Apap smear, a gold standard test, for cervical cancer screening may not be feasible in India due to inadequate infrastructure, lack of trained doctors, and relatively high cost. On the other hand, cervical cancer screening using visual inspection with acetic acid (VIA) appears promising. A large clinical trial using VIA screening carried out by Dr. Surendra Sashtri and others from Mumbai’s Tata Memorial Centre showed the efficacy of the screening method. Health workers trained for three weeks carried out the trial.
Using acetic acid for cervical cancer screening is inexpensive and can reduce the lifetime risk of cervical cancer by nearly 25-36%. The sensitivity for detection of cervical precancer and invasive cervical cancer varied from 67-79% and specificity was between 49 and 86%.
Currently, detection of cervical intraepithelial neoplasia (CIN) on application of acetic acid is through visual inspection and is therefore technician-dependent, more so as health workers often carry out initial screening.
A team of researchers led by Dr. Aravind Kumar Rengan from the Department of Biomedical Engineering at Indian Institute of Technology (IIT) Hyderabad is attempting to improve the sensitivity by quantifying the visual inspection technique and making it technician-independent.
Compared with normal epithelium, precancerous lesions contain abnormally higher load of cellular proteins. Acetic acid applied on the cervix reacts with the proteins in precancerous lesions leading to protein coagulation. The protein coagulation appears opaque and white. Identifying the white patch can be tricky in some cases leading to reduced sensitivity of the VIA technique.
More acetic acid gets used up when there is CIN and Dr. Rengan’s team is relying on the reduced amount of retrieved acetic acid for quantification. The acetic acid retrieved is made up to a fixed volume through the addition of reacting components such as gold chloride and other reactants. The reactants will form gold-based nanoparticles. Depending on the amount of retrieved acetic acid, the shape and size of the gold-based nanoparticles will vary resulting in difference in colour of the solution.
“When more acetic acid is retrieved from the cervix of women with no cervical intraepithelial neoplasia the nanoparticles produced will be of a particular shape and size than when less acetic acid is retrieved,” says Tejaswini Appidi from the Department of Biomedical Engineering at IIT Hyderabad who won the BIRAC-SRISTI Gandhian Young Technological Innovation award for this innovation. “Nanoparticles of different shapes and sizes produced by acetic acid of different quantities absorb different colours which results in colour differences.” The award comes with Rs.15 lakh seed funding to develop a product.
Do it yourself kit
“We intend to develop a calorimetric-based kit for cervical cancer detection. The ultimate goal is to develop an affordable and sensitive screening method which women can use themselves,” says Dr. Rengan.
The researchers aim to remove the flaws involved in the visual inspection method and make it more robust. “The visual method is currently a yes or no procedure. Our method will allow grading of pre-cancerous lesions based on severity,” Appidi says.
The challenge will be to deliver acetic acid to the cervical site and to recover the unused acetic acid. “In collaboration with Prof. Rohit Srivastava’s lab at IIT Bombay, we are developing a device that can directly deliver acetic acid to the site of cervix. We are in the process of filing a joint patent,” Dr. Rengan says.
The team has developed the protocol and has completed preliminary testing. They are in the process of tying up with hospitals to get clinical samples. “It will take two-three years to develop the final product,” he says.