14 January 2012

Reassessing The Symptoms Indeces of Ovarian Cancer

According to a study, symptoms indices used to identify patients with ovarian cancer may need to be reassessed for better detection.

Ovarian cancer as the name suggests, begins in the woman's ovaries. There are 2 ovaries located one on each side of the uterus in the pelvis. These ovaries produce eggs (called ova)and are also the main source of a woman's female hormones, estrogen and progesterone.

Tumors can start in the ovaries. Some are benign (not cancerous) and never spread beyond the ovary. These kind of tumors can be treated by taking out either the ovary or the part of the ovary that has the tumor. Other types of tumors are cancerous and can spread to other parts of the body.

Tumors in the ovary are named for the kinds of cells the tumor started from and whether the tumor is benign or cancerous. There are 3 main types of tumors:
  • Epithelial tumors: These tumors start from the cells that cover the outer surface of the ovary. Most ovarian tumors are epithelial cell tumors.
  • Germ cell tumors: These start from the cells that produce the eggs.
  • Stromal tumors: These start from cells that hold the ovary together and make the female hormones.

Although ovarian cancer usually happens with women aged 50 and over, it can also affect younger women. The cause of ovarian cancer is unknown and is hard to detect. Most women do not manifest symptoms of the disease until it is in an advanced stage and is harder to treat.

Symptoms of Ovarian cancer may include:
  • Heavy feeling in pelvis
  • Pain in lower abdomen
  • Bleeding from the vagina
  • Weight gain or loss
  • Abnormal periods
  • Unexplained back pain that gets worse
  • Gas, nausea, vomiting, or loss of appetite
Video: Recognizing Ovarian Cancer

The use of symptom indices to identify patients with symptoms associated with ovarian cancer who may need further screening is increasing in both the UK and the US in an attempt to promote earlier diagnosis, but they may need to be reassessed in order to help better detect cancer, according to a study published January 13 in the Journal of the National Cancer Institute.

Ovarian cancer is a disease which is perceived to rarely produce symptoms until the disease has spread to other organs of the body, allowing the disease to reach an advanced stage before it is caught. Some evidence suggests patient-reported symptoms may help detect the cancer early on, and in fact, the Goff index, which uses questionnaire data, has been reported to be effective in identifying women who are at a low to moderate risk of ovarian cancer. However, symptom assessment may greatly influence index performance.

Video: Ovarian Cancer

To determine the effectiveness of the symptom indices, Anita Wey Wey Lim of the Centre for Cancer Prevention, Wolfson Institute of Preventive Medicine, at Queen Mary University of London and associates looked at data from 194 women who had recently been diagnosed with ovarian cancer and 268 control subjects who underwent ovarian cancer screenings. The symptom data was assessed through questionnaires, telephone interviews, and general practitioner notes. The sensitivity of the symptoms reported within a few months of the diagnosis was also determined by comparing two 12 month periods (0-11 and 3-14 months before diagnosis).

The researchers found that the results were similar to those found in previous reports on the Goff index and that the sensitivity of the symptoms were stronger in late- vs early-stage disease. The assessment also shows that there is only a slight variation in the symptoms reported by women with early- vs late-stage disease.

The authors note that a strong point in the study comes from a comparison of multiple data sources, which had never been done before. Even so, they write that, "The small differences between the three indices indicate that there is little to gain from deriving new symptom indices." They also suggest that while a symptom index could advance the diagnosis of ovarian cancer, the benefits of such are greatly overemphasized, given that most symptoms of the disease emerge within three months before diagnosis. They write, "At best, a symptom index might advance diagnosis of ovarian cancer by 3 months or more in two-thirds of women. For a more specific index, the sensitivity would be approximately one-third."

In an accompanying editorial, Patricia Hartge, ScD, at National Cancer Institute's Division of Cancer Epidemiology and Genetics, and James L. Speyer, MD, from the NYU Langone Cancer Center, write that symptom indices such as the Goff index and two novel indices described in the study are viewed as good for detecting early-stage ovarian cancer with the assumption that an early detection and therapy can achieve a better patient outcome. While this can be true, they caution that these indices were not highly specific and that the screeners found the cancer symptoms close to the time in which the patient was diagnosed. "The study design permits no calculation of years of life that might have been saved or lost if screeners actually were used—only a large and expensive randomized trial would do that—but clinical gains likely would be minor, and many women would undergo unnecessary diagnostic procedures to assure that they are cancer free." They also point out that the difficulty of detecting ovarian cancer early persists for various reasons. "The biology of ovarian cancer, the arithmetic of screening, and the clinical characteristics of the disease and its treatment collude to make it difficult to find ovarian cancer early enough to matter."


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