Parameter | Rate ratio (95% CI) | |||
---|---|---|---|---|

Surgery | Chemotherapy | Radiotherapy | Untreated | |

Relative change in rate (prepandemic slope) | 0.9998 (0.9997–0.9999) | 1.0008 (1.0007–1.0010) | 1.0004 (1.0002–1.0005) | 0.9996 (0.9995–0.9997) |

Relative change in mean rate at the start of the pandemic (relative change in intercept) | 0.91 (0.88–0.95) | 1.30 (1.23–1.36) | 1.13 (1.07–1.19) | 0.85 (0.80–0.91) |

Relative change in rate (further change in slope from prepandemic to the pandemic) | 1.004 (1.002–1.006) | 0.991 (0.989–0.994) | 0.996 (0.994–0.998) | 1.004 (1.001–1.006) |

↵* Parameters were estimated from segmented Poisson regression using the standard parameterization. For each parameter, we report the ratio and the associated 95% confidence interval. The regression coefficients can be interpreted as follows: the rate of receiving surgery as first cancer treatment over the next year per thousand patients was decreasing marginally by 0.02% for each week for those diagnosed with cancer in the prepandemic period, followed by a decline in mean 1-year surgical rate of 9% for those diagnosed at the start of the pandemic, then a weekly rise of 0.4% (i.e., 1.004 × 0.9998 = 1.004 or an 0.4% overall weekly increase) for those diagnosed with cancer during the pandemic. Details of this model can be found in Appendix 3 (available at www.cmajopen.ca/content/11/3/E426/suppl/DC1). The prepandemic period is from Jan. 3, 2016, to Mar. 14, 2020, and the pandemic period is from Mar. 15, 2020, to Nov. 7, 2020.