Stroke Risk in Survivors of Head and Neck Cancer: A Descriptive Epidemiologic Cohort Study

PURPOSE/OBJECTIVE(S)

Survivors of head and neck cancer (HNC) have an increased risk of stroke. However, the evidence on the risk of stroke in various subpopulations of HNC defined by patient, disease and treatment factors remains unclear. This study aimed to determine whether age-standardized incidence rate ratios (SIRs) and risk differences (SIRDs) of stroke varied across different subpopulations of survivors of HNC.

MATERIALS/METHODS

We used data from the national stroke and cancer registries to identify all cases of HNC who developed their first stroke after HNC diagnosis from January 2005 to December 2020. We estimated the SIRs and SIRDs of stroke in various subgroups of HNC defined by patient, disease and treatment factors using the Singapore general population as the reference group.

RESULTS

A total of 8839 cases of HNC were identified and 308 cases (3.4%) developed stroke after HNC diagnosis at median follow up of 42.5 months (interquartile range 15.0 - 94.5 months). The overall SIR and SIRD were 2.46 (95% CI 2.21 - 2.74) and 4.11 cases per 1000 person-years (PY) (95% CI 3.37 - 4.85). The SIR and SIRD were higher among those post five years from HNC diagnosis compared to those with 5 or fewer years from HNC diagnosis (SIR: 3.92 (3.36 - 4.58) vs 1.84 (1.59 - 2.14), SIRD: 6.64 (5.26 - 8.03) vs 2.65 (1.80 - 3.50) cases per 1000 PY). The SIR was highest for those less than 40 years old (< 40 years: 30.55; 40 - 49 years: 5.84; 50 - 59 years: 3.13; 60 - 69 years: 2.38, 70 - 79 years: 1.53, > = 80 years: 1.41) while SIRD was highest for those with age 80 years and above (< 40 years: 2.16; 40 - 49 years: 3.44, 50 - 59 years: 4.25, 60 - 69 years: 5.55, 70 - 79 years: 4.16, > = 80 years: 6.14). Among those who had treatment within 6 months of HNC diagnosis, the SIR and SIRD were significantly higher among those who had primary radiation treatment approach (radiation only, radiation and chemotherapy) (SIR: 3.01 (2.64 - 3.43), SIRD: 5.12 (4.18 - 6.29) cases per 1000 PY) compared to primary surgery treatment approach (surgery only, surgery and radiation, surgery and chemotherapy and radiation) (SIR: 1.64 (1.31 - 2.05), SIRD: 1.84 (0.92 - 3.67)).

CONCLUSION

The risk of stroke varied across different subpopulations of survivors of HNC with higher risk observed in those surviving five years post HNC diagnosis, less than 40 years old or received primary radiation treatment approach within 6 months from HNC diagnosis. A risk based prophylactic measures for stroke should be considered for different subpopulations of survivors of HNC.

Adjuvant Breast Radiation Therapy for Early-Stage Breast Cancer or Ductal Carcinoma In-Situ in the Breast: A Systematic Review and Network Meta-Analysis of Randomized Trials

PURPOSE/OBJECTIVE(S)

For selected patients with early-stage breast cancer (BC) or ductal carcinoma in-situ (DCIS) in the breast, adjuvant breast radiation therapy (RT) approaches include partial breast irradiation (PBI), altered fractionation (AF) whole breast irradiation (WBI) or tumor bed boost (TBB). However, it is unclear which is the optimal approach. This study aims to compare the effects of different PBI, AF-WBI and TBB options on ipsilateral breast tumor recurrence (IBTR), overall survival (OS) and patient reported cosmesis (PRC) outcomes.

MATERIALS/METHODS

We searched various biomedical electronic databases for eligible randomized trials (RCTs) from date of inception to January 2023. We constructed six separate random effects frequentist network meta-analyses (NMA) to compare the effects of various PBI options using WBI as the reference; various AF-WBI options using conventional fractionated (CF) WBI as the reference and various TBB options using no TBB as the reference on IBTR and OS. The GRADE approach was used to assess the certainty of evidence. The synthesis without meta-analysis approach was pre-specified for evaluation of PRC in anticipation of various assessment and reporting methods.

RESULTS

We included 34 RCTs comprising 49,899 participants and 11 treatment options. Evidence suggests that accelerated PBI (Hazard Ratio (HR) 1.36 (95% confidence interval (CI) 0.77 - 2.41, moderate certainty), moderately hypofractionated (MHF) PBI (HR 1.38 (0.60 - 3.19), moderate certainty) and intraoperative PBI (HR 1.47 (0.81 - 2.68), low certainty) was associated with a modest but not statistically significant increase in the hazards for IBTR when compared to WBI. There was moderate certainty evidence that there were no significant differences among the accelerated ultra-hypo fractionated (AUHF) WBI (HR 0.76 (0.50 - 1.14)), MHF-WBI (HR 0.99 (0.84 - 1.16)) or UHF-WBI (HR (1.35 (0.47 - 3.92)) when compared with CF-WBI for IBTR. The effects of sequential TBB (seqTBB) (HR 0.61 (0.52 - 0.70), high certainty) and simultaneous integrated TBB (simTBB) (HR 0.77 (0.55 - 1.09), moderate certainty) on IBTR were similar when compared to no TBB. There were no significant differences in OS between PBI options and WBI, AF-WBI options and CF-WBI, TBB options and no TBB. Among the PBI vs WBI trials, MHF-PBI and APBI may be associated with fewer adverse PRC events. Among the AF-WBI vs CF-WBI trials, half of the included trials reported fewer adverse PRC events with MHF-WBI. SeqTBB and simTBB had similar adverse PRC outcome.

CONCLUSION

There were no significant differences among the PBI, AF-WBI and TBB options for IBTR and OS. PBI and AF-WBI may be associated with less adverse PRC events compared with WBI and CF-WBI respectively. There was no evidence to suggest a difference between seqTBB and simTBB for PRC outcome. This study is registered with PROSPERO CRD 42021245074.