Treatment planning and dosimetric comparison study on two different volumetric modulated arc therapy delivery techniques

Aim

To compare and evaluate the performance of two different volumetric modulated arc therapy delivery techniques.

Background

Volumetric modulated arc therapy is a novel technique that has recently been made available for clinical use. Planning and dosimetric comparison study was done for Elekta VMAT and Varian RapidArc for different treatment sites.

Materials and methods

Ten patients were selected for the planning comparison study. This includes 2 head and neck, 2 oesophagus, 1 bladder, 3 cervix and 2 rectum cases. Total dose of 50 Gy was given for all the plans. All plans were done for RapidArc using Eclipse and for Elekta VMAT with Monaco treatment planning system. All plans were generated with 6 MV X-rays for both RapidArc and Elekta VMAT. Plans were evaluated based on the ability to meet the dose volume histogram, dose homogeneity index, radiation conformity index, estimated radiation delivery time, integral dose and monitor units needed to deliver the prescribed dose.

Results

RapidArc plans achieved the best conformity (CI_95% = 1.08 ± 0.07) while Elekta VMAT plans were slightly inferior (CI_95% = 1.10 ± 0.05). The in-homogeneity in the PTV was highest with Elekta VMAT with HI equal to 0.12 ± 0.02 Gy when compared to RapidArc with 0.08 ± 0.03. Significant changes were observed between the RapidArc and Elekta VMAT plans in terms of the healthy tissue mean dose and integral dose. Elekta VMAT plans show a reduction in the healthy tissue mean dose (6.92 ± 2.90) Gy when compared to RapidArc (7.83 ± 3.31) Gy. The integral dose is found to be inferior with Elekta VMAT (11.50 ± 6.49) × 10⁴ Gy cm³ when compared to RapidArc (13.11 ± 7.52) × 10⁴ Gy cm³. Both Varian RapidArc and Elekta VMAT respected the planning objective for all organs at risk. Gamma analysis result for the pre-treatment quality assurance shows good agreement between the planned and delivered fluence for 3 mm DTA, 3% DD for all the evaluated points inside the PTV, for both VMAT and RapidArc techniques.

Conclusion

The study concludes that a variable gantry speed with variable dose rate is important for efficient arc therapy delivery. RapidArc presents a slight improvement in the OAR sparing with better target coverage when compared to Elekta VMAT. Trivial differences were noted in all the plans for organ at risk but the two techniques provided satisfactory conformal avoidance and conformation.     

Improvement of VMAT plan quality for head and neck cancer with high resolution fluences generated by couch shift between arcs

PurposeTo investigate the changes in quality of the volumetric modulated arc therapy (VMAT) plans with couch-shift between arcs by half of a multi-leaf collimator (MLC) leaf width.MethodsA total of 22 patients with head-and-neck cancer were retrospectively selected. Since the smallest MLC leaf width was 5 mm in this study, the couch was shifted by 2.5 mm in the longitudinal-direction between arcs to increase the resolution of fluence map. A total of three types of VMAT plans were generated for each patient; the three types of plans were a two-full-arc plan without couch-shift (NS plan), a two-half-arc-pair plan with couch-shift (HAS plan), and a two-full-arc pair plan with couch-shift (FAS plan). Changes in the dose-volumetric parameters were investigated.ResultsThe FAS plan showed the best plan quality for the target volumes and organs at risk compared to the NS and HAS plans. However, the magnitudes of differences among the three types of plans were minimal, and every plan was clinically acceptable. The average integral doses of the NS, HAS, and FAS plans were 160,549 ± 37,600 Gy-cc, 147,828 ± 33,343 Gy-cc, and 156,030 ± 36,263 Gy-cc, respectively. The average monitor unit of the NS, HAS, and FAS plans were 717 ± 120 MU, 648 ± 100 MU, and 763 ± 158 MU, respectively.ConclusionsThe HAS plan was better than the others in terms of normal tissue sparing and plan efficiency. By shifting the couch by half of the MLC leaf width in the longitudinal direction between arcs, the VMAT plan quality could be improved.     

Static and rotational intensity modulated techniques for head-neck cancer radiotherapy: A planning comparison

PurposeTo compare helical Tomotherapy (HT), two volumetric-modulated arc techniques and conventional fixed-field intensity modulated techniques (S-IMRT) for head-neck (HN) cancers.Methods and materialsEighteen HN patients were considered. Four treatment plans were generated for each patient: HT, S-IMRT optimised with Eclipse treatment planning system and two volumetric techniques using Elekta–Oncentra approach (VMAT) and Varian-RapidArc (RA), using two full arcs. All techniques were optimised to simultaneously deliver 66Gy to PTV1 (GTV and enlarged nodes) and 54Gy to PTV2 (subclinical and electively treated nodes). Comparisons were assessed on several dosimetric parameters and, secondarily, on planned MUs and delivery time.ResultsConcerning PTV coverage, significantly better results were found for HT and RA. HT significantly improved the target coverage both compared to S-IMRT and VMAT. No significant differences were found between S-IMRT and volumetric techniques in terms of dose homogeneity. For OARs, all the techniques were able to satisfy all hard constraints; significantly better results were found for HT, especially in the intermediate dose range (15–30 Gy). S-IMRT reached a significantly better OARs sparing with respect to VMAT and RA. No significant differences were found for body mean dose, excepting higher values of V5–V10 for HT. A reduction of planned MUs and delivery treatment time was found with volumetric techniques.ConclusionsThe objectives of satisfying target coverage and sparing of critical structures were reached with all techniques. S-IMRT techniques were found more advantageous compared to RA and VMAT for OARs sparing. HT reached the best overall treatment plan quality.     

Current status of IMRT in head and neck cancer

Background

IMRT provides highly conformal dose distributions creating non uniform spatial intensity using different segments in the beam.

Material & Methods and Results

Different retrospective studies have shown a high capability of IMRT to treat tumours close to the base of skull. Prospective studies have shown a decrease in xerostomia compared with conventional 3D conformal treatment (3DCRT). Modulation of intensity is performed by the movement of the multileaf collimator (MLC) that can deliver the radiation in different ways, such as static field segments, dynamic field segments and rotational delivery (arc therapy and tomotherapy). There are slight differences among the different techniques in terms of homogeneity, dose conformity and treatment delivery time.

Conclusions

The best method to deliver IMRT will depend on multiple factors such as deliverability, practicality, user training and plan quality.     

Application of radiomics and machine learning in head and neck cancers

With the continuous development of medical image informatics technology, more and more high-throughput quantitative data could be extracted from digital medical images, which has resulted in a new kind of omics-Radiomics. In recent years, in addition to genomics, proteomics and metabolomics, radiomic has attracted the interest of more and more researchers. Compared to other omics, radiomics can be perfectly integrated with clinical data, even with the pathology and molecular biomarker, so that the study can be closer to the clinical reality and more revealing of the tumor development. Mass data will also be generated in this process. Machine learning, due to its own characteristics, has a unique advantage in processing massive radiomic data. By analyzing mass amounts of data with strong clinical relevance, people can construct models that more accurately reflect tumor development and progression, thereby providing the possibility of personalized and sequential treatment of patients. As one of the cancer types whose treatment and diagnosis rely on imaging examination, radiomics has a very broad application prospect in head and neck cancers (HNC). Until now, there have been some notable results in HNC. In this review, we will introduce the concepts and workflow of radiomics and machine learning and their current applications in head and neck cancers, as well as the directions and applications of artificial intelligence in the treatment and diagnosis of HNC.     

Immunotherapy for head and neck cancer

Head and neck cancer represents a challenging disease. Despite recent treatment advances, which have improved functional outcomes, the long-term survival of head and neck cancer patients has remained unchanged for the past 25 years. One of the goals of adjuvant cancer therapy is to eradicate local regional microscopic and micrometastatic disease with minimal toxicity to surrounding normal cells. In this respect, antigen-specific immunotherapy is an attractive therapeutic approach. With the advances in molecular genetics and fundamental immunology, antigen-specific immunotherapy is being actively explored using DNA, bacterial vector, viral vector, peptide, protein, dendritic cell, and tumor-cell based vaccines. Early phase clinical trials have demonstrated the safety and feasibility of these novel therapies and the emphasis is now shifting towards the development of strategies, which can increase the potency of these vaccines. As the field of immunotherapy matures and as our understanding of the complex interaction between tumor and host develops, we get closer to realizing the potential of immunotherapy as an adjunctive method to control head and neck cancer and improve long-term survival in this patient population.     

Five-year relative survival and determinants of excess mortality in patients with head and neck and thyroid cancers: A population-based study from Golestan province,Northern Iran

BackgroundWe aimed to assess relative survival (RS) and determinants of excess mortality rate in patients with head and neck squamous cell carcinomas (HNSCC) and thyroid cancer in Golestan province, Northern Iran.MethodsWe recruited new primary HNSCC and thyroid cancer cases from Golestan, 2006–2016. Five-year age-standardized RS with their 95% confidence intervals (CIs) were calculated. The relationships between different variables with excess mortality rates were assessed by estimating adjusted excess hazard ratios (aEHRs) with their 95% CIs.ResultsOverall, 718 cases of HNSCC and 386 thyroid cancer cases were enrolled. Five-year age-standardized RS (95% CI) were 36% (31−41) and 61% (52−69) in HNSCC and thyroid cancer patients, respectively. There were significant relationship between excess mortality rates in HNSCC patients with metastasis (aEHR= 3.31; 95%CI: 2.26–4.84), treatment type (4.19; 2.54–6.91, for no treatment as compared to receiving both surgery and chemoradiotherapy), age (2.16; 1.57–2.96, for older age group) and smoking (2.00; 1.45–2.75, for smokers as compared to non-smokers). Determinant of the excess mortality in thyroid cancer patients included metastasis (19.65; 8.08–47.79), tumor morphology (12.27; 4.62–32.58, for anaplastic cancer as compared to papillary cancer), treatment type (8.95, 4.13–19.4, for no treatment as compared to receiving both surgery and iodine therapy) and age (2.31; 1.17–4.54, for older age group).ConclusionOur findings suggested low RS for thyroid cancer in our population, while the estimates for HNSCC were comparable with other population. Metastasis, treatment type and age were determinants of mortality both in thyroid and HNSCC patients.     

Dosimetric and Monte Carlo verification of jaws-only IMRT plans calculated by the Collapsed Cone Convolution algorithm for head and neck cancers

AimThe aim of this study is to verify the Prowess Panther jaws-only intensity modulated radiation therapy (JO-IMRT) treatment planning (TP) by comparing the TP dose distributions for head-and-neck (H&N) cancer with the ones simulated by Monte Carlo (MC).BackgroundTo date, dose distributions planned using JO-IMRT for H&N patients were found superior to the corresponding three-dimensional conformal radiotherapy (3D-CRT) plans. Dosimetry of the JO-IMRT plans were also experimentally verified using an ionization chamber, MapCHECK 2, and Octavius 4D and good agreements were shown.Materials and methodsDose distributions of 15 JO-IMRT plans of nasopharyngeal patients were recalculated using the EGSnrc Monte Carlo code. The clinical photon beams were simulated using the BEAMnrc. The absorbed dose to patients treated by fixed-field IMRT was computed using the DOSXYZnrc. The simulated dose distributions were then compared with the ones calculated by the Collapsed Cone Convolution (CCC) algorithm on the TPS, using the relative dose error comparison and the gamma index using global methods implemented in PTW-VeriSoft with 3%/3 mm, 2%/2 mm, 1%/1 mm criteria.ResultsThere is a good agreement between the MC and TPS dose. The average gamma passing rates were 93.3 ± 3.1%, 92.8 ± 3.2%, 92.4 ± 3.4% based on the 3%/3 mm, 2%/2 mm, 1%/1 mm criteria, respectively.ConclusionsAccording to the results, it is concluded that the CCC algorithm was adequate for most of the IMRT H&N cases where the target was not immediately adjacent to the critical structures.     

A comparative study between open-face and closed-face masks for head and neck cancer (HNC) in radiation therapy

AimTo determine the setup reproducibility in the radiation treatment of Head and Neck (HN) patients using open face head and shoulder masks (OHSM) with customized headrest (CHR) versus standard closed head and shoulder masks (CHSM) and to determine the patient’s level of comfort and satisfaction for both masks.MethodsForty patients were prospectively randomized into two groups using simple random sampling. Group 1 was assigned with CHSMs, immobilized with a standard HR (SHR) while Group 2 was assigned with OHSMs, and immobilized with CHR. Cone beam computed tomography (CBCT) was taken the first 3 days, followed by weekly CBCT (prior treatment) with results registered to the planning CT to determine translational and rotational inter-fraction shifts and to verify accuracy. Mean (M) and standard deviation (SD) of the systematic and random setup errors of the 2 arms in the translational and rotational directions were analyzed, using Independent t-test and Mann–Whitney U test. Patient comfort was measured using a Likert questionnaire.ResultsThe vertical, lateral, longitudinal and Z/roll rotational shifts were not significantly different between the two masks. X/yaw and Y/pitch rotational shifts were significantly greater in Group 2 versus Group 1, for both systematic (p = 0.009 and 0.046, respectively) and random settings (p = 0.016 and 0.020) but still within three degrees. Patients reported higher neck and shoulder comfort (p = 0.020) and overall satisfaction (p = 0.026) using the OHSM with the CHR versus the CHSM with the SHR during CT simulation.ConclusionOpen masks provide comparable yet comfortable immobilization to closed masks for HN radiotherapy.     

Incidence of radiation-induced hypothyroidism following head and neck irradiation: a single-center analysis

BackgroundThe purpose of this study was to investigate the incidence of primary hypothyroidism (HT), as well as any correlation between dosimetric parameters and thyroid dysfunctions after neck radiotherapy (RT) in head and neck cancer (HNC) patients.Materials and methodsThis study retrospectively reviewed HNC patients who finished neck RT for at least 12 months and who had available back-up treatment information. Eligible patients further received a single thyroid function test (TFT). Dosimetric parameters of the thyroid glands were retrospectively evaluated in order to detect any correlation between dose-volume parameters and primary HT.ResultsWe reviewed 1,102 HNC patients. Accordingly, 64 patients were deemed eligible and were included in this study. The median time interval between RT completion and TFT was 21 months (interquartile range, 14–34 months), while 26 patients (40.6%) were diagnosed with HT. The thyroid volume spared from a dose of 50 Gy (VS50_Gy) was found to be statistically significant and considered an associated factor for developing HT (p = 0.047). Furthermore, there was an observable trend indicating a reduction in the risk of HT when VS50_Gy was more than 5 cm³ (p = 0.052).ConclusionIn our study, VS50_Gy was determined to be a significant predictive parameter of radiation-induced HT.     

Skin barrier function in patients under radiation therapy due to the head and neck cancers - Preliminary study

AimTo present the possibility of non-invasive monitoring of the skin after radiotherapy in regards of epidermal barrier function.BackgroundRadiodermatitis constitutes 95% of all side effects in patients after radiotherapy. The proper assessment of the severity of radiodermatitis can be determined using semi-quantitative clinical scores [Common Terminology Criteria for Adverse Events v 4.0 (CTCAE)].The most accepted way to analyze the epidermal barrier function is to determine Transepidermal Water Loss (TEWL).Material and methodsIn prospective study, we included 16 patients diagnosed with head and neck cancer treated with radiotherapy or concomitant chemoradiation in whom we performed non-invasive assessments of the skin barrier function, including TEWL measurement. The final analysis included 6 patients (4 treated with adjuvant radiotherapy, 2 with radical chemoradiation). Clinical assessment of irradiated skin was based on target lesion score (TLS) and CTCAE v 4.0ResultsThe mean TLS score in the middle of irradiation was 1.6 points, after last irradiation it was 2.3 points; 3 months later the mean TLS score was: 0. CTCAE v 4.0 criteria: 2 patients had grade 0, 3 patients - grade 1; 1 patient - grade 2. There were statistically significant differences in TEWL related to irradiated skin in the following time intervals: before vs. in the middle; before vs. day after; in the middle vs. day after; in the middle vs. 3 months after; day after vs. 3 months after.ConclusionsThe study showed that radiotherapy causes skin barrier dysfunction in all patients independently of clinical radiodermatitis. The biophysical features of this dysfunction can precede clinical symptoms and they can be assessed by non-invasive and objective methods.     

Differences in risk factors for head and neck cancer among men and women in Nepal: A case-control study

BackgroundHead and neck cancer (HNC) is a major cause of cancer morbidity and mortality in Nepal. The study aims to investigate differences in risk factors for head and neck cancer by sex in Nepal.MethodsA hospital-based case-control study was conducted at the B.P. Koirala Memorial Cancer Hospital in Nepal from 2016 to 2018. A semi-structured questionnaire consisting of socio-demographic characteristics, dietary habits, reproductive factors, household air pollution, tobacco use (smoking and chewing), alcohol consumption, and second-hand smoking was used to collect the data. Odds ratios (OR) and 95 % confidence intervals (CI) were estimated using unconditional logistic regression adjusting for potential confounders.ResultsA total of 549 HNC cases (438 men and 111 women) and 601 age-matched healthy controls (479 men and 122 women) were recruited in this study. An increased risk of HNC for low education level and family income were observed among men (adjusted odds ratio (AOR) for 3rd grade and less= 1.58, 95 % CI= 1.14–2.18; AOR for family monthly income < 5000 Rupees = 1.64, 95 % CI 1.20–2.24). The AORs among women were higher than the men for known risk factors (AOR for smoking 1.34 (95 % CI 0.96–1.86) for men, 2.94 (95 % CI 1.31–6.69) for women; AOR for tobacco chewing 1.76 (95 % CI 1.27–2.46) for men, 10.22 (95 % CI 4.53–23.03) for women).ConclusionOur results point to an effect modification by sex for HNC risk factors with high AORs observed among women.     

Treatment of head and neck cancers with BRMs

It has been reported that immunologic function is deteriorated in head and neck cancer patients by primary therapies such as surgery, irradiation and chemotherapy or tumor itself. As previously described by us, immunologic dysfunction in such patients may be recovered by treatment with BRMs. In the present study, we investigated the effects of BRMs on survival of patients who had primarily been treated in our clinic. Fifty-one patients (23 patients; Stage I or Stage II, 28 patients; Stage III or Stage IV) were treated with BRMs (BRM group), and 49 patients (22 patients; Stage I or Stage II, 27 patients; Stage III or Stage IV) were employed as controls (Control group). The results obtained were as follows: (1) In patients of all Stages, the survival period was significantly (p<0.05) longer in BRM group than in Control group; (2) The survival periods of patients of Stage I or Stage II were not different between the groups; and (3) The survival period of BRM group was significantly (p<0.05) longer than that of Control group in patients of Stage III or Stage IV. There were observed more patients in BRM group who survived for a prolonged period. These results suggest that BRMs may be useful for recovering immunologic function in head and neck cancer patients particularly of Stage III or Stage IV who usually receive multimodality therapy.     

Comparative study of DNA damage and repair in head and neck cancer after radiation treatment

We compared DNA damage and the efficacy of its repair after genotoxic treatment with γ-radiation of lymphocytes and tissue cells isolated from patients with squamous cell carcinoma of head and neck (HNSCC) and healthy donors. Thirty-seven subjects with HNSCC and 35 healthy donors were enrolled in the study. The extent of DNA damage including oxidative lesions and efficiency of the repair were examined by alkaline comet assay. HNSCC cancer cells were more sensitive to genotoxic treatment and displayed impaired DNA repair. In particular, lesions caused by γ-radiation were repaired less effectively in metastasis of HNSCC than in healthy controls. The differences in radiation sensitivity of cancer and control cells suggested that DNA repair might be critical for HNSCC treatment. We conclude that γ-radiation might be considered as an effective therapeutic strategy for head and neck cancers, including patients in advanced stage of the disease with clear evidence of metastasis.     

Clinical application of recombinant human erythropoietin for treatments in patients with head and neck cancer

Summary The therapeutic effects of intravenous recombinant human erythropoietin (r-hEPO) administration on anemia induced by radiation therapy (3 cases), chemotherapy (18 cases) and combined therapies (5 cases) in patients with head and neck malignancies were examined. The effectiveness was evaluated by the changes in the hemoglobin concentration examined before and after the r-hEPO administration. The r-hEPO administration combined with anticancer therapies improved anemia induced by all three treatments. The therapeutic effectiveness of r-hEPO injection was also noted on anemia induced by all of four different chemotherapeutic regimens that have been ordinarily used for head and neck malignancies. Furthermore, the efficacy of the different dose schedules, 3000 IU (12 cases) or 6000 IU (14 cases), three times a week, was compared. Both of the r-hEPO dose schedules were effective for anemia, but the efficacy of 6000 IU was superior to that of 3000 IU. No significant changes were observed in the number of white blood cells and platelets and the results of biochemical examinations after the r-hEPO injection. There were no objective side-effects related to the r-hEPO administration. These results suggest that anemia induced by chemotherapy and/or radiotherapy could be prevented by r-hEPO administration. The addition of r-hEPO to anticancer therapies would make it possible to pursue the planned therapeutic schedules, prevent the decrease of immunity after allogeneic blood transfusion and bring about an improvement in the prognosis of patients with malignancies.     

Accuracy of dose calculation on iterative CBCT for head and neck radiotherapy

PurposeTo evaluate the feasibility of the use of iterative cone-beam computed tomography (CBCT) for dose calculation in the head and neck region.MethodsThis study includes phantom and clinical studies. All acquired CBCT images were reconstructed with Feldkamp–Davis–Kress algorithm-based CBCT (FDK-CBCT) and iterative CBCT (iCBCT) algorithm. The Hounsfield unit (HU) consistency between the head and body phantoms was determined in both reconstruction techniques. Volumetric modulated arc therapy (VMAT) plans were generated for 16 head and neck patients on a planning CT scan, and the doses were recalculated on FDK-CBCT and iCBCT with Anisotropic Analytical Algorithm (AAA) and Acuros XB (AXB). As a comparison of the accuracy of dose calculations, the absolute dosimetric difference and 1%/1 mm gamma passing rate analysis were analyzed.ResultsThe difference in the mean HU values between the head and body phantoms was larger for FDK-CBCT (max value: 449.1 HU) than iCBCT (260.0 HU). The median dosimetric difference from the planning CT were <1.0% for both FDK-CBCT and iCBCT but smaller differences were found with iCBCT (planning target volume D_50%: 0.38% (0.15–0.59%) for FDK-CBCT, 0.28% (0.13–0.49%) for iCBCT, AAA; 0.14% (0.04–0.19%) for FDK-CBCT, 0.07% (0.02–0.20%) for iCBCT). The mean gamma passing rate was significantly better in iCBCT than FDK-CBCT (AAA: 98.7% for FDK-CBCT, 99.4% for iCBCT; AXB: 96.8% for FDK_CBCT, 97.5% for iCBCT).ConclusionThe iCBCT-based dose calculation in VMAT for head and neck cancer was accurate compared to FDK-CBCT.     

Macrophage and dendritic cell infiltration in head and neck squamous-cell carcinoma; an immunohistochemical study

A study was undertaken to help us reach a better understanding of the tumor-infiltrating pattern of lymphoid cells and in particular of monocyte-derived cells, namely the CD68⁺, acid-phosphatase-expressing scavenger macrophages and the MHC-class-II- and S100-antigen-presenting dendritic cells in head and neck squamous-cell carcinoma. In the stroma of the tumors distinctive small fields of lymphocytes were found, the T cell areas of these fields being intermingled with dendritic cells. Intra-epithelial dendritic cell infiltration was low. The infiltrative pattern of macrophages was similar to patterns described in earlier studies with substantial stromal invasion and inconsistent intra-epithelial invasion, but small granuloma-like structures of CD68⁺ macrophage-like cells, found in the stroma of tumors, have not been reported before. The histochemical localization of the tumor-infiltrated dendritic cells and macrophages supports the view that the former cells are involved in the sensitization to tumor antigens, whereas the latter cells are involved in tumor cytotoxicity/scavenging of tumor cell debris. Although it has been shown in the past that transmembranal (TM) factors (p15E-like factors) present in the serum and tumor of patients with cancer of the head and neck have suppressive effects on monocyte/macrophage/dendritic cell function, a relationship between the intensity of epithelial staining for TM factors and the infiltrative pattern of monocytes/macrophages/dendritic cells could not be demonstrated.     

Risk factors associated with head and neck cancer in former smokers: A Brazilian multicentric study

BackgroundReduced tobacco consumption in the population has not been associated with reduced incidence rates of head and neck cancer in several countries.ObjectiveTo explore the associations between HNC and sociodemographic characteristics and lifestyle of former smokers from three Brazilian cancer centers.MethodsA multicenter case-control study was conducted with 229 former smokers diagnosed with squamous cell carcinoma of the oral cavity, oropharynx, larynx, and 318 controls (former smokers without head and neck cancer). Bivariate and multiple logistic regression analyses were conducted to estimate odds ratios (ORs) with a 95% confidence interval (CI).Results11–20 years after smoking cessation showed significant impact on HNC reduction (OR 0.22, 95% CI, 0.12–0.39), which reached 82% (95% CI, 0.09–0.35) among 20 + former smokers when compared to individuals who had stopped smoking for up to 5 years. A history of high-intensity smoking (>40 pack-years) increased HNC risk by 2.09 times (95% CI 1.13–3.89) when compared to subjects who smoked up to 20 pack-years. Past alcohol consumption (OR 1.99, 95% CI, 1.06–3.82) was also associated with head and neck cancer risk in former smokers when compared to no alcohol consumption. There was a decreased head and neck cancer risk in former smokers who had high school level of education (OR 0.38, 95% CI, 0.16–0.91) compared to illiterate former smokers; and former smokers with moderate intake of vegetables (OR 0.49, 95% CI, 0.28–0.85) and fruits (OR 0.43, 95% CI, 0.25–0.73) compared to those with low intake.ConclusionHead and neck cancer risk in former smokers decreases after 11 years after smoking cessation, former smokers with past alcohol consumption showed an increased risk of HNC. High school level of education and moderate intake of vegetables and fruits reduced HNC risk among former smokers.