Table 5.

Examples of clinical cases of patients with synchronous advanced multiple primary tumours

Patient characteristics	Malignancy 1	Malignancy 2	Therapeutic dilemma	Current management strategy
60-year-old man, former smoker	Small cell lung cancer (SCLC) Progression: after 6 cycles of cisplatin/etoposide	Aplastic anaemia Diagnosed 4 months after completion of cisplatin/etoposide	•Chemotherapy at progression of SCLC not possible due to grade 4 neutropenia and thrombocytopenia in the setting of aplastic anaemia •Immunosuppressive therapy for aplastic anaemia with possible negative impact on SCLC	•Supportive treatment with eltrombopag for thrombocytopenia •In case of stabilisation of pancytopenia, evaluation of second line therapy for SCLC
71-year-old man, hereditary haemochromatosis	Castration-resistant prostate cancer with bone and lymph node metastases	Renal cell carcinoma with lung metastases	•Drugs active in for CRPC different than agents in RCC •TKI used for RCC endocrine drugs (abiraterone/enzalutamide) used for CRPC: combinations not tested, no safety data, possible drug–drug interactions, expensive combinations	•Alternating treatment for the two malignancies: for example, TKI for 3–4 months for mRCC, then interruption and treatment for mCRPC for 3–4 months depending on the most significant tumour
64-year-old man, former smoker	Non-small cell lung cancer (NSCLC) stage IIIB	Rectal cancer stage I	•Chemotherapy regimens active in NSCLC generally not active in rectal cancer •NSCLC stage IIIB prognosis-defining, but untreated rectal cancer bears high risk of local complications (eg, bowel obstruction)	•Curative resection of rectal cancer (node-negative) with protective colostomy •Chemoradiation with curative intent for NSCLC (IIIB)
65-year-old woman, former smoker	NSCLC, metastatic to lymph nodes and bone, KRAS proto-oncogene (KRAS)-mutated, programmed death receptor ligand (PD-L1) expression 0%	Acute myeloid leukaemia (AML) Diagnosed simultaneously with NSCLC	•Chemotherapy for NSCLC not possible due to grade 4 neutropenia in the setting of AML •State-of-the art treatment for AML in the setting of metastatic NSCLC	•Treatment with azacitidin for AML •In case of stabilisation of AML, evaluation of treatment for NSCLC (checkpoint inhibitor rather than chemotherapy due to limited bone marrow reserve)