Pesticide Exposure and the Risk of Ovarian Cancer among Postmenopausal Women in Rural Punjab, India

Punjab, a state in Northern India, has reported an alarming rise in cancer cases, which has been linked to the extensive use of pesticides in agriculture. Ovarian cancer, often diagnosed at late stages, lacks systematic screening within the population under the national program. The present study aimed to screen postmenopausal women for ovarian cancer and to evaluate pesticide exposure as a potential risk factor.

A total of 1,327 postmenopausal women, residing in 48 villages for at least ten years, were screened annually for CA-125 levels. Women with CA-125 levels >35 U/mL were referred for transvaginal ultrasound. Demographic data were collected through a semi-structured questionnaire. For pesticide profiling, a case-control design was adopted. Blood samples were collected and analyzed for organochlorine and organophosphate residues using gas chromatography.

Among 1,327 postmenopausal women screened, 30 (2.3%) had elevated CA-125 levels (>35 U/ml); no ovarian cancers were detected during follow-up imaging and specialist evaluation. In the case-control analysis (24 cases; 42 controls), detectable pesticide residues were associated with a crude 6.7-fold increased odds of ovarian cancer (95% CI: 1.4-32.7). After multivariable adjustment for parity and education, Ethion (aOR = 6.29, 95% CI: 1.37-28.8) and DDE (aOR = 6.39, 95% CI: 1.35-30.3) remained associated, though confidence intervals were wide, reflecting small sample size. In agricultural participants, chlorpyrifos detections were more frequent among controls (OR = 0.12, p = 0.008).

Although no ovarian cancer cases were detected during screening, the study highlights the prevalence of pesticide exposure among women in Punjab's Malwa region and its possible association with ovarian cancer risk. Routine population screening using CA-125 is not supported in light of current evidence and guidelines. Instead, strengthening diagnostic and registry systems in rural areas, reducing harmful exposures through safer agricultural practices, and conducting well-powered prospective studies with repeated exposure assessments are essential to clarify risks and inform targeted strategies in high-exposure settings.