Survival

To evaluate the patient survival, we used the so-called overall survival, which corresponds to the overall monitored survival, regardless of the cause of death. The overall one-, two-, three-, four- and five-year (x-year) survival was calculated using the life tables method with one-year intervals, where death from any cause was the event of interest. Only the first malignant neoplasms in the monitored location (ICCC subgroup) were evaluated. The follow-up of patients was ended on 30 June 2017, which means that patients who were alive on this date are considered as censored ones.

The period analysis [1] was used to calculate survival rates for three periods: 1999–2004, 2005–2010 and 2011–2016. The period analysis involves not only patients diagnosed in a given period, but also those whose follow-up was ended in that period (but started no more than 1, 2, 3, 4 or 5 years, respectively, before the start of a specific period – depending on the required x-year survival).

Survival rates of patients aged under 19 are age-standardised to the structure of patients in the period 2011–2016 according to the following age categories:

  1. <1 year, 1–4 years, 5–9 years, 10–14 years and 15–19 years (all patients, regardless of ICCC groups).
  2. 0–4 years, 5–9 years, 10–14 years and 15–19 years (patients classified into ICCC I, III and IX groups).
  3. 0–9 years, 10–14 years and 15–19 years (patients classified into ICCC II and VIII groups).
  4. 0–14 years and 15–19 years (patients classified into ICCC X and XI groups).
  5. <1 year, 1–4 years, 5–19 years (patients classified into ICCC IV, V, VI and VII groups).

Survival rates of patients aged under 14 are age-standardised to the structure of patients in the period 2011–2016 according to the following age categories:

  1. <1 year, 1–4 years, 5–9 years and 10–14 years (all patients, regardless of ICCC groups).
  2. 0–4 years, 5–9 years and 10–14 years (patients classified into ICCC I, III and IX groups).
  3. 0–9 years and 10–14 years (patients classified into ICCC II, VIII, X and XI groups).
  4. <1 year, 1–4 years, 5–14 years (patients classified into ICCC IV, V, VI and VII groups).

Age standardisation was carried out both for survival of all patients and for survival by ICCC groups and by sex. To evaluate survival by individual age categories, overall survival rates without age standardisation are considered.

Survival rates are provided only for those ICCC groups (or sex or age categories) where the number of patients is sufficient (N ≥ 20).

Literature

  1. Brenner H, Gefeller O. An alternative approach to monitoring cancer patient survival. Cancer 1996; 78(9): 2004–2010.