Retrospective study of 10,000 cases; Ovary or breast: site of first ca impacts prognosis

OB/GYN News, May 15, 2004 by Kate Johnson

SAN DIEGO -- Patients who are at high risk for developing dual primary cancers of the breast and ovary have different prognoses depending on which of their cancers develops first. Dr. Alexander Olawaiye reported.

"Women who develop ovarian cancer first can be told that if they develop breast cancer it may not be for about 7 years. However, those who develop breast cancer first should be told that if they develop ovarian cancer it could happen within 4 years," said Dr. Olawaiye of the Roswell Park Cancer Institute in Buffalo, New York.

In addition, those whose have ovarian cancer first also survive longer, he reported at the annual meeting of the Society of Gynecologic Oncologists.

In a retrospective study of 10,000 cases of breast and ovarian cancers from their tumor registry from 1971 to 2001, Dr. Olawaiye and his associates identified 49 patients with dual primary cancers of the breast and ovary. Of them, 26 patients developed breast cancer before ovarian cancer, and 23 patients developed ovarian cancer first. The mean age at the time of the first diagnosis was 50 years in both groups.

Those patients who developed ovarian cancer first had a mean interval of 86 months before their diagnosis of breast cancer.

Those who developed breast cancer first had a mean interval of 45 months before they developed ovarian cancer.

Overall, 65% of breast cancer diagnoses were at an early stage, whereas 63% of ovarian cancer diagnoses were at advanced stages.

Median progression-free survival and overall survival were longer in patients who developed ovarian cancer first. (See table.)

"This is likely due to the fact that the patients who were diagnosed with ovarian cancer first had oophorectomies and chemotherapy which no doubt modified their breast cancer," he said in an interview. Treatment for those who had breast cancer diagnosed first would not have had such a positive impact on any occult ovarian cancer.

The patients did not undergo genetic testing for the BRCA gene mutations because this testing had not yet become available at the time of the study.

However, using a formula based on personal and family history as well as prevalence data on the BRCA mutations, it was estimated that patients who developed ovarian cancer first had a 36% chance of carrying a mutation, while those patients who developed breast cancer first had a 49% chance of carrying a BRCA mutation.

"This is valuable information when it comes to counseling patients because we can tell ovarian cancer patients that if they are going to develop breast cancer they may not do so for about 7 years. This gives them a bit of time to discuss interventions, which may include tamoxifen therapy or prophylactic mastectom," he said.

"On the other hand, for breast cancer patients you may want to sound a note of urgency that if she doesn't have her ovaries removed, she may develop ovarian cancer as soon as 4 years after the breast cancer diagnosis. And unlike breast cancer, ovarian cancer is a disease that is very difficult to screen for," Dr. Olawaiye continued.

Median Survival by Type of First Cancer
(in months)

                      Breast Cancer             Ovarian Cancer
First Cancer  Progression Free  Overall  Progression Free  Overall

Ovarian           161            250         132             277
Breast             61            115          39              42

Source: Dr. Alexander Olawaiye

BY KATE JOHNSON

Contributing Writer