Frequency of PIK3CA mutations in different subsites of head and neck squamous cell carcinoma in southern Thailand

Background@#Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) mutations have been reported in many cancers, including head and neck squamous cell carcinoma (HNSCC). The frequency of these mutations varies among tumor locations and might be relevant to treatment outcomes among HNSCC. In this study, we examined the frequency of PIK3CA mutations in the different subsites of HNSCC. @*Methods@#Ninety-six fresh biopsy specimens were investigated for mutations in PIK3CA exons 4, 9, and 20 using allele-specific real-time polymerase chain reaction. Patient characteristics and survival were analyzed and compared between specimens with or without PIK3CA mutations. @*Results@#The study included primary tumors originating from the oral cavity (n=63), hypopharynx (n=23), and oropharynx (n=10). We identified mutations in 10.4% of patients (10 of 96 specimens). The overall mutational frequency was 17.4% (4/23) and 9.5% (6/63) in the hypopharynx and oral cavity, respectively. No patients with oropharyngeal carcinoma had mutations. Among the 10 mutant specimens, five were missense mutations (exon 9 [E545K] in two samples and exon 20 [H1047R] in three samples) and five were silent mutations in exon 20 (T1025T). Mutations were not found in exon 4. Among 84 patients with available clinical data, we found no significant differences in clinical characteristics and survival based on the presence or absence of PIK3CA mutations. @*Conclusions@#The results indicate that PIK3CA mutations are involved in HNSCC carcinogenesis, and the hypopharynx should be considered a primary site of interest for future studies, particularly in Southeast Asian populations.

Hepatitis B screening rates and reactivation in solid organ malignancy patients undergoing chemotherapy in Southern Thailand

BACKGROUND/AIMS: Hepatitis B virus reactivation (HBVr) following chemotherapy (CMT) is well-known among hematologic malignancies, and screening recommendations are established. However, HBVr data in solid organ malignancy (SOM) patients are limited. This study aims to determine hepatitis B surface antigen (HBsAg) screening rates, HBV prevalence, and the rate of significant hepatitis caused by HBVr in SOM patients undergoing CMT.METHODS: Based on the Oncology unit’s registration database from 2009–2013, we retrospectively reviewed records of all SOM patients ≥18 years undergoing CMT at Songklanagarind Hospital who were followed until death or ≥6 months after CMT sessions. Exclusion criteria included patients without baseline liver function tests (LFTs) and who underwent CMT before the study period. We obtained and analyzed baseline clinical characteristics, HBsAg screening, and LFT data during follow-up.RESULTS: Of 3,231 cases in the database, 810 were eligible. The overall HBsAg screening rate in the 5-year period was 27.7%. Screening rates were low from 2009–2012 (7.8–21%) and increased in 2013 to 82.9%. The prevalence of HBV among screened patients was 7.1%. Of those, 75% underwent prophylactic antiviral therapy. During the 6-month follow-up period, there were three cases of significant hepatitis caused by HBVr (4.2% of all significant hepatitis cases); all were in the unscreened group.CONCLUSIONS: The prevalence of HBV in SOM patients undergoing CMT in our study was similar to the estimated prevalence in general Thai population, but the screening rate was quite low. Cases of HBVr causing significant hepatitis occurred in the unscreened group; therefore, HBV screening and treatment in SOM patients should be considered in HBV-endemic areas.

Renal and liver impairment in patients receiving cytotoxic chemotherapy

Chemotherapeutic agents can affect the glomerulus, renal tubules, interstitium ormicrovasculature. In renal impairment, drug excretion pathways by glomerular filtration and tubular secretion are inhibited, leading to increased systemic toxicity. Dose reductions were required in many drugs based on an estimation of glomerular filtration rate (GFR) and clinical signs of drug toxicity. Also, cytotoxic chemotherapy affected liver function by direct chemical reaction such as intrinsic hepatotoxicity or idiosyncratic reactions or immune mediated hypersensitivity. Therefore, liver function should be carefully assessed both prior to treatment and during therapy because an alteration of metabolism and excretion of chemotherapeutic drugs can lead to higher or more persistent drug levels, resulting in increased systemic toxicity (particularly myelosuppression) or worsening of chemotherapyinduced hepatotoxicity.