ABSTRACT
OBJECTIVES: Long-term risk of second primary cancer (SPC) after definitive intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma (NPC) remains unclear. This study aims to evaluate the risk, predictive factors and survival impact of SPC in a large territory-wide cohort of NPC survivors in an endemic region. MATERIALS AND METHODS: In this multicenter study, consecutive NPC patients (nâ¯=â¯3166) who underwent definitive IMRT in all six public oncology centers in Hong Kong between 2001 and 2010 were included. SPC risks were quantified by standardized incidence ratios (SIRs) and absolute excess risks (AERs) estimated from corresponding age-, sex-, and calendar year-specific population cancer incidence data from the Hong Kong Cancer Registry. Predictive factors and SPC-specific mortality were analyzed. RESULTS: Over a median follow-up period of 10.8â¯years, 290 cases of SPC were observed with a crude incidence of 9.2%. Cancer risk in NPC survivors was 90% higher than that in general population [SIR, 1.9; 95% confidence interval (CI), 1.7-2.2], with an AER of 52.1 (95% CI, 36.8-67.3) per 10,000 person-years at risk. Significant excess cancer risks were observed for oral cavity, sarcoma, oropharynx, paranasal sinus, salivary gland, thyroid, skin and lung. Advanced age, smoking, hepatitis B status, and re-irradiation were independent predictive factors. SPC accounted for 9.4% of all deaths among NPC survivors during the study period, and 10-year SPC-specific mortality was 3.4%. CONCLUSIONS: Second cancer risk after IMRT was substantial among NPC patients. SPC impairs long-term survival, and close surveillance is warranted as part of survivorship care.
Subject(s)
Nasopharyngeal Carcinoma/radiotherapy , Nasopharyngeal Neoplasms/radiotherapy , Neoplasms, Second Primary/epidemiology , Radiotherapy, Intensity-Modulated/adverse effects , Adolescent , Adult , Aged , Aged, 80 and over , Female , Hong Kong/epidemiology , Humans , Incidence , Male , Middle Aged , Nasopharyngeal Carcinoma/mortality , Nasopharyngeal Neoplasms/mortality , Neoplasms, Second Primary/mortality , Risk Assessment , Smokers , Young AdultABSTRACT
BACKGROUND: This study identifies potential pitfalls in incorporating plasma Epstein-Barr virus (EBV) DNA into the management of nasopharyngeal carcinoma (NPC). METHODS: A total of 208 NPC patients without distant metastasis who received radical treatment and had measurements of EBV DNA at baseline, 8 weeks and 26 weeks postradiotherapy were analyzed. Prognostic and predictive values at each time-point were compared. RESULTS: Risk stratification by pretreatment level failed to identify a poor prognostic group. Detectable EBV DNA at 8 weeks and 26 weeks postradiotherapy were both associated with significantly poorer 5-year disease-free survival (HR 0.30, P < .001 and HR 0.03, P < .001, respectively) and overall survival (HR 0.27, P = .009 and HR 0.03, P < .001, respectively). Eighty percentage had detectable EBV DNA at recurrence (53.3% for local only, 100% for regional only, and 100% for distant failure). CONCLUSIONS: Posttreatment EBV DNA, particularly at 26 weeks post-radiotherapy, has high prognostic and predictive values. Surveillance endoscopy/imaging are recommended for the detection of local recurrence.
Subject(s)
Epstein-Barr Virus Infections , Nasopharyngeal Neoplasms , DNA, Viral , Herpesvirus 4, Human/genetics , Humans , Nasopharyngeal Carcinoma/therapy , Nasopharyngeal Neoplasms/radiotherapy , Neoplasm Recurrence, Local , PrognosisABSTRACT
BACKGROUND: This study evaluates the contemporary care for patients with locally recurrent nasopharyngeal carcinoma after failure of the primary course of intensity modulated radiotherapy. METHODS: Eligible patients were identified through the Hong Kong Cancer Registry database. Patterns of care and treatment outcomes were analyzed. RESULTS: Two hundred seventy-two patients with locally recurrent tumors were identified. Of them, 30.9% received surgery, whereas 35.7% received re-irradiation (re-RT). The 5-year overall survival (OS) for the whole group was 30.2%. Old age and advanced rT classification were adverse prognostic factors, whereas surgery (mainly in resectable recurrence) was associated with favorable survival outcome. The 5-year OS rates for patients who received surgery and re-RT were 56.3% and 21.8%, respectively. CONCLUSIONS: Early detection of resectable recurrence is of paramount importance as surgery for resectable tumors offers the potential to achieve excellent outcomes. Re-RT could be considered in selected patients with unresectable disease and favorable prognostic features.
Subject(s)
Nasopharyngeal Carcinoma/radiotherapy , Nasopharyngeal Neoplasms/radiotherapy , Neoplasm Recurrence, Local/radiotherapy , Radiotherapy, Intensity-Modulated/adverse effects , Registries , Adult , Aged , Cause of Death , Disease-Free Survival , Female , Hong Kong , Humans , Male , Middle Aged , Nasopharyngeal Carcinoma/mortality , Nasopharyngeal Carcinoma/pathology , Nasopharyngeal Neoplasms/mortality , Nasopharyngeal Neoplasms/pathology , Neoplasm Invasiveness/pathology , Neoplasm Recurrence, Local/mortality , Neoplasm Recurrence, Local/pathology , Neoplasm Staging , Radiotherapy, Intensity-Modulated/methods , Re-Irradiation/methods , Salvage Therapy , Survival AnalysisABSTRACT
Head and neck cancer is a major cause of morbidity and mortality in Hong Kong. HNC is well-known for its heterogeneity in epidemiology, clinical behavior, clinic-pathological features and patient characteristics. Treatment strategies for this heterogeneous disease vary greatly in different parts of the world, depending on availability of resources, local expertise and experience. Extensive research in head and neck cancer, particularly nasopharyngeal carcinoma, has been conducted in Hong Kong in the past few decades. In this article, we will review the available local evidence and summarize common practice in management of head and neck cancer in Hong Kong.
