Head and Neck Cancer Among Lifelong Never-Smokers and Ever-Smokers: Matched-Pair Analysis of Outcomes After Radiation Therapy

Cigarette smoking cessation, duration of smoking abstinence, and head and neck squamous cell carcinoma prognosis

BACKGROUND

Tobacco use is a major risk factor for developing head and neck squamous cell carcinoma (HNSCC). However, the prognostic associations with smoking cessation are limited. The authors assessed whether smoking cessation and increased duration of abstinence were associated with improved overall (OS) and HNSCC-specific survival.

METHODS

Clinicodemographic and smoking data from patients with HNSCC at Princess Margaret Cancer Center (2006-2019) were prospectively collected. Multivariable Cox and Fine and Gray competing-risk models were used to assess the impact of smoking cessation and duration of abstinence on overall mortality and HNSCC-specific/noncancer mortality, respectively.

RESULTS

Among 2482 patients who had HNSCC, former smokers (adjusted hazard ratio [aHR], 0.71; 95% CI, 0.58-0.87; p = .001; N = 841) had a reduced risk of overall mortality compared with current smokers (N = 931). Compared with current smokers, former smokers who quit >10 years before diagnosis (long-term abstinence; n = 615) had the most improved OS (aHR, 0.72; 95% CI, 0.56-0.93; p = .001). The 5-year actuarial rates of HNSCC-specific and noncancer deaths were 16.8% and 9.4%, respectively. Former smokers (aHR, 0.71; 95% CI, 0.54-0.95; p = .019) had reduced HNSCC-specific mortality compared with current smokers, but there was no difference in noncancer mortality. Abstinence for >10 years was associated with decreased HNSCC-specific death compared with current smoking (aHR, 0.64; 95% CI, 0.46-0.91; p = .012). Smoking cessation with a longer duration of quitting was significantly associated with reduced overall and HNSCC-specific mortality in patients who received primary radiation.

CONCLUSIONS

Smoking cessation before the time of diagnosis reduced overall mortality and cancer-specific mortality among patients with HNSCC, but no difference was observed in noncancer mortality. Long-term abstinence (>10 pack-years) had a significant OS and HNSCC-specific survival benefit.

The clinical impact of continued smoking in patients with breast and other hormone-dependent cancer: A systematic literature review

We conducted a systematic review of studies that investigated whether quitting smoking at or around diagnosis improves survival of patients with hormone-dependent cancers (HDC). Nine studies published in 2013-2022 were included. Studies were very diverse in terms of design, definition of quitters and continued smokers, and prevalence of prognostic factors other than smoking cessation (e.g. patients' demographics, tumour characteristic, and treatments). For breast, ovarian, and endometrial cancer, all included studies found that quitters had better overall, disease specific, and disease-free survival than continued smokers. For prostate cancer, there was no evidence of an association of smoking cessation with improved survival. This literature review provided suggestive evidence that female smokers diagnosed with cancer of the breast, ovary, or endometrium may improve their chances of surviving by stopping smoking. Smoking cessation counselling should become part of standard oncological care for these patients and integrated into breast cancer screening programs.

Post-diagnosis smoking cessation and survival of patients with head and neck cancer: a systematic review and meta-analysis

Cigarette smoking is the main risk factor for head and neck cancer (HNC) and many HNC patients are active smokers at diagnosis. We conducted a systematic literature review and meta-analysis to quantify the survival impact of smoking cessation at or around the time of HNC diagnosis. We searched studies published until December 31, 2021, and used random-effects meta-analysis to pool study-specific estimates into summary hazard ratio (SHR) and corresponding 95% confidence intervals (CI). Sixteen studies were published between 1983 and 2021, and over 2300 HNC patients were included. Studies were diverse in terms of design, patients, tumours and treatment characteristics, and criteria used to discriminate quitters from continued smokers. HNC patients who quit smoking at or around diagnosis had significantly better overall survival than continued smokers (SHR 0.80, 95% CI 0.70-0.91, n studies = 10). A beneficial effect of post-diagnosis smoking cessation was suggested for other survival endpoints as well, but the results were based on fewer studies (n = 5) and affected by publication bias. Cessation counselling should be offered to all smokers who start a diagnostic workup for HNC and should be considered standard multidisciplinary oncological care for HNC patients. PROSPERO registration number CRD42021245560.

Advances in Organ Preservation for Laryngeal Cancer

OPINION STATEMENT

At the University of Wisconsin, all treatment of head and neck cancer patients begins with discussion at our multi-disciplinary tumor board. Most patients with T4 disease, with existing laryngeal dysfunction, considered unlikely to complete definitive CRT or who have a high risk of persistent aspiration after non-operative management undergo total laryngectomy. A laryngeal sparing approach is attempted on most other patients. Radiotherapy is delivered over 6.5 weeks, preferably with concurrent weekly cisplatin. If the patient is hesitant of chemotherapy or has contraindications to cisplatin, concurrent cetuximab may be offered. Patients treated with RT alone are often treated to the same dose, but via an accelerated schedule by adding a 6th fraction per week. The 6th fraction is given by delivering two treatments at least 6 h apart on a weekday of the patient's choosing. We consider the following to be major risk factors for clinically significant weight loss during treatment: a 10% or greater loss of weight in the 6 months prior to starting treatment, delivery of concurrent cisplatin, and treatment of the bilateral neck with radiation. Patients who have 2-3 of these characteristics are often given gastrostomy tubes prophylactically. Patients are seen 2 weeks after completion of therapy, and then every 3 months after completion for 2 years. A CT neck and PET-CT are performed at the first 3-month visit. They are seen twice in year three, and then yearly until years 5-7. At each of these visits, we have a low threshold to present the patient at our multidisciplinary tumor board for consideration of salvage laryngectomy if there are signs of progression.

[The impact of smoking habit alteration on prognosis of head and neck cancer patients]

INTRODUCTION

The influence of smoking on survival in patients with HNSCC is well documented in the literature. There is little data on changes in smoking habits after diagnosis. Here, the effect on survival of the reduction of smoking compared to full smoking cessation is investigated.

PATIENTS AND METHODS

Patient records and tumor documentation of 643 consecutive HNSCC cases of the Head and Neck Tumor Center of the University Hospital Kiel are evaluated retrospectively: smoking habits before and after treatment and survival are evaluated.

RESULTS

Change in smoking behavior at the initial diagnosis of HNSCC leads to a significant positive effect on the prognosis compared to continued smoking. There is no difference between smoke reduction and weaning. This effect is based solely on those patients who are treated exclusively by surgery. Lifelong non-smokers have a significant survival advantage over active and ex-smokers, with no difference between the latter two groups.

CONCLUSIONS

The positive influence of changed smoking habits on the prognosis runs parallel to the negative direct effect of active smoking on therapy, which is attributed to peritumoral hypoxia with a negative effect on the effectiveness of R(C)T. The positive effect of the change in smoking behaviour during surgery alone is most likely due to reduced peri-operative complications. Patients should be encouraged to at least minimize smoking with the cancer diagnosis. In addition, former smokers should be considered active smokers for survival estimates and therapy planning.

Radiotherapy-Specific Chronic Pain Syndromes in the Cancer Population: An Evidence-Based Narrative Review

While radiation therapy is increasingly utilized in the treatment paradigm of many solid cancers, the chronic effects of radiation therapies are poorly characterized. Notably, understanding radiation-specific chronic pain syndromes is paramount given that the diagnosis and management of these conditions can serve to prevent long-standing functional impairments, optimize quality of life, and even allow for continued radiotherapy candidacy. These radiation-specific chronic pain phenomena include dermatitis, mucositis, enteritis, connective tissue fibrosis, lymphedema, and neuropathic pain syndromes. It is necessary to maintain a low threshold of suspicion for appropriately diagnosing these conditions as there exists a variance in when these symptoms arise after radiation. However, we present key epidemiological data delineating vulnerable cancer populations for each pain syndrome along with the available evidence for the management for each specific condition.

Partial and Total Flap Failure after Fibula Free Flap in Head and Neck Reconstructive Surgery: Retrospective Analysis of 180 Flaps over 19 Years

Fibula free flap (FFF) is widely used in head and neck reconstructive surgery and is considered as a standard and therapy of choice after ablative cancer surgery. The aim of this retrospective monocenter study was to determine the success rates of fibula free flaps for jaw reconstruction after ablative tumor surgery. The disease course of patients who underwent jaw reconstructive surgery with FFF from January 2002 to June 2020 was evaluated regarding the flap success rate. Flap failure was analyzed in detail and categorized into two groups: partial flap failure (PFF) and total flap failure (TFF). A total of 180 free fibular flaps were performed over the last 19 years and a total of 36 flap failures were recorded. TFF occurred in n = 20 (56.6%) and PFF in n = 16 cases (44.4%) cases. No statistically significant differences were found concerning patients' age at flap transfer, sex, BMI, ASA-Score, preoperative non-virtual or virtual surgical planning (non-VSP vs. VSP), and time of reconstruction (immediately vs. delayed). Duration of hospitalization shows statistically significant differences between both groups (p = 0.038), but no differences concerning operating time and duration on Intensive Care Unit (ICU). Partial flap failure appears to be underreported in literature. Sub- and complete failure of the skin paddle leads to clinical complaints like uncovered bone segments and plate exposure. Partial or complete FFF failure lead to infections on the recipient site and prolonged wound healing and therefore may cause a delay of the beginning of adjuvant radiation therapy (RT). PFF of hard tissue can be induced by RT.

Alteration of smoking habit at time of first diagnosis influences survival of patients with HNSCC

The impact of smoking on survival in patients with squamous cell carcinoma of the head and neck is well established, despite some conflicting data in the literature. However, data on alterations of smoking habit following cancer diagnosis is sparse. In the present study, the effect of reduction of smoking compared with cessation on the course of disease was studied. Data from 643 patients with HNSCC from the tumor documentation registry of the Department of Otorhinolaryngology, Head and Neck Surgery of the Christian-Albrechts-University Kiel were collected and statistically analyzed, looking at pre- and post-treatment smoking habit and survival. Alteration of smoking at the first diagnosis of HNSCC led to a significantly beneficial effect on survival outcomes compared with continued smoking, without significant differences between reduction and cessation of smoking. Detailed analysis revealed that this effect was solely dependent on patients treated by surgery only. Lifelong non-smokers exhibited a significant survival advantage compared with active and former smokers, with no difference in survival between these last two groups. The positive influence of altered smoking habit following first time diagnosis on disease-specific survival paralleled the negative direct effect of active smoking on therapy, which is predominantly attributed to peritumoral tissue hypoxia leading to impaired efficacy of radiochemotherapy (RCT). In the present study cohort, the positive effect of smoking habit alterations were primarily observed in patients treated by surgery only instead of RCT, possibly due to fewer perioperative complications. These findings indicated that patients should be encouraged to at least minimize smoking following cancer diagnosis. Furthermore, for survival estimates and therapy planning, former smokers should be considered as active smokers.

Significance of the neutrophil-to-lymphocyte ratio in young patients with oral squamous cell carcinoma

Background

The main goal of this study was to evaluate the prognosis of young patients with oral squamous cell carcinoma (SCC) with a focus on the value of the pretreatment neutrophil-to-lymphocyte ratio (NLR).

Materials and methods

Young (≤40 years old) patients with oral SCC were retrospectively enrolled, and each young patient was matched with an old (≥60 years old) oral SCC patient. Associations between the NLR and clinicopathological variables were analyzed by the chi-square test, and the Kaplan–Meier method was used to analyze recurrence-free survival (RFS) and disease-specific survival (DSS) rates.

Results

A total of 103 young patients were enrolled, and compared to the old group, the young group had a significantly lower NLR value (p=0.012). In the young group, the 5-year RFS and DSS rates were 82% and 85%, respectively. In the old group, the 5-year RFS and DSS rates were 65% and 71%, respectively, and the differences between the groups were significant (both p<0.05). In the young patients with an NLR≤2.56, the 5-year DSS rate was 93%, while in the young patients with an NLR >2.56, the 5-year DSS rate was 76%. This difference was significant (p=0.020). A further Cox model analysis confirmed that the NLR was an independent prognostic factor for DSS.

Conclusion

Young patients with oral SCC have a better prognosis than old oral SCC patients, and the NLR is significantly associated with DSS in young patients.

Premature discontinuation of curative radiation therapy: Insights from head and neck irradiation

Purpose

Factors related to premature discontinuation of curative radiation therapy (PDCRT) are understudied. This study aimed to examine causes and clinical outcomes of PDCRT at our institution by investigating the most common anatomical site associated with PDCRT.

Methods and materials

Among the 161 patients with PDCRT of various anatomic sites at our institution between 2010 and 2017, 36% received radiation to the head and neck region. Pertinent demographic, clinical, and treatment-related data on these 58 patients were collected. Survival was examined using the life-table method and log-rank test.

Results

The majority of patients were male (81%), white (67%), ≥60 years old (59%), living ≥10 miles away from the hospital (60%), single (57%), with Eastern Cooperative Oncology Group score ≥1 (86%), experiencing significant pain issues (67%), and had treatment interruptions in radiation therapy (RT; 66%). The most common reasons for PDCRT were discontinuation against medical advice (33%), medical comorbidity (24%), and RT toxicity (17%). Of the comorbidities leading to PDCRT, 50% was acute cardiopulmonary issues and 43% was infection. The mean follow-up time was 15.9 months, and the 2-year overall survival and disease-specific survival rates were 61% and 78%, respectively. Patients with illicit substance abuse, cardiovascular disease, and Eastern Cooperative Oncology Group score ≥2 had worse survival. A trend toward improved survival with total completed dose ≥50 Gy versus <50 Gy existed (74% versus 44%, respectively; P = .07).

Conclusions

In this largest-to-date, modern analysis of PDCRT, the most common cause of discontinuation was discontinuation against medical advice, which underscores the importance of patient education, optimization of RT symptoms, involvement of social work, and integration of other supportive services early in treatment. Survival remains suboptimal after PDCRT for H&N tumors, with a 2-year overall survival rate of 61%. Completing >50 Gy appears to confer a relative therapeutic benefit.

Does Quitting Smoking Make a Difference Among Newly Diagnosed Head and Neck Cancer Patients?

INTRODUCTION

To determine if smoking after a cancer diagnosis makes a difference in mortality among newly diagnosed head and neck cancer patients.

METHODS

Longitudinal data were collected from newly diagnosed head and neck cancer patients with a median follow-up time of 1627 days (N = 590). Mortality was censored at 8 years or September 1, 2011, whichever came first. Based on smoking status, all patients were categorized into four groups: continuing smokers, quitters, former smokers, or never-smokers. A broad range of covariates were included in the analyses. Kaplan-Meier curves, bivariate and multivariate Cox proportional hazards models were constructed.

RESULTS

Eight-year overall mortality and cancer-specific mortality were 40.5% (239/590) and 25.4% (150/590), respectively. Smoking status after a cancer diagnosis predicted overall mortality and cancer-specific mortality. Compared to never-smokers, continuing smokers had the highest hazard ratio (HR) of dying from all causes (HR = 2.71, 95% confidence interval [CI] = 1.48-4.98). Those who smoked at diagnosis, but quit and did not relapse-quitters-had an improved hazard ratio of dying (HR = 2.38, 95% CI = 1.29-4.36) and former smokers at diagnosis with no relapse after diagnosis-former smokers-had the lowest hazard ratio of dying from all causes (HR = 1.68, 95% CI = 1.12-2.56). Similarly, quitters had a slightly higher hazard ratio of dying from cancer-specific reasons (HR = 2.38, 95% CI = 1.13-5.01) than never-smokers, which was similar to current smokers (HR = 2.07, 95% CI = 0.96-4.47), followed by former smokers (HR = 1.70, 95% CI = 1.00-2.89).

CONCLUSIONS

Compared to never-smokers, continuing smokers have the highest HR of overall mortality followed by quitters and former smokers, which indicates that smoking cessation, even after a cancer diagnosis, may improve overall mortality among newly diagnosed head and neck cancer patients. Health care providers should consider incorporating smoking cessation interventions into standard cancer treatment to improve survival among this population.

IMPLICATIONS

Using prospective observational longitudinal data from 590 head and neck cancer patients, this study showed that continuing smokers have the highest overall mortality relative to never-smokers, which indicates that smoking cessation, even after a cancer diagnosis, may have beneficial effects on long-term overall mortality. Health care providers should consider incorporating smoking cessation interventions into standard cancer treatment to improve survival among this population.

[Systematizing support in cessation smoking to improve care for cancer patients]

Approximately 20% of cancer patients smoke at diagnosis (all localizations included), and over two thirds continue despite the therapeutic management of their cancer, especially when cancer is not associated with tobacco. The impact of smoking on quality of care for patients is actually not enough considered. A literature review conducted by the French National Cancer Institute emphasizes the importance of tobacco cessation to improve the prognosis (decreased mortality from all causes and specific); to reduce the risk of second primary cancers; to reduce per- and post-surgical risks as long as some toxicities related to treatments and to improve the quality of physical and mental life of patients. It is important that a communication with the patient takes place at the beginning of the treatment to impact the smoking behavior. All oncology health professionals should deliver a clearly and personalized cessation advice in the light of scientific data and ensure that smoking cessation help will be offered to the patient.

Epidemiology of head and neck cancer

This article discusses risk factors, incidence trends, and prognostic considerations for head and neck cancer (HNC). The primary causes of HNC are tobacco and alcohol use, and human papillomavirus (HPV). Tobacco-related HNC incidence rates are decreasing in countries where tobacco use has declined. HPV-HNC, which occurs primarily in the oropharynx and is associated with sexual behaviors, has been increasing over the past several decades, among white men in particular. The prognosis for HNC overall has improved slightly since the 1990s, and is influenced by site, stage, and HPV status. Prognosis for HPV-HNC is significantly better than for HPV-negative disease.

The effect of prophylactic percutaneous endoscopic gastrostomy (PEG) tube placement on swallowing and swallow-related outcomes in patients undergoing radiotherapy for head and neck cancer: a systematic review

Patients undergoing radiotherapy for head and neck cancer (HNC) often experience malnutrition and dehydration during treatment. As a result, some centres place PEG tubes prophylactically (pPEG) to prevent these negative consequences. However, recent research has suggested that pPEG use may negatively affect swallowing physiology, function and/or quality of life, especially in the long term. The purpose of this study was to systematically review the literature on pPEG use in HNC patients undergoing radiotherapy and to determine its impact on swallowing-related outcomes. The following electronic databases were searched for all relevant primary research published through February 24, 2014: AMED, CINAHL, the Cochrane Library, Embase, Healthstar, Medline, and PsycINFO. Main search terms included HNC, radiotherapy, deglutition disorders, feeding tube(s), and prophylactic or elective. References for all accepted papers were hand searched to identify additional relevant research. Methodological quality was assessed using Cochrane's Risk of Bias. At all levels, two blinded raters provided judgments. Discrepancies were resolved by consensus. The search retrieved 181 unique citations. Twenty studies met our inclusion criteria. Quality assessment revealed that all studies were at risk for bias due to non-randomized sampling and unreported or inadequate blinding. Ten studies demonstrated selection bias with significant baseline differences between pPEG patients and controls. Results regarding the frequency and severity of dysphagia and swallowing-related outcomes were varied and inconclusive. The impact of pPEG use on swallowing and swallowing-related outcomes remains unclear. Well-controlled, randomized trials are needed to determine if pPEG places patients at greater risk for developing long-term dysphagia.

Smoking is a poor prognostic factor for male nasopharyngeal carcinoma treated with radiotherapy

BACKGROUND AND PURPOSE

To evaluate the effect of smoking on prognosis of male nasopharyngeal carcinoma by comparing the treatment outcomes between smokers and non-smokers.

MATERIALS AND METHODS

A total of 2450 nasopharyngeal carcinoma patients were enrolled, including 1865 male patients. Matching was performed between smokers and non-smokers in male patients according to age, UICC clinical stage, T stage, N stage and treatment. Survival outcomes were compared using Kaplan-Meier analysis and Cox regression. Smoking index was calculated by multiplying cigarette packs per day and smoked time (year).

RESULTS

In male patients, smokers had significantly lower 5-year overall survival (70.1% vs. 77.5%, P<0.001) and locoregional recurrent free survival (76.8% vs.82.4%, P = 0.002) compared with non-smokers. Matched-pair analysis showed that smokers kept a high risk of death compared with non-smokers (HR = 2.316, P<0.001). High degree of smoking index (>15 pack-years) had a poor effect on overall survival (HR = 1.225, P = 0.016). When smoking index was more than 45 and 60 pack-years, the risk for death increased to 1.498 and 1.899 fold compared with non-smokers (P = 0.040, 0.001), respectively.

CONCLUSIONS

Smoking was a poor prognostic factor for male nasopharyngeal carcinoma. The heavier the patients smoked, the poorer prognosis they suffered.

Deintensification candidate subgroups in human papillomavirus-related oropharyngeal cancer according to minimal risk of distant metastasis

PURPOSE

To define human papillomavirus (HPV) -positive oropharyngeal cancers (OPC) suitable for treatment deintensification according to low risk of distant metastasis (DM).

PATIENTS AND METHODS

OPC treated with radiotherapy (RT) or chemoradiotherapy (CRT) from 2001 to 2009 were included. Outcomes were compared for HPV-positive versus HPV-negative patients. Univariate and multivariate analyses identified outcome predictors. Recursive partitioning analysis (RPA) stratified the DM risk.

RESULTS

HPV status was ascertained in 505 (56%) of 899 consecutive OPCs. Median follow-up was 3.9 years. HPV-positive patients (n = 382), compared with HPV-negative patients (n = 123), had higher local (94% v 80%, respectively, at 3 years; P < .01) and regional control (95% v 82%, respectively; P < .01) but similar distant control (DC; 90% v 86%, respectively; P = .53). Multivariate analysis identified that HPV negativity (hazard ratio [HR], 2.9; 95% CI, 2.0 to 5.0), N2b-N3 (HR, 2.9; 95% CI, 1.8 to 4.9), T4 (HR, 1.8; 95% CI, 1.2 to 2.9), and RT alone (HR, 1.8; 95% CI, 1.1 to 2.5) predicted a lower recurrence-free survival (RFS; all P < .01). Smoking pack-years > 10 reduced overall survival (HR, 1.72; 95% CI, 1.1 to 2.7; P = .03) but did not impact RFS (HR, 1.1; 95% CI, 0.7 to 1.9; P = .65). RPA segregated HPV-positive patients into low (T1-3N0-2c; DC, 93%) and high DM risk (N3 or T4; DC, 76%) groups and HPV-negative patients into different low (T1-2N0-2c; DC, 93%) and high DM risk (T3-4N3; DC, 72%) groups. The DC rates for HPV-positive, low-risk N0-2a or less than 10 pack-year N2b patients were similar for RT alone and CRT, but the rate was lower in the N2c subset managed by RT alone (73% v 92% for CRT; P = .02).

CONCLUSION

HPV-positive T1-3N0-2c patients have a low DM risk, but N2c patients from this group have a reduced DC when treated with RT alone and seem less suited for deintensification strategies that omit chemotherapy.

Importance of hemoglobin concentration and its modification for the outcome of head and neck cancer patients treated with radiotherapy

INTRODUCTION

Hypoxia induced radioresistance has been acknowledged for decades. One of the indirect evidences of the influence of hypoxia on radiation response comes from the observations of a correlation between tumor control and hemoglobin level. This review examines the clinical data on the prognostic and predictive role of hemoglobin level and hemoglobin manipulation in radiotherapy of squamous cell carcinomas of the head and neck, a tumor type where hypoxic radioresistance have been previously documented.

THE INFLUENCE OF HEMOGLOBIN CONCENTRATION ON TUMOR OXYGENATION AND OUTCOME

The aim is to evaluate the existing literature for information of the influence of hemoglobin concentration and hemoglobin modifications on tumor oxygenation and outcome in head and neck squamous cell cancer patients. The data from several randomized trials show that while most studies have confirmed the prognostic value of hemoglobin, increasing the hemoglobin level through transfusion or erythropoietin stimulation did not result in improved outcome for patients with low initial hemoglobin levels. Clinical studies showed that smoking reduced the oxygen carrying capacity of the blood through formation of carboxyhemoglobin, and lead to poorer response to radiotherapy in smokers compared to non-smokers. Smoking also increased the risk of the development of secondary cancers.

CONCLUSION AND FUTURE PERSPECTIVES

In conclusion, low hemoglobin is a significant negative prognostic factor for radiotherapy of head and neck cancer. Correction of pre-treatment low hemoglobin by blood transfusion and/or erythropoietin stimulating agents does, however, not improve the outcome. Smoking leads to a decrease in effective hemoglobin and poorer treatment outcome. Smoking should be avoided in order to improve the therapeutic efficacy of radiotherapy and development of other smoking-related diseases and/or secondary cancers.

Effect of smoking on oxygen delivery and outcome in patients treated with radiotherapy for head and neck squamous cell carcinoma--a prospective study

BACKGROUND

Head and neck cancer patients with high hemoglobin respond better to irradiation compared to patients with low hemoglobin possibly due to hypoxia induced radioresistance. The hemoglobin level is, however, a crude indicator of the amount of oxygen available to the tissue and may be influenced by a number of factors, smoking being of potential importance. The aim of the present study was to examine the effect of smoking on available oxygen to tumors and the effect on outcome in head and neck cancer patients treated with radiotherapy in a prospective study.

MATERIALS AND METHODS

A total of 232 consecutive patients with squamous cell carcinoma of the larynx, pharynx and oral cavity completed questionnaires on smoking habits prior to treatment. Venous blood samples were collected before and/or during treatment to determine the hemoglobin and carboxyhemoglobin level. Patients were treated with primary curative radiotherapy 62-68 Gy, 2 Gy/fx, 5 fx/week.

RESULTS

All but 12 patients had a history of smoking, 35 were long term quitters, 23 recent quitters, 54 moderate smokers and 108 heavy smokers (>1 pack/day). There was no relationship between total hemoglobin and carboxyhemoglobin, but effective hemoglobin and carboxyhemoglobin were linearly correlated. The amount of carboxyhemoglobin increased with increasing smoking status. Actuarial 5-year univariate analysis showed that heavy smokers had a significantly reduced probability of loco-regional control (44% vs. 65%, p = 0.001), disease-specific (56% vs. 77%, p = 0.003) and overall survival (39% vs. 66%, p = 0.0004) compared to non-smoking patients. Multivariate analyses showed that patients characterized as non-smokers, with low T and N classifications and high hemoglobin level had the best outcome measurements. A rise in carboxyhemoglobin significantly decreased the probability of loco-regional control and each additional pack year increased the risk of death. Smokers and former smokers develop secondary cancers.

CONCLUSION

The study showed a significant negative impact of smoking during radiotherapy for head and neck cancer and the risk of death was increased with each additional pack year of smoking. The effect on loco-regional control could be explained by a rise in carboxyhemoglobin level in smokers, e.g. a reduced oxygen supply to tumors. The data strongly advocate that smoking should be avoided in order to improve the therapeutic efficacy of radiotherapy and development of other smoking-related diseases and/or secondary cancers.