap smears. Women with a lower educational level may avoid follow-up Pap smears (Bornstein 2004). Additionally, those with lower socioeconomic status may lack access to appropriate health care.
- Diethylstilbestrol (DES). DES was given to expectant mothers from the late 1930s until 1970 to prevent early delivery. However, many mothers were unaware that the drug was being administered to them; sometimes it was given with a vitamin supplement. Unfortunately, it resulted in increased cervical cancer in female offspring. Current research regarding the use of DES focuses on the effects of the drug in granddaughters and grandsons of those who received it (Centers for Disease Control 2005).
- Compromised immune function. Women with medical conditions that affect the immune system are at greater risk for cervical dysplasia. These conditions include HIV, systemic lupus erythematosus, and transplanted organs (Duerr 2001; Robinson 2002; Bernatsky 2004; Malouf 2004; Ozsaran 1999).
- Other sexually transmitted diseases. One study concluded that the presence of other sexually transmitted diseases, such as Herpes simplex virus and Chlamydia trachomatis, can cause dysplasia to progress to cervical cancer (Smith 2002a; Smith 2002b). However, other studies failed to show an association between these sexually transmitted diseases and cervical cancer progression (Castle 2003; Tran-Thanh 2003).