Development and validation of the measure of ovarian symptoms and treatment concerns for surveillance (MOST-S26): An instrument to complement the clinical follow-up of women with ovarian cancer after completion of first-line treatment

Objective The Measure of Ovarian Symptoms and Treatment (MOST-T35) is a patient-reported symptom index, developed and validated in the context of palliative chemotherapy for recurrent ovarian cancer (OC). We aimed to develop and validate a version suitable for surveillance of symptoms following first-line treatment for OC to support clinical follow-up. Methods In a prospective study of women following completion of first-line chemotherapy for OC, patients completed MOST-T35 every 3 months for up to 3.5 years and other patient-reported outcome measures. Construct validity (Spearman's correlations), discriminative validity (t-tests/ANOVAs assessing differences between clinically distinct groups), ability to detect clinically important symptoms (receiver operating characteristic analysis), and responsiveness (t-tests examining change) were assessed. Results Data from 726 women who received ≥3 cycles of chemotherapy, did not progress within 3 months, and completed ≥one MOST-T35 were analysed. The revised version, MOST-S26, has 26 items and 5 multi-item indexes: peripheral neuropathy (MOST-NTx), disease or treatment-related (MOST-DorT), abdominal (MOST-Abdo), and psychological symptoms (MOST-Psych), and MOST-Wellbeing, plus 9 individual items. Construct validity was confirmed (r range = 0.43–0.88). Discriminative validity confirmed expected differences between groups. MOST-NTx and MOST-Psych detected improvements in peripheral neuropathy and psychological symptoms respectively, whereas MOST-Abdo detected worsening of abdominal symptoms pre-recurrence. Conclusions This study developed and validated the MOST-S26, for surveillance of women in follow-up after first-line chemotherapy for OC. MOST-S26 reliably detected improvement in symptoms of peripheral neuropathy, psychological distress and may detect symptoms of relapse. Administration of MOST-S26 in follow-up consultations could identify concerning symptoms and facilitate timely and appropriate intervention.