Conditional survival of patients with stage I–III squamous cell carcinoma of the penis: temporal changes in cancer-specific mortality
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To test the conditional survival that examined the effect of event-free survival on cancer-specific mortality after primary tumour excision (PTE) in patients with squamous cell carcinoma of the penis (SCCP).
Materials and methods
Within the SEER database (1998–2015), 2282 stage I–III SCCP patients were identified. Conditional survival estimates were used to calculate cancer-specific mortality (CSM) after event-free survival intervals of 1, 2, 3, and 5 years. Multivariable Cox regression models predicted CSM according to event-free survival.
After PTE, 5-year CSM-free rate was 78.0% and increased to 84.6%, 88.1%, 92.0%, and 94.2% in patients who survived ≥ 1, ≥ 2, ≥ 3, and ≥ 5 years. After stratification according to tumour characteristics, 5-year CSM-free rates increased from 85.9 to 95.4%, 79.0 to 97.1%, 78.9 to 90.0%, and from 54.5 to 86.0% in those survived ≥ 5 years, respectively, in T1N0, T2N0, T3N0, and N1-2 patients. In multivariable analyses, T2N0 [hazard ratio (HR) 1.68; p value < 0.001], T3N0 (HR 1.94; p value 0.001), and N1-2 (HR 6.61; p value < 0.001) were independent predictors of higher CSM rate at baseline, relative to T1N0. A decrease in all HRs was assessed over time in patients who survived. Attrition due to CSM was highest in N1-2 cohort and lowest in T1N0.
Conditional survival models showed a direct relationship between event-free survival duration and subsequent CSM in SCCP patients. Even patients with non-organ-confined disease may achieve survival probabilities similar to those with organ-confined disease after at least 5 years of event-free survival since PTE.
KeywordsPenile neoplasms Squamous cell carcinoma Mortality SEER program
International classification of disease for oncology
Inguinal lymph-node dissection
Primary tumour excision
Squamous cell carcinoma of the penis
Surveillance, epidemiology, and end results
FAM: project development, data collection, data analysis and interpretation, and manuscript writing. CP: manuscript writing. SK: data collection. EM: data analysis and interpretation. AP: data collection. ZT: data analysis. GM: manuscript editing. PP: manuscript editing. EM: manuscript review. SFS: manuscript review. FS: manuscript review. AB: manuscript editing. OC: manuscript review. PIK: project development and manuscript editing.
Compliance with ethical standards
Conflict of interest
Authors declare no conflicts of interest, including specific financial interests or relationships or affiliations relevant to the subject matter or materials discussed in the manuscript.
The retrospective and anonymously coded study design was approved by the Institutional Review Board of the Centre Hospitalier de l’Université de Montreal.
- 13.SEER Cancer Statistics Review (2017) Available from: https://seer.cancer.gov/data-software/documentation/seerstat/nov2016/. Accessed 1 Oct 2018