***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: PURPOSE Recent increases in incidence and survival of oropharyngeal cancers in the United States have been attributed to human papillomavirus ( HPV ) infection , but empirical evidence is lacking . PATIENTS AND METHODS HPV status was determined for all 271 oropharyngeal cancers ( 1984 - 2004 ) collected by the three population -based cancer registries in the Surveillance , Epidemiology , and End Results ( SEER ) Residual Tissue Repositories Program by using polymerase chain reaction and genotyping ( Inno-LiPA ) , HPV16 viral load , and HPV16 mRNA expression . Trends in HPV prevalence across four calendar periods were estimated by using logistic regression . Observed HPV prevalence was reweighted to all oropharyngeal cancers within the cancer registries to account for nonr and om selection and to calculate incidence trends . Survival of HPV-positive and HPV-negative patients was compared by using Kaplan-Meier and multivariable Cox regression analyses . RESULTS HPV prevalence in oropharyngeal cancers significantly increased over calendar time regardless of HPV detection assay ( P trend < .05 ) . For example , HPV prevalence by Inno-LiPA  increased from 16.3 % during 1984 to 1989 to 71.7 % during 2000 to 2004 . Median survival was significantly longer for HPV-positive than for HPV-negative patients ( 131 v 20 months ; log-rank P < .001 ; adjusted hazard ratio , 0.31 ; 95 % CI , 0.21 to 0.46 ) . Survival significantly increased across calendar periods for HPV-positive ( P = .003 ) but not for HPV-negative patients ( P = .18 ) . Population -level incidence of HPV-positive oropharyngeal cancers increased by 225 % ( 95 % CI , 208 % to 242 % ) from 1988 to 2004 ( from 0.8 per 100,000 to 2.6 per 100,000 ) , and incidence for HPV-negative cancers declined by 50 % ( 95 % CI , 47 % to 53 % ; from 2.0 per 100,000 to 1.0 per 100,000 ) . If recent incidence trends continue , the annual number of HPV-positive oropharyngeal cancers is expected to surpass the annual number of cervical cancers by the year 2020 . CONCLUSION Increases in the population -level incidence and survival of oropharyngeal cancers in the United States since 1984 are caused by HPV infection BACKGROUND A r and omized phase 3 trial of the treatment of squamous-cell carcinoma of the head and neck compared induction chemotherapy with docetaxel plus cisplatin and fluorouracil ( TPF ) with cisplatin and fluorouracil ( PF ) , followed by chemoradiotherapy . METHODS We r and omly assigned 501 patients ( all of whom had stage III or IV disease with no distant metastases and tumors considered to be unresectable or were c and i date s for organ preservation ) to receive either TPF or PF induction chemotherapy  , followed  by chemoradiotherapy with weekly carboplatin therapy and radiotherapy for 5 days per week . The primary end point was overall survival . RESULTS With a minimum of 2 years of follow-up ( > or =3 years for 69 % of patients ) , significantly more patients survived in the TPF group than in the PF group ( hazard ratio for death , 0.70 ; P=0.006 ) . Estimates of overall survival at 3 years were 62 % in the TPF group and 48 % in the PF group ; the median overall survival was 71 months and 30 months , respectively ( P=0.006 ) . There was better locoregional control in the TPF group than in the PF group ( P=0.04 ) , but the incidence of distant metastases in the two groups did not differ significantly ( P=0.14 ) . Rates of neutropenia and febrile neutropenia were higher in the TPF group ; chemotherapy was more frequently delayed because of hematologic adverse events in the PF group . CONCLUSIONS Patients with squamous-cell carcinoma of the head and neck who received docetaxel plus cisplatin and fluorouracil induction chemotherapy plus chemoradiotherapy had a significantly longer survival than did patients who received cisplatin and fluorouracil induction chemotherapy plus chemoradiotherapy . ( Clinical Trials.gov number , NCT00273546 [ Clinical Trials.gov ] . ) PURPOSE To evaluate irradiation alone for treatment of base-of-tongue cancer . PATIENTS AND METHODS Two hundred seventeen patients with squamous cell carcinoma of the base of tongue were treated with radiation alone and had follow-up for > /= 2 years . RESULTS Local control rates at 5 years were as follows : T1 , 96 % ; T2 , 91 % ; T3 , 81 % ; and T4 , 38 % . Multivariate analysis revealed that T stage ( P = .0001 ) and overall treatment time ( P = .0006 ) significantly influenced local control . The 5-year rates of local-regional control were as follows : I , 100 % ; II , 100 % ; III , 83 % ; IVA , 64 % ; and IVB , 65 % . Multivariate analysis revealed that the following parameters significantly affect the probability of this end point : T stage ( P = .0001 ) , overall treatment time ( P = .0001 ) , overall stage ( P = .0131 ) , and addition of a neck dissection ( P = .0021 ) . The rates of absolute and cause-specific survival at 5 years were as follows : I , 50 % and 100 % ; II , 81 % and 100 % ; III , 65 % and 76 % ; IVA , 42 % and 56 % ; and IVB , 44 % and 52 % . Severe radiation complications developed in eight patients ( 4 % ) . CONCLUSION The likelihood of cure after external-beam irradiation was related to stage , overall treatment time , and addition of a planned neck dissection . The local-regional control rates and survival rates after radiation therapy were comparable to those after surgery , and the morbidity associated with irradiation was less OBJECTIVES /HYPOTHESIS The purpose of this study was to determine the regional recurrence rate of node-positive oropharyngeal squamous cell carcinoma ( OPSCC ) in patients undergoing transoral robotic surgery ( TORS ) and selective neck dissection ( SND ) followed by observation , radiation , or concurrent chemoradiation .  STUDY DESIGN A prospect i ve , phase I , single-arm study was conducted . All OPSCC patients who voluntarily participated in a surgical trial with TORS and SND at an academic tertiary referral center from May 2005 to July 2007 were included . METHODS Thirty-one patients with previously untreated OPSCC undergoing TORS and SND ( 29 unilateral and two bilateral ) were included . There were 29 males and two females , with ages ranging from 36 to 76 years ( median = 55 years ) with one palate , one lateral wall , 17 tonsil , 11 base of tongue , and one vallecula primary tumor classified as follows : T1 ( n = 9 , 29 % ) , T2 ( n = 15 , 48.4 % ) , T3 ( n = 7 , 22.6 % ) , N0 ( n = 6 , 19.4 % ) , N1 ( n = 15 , 48.4 % ) , N2b ( n = 10 , 32.3 % ) , and N2c ( n = 1 , 3.2 % ) . There were three stage I ( 9.7 % ) , two stage II ( 6.5 % ) , 15 stage III ( 48.4 % ) and 11 stage IVa ( 35.5 % ) patients . Twenty-two patients were treated postoperatively with adjuvant therapy ( 12 radiation alone and 12 combined radiation and chemotherapy ) . Primary outcome measured was regional recurrence rate . RESULTS There was one regional recurrence on the contralateral , non-operated neck and one distant recurrence among the 31 patients who underwent SND . CONCLUSIONS SND after TORS resection of primary OPSCC enables the use of selective and deintensified adjuvant therapy to reduce regional recurrence rates OBJECTIVE to report 2-year survival outcomes for head and neck squamous cell carcinoma using transoral robotic-assisted resection . DESIGN prospect i ve case study . SETTING two tertiary care centers . PATIENTS eighty-nine patients from 2 tertiary care centers ( University of Alabama at Birmingham and the Mayo Clinic in Rochester , Minnesota ) with head and neck squamous cell carcinoma of all stages and subsites , who underwent transoral robotic-assisted resection between March 2007 and December 2008 , with a median follow-up time of 26 months . MAIN OUTCOME MEASURES disease-free survival , cancer recurrence , and gastrostomy tube dependence RESULTS seventy-one patients had T1 ( n = 29 ) or T2 ( n = 42 ) tumors while 18 patients had T3 ( n = 8) or T4 ( n = 10 ) tumors . There were 24 patients with overall stage I or II disease and 65 with stage III or IV disease . At the time of the last follow-up visit ( median , 26 months ) , there had been a total of 11 patients with recurrent cancer : 3 with local ; 7 , regional ( 2 of whom also had distant metastases ) ; and 1 , distant . Seven patients were treated for recurrent disease . Eighty-two patients had no evidence of disease , 1 patient died of the disease , 2 died of other disease , and 4 were alive with disease at the last follow-up visit . Results of Kaplan-Meier survival analysis showed that the 2-year recurrence-free survival rate for the cohort was 86.5 % . None of the patients were gastrostomy tube dependent at the last follow-up visit . CONCLUSION the 2-year functional and oncologic results justify the continued treatment of select patients with head and neck squamous cell carcinoma with robotic-assisted surgical resection Transoral robotic surgery ( TORS ) is an emerging technique for the treatment of head and neck tumors . The objective of this study is to describe our first steps and present our experience on the technical feasibility , safety , and efficacy of TORS for the treatment of selected malignant lesions . From April 2008 to September 2009 , 24 patients were enrolled in this prospect i ve trial . Inclusion criteria were : adults with T1 , T2 and selected T3 tumors involving the oral cavity , pharynx , and supraglottic larynx and a signed informed consent was obtained from the patient . Exclusion criteria were : tumors not accessible to TORS after unsuccessful attempts to expose properly the lesion to operate . The ethical committee ’s approval was obtained to perform this study . Twenty-four patients were included in this study : 10 supraglottic tumors , 10 pharyngeal tumors and 4 oral cavity tumors . Nine patients had T1 tumors , 12 had T2 tumors , and 1 patient had a T3 tumor . In all cases , tumor resection could be performed by robotic surgery exclusively and negative resection margins were achieved with control by frozen section . None of them received intraoperative reconstruction . None of the patients required tracheotomy . There was no intraoperative complication related to the use of the robot . The average setup time was 24 ± 14 min ( range 10–60 min ) . The average surgical time was 67 ± 46 min ( range 12–180 min ) . Surgical and setup time decreased after the first cases . The mean hospital stay was 9 days . Oral feeding was resumed at 3 days . TORS seems to be a safe , feasible , minimally invasive treatment modality for malignant head and neck tumors with a short learning curve for surgeons already experienced in endoscopic surgery OBJECTIVE To describe and show the feasibility of a new surgical technique for transoral robotic surgery ( TORS ) radical tonsillectomy .  DESIGN A prospect i ve , phase 1 clinical trial . SETTING Academic , tertiary referral center . PATIENTS A total of 27 participants were prospect ively selected using a volunteer sample . All eligible patients agreed to participate in the study . INTERVENTIONS Patients underwent TORS radical tonsillectomy for previously untreated invasive squamous cell carcinoma of the tonsillar region without free-flap reconstruction , staged neck dissection , and adjuvant therapy . MAIN OUTCOME MEASURES Outcome measures included final pathologic margin status , need for short- and long-term tracheotomy tube placement , and need for gastrostomy tube feedings among patients with a minimum 6-month follow-up . The incidence of significant postoperative complications was recorded . RESULTS No mortality occurred . Final margins found to be negative for cancer were achieved in 25 of 27 patients ( 93 % ) . Surgical complications included 1 case each of postoperative mucosal bleeding , delirium tremens , unplanned tracheotomy for temporary exacerbation 
    Output:
    
Also , a growing amount of clinical evidence supports the use of TORS in the management of carcinoma of unknown primary site and in selected patients with recurrent OPSCC with acceptable oncologic and better functional outcomes in comparison with traditional surgical approaches .
Comparative studies with other therapeutic modalities ( conventional surgical and nonsurgical ) showed that TORS can be used to treat OPSCC , reducing morbidity and treatment costs , while providing equivalent oncologic results .