Objective To develop a simple prognostic survival rule from easily obtained characteristics of patients undergoing potentially curative resection of head and neck squamous cell carcinoma using classification and regression trees.
Design Inception cohort.
Setting Tertiary care center.
Patients Consecutive patients undergoing resection lasting at least 2 hours, from July 1993 through June 1997.
Main Outcome Measure Survival, age, TNM tumor stage, functional class, systolic and diastolic blood pressure, body mass index, and serum albumin concentration were evaluated as predictors.
Results Four hundred six patients were followed up for 5 to 1446 days (median, 391 days), during which time 172 deaths occurred. Median survival was 687 days. Patients with TNM stage I, II, or III squamous cell carcinoma had a mean survival of 1068 days. Patients with TNM stage IV or recurrent disease were further stratified. Those with a serum albumin concentration less than 3.85 g/dL had a median survival of 404 days (95% confidence interval, 286-532 days), and those with an serum albumin concentration of 3.85 g/dL or above had a median survival of 625 days (95% confidence interval, 536-1032 days). A similar survival was found using age younger than 66.5 years as a predictor instead of serum albumin concentration less than 3.85 g/dL.
Conclusions At our institution, patients with stage I, II, or III squamous cell carcinoma had a mean survival of approximately 3 years. Those with stage IV or recurrent squamous cell carcinoma could be stratified by either serum albumin concentration or by age into 2 groups with a median survival of 1 or 2 years.
PROGNOSIS, including the prognosis of survival, is a fundamental function of physicians, especially physicians who care for patients with cancer. The objective of this study is to develop a simple prognostic survival rule for patients undergoing potentially curative resection of head and neck squamous cell carcinoma (SCC)1by using classification and regression trees (CART).2
Typically, the only patient characteristics considered are age, sex, and performance status. Other characteristics, including blood pressure,3,4body mass index,5,6and serum albumin concentration,7,8are easily obtained at the preoperative evaluation and have been shown to predict survival for other conditions. To our knowledge, these factors have not previously been studied in head and neck SCC. Many tumor-related characteristics have been studied, but only disease stage (American Joint Committee on Cancer TNM stage9[http://www.cancerstaging.org] or T and N Integer Score [TANIS]10,11) are prognostically significant and routinely available preoperatively.
Recursive partitioning is an analytic technique that creates increasingly more homogeneous subsets of data with respect to a particular outcome (eg, survival) based on a selected predictor. The method is recursively and independently applied to each subset so that different characteristics may emerge as predictors to further subdivide the subsets. Schematically, this creates a tree subdividing the original population, with each branch being more homogeneous, enabling more accurate prediction. The tree is then pruned of the smallest branches to avoid overfitting the data. This pruned, simplified tree can then be translated into a prognostic rule. Goldman et al12and Lee et al13used a recursive partitioning method (CART) to determine probability of myocardial infarction in patients with chest pain. Cooper et al14used recursive partitioning to determine prognostic characteristics in 2105 patients in the Radiation Therapy Oncology Group studies of head and neck SCC. The purpose of the present article is to use CART to determine which routinely available preoperative patient and tumor-related characteristics can predict postsurgical survival in patients undergoing potentially curative resection of head and neck SCC.
The study population comprised consecutive patients undergoing potentially curative resection of head and neck SCC by one of us (D.E.S.), lasting at least 2 hours, from July 1993 through June 1997, at the Arthur G. James Cancer Hospital and Richard J. Solove Research Institute of The Ohio State University, Columbus. All patients underwent preoperative evaluation by one of us (H.G.W.), who prospectively collected all data except serum albumin concentration, which was ascertained by retrospective medical record review. Cause of death was ascertained from the hospital electronic record, the clinic chart, or interviews with family members. Only patients with complete data were used.
Age, tumor stage, self-reported functional class, systolic blood pressure, diastolic blood pressure, body mass index, and serum albumin concentration were evaluated as predictors of survival. Survival time was measured from the initial surgery. Vital status was ascertained from the patient, their family, medical center records, and the cancer center's tumor registry. Age was the age on the surgical date. Blood pressure measurement from the preoperative evaluation was used. Tumor stage was determined by one of us (D.E.S.) according to the TNM classification.15Stage V was defined as recurrent disease. During analysis, the tumor stages were combined into 4 groups; stages I and II were combined owing to the small number of patients in stage I (n = 13). Functional classes as determined by the Specific Activity Scale16were combined into 3 groups; classes 3 and 4 were combined owing to the small number of patients in group 4 (n = 7).
Mean and median survival with 95% confidence intervals (CIs) were estimated with the Kaplan-Meier method.17Recursive partitioning repeatedly separates more and more homogeneous subgroups from the larger population, and the result can be represented schematically as a tree. It has been applied to classification and regression problems. For survival analysis, exponential regression can be used to distinguish the subgroups. To avoid overfitting the data, the complete tree is then pruned using a complexity measure and cross-validation. Cross-validation is usually applied in a "leave-one-out" process to estimate the true predictive error rate. In this process, the population is randomly divided into n subsets. A decision rule is then developed using all but one of the subsets. It is then tested on the "left-out" subset, generating an estimate for the error rate. This is repeated n times, leaving out a different subset each time, and the error estimates are combined to estimate the true predictive error rate. By balancing the cross-validation error estimate and the complexity of the model, a decision rule that reduces overfit can be selected. In the present study, CART2with exponential regression was used to determine predictors of survival. The resulting regression tree was pruned based on the complexity parameter with 10-fold cross-validation. The resulting subsets were evaluated by Kaplan-Meier analysis to determine mean and median survival with 95% CIs.
All statistical tests were run with R 1.4 software,18using rpart (recursive partitioning)19for the CART analysis. The Ohio State University institutional review board approved this study.
There were 454 patients in the cohort, 406 (89%) of whom had complete data. Data were missing for serum albumin concentration for 45 patients, follow-up time for 1 patient, tumor stage for 1 patient, and functional class for 1 patient. Patient characteristics are given inTable 1. There were no statistically significant differences between patients with complete data and those missing data for age, body index mass, sex, grouped tumor stage, or survival. Between patients with complete data and those missing data there were statistically significant differences for diastolic blood pressure (measurements for blood pressure are mean ± SD mm Hg) (complete data: 88.0 ± 12.62; missing data: 83.3 ± 13.52;tvalue, 1.9936;P= .05), systolic blood pressure (complete data: 134.0 ± 22.51; missing data: 144.2 ± 23.46;tvalue, 2.2132;P= .03), and grouped functional class (χ2= 11.8037;P= .008). A cause of death was ascertained in 145 of the 172 deceased patients; 126 patients (87% of patients with a known cause of death) died of their cancer or of a cancer-related cause, and 12 patients (8%) died of a cardiovascular cause.
Individual patients were followed up between 5 and 1446 days (median, 391 days). There were 172 deaths. The Kaplan-Meier estimate for median survival was 687 days (95% CI, 599-1023 days). Mean survival was 817 days.
Classification and regression tree survival analysis
The model developed using CART to determine survival predictors from among the full set of patient characteristics is shown inFigure 1. After pruning, a model with 3 leaves was selected (Figure 2A). The population was initially split based on TNM stage. Separating out stages I, II, and III, patients selected a group with above-average survival: the mean survival was 1068 days (95% CI, 1023-∞). No median survival could be calculated because more than half of the subgroup survived through the follow-up period. Patients with stage IV or recurrent disease were further subdivided into 2 subgroups based on serum albumin concentration. The subgroup with an albumin concentration of 3.85 g/dL or more (ie, the split was between 3.8 and 3.9 g/dL) had a median survival of 625 days (95% CI, 536-1032 days) and a mean survival of 784 days. The remaining subgroup (those with stage IV or recurrent disease and with a serum albumin concentration <3.85 g/dL) had a median survival of 404 days (95% CI, 286-532 days) and a mean survival of 496 days. The log-rank test revealed a statistically significant difference among the 3 groups' survival rates over time (χ22= 43.9;P<.001;Figure 2B). The next best characteristic to serum albumin concentration for the split was age younger than 66.5 years (ie, the split was between 66 and 67 years old) (Figure 3).
We evaluated survival in an inception cohort of patients with head and neck SCC undergoing surgery with the intent of cure. Median postsurgical survival was less than 2 years. The strongest predictor of survival was tumor stage. In patients with stage IV or recurrent disease, either a low serum albumin concentration (with a split between 3.8 and 3.9 g/dL) or an advanced age (with a split between 66 and 67 years) indicated an especially poor prognosis. We recommend using age as the prognostic indicator because age is usually easier and less expensive to obtain.
To exemplify the rules, consider the following hypothetical patients. First, consider a 72-year-old man with stage II cancer. For a patient with stage II cancer, the expected mean survival is about 3 years. Because the patient's cancer is stage II, age is irrelevant. Patient sex is always irrelevant in this model. Next, consider a 69-year-old patient with stage IV cancer. For a patient with stage IV cancer, age must also be considered to prognose survival. For a patient who is 67 years or older, the expected median survival is a little more than 1 year. If this patient were younger than 67 years, then the expected median survival would be about 2 years.
Church et al20conducted a systematic review of prognostic factors in head and neck SCC for articles published between January 1993 and August 1997. They found that age, sex, and performance status predicted survival in all studies and that family history was also prognostic in some studies. Ildstad et al21found only age, stage, and tonsillar location of the prime tumor to be predictive of survival. Stell,22using univariate analysis in a series of 4319 patients, found only Eastern Cooperative Oncology Group performance status to be a significant predictor of survival.
In the present study, tumor stage, with either serum albumin concentration or age, best predicted survival. The Specific Activity Scale was not of additional prognostic value. The Specific Activity Scale is a measure of cardiopulmonary exercise capacity and not comparable with performance measures of activities of daily living, such as the Eastern Cooperative Oncology Group performance status. Although up to 10% of patients with head and neck SCC die of cardiac or pulmonary disease unrelated to their cancer within 5 years of cancer surgery (unpublished data, 1995), in this study, a cardiopulmonary functional capacity measure did not predict survival.
The present study differs from that of Cooper et al14in 3 respects: study subjects, development algorithm, and prediction rule. First, in the study by Cooper et al, the subjects received radiation therapy as primary treatment, whereas our subjects received surgery as primary treatment; second, in Cooper et al's studies, the development algorithm was recursive partitioning using Kaplan-Meier analysis for the regression, whereas our algorithm was CART, using exponential regression. And third, in Cooper et al's study, the prediction rule requires N and T stage, primary site, number of primary fractions, Karnofsky performance status, age, and interruptions in treatment, resulting in 6 survival subgroups, whereas our rule requires only tumor stage and patient age, resulting in 3 survival subgroups.
The present study is especially strong because an inception cohort of patients undergoing similar primary treatment was followed prospectively from the time of surgery, data collection was uniform, there was complete data on 89.4% of patients, and survival data on 99.8% of patients. However, external validity (generalizability) of this study's findings is limited because it was conducted at a single institution and included only patients presenting for potentially curative resection. Furthermore, the entire cohort was used to develop the prognostic rule; the rule was not tested in a validation cohort.
Simple preoperative characteristics can predict survival of patients undergoing potentially curative resection of head and neck SCC. Patients with stage I, II, or III cancer have the best survival, whereas patients with stage IV or recurrent cancer who are older than 66.5 years have the worst survival. Patients with stage IV or recurrent cancer who are younger than 66.5 years have intermediate survival. These findings need to be independently validated.
Accepted for publication May 6, 2002.
This study was supported in part by grant P30 CA 16058 from the National Cancer Institute, Bethesda, Md, The Ohio State University Comprehensive Cancer Head and Neck Oncology Group, Columbus, and the Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, Columbus.
We would like to thank Michelle Blackwood, BS, RD, for collating the cause of death information; Elizabeth C. Miller, BS, RD, for collecting serum albumin values; Hetal Parikh for collecting survival data; and Dawn Wray, BS, BA, for her help preparing the graphics.
Corresponding author: Mitchell A. Medow, MD, PhD, General Internal Medicine, 456 W 10th Ave, Room 4510, Columbus, OH 43210 (e-mail:firstname.lastname@example.org).
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The prognosis of patients with recurrent or metastatic head and neck squamous cell cancer is generally poor. The median survival in most series is 6 to 15 months depending on patient- and disease-related factors. Symptom-directed care plays an important role in the management of these patients.What is the survival rate for HNSCC at 5 years? ›
The reported overall survival (OS) for HPV-associated OPSCC, regardless of stage, is approximately 80% at 5 years. Few studies have examined OS in HNSCC beyond 5 years and none with stratification by HPV status.What is the prognosis for squamous cell carcinoma in the neck lymph nodes? ›
HNSCC can spread (metastasize ) to other parts of the body, such as the lymph nodes or lungs. If it spreads, the cancer has a worse prognosis and can be fatal. About half of affected individuals survive more than five years after diagnosis.What is the survival rate for HNSCC? ›
However, the 3-year survival rate does not exceed 40% in a subset of patients with localised HNSCC. HPV-positive oropharyngeal cancer (OPC) patients show better response to treatment, and survival is improved by approximately 50%.What is a good prognosis for squamous cell carcinoma? ›
Squamous cell carcinoma (SCC) generally has a high survival rate. The 5-year survival is 99 percent when detected early. Once SCC has spread to the lymph nodes and beyond, the survival rates are lower. Yet this cancer is still treatable with surgery and other therapies, even in its advanced stages.What is the long term survival of head and neck squamous cell carcinoma after bone marrow transplant? ›
The 2-year overall survival (OS) was 82.8%, 5-year OS was 68.7%. Conclusion: HNSCC can develop many years after BMT in patients without the classic risk factors for head and neck cancer.What is the 5 year survival rate for squamous cell carcinoma of skin? ›
Squamous cell carcinoma is most curable in the early stages before it spreads. If it's diagnosed early, the five-year survival rate is approximately 99%. To protect yourself, get a professional skin cancer examination at least once a year and perform monthly self-examinations of your skin.What is the prognosis of head and neck tumor? ›
What is the survival rate for head and neck cancer? The survival rate for people with Stage I or Stage II cancer ranges from 70% to 90%. These numbers mean that 70% to 90% of people diagnosed with a head and neck cancer at these stages are alive after five years. Keep in mind, though, that these numbers are general.What is the 5 year survival rate for ccRCC? ›
The 5-year survival rate for patients with ccRCC is 50-69%. When ccRCC is already large or has spread to other parts of the body, treatment is more difficult and the 5-year survival rate is about 10%.When is squamous cell carcinoma fatal? ›
Untreated squamous cell carcinoma of the skin can destroy nearby healthy tissue, spread to the lymph nodes or other organs, and may be fatal, although this is uncommon. The risk of aggressive squamous cell carcinoma of the skin may be increased in cases where the cancer: Is particularly large or deep.
Metastasis of cutaneous squamous cell carcinoma (cSCC) is rare. However, certain tumor and patient characteristics increase the risk of metastasis. Prior studies have demonstrated metastasis rates of 3-9%, occurring, on average, one to two years after initial diagnosis .How do I know if my squamous cell carcinoma has metastasized? ›
Metastatic squamous neck cancer with occult primary is a disease in which squamous cell cancer spreads to lymph nodes in the neck and it is not known where the cancer first formed in the body. Signs and symptoms of metastatic squamous neck cancer with occult primary include a lump or pain in the neck or throat.Is squamous cell carcinoma of the neck treatable? ›
Firstline treatment for squamous cell carcinoma of the head and neck is usually TransOral Robotic Surgery (TORS). Radiation therapy and chemotherapy may be used following surgery depending on the diagnosis and stage of cancer. TransOral Robotic Surgery (TORS) offers a minimally invasive surgical option.What is the average age for HNSCC? ›
HNSCC is a cancer of adults, with a median age at diagnosis of 66 years for HPV-negative HNSCC, 53 years for HPV-positive HNSCC and 50 years for EBV-positive HNSCC16,17,141.What is stage 4 squamous cell carcinoma neck? ›
Stage 4 head and neck cancer
The head and neck cancer tumor is any size and is growing into nearby structures. Cancer cells may not be present in the lymph nodes, or they may have spread to one lymph node, which is located on the same side of the head or neck as the primary tumor and is smaller than 3 cm across.
Untreated squamous cell carcinoma of the skin can destroy nearby healthy tissue, spread to the lymph nodes or other organs, and may be fatal, although this is uncommon.What is the most common site of squamous cell carcinoma head and neck? ›
Squamous cell carcinoma of the head and neck occurs in the outermost surface of the skin or certain tissues within the head and neck region including the throat, mouth, sinuses and nose. Squamous cell carcinoma makes up about 90 percent of all head and neck cancers.What is the life expectancy of someone with squamous cell carcinoma? ›
Most (95% to 98%) of squamous cell carcinomas can be cured if they are treated early. Once squamous cell carcinoma has spread beyond the skin, though, less than half of people live five years, even with aggressive treatment.What is considered high risk squamous cell carcinoma on the head? ›
However, a subset is diagnosed with a high-risk cutaneous squamous cell carcinoma. High-risk factors include size (>2 cm), thickness/depth of invasion (>4 mm), recurrent lesions, the presence of perineural invasion, location near the parotid gland, and immunosuppression.