ICHNO-ECHNO 2022 - Abstract Book

S9

ICHNO-ECHNO 2022

Materials and Methods Medically fit patients aged 18-65 years with AJCC Stage (2005) –III/IV resected OCSCC with one or more adverse histopathological features{Extracapsular Extension (ECE), involvement of >2 regional lymph nodes, margins of resection involved by invasive cancer, extensive soft tissue and/or skin infiltration requiring major reconstructive procedure, perineural invasion(PNI) or lymphovascular embolisation (LVE)} were randomized 1:1:1 to Conventional 5D –RT (Arm A), CTRT with concurrent weekly Cisplatin (Arm B) and 6D-RT (Arm C). The primary endpoint was Locoregional Control (LRC) and the secondary endpoint was Overall Survival (OS). Results Between June 2005 and March 2013, nine hundred patients were accrued . Advanced gingivobuccal complex cancers comprised 65-72% of all cases. 90% of patients presented with T3-T4 primaries and nearly half had advanced neck nodal disease (N2-N3). Extracapsular extension was present in 55% of cases. Bone infiltration, skin infiltration, extensive soft tissue infiltration, LVE and PNI were present in 36.8%-42.7%,14.3%-18.6%,85.3%-87%,2.3-3.7% and 24.7%-28.4% patients, respectively. Microscopic positive margins were present in 0.3%,0.7% and 0.3% of patients in the 5D-RT, CTRT and 6D-RT arms, respectively. At a median follow up of surviving patients of 95.9 months (Interquartile Range -76.1-122.4 months), the 10 year actuarial estimates of LRC and OS in arms A, B and C were 57.3% (95%CI, 51%-64.5%), 62.3% (95% CI, 56.3%-68.8%,) and 59.6% (95% CI, 53.3%-66.7%) and 40.7% (95% CI-34.8%-47.6%), 40.4% (95% CI-34%-47.9%) and 46.4% (95% CI-40.5%-53.4%), respectively with no benefit seen for treatment intensification in the overall trial population. Patients harbouring a high-risk profile (with simultaneous ECE, T3-T4 primary and N2-N3 nodal disease) (n=311) were found to derive benefit from treatment intensification in OS (p=0.001, Arm B vs Arm A HR =0.58, 95% CI-0.42-0.81, Arm C vs Arm A HR =0.60, 95% CI-0.43-0.84). The increase in Grade 3 toxicity was minimal but statistically significant for treatment intensification and easily managed with no consequential increase in the late toxicity. Conclusion All locally advanced OCSCC do not warrant intensification of adjuvant treatment after complete resection. Treatment intensification is justified only in those patients harbouring multiple adverse factors simultaneously on histopathology and is achieved with manageable rates of severe toxicity.

Symposium: Modern management of unknown primary H&N tumours

SP-0018 What have we learned from TORS mucosectomy in management of unknown primary Vin Paleri United Kingdom

Abstract not available

SP-0019 Advances in pathology for unknown primary Senada Koljenovic The Netherlands Abstract not available

SP-0020 Evolving radiation oncology practice for the management of unknown primary cancers Vincent Grégoire France Abstract not available

Keynote lecture: New concepts in the management of oligmetastatic disease

SP-0022 New concepts in the management of oligometastatic disease

P. Szturz 1

1 University of Lausanne (UNIL) and Lausanne University Hospital (CHUV), Department of Oncology, Lausanne, Switzerland

Abstract Text The term oligometastatic refers to an uncommon pattern of malignant dissemination to distant organs which can be safely treated with local approaches with the intent of improving overall survival. Although typically characterized by the number of metastases not surpassing 3 – 5 lesions, emerging evidence suggests that a diagnosis based on a single snapshot imaging does not sufficiently provide for an accurate detection of a true oligometastatic disease. In fact, in order to be amenable to successful local treatment, even aiming for cure, the following criteria have to be met. First, the disease progression has to be very slow, including tumour growth rate and formation of new metastases (probably less than 0.6 new metastases per year as shown in lung cancer). Moreover, implying the presence of only few lesions in limited organ sites, the overall tumour burden has to be low to enable safe ablation using local interventions. Last but not the least, there should be no occult metastases. Obviously, not all of these criteria can be checked easily, but the probability of an oligometastatic presentation increases when dealing with a metachronous (versus synchronous) manifestation with a long disease-free interval after primary treatment, and a series of follow-up imaging studies shows corresponding tumour growth kinetics. In addition, using complementary nuclear medicine and radiological imaging techniques and evaluating relevant laboratory parameters, such as circulating markers in some cancers, help us lower the detection threshold for subclinical disease.