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Cervical cancer advanced by one stage approximately every 8.6 weeks before radiotherapy

Cervical cancer stage progression was estimated every 8.6 weeks of treatment delay and was faster among women living with HIV.

RadOncToday · ·1 min read

KEY POINTS

  • This prospective analysis included 763 women with cervical cancer treated with radiotherapy in Botswana between 2012 and 2019. Investigators used predictable seasonal disruptions in radiotherapy access as an instrumental variable to estimate how additional waiting time affected FIGO 2009 stage at treatment initiation.
  • Women diagnosed during routine-access periods started radiotherapy after a mean 11.2 weeks, compared with 12.4 weeks during delayed-access periods. Baseline characteristics were well balanced after weighting, and the instrumental variable had adequate strength with a first-stage F-statistic of 13.1.
  • The model estimated that cervical cancer advanced by one FIGO stage increment—such as IIIA to IIIB—over a mean 8.6 weeks (95% CI 7.1–10.9). The modeled risk of stage progression began to become apparent at approximately 4 weeks after diagnosis.
  • Progression was estimated to occur more rapidly among women living with HIV, who represented nearly 70% of the cohort. Mean time per stage increment was 7.6 weeks (95% CI 6.4–9.2) with HIV versus 8.7 weeks (95% CI 6.1–15.3) without HIV (p<0.001).
  • Stage at radiotherapy initiation had a strong relationship with survival. Each one-step increase in FIGO stage was associated with a 38% shorter survival time, corresponding to a time ratio of 0.62 (95% CI 0.56–0.67). The effect was similar with and without HIV.
  • During follow-up, 372 of 763 women (49%) died; median follow-up was 36 months. Approximately two-thirds received concurrent platinum chemotherapy, and most treatment incorporated external-beam radiotherapy and brachytherapy.
  • Stage was measured only when patients arrived for radiotherapy rather than repeatedly within individual patients, so progression time was model-derived rather than directly observed. The causal interpretation also relies on instrumental-variable assumptions, and women unable to reach treatment centers or too unwell to travel were underrepresented.

CLINICAL TAKEAWAY

These data put a clinically meaningful number on waiting: cervical cancer may advance by a FIGO stage in roughly two months, with risk becoming relevant from around four weeks. The study supports efforts to start treatment within four weeks of diagnosis, but the estimated progression rate comes from quasi-experimental modeling rather than serial staging of individual tumors.

SOURCE

International Journal of Radiation Oncology, Biology, Physics