The mean (average) blood pressure is the generally recognized indication and representative of one's true blood pressure. Variability in blood pressure is usually dismissed as uninformative and random, And your 155 systolic reading is not excessively high.
If there are episodes of a severe increase in blood pressure that can occur with sudden release of a large amount of adrenaline hormones from the tumor. Any reading above 180/110 is considered severe high blood pressure. This can lead to life-threatening conditions, such as stroke or abnormal heart rhythm as I read from a Mayo Clinic published information article.
I don't know if you should be concerned, but if the episodes are recognized and continuing pattern you may want to consult with your doctor especially if the systolic pressure is in the severe range,
Thanks for your question, and if you have any further questions or comments you are welcome to respond. Take care.