ESTRO meets Asia 2024 - Abstract Book

S88

Interdisciplinary – Breast

ESTRO meets Asia

The COVID cohort had 464 patients and the control pre-COVID cohort had 450 newly diagnosed breast cancer patients. The pandemic resulted in a significant reduction in registration from 430 to 97 new breast cancer patients per month (p=0.001), with more patients presenting with advanced or metastatic cancer (25% versus 14% p=0,001) and receiving palliative treatment (19% vs 10.6%, p=0.001). Deviation from the standard of care increased significantly during the pandemic - delay in surgery, mostly due to COVID-positive pre-op screening test (9.6% vs 3.1 %, p=0.001); use of 5 fraction ultra hypo-fractionated radiotherapy (60.2% vs 1.5%, p <0.001) and greater use of Neo-Adjuvant hormone therapy instead of Neo-Adjuvant chemotherapy (14.7% vs 5.9%, p 0.02). Adjuvant chemotherapy defaulters increased during lockdown (56.2% vs 20.%). Breast Conserving Surgery (BCS) rates significantly decreased from 41.1% to 28.1% (p = 0.007). Simultaneous Integrated Boost (SIB) use increased from 8.6% to 52.3% during the pandemic. No significant difference was noted in the acute and late radiation toxicities, but a valid comparison could not be drawn as toxicity details were not available for a third of cases. COVID-19 infection was documented in 29 cases and 3 patients in the COVID cohort succumbed to COVID. At a median follow-up of 36.2 months in the pandemic cohort (95% CI 34.3 - 38 months) and 53.2 months (95% CI 51.7 - 54.6 months) in the control cohort, significantly inferior 3-year overall survival probability (76% vs 86%, p= 0.002) and recurrence-free survival probability (64% vs 78 %, p<0.0001) were seen in the pandemic cohort.

Conclusion:

The COVID-19 pandemic and the lockdown resulted in a major reduction in monthly registration of new breast cancer cases in the largest tertiary cancer hospital in India. There was a major stage migration with more advanced and metastatic cases presenting during strict lockdown. Patients with early-stage cancer and less compelling physical symptoms perhaps chose to stay at home or seek local care. Planned and unplanned deviation from the standard of care was common. The use of 5-fraction adjuvant RT allowed us to give RT to over 95% of patients who required adjuvant RT. Significantly worse 3 years overall and recurrence-free survival is possibly due to more advanced disease stage, deviations from standard of care, and treatment deintensification. The COVID cohort and pre-pandemic control cohort will be followed to assess the long-term impact.

Keywords: COVID, Breast cancer, Impact of pandemic

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