Screening for ovarian cancer uses neighboring cells
Pioneering biophotonics technology is the first screening method to detect the early presence of ovarian cancer in humans. This technology examines cells easily brushed from the neighboring cervix or uterus, and not from the ovaries themselves. Partial wave spectroscopic (PWS) microscopy was used to see diagnostic changes in cells taken from the cervix or uterus of patients with ovarian cancer even though the cells looked normal under a microscope.
The results have the potential to translate into a minimally invasive early-detection method for ovarian cancer that uses cells collected by a swab, exactly like a Pap smear. Currently, no reliable early detection method exists for ovarian cancer, which ranks fifth in cancer fatalities among American women. Usually ovarian cancer goes undetected until it has spread elsewhere. The cancer is difficult to treat at this late stage and often is fatal.
This ovarian cancer study was published this month by the International Journal of Cancer (2013; doi: 10.1002/ijc.28122). Previously, the PWS technique has shown promising results in the early detection of colon, pancreatic and lung cancers using cells from neighboring organs. If commercialized, PWS could be in clinical use for one or more cancers in approximately five years.
PWS uses light scattering to examine the architecture of cells at the nanoscale and can detect profound changes that are the earliest known signs of carcinogenesis. These changes can be seen in cells far from the tumor site or even before a tumor forms. PWS can detect cell features as small as 20 nanometers, uncovering differences in cells that appear normal using standard microscopy techniques. PWS measures the disorder strength of the nanoscale organization of the cell, which is a strong marker for the presence of cancer in the organ or in a nearby organ.
The study included 26 participants. Endometrial cells were collected from 26 patients (11 with ovarian cancer and 15 controls) and endocervical cells were collected from 23 patients (10 with ovarian cancer and 13 controls). The small size of the study reflects the difficulty in recruiting ovarian cancer patients.
"We were surprised to discover we could see diagnostic changes in cells taken from the endocervix in patients who had ovarian cancer," said Vadim Backman, who developed PWS at Northwestern University HealthSystem (NorthShore) in Evanston, Illinois. "The advantage of nanocytology—and why we are so excited about it—is we don't need to wait for a tumor to develop to detect cancer."
"The changes we have seen in cells have been identical, no matter which organ we are studying," Backman said. "We have stumbled upon a universal cell physiology that can help us detect difficult cancers early. If the changes are so universal, they must be very important.""This intriguing finding may represent a breakthrough that would allow personalization of screening strategies for ovarian cancer via a minimally intrusive test that could be coupled to the Pap smear," said coauthor Hemant K. Roy, MD.